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PerformanceAwareProgramming/part1/sim8086.c

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#define WIN32_MEAN_AND_LEAN
#define NOMINMAX
#include <Windows.h>
#include <immintrin.h>
#include <stdint.h>
#include <stdio.h>
#include <stdarg.h>
#include <stdbool.h>
#include "sim8086_stdlib.h"
#include "sim8086.h"
#include "sim8086_stdlib.c"
bool S86_RegisterFileFlagsEq(S86_RegisterFileFlags lhs, S86_RegisterFileFlags rhs)
{
bool result = lhs.carry == rhs.carry &&
lhs.zero == rhs.zero &&
lhs.sign == rhs.sign &&
lhs.overflow == rhs.overflow &&
lhs.parity == rhs.parity &&
lhs.auxiliary_carry == rhs.auxiliary_carry;
return result;
}
S86_Str8 S86_MnemonicStr8(S86_Mnemonic type)
{
S86_Str8 result = {0};
switch (type) {
case S86_Mnemonic_MOV: result = S86_STR8("mov"); break;
case S86_Mnemonic_PUSH: result = S86_STR8("push"); break;
case S86_Mnemonic_POP: result = S86_STR8("pop"); break;
case S86_Mnemonic_XCHG: result = S86_STR8("xchg"); break;
case S86_Mnemonic_IN: result = S86_STR8("in"); break;
case S86_Mnemonic_OUT: result = S86_STR8("out"); break;
case S86_Mnemonic_XLAT: result = S86_STR8("xlat"); break;
case S86_Mnemonic_LEA: result = S86_STR8("lea"); break;
case S86_Mnemonic_LDS: result = S86_STR8("lds"); break;
case S86_Mnemonic_LES: result = S86_STR8("les"); break;
case S86_Mnemonic_LAHF: result = S86_STR8("lahf"); break;
case S86_Mnemonic_SAHF: result = S86_STR8("sahf"); break;
case S86_Mnemonic_PUSHF: result = S86_STR8("pushf"); break;
case S86_Mnemonic_POPF: result = S86_STR8("popf"); break;
case S86_Mnemonic_ADD: result = S86_STR8("add"); break;
case S86_Mnemonic_ADC: result = S86_STR8("adc"); break;
case S86_Mnemonic_INC: result = S86_STR8("inc"); break;
case S86_Mnemonic_AAA: result = S86_STR8("aaa"); break;
case S86_Mnemonic_DAA: result = S86_STR8("daa"); break;
case S86_Mnemonic_SUB: result = S86_STR8("sub"); break;
case S86_Mnemonic_SBB: result = S86_STR8("sbb"); break;
case S86_Mnemonic_DEC: result = S86_STR8("dec"); break;
case S86_Mnemonic_NEG: result = S86_STR8("neg"); break;
case S86_Mnemonic_CMP: result = S86_STR8("cmp"); break;
case S86_Mnemonic_AAS: result = S86_STR8("aas"); break;
case S86_Mnemonic_DAS: result = S86_STR8("das"); break;
case S86_Mnemonic_MUL: result = S86_STR8("mul"); break;
case S86_Mnemonic_IMUL: result = S86_STR8("imul"); break;
case S86_Mnemonic_AAM: result = S86_STR8("aam"); break;
case S86_Mnemonic_DIV: result = S86_STR8("div"); break;
case S86_Mnemonic_IDIV: result = S86_STR8("idiv"); break;
case S86_Mnemonic_AAD: result = S86_STR8("aad"); break;
case S86_Mnemonic_CBW: result = S86_STR8("cbw"); break;
case S86_Mnemonic_CWD: result = S86_STR8("cwd"); break;
case S86_Mnemonic_NOT: result = S86_STR8("not"); break;
case S86_Mnemonic_SHL_SAL: result = S86_STR8("sal"); break;
case S86_Mnemonic_SHR: result = S86_STR8("shr"); break;
case S86_Mnemonic_SAR: result = S86_STR8("sar"); break;
case S86_Mnemonic_ROL: result = S86_STR8("rol"); break;
case S86_Mnemonic_ROR: result = S86_STR8("ror"); break;
case S86_Mnemonic_RCL: result = S86_STR8("rcl"); break;
case S86_Mnemonic_RCR: result = S86_STR8("rcr"); break;
case S86_Mnemonic_AND: result = S86_STR8("and"); break;
case S86_Mnemonic_TEST: result = S86_STR8("test"); break;
case S86_Mnemonic_OR: result = S86_STR8("or"); break;
case S86_Mnemonic_XOR: result = S86_STR8("xor"); break;
case S86_Mnemonic_REP: result = S86_STR8("rep"); break;
case S86_Mnemonic_CALL: result = S86_STR8("call"); break;
case S86_Mnemonic_JMP: result = S86_STR8("jmp"); break;
case S86_Mnemonic_RET: result = S86_STR8("ret"); break;
case S86_Mnemonic_JE_JZ: result = S86_STR8("je"); break;
case S86_Mnemonic_JL_JNGE: result = S86_STR8("jl"); break;
case S86_Mnemonic_JLE_JNG: result = S86_STR8("jle"); break;
case S86_Mnemonic_JB_JNAE: result = S86_STR8("jb"); break;
case S86_Mnemonic_JBE_JNA: result = S86_STR8("jbe"); break;
case S86_Mnemonic_JP_JPE: result = S86_STR8("jp"); break;
case S86_Mnemonic_JO: result = S86_STR8("jo"); break;
case S86_Mnemonic_JS: result = S86_STR8("js"); break;
case S86_Mnemonic_JNE_JNZ: result = S86_STR8("jne"); break;
case S86_Mnemonic_JNL_JGE: result = S86_STR8("jnl"); break;
case S86_Mnemonic_JNLE_JG: result = S86_STR8("jg"); break;
case S86_Mnemonic_JNB_JAE: result = S86_STR8("jnb"); break;
case S86_Mnemonic_JNBE_JA: result = S86_STR8("ja"); break;
case S86_Mnemonic_JNP_JO: result = S86_STR8("jnp"); break;
case S86_Mnemonic_JNO: result = S86_STR8("jno"); break;
case S86_Mnemonic_JNS: result = S86_STR8("jns"); break;
case S86_Mnemonic_LOOP: result = S86_STR8("loop"); break;
case S86_Mnemonic_LOOPZ_LOOPE: result = S86_STR8("loopz"); break;
case S86_Mnemonic_LOOPNZ_LOOPNE: result = S86_STR8("loopnz"); break;
case S86_Mnemonic_JCXZ: result = S86_STR8("jcxz"); break;
case S86_Mnemonic_INT: result = S86_STR8("int"); break;
case S86_Mnemonic_INT3: result = S86_STR8("int3"); break;
case S86_Mnemonic_INTO: result = S86_STR8("into"); break;
case S86_Mnemonic_IRET: result = S86_STR8("iret"); break;
case S86_Mnemonic_CLC: result = S86_STR8("clc"); break;
case S86_Mnemonic_CMC: result = S86_STR8("cmc"); break;
case S86_Mnemonic_STC: result = S86_STR8("stc"); break;
case S86_Mnemonic_CLD: result = S86_STR8("cld"); break;
case S86_Mnemonic_STD: result = S86_STR8("std"); break;
case S86_Mnemonic_CLI: result = S86_STR8("cli"); break;
case S86_Mnemonic_STI: result = S86_STR8("sti"); break;
case S86_Mnemonic_HLT: result = S86_STR8("hlt"); break;
case S86_Mnemonic_WAIT: result = S86_STR8("wait"); break;
case S86_Mnemonic_LOCK: result = S86_STR8("lock"); break;
case S86_Mnemonic_SEGMENT: result = S86_STR8("segment"); break;
}
return result;
}
S86_MnemonicOp S86_MnemonicOpFromWReg(bool w, uint8_t reg)
{
S86_ASSERT(reg < 8);
S86_MnemonicOp const type_table[2][8] = {
[0b0] = {
[0] = S86_MnemonicOp_AL,
[1] = S86_MnemonicOp_CL,
[2] = S86_MnemonicOp_DL,
[3] = S86_MnemonicOp_BL,
[4] = S86_MnemonicOp_AH,
[5] = S86_MnemonicOp_CH,
[6] = S86_MnemonicOp_DH,
[7] = S86_MnemonicOp_BH,
},
[0b1] = {
[0] = S86_MnemonicOp_AX,
[1] = S86_MnemonicOp_CX,
[2] = S86_MnemonicOp_DX,
[3] = S86_MnemonicOp_BX,
[4] = S86_MnemonicOp_SP,
[5] = S86_MnemonicOp_BP,
[6] = S86_MnemonicOp_SI,
[7] = S86_MnemonicOp_DI,
},
};
S86_MnemonicOp result = type_table[w][reg];
return result;
}
S86_MnemonicOp S86_MnemonicOpFromSR(uint8_t sr)
{
S86_ASSERT(sr < 4);
S86_MnemonicOp result = S86_MnemonicOp_ES + sr;
return result;
}
S86_Str8 S86_MnemonicOpStr8(S86_MnemonicOp type)
{
S86_Str8 result = {0};
switch (type) {
case S86_MnemonicOp_Invalid: result = S86_STR8(""); break;
case S86_MnemonicOp_AL: result = S86_STR8("al"); break;
case S86_MnemonicOp_CL: result = S86_STR8("cl"); break;
case S86_MnemonicOp_DL: result = S86_STR8("dl"); break;
case S86_MnemonicOp_BL: result = S86_STR8("bl"); break;
case S86_MnemonicOp_AH: result = S86_STR8("ah"); break;
case S86_MnemonicOp_CH: result = S86_STR8("ch"); break;
case S86_MnemonicOp_DH: result = S86_STR8("dh"); break;
case S86_MnemonicOp_BH: result = S86_STR8("bh"); break;
case S86_MnemonicOp_AX: result = S86_STR8("ax"); break;
case S86_MnemonicOp_CX: result = S86_STR8("cx"); break;
case S86_MnemonicOp_DX: result = S86_STR8("dx"); break;
case S86_MnemonicOp_BX: result = S86_STR8("bx"); break;
case S86_MnemonicOp_SP: result = S86_STR8("sp"); break;
case S86_MnemonicOp_BP: result = S86_STR8("bp"); break;
case S86_MnemonicOp_SI: result = S86_STR8("si"); break;
case S86_MnemonicOp_DI: result = S86_STR8("di"); break;
case S86_MnemonicOp_BX_SI: result = S86_STR8("bx+si"); break;
case S86_MnemonicOp_BX_DI: result = S86_STR8("bx+di"); break;
case S86_MnemonicOp_BP_SI: result = S86_STR8("bp+si"); break;
case S86_MnemonicOp_BP_DI: result = S86_STR8("bp+di"); break;
case S86_MnemonicOp_DirectAddress: result = S86_STR8(""); break;
case S86_MnemonicOp_Immediate: result = S86_STR8(""); break;
case S86_MnemonicOp_ES: result = S86_STR8("es"); break;
case S86_MnemonicOp_CS: result = S86_STR8("cs"); break;
case S86_MnemonicOp_SS: result = S86_STR8("ss"); break;
case S86_MnemonicOp_DS: result = S86_STR8("ds"); break;
case S86_MnemonicOp_MOVS: result = S86_STR8("movs"); break;
case S86_MnemonicOp_CMPS: result = S86_STR8("cmps"); break;
case S86_MnemonicOp_SCAS: result = S86_STR8("scas"); break;
case S86_MnemonicOp_LODS: result = S86_STR8("lods"); break;
case S86_MnemonicOp_STOS: result = S86_STR8("stos"); break;
case S86_MnemonicOp_DirectInterSegment: result = S86_STR8(""); break;
case S86_MnemonicOp_Jump: result = S86_STR8(""); break;
}
return result;
}
bool S86_MnemonicOpIsAccumulator(S86_MnemonicOp type)
{
bool result = type == S86_MnemonicOp_AX ||
type == S86_MnemonicOp_AL ||
type == S86_MnemonicOp_AH;
return result;
}
bool S86_MnemonicOpIsRegister(S86_MnemonicOp type)
{
bool result = (type >= S86_MnemonicOp_AL && type <= S86_MnemonicOp_DI) ||
(type >= S86_MnemonicOp_ES && type <= S86_MnemonicOp_DS);
return result;
}
S86_Str8 S86_RegisterFileRegArrayStr8(S86_RegisterFileRegArray type)
{
S86_Str8 result = {0};
switch (type) {
case S86_RegisterFileRegArray_AX: result = S86_MnemonicOpStr8(S86_MnemonicOp_AX); break;
case S86_RegisterFileRegArray_BX: result = S86_MnemonicOpStr8(S86_MnemonicOp_BX); break;
case S86_RegisterFileRegArray_CX: result = S86_MnemonicOpStr8(S86_MnemonicOp_CX); break;
case S86_RegisterFileRegArray_DX: result = S86_MnemonicOpStr8(S86_MnemonicOp_DX); break;
case S86_RegisterFileRegArray_SP: result = S86_MnemonicOpStr8(S86_MnemonicOp_SP); break;
case S86_RegisterFileRegArray_BP: result = S86_MnemonicOpStr8(S86_MnemonicOp_BP); break;
case S86_RegisterFileRegArray_SI: result = S86_MnemonicOpStr8(S86_MnemonicOp_SI); break;
case S86_RegisterFileRegArray_DI: result = S86_MnemonicOpStr8(S86_MnemonicOp_DI); break;
case S86_RegisterFileRegArray_ES: result = S86_MnemonicOpStr8(S86_MnemonicOp_ES); break;
case S86_RegisterFileRegArray_CS: result = S86_MnemonicOpStr8(S86_MnemonicOp_DS); break;
case S86_RegisterFileRegArray_SS: result = S86_MnemonicOpStr8(S86_MnemonicOp_SS); break;
case S86_RegisterFileRegArray_DS: result = S86_MnemonicOpStr8(S86_MnemonicOp_DS); break;
case S86_RegisterFileRegArray_Count: break;
}
return result;
}
void S86_PrintOpcodeMnemonicOp(S86_Opcode opcode, bool src)
{
// TODO: It sucks to have these enums that specify source or dest because
// we can't have a nice generic codepath to handle the dest, src mnemonic
// ops without these pre-emptive checks here inorder to make it generic
// here.
//
// It's probably better to just have flags for the src and dest mnemonic op
// and then you can have one code path that just checks the flags on each op
S86_MnemonicOp mnemonic_op = src ? opcode.src : opcode.dest;
bool effective_addr = ( src && opcode.effective_addr == S86_EffectiveAddress_Src) ||
(!src && opcode.effective_addr == S86_EffectiveAddress_Dest);
if (mnemonic_op == S86_MnemonicOp_Invalid)
return;
if (src)
S86_PrintFmt(", ");
else
S86_PrintFmt(" ");
if (!src && opcode.word_byte_prefix != S86_WordBytePrefix_None)
S86_PrintFmt("%s ", opcode.word_byte_prefix == S86_WordBytePrefix_Word ? "word" : "byte");
if (effective_addr && opcode.seg_reg_prefix != S86_MnemonicOp_Invalid) {
S86_Str8 prefix = S86_MnemonicOpStr8(opcode.seg_reg_prefix);
S86_PrintFmt("%.*s:", S86_STR8_FMT(prefix));
}
if (opcode.effective_addr_loads_mem && effective_addr)
S86_Print(S86_STR8("["));
if (mnemonic_op == S86_MnemonicOp_DirectAddress) {
S86_PrintFmt("%s%d",
opcode.displacement >= 0 ? "+" : "-",
opcode.displacement >= 0 ? opcode.displacement : -opcode.displacement);
} else if (mnemonic_op == S86_MnemonicOp_Jump) {
// NOTE: Account for the opcode itself which is 2 bytes, e.g. we can print $+2-8 or just $-6
int32_t displacement = opcode.displacement + 2;
S86_PrintFmt("$%c%d",
displacement > 0 ? '+' : '-',
displacement > 0 ? displacement : -displacement);
} else if (mnemonic_op == S86_MnemonicOp_Immediate) {
if (opcode.immediate_is_8bit) {
S86_PrintFmt("%d", (int8_t)opcode.immediate);
} else {
S86_PrintFmt("%u", (uint16_t)opcode.immediate);
}
} else if (mnemonic_op == S86_MnemonicOp_DirectInterSegment) {
uint16_t left = (uint32_t)opcode.displacement >> 16;
uint16_t right = (uint32_t)opcode.displacement & 0xFFFF;
S86_PrintFmt("%u:%u", left, right);
} else {
S86_Str8 reg_str8 = S86_MnemonicOpStr8(mnemonic_op);
S86_PrintFmt("%.*s", S86_STR8_FMT(reg_str8));
if (mnemonic_op >= S86_MnemonicOp_MOVS && mnemonic_op <= S86_MnemonicOp_STOS) {
S86_PrintFmt("%c", opcode.wide ? 'w' : 'b');
}
if (effective_addr && opcode.displacement) {
S86_PrintFmt("%s%d",
opcode.displacement >= 0 ? "+" : "-",
opcode.displacement >= 0 ? opcode.displacement : -opcode.displacement);
}
}
if (effective_addr && opcode.effective_addr_loads_mem)
S86_Print(S86_STR8("]"));
}
void S86_PrintOpcode(S86_Opcode opcode)
{
if (opcode.mnemonic == S86_Mnemonic_SEGMENT)
return;
S86_Str8 mnemonic = S86_MnemonicStr8(opcode.mnemonic);
S86_PrintFmt("%.*s", S86_STR8_FMT(mnemonic));
S86_PrintOpcodeMnemonicOp(opcode, false /*src*/);
S86_PrintOpcodeMnemonicOp(opcode, true /*dest*/);
if (opcode.mnemonic == S86_Mnemonic_LOCK)
S86_Print(S86_STR8(" "));
}
void S86_DecodeEffectiveAddr(S86_Opcode *opcode, S86_BufferIterator *buffer_it, uint8_t rm, uint8_t mod, uint8_t w)
{
// NOTE: Calculate displacement
// =========================================================================
bool direct_address = mod == 0b00 && rm == 0b110;
int16_t displacement = 0;
if (mod == 0b10 || direct_address) { // Mem mode 16 bit displacement
uint8_t disp_lo = S86_BufferIteratorNextByte(buffer_it);
uint8_t disp_hi = S86_BufferIteratorNextByte(buffer_it);
displacement = (int16_t)((uint16_t)disp_lo << 0 | (uint16_t)disp_hi << 8);
} else if (mod == 0b01) { // Mem mode 8 bit displacement
displacement = (int8_t)S86_BufferIteratorNextByte(buffer_it);
} else {
S86_ASSERT(mod == 0b00 || mod == 0b11 /*Mem mode (no displacement)*/);
}
opcode->wide = w;
opcode->displacement = displacement;
opcode->effective_addr = S86_EffectiveAddress_Dest;
if (mod == 0b11) {
opcode->dest = S86_MnemonicOpFromWReg(w, rm);
} else {
// NOTE: Effective address calculation w/ displacement
// =====================================================================
opcode->effective_addr_loads_mem = true;
if (direct_address) {
opcode->dest = S86_MnemonicOp_DirectAddress;
} else {
switch (rm) {
case 0b000: opcode->dest = S86_MnemonicOp_BX_SI; break;
case 0b001: opcode->dest = S86_MnemonicOp_BX_DI; break;
case 0b010: opcode->dest = S86_MnemonicOp_BP_SI; break;
case 0b011: opcode->dest = S86_MnemonicOp_BP_DI; break;
case 0b100: opcode->dest = S86_MnemonicOp_SI; break;
case 0b101: opcode->dest = S86_MnemonicOp_DI; break;
case 0b110: opcode->dest = S86_MnemonicOp_BP; break;
case 0b111: opcode->dest = S86_MnemonicOp_BX; break;
default: S86_ASSERT(!"Invalid rm value, must be 3 bits"); break;
}
}
}
}
S86_Opcode S86_DecodeOpcode(S86_BufferIterator *buffer_it,
S86_OpDecode const *decode_table,
uint16_t decode_table_size,
bool *lock_prefix,
S86_MnemonicOp *seg_reg)
{
size_t buffer_start_index = buffer_it->index;
char op_code_bytes[2] = {0};
size_t op_code_size = 0;
op_code_bytes[op_code_size++] = S86_BufferIteratorNextByte(buffer_it);
// NOTE: Match the assembly bytes to the desired instruction
// =====================================================================
S86_OpDecodeType op_decode_type = S86_OpDecodeType_Count;
S86_OpDecode const *op_decode = NULL;
for (size_t op_index = 0;
op_decode_type == S86_OpDecodeType_Count && op_index < decode_table_size;
op_index++)
{
S86_OpDecode const *item = decode_table + op_index;
// NOTE: Check first instruction byte
// =================================================================
if ((op_code_bytes[0] & item->op_mask0) != item->op_bits0)
continue;
// NOTE Check multi-byte instruction
// =================================================================
// If the matched instruction has a bit mask for the 2nd byte, this
// is a multi-byte instruction. Check if the 2nd byte checks out.
bool op_match = true;
if (item->op_mask1) {
// TODO: This assumes the iterator is valid
uint8_t op_byte = S86_BufferIteratorPeekByte(buffer_it);
op_match = (op_byte & item->op_mask1) == item->op_bits1;
if (op_match) {
op_code_bytes[op_code_size++] = op_byte;
S86_BufferIteratorNextByte(buffer_it);
}
}
if (op_match) {
op_decode_type = op_index;
op_decode = item;
}
}
// NOTE: Disassemble bytes to assembly mnemonics
// =================================================================
S86_ASSERT(op_code_size > 0 && op_code_size <= S86_ARRAY_UCOUNT(op_code_bytes));
S86_ASSERT(op_decode_type != S86_OpDecodeType_Count && "Unknown instruction");
S86_Opcode result = {0};
result.mnemonic = op_decode->mnemonic;
result.lock_prefix = *lock_prefix;
result.seg_reg_prefix = *seg_reg;
S86_ASSERT(*seg_reg == S86_MnemonicOp_Invalid || (*seg_reg >= S86_MnemonicOp_ES && *seg_reg <= S86_MnemonicOp_DS));
switch (op_decode_type) {
// NOTE: Instruction Pattern => [0b0000'0000W | 0bAA00'0CCC | DISP-LO | DISP-HI]
// Where, W: Optional, AA: mod, CCC: R/M
case S86_OpDecodeType_JMPIndirectWithinSeg: /*FALLTHRU*/
case S86_OpDecodeType_CALLIndirectWithinSeg: /*FALLTHRU*/
case S86_OpDecodeType_NOT: /*FALLTHRU*/
case S86_OpDecodeType_SHL_SAL: /*FALLTHRU*/
case S86_OpDecodeType_SHR: /*FALLTHRU*/
case S86_OpDecodeType_SAR: /*FALLTHRU*/
case S86_OpDecodeType_ROL: /*FALLTHRU*/
case S86_OpDecodeType_ROR: /*FALLTHRU*/
case S86_OpDecodeType_RCL: /*FALLTHRU*/
case S86_OpDecodeType_RCR: /*FALLTHRU*/
case S86_OpDecodeType_MUL: /*FALLTHRU*/
case S86_OpDecodeType_IMUL: /*FALLTHRU*/
case S86_OpDecodeType_DIV: /*FALLTHRU*/
case S86_OpDecodeType_IDIV: /*FALLTHRU*/
case S86_OpDecodeType_INCRegOrMem: /*FALLTHRU*/
case S86_OpDecodeType_DECRegOrMem: /*FALLTHRU*/
case S86_OpDecodeType_NEG: /*FALLTHRU*/
case S86_OpDecodeType_POPRegOrMem: /*FALLTHRU*/
case S86_OpDecodeType_PUSHRegOrMem: {
S86_ASSERT(op_code_size == 2);
uint8_t mod = (op_code_bytes[1] & 0b1100'0000) >> 6;
uint8_t rm = (op_code_bytes[1] & 0b0000'0111) >> 0;
S86_ASSERT(mod < 4); S86_ASSERT(rm < 8);
uint8_t w = 1;
if (op_decode_type == S86_OpDecodeType_INCRegOrMem ||
op_decode_type == S86_OpDecodeType_DECRegOrMem ||
op_decode_type == S86_OpDecodeType_NEG ||
op_decode_type == S86_OpDecodeType_MUL ||
op_decode_type == S86_OpDecodeType_MUL ||
op_decode_type == S86_OpDecodeType_IMUL ||
op_decode_type == S86_OpDecodeType_DIV ||
op_decode_type == S86_OpDecodeType_IDIV ||
(op_decode_type >= S86_OpDecodeType_NOT &&
op_decode_type <= S86_OpDecodeType_RCR)) {
w = op_code_bytes[0] & 0b0000'0001;
}
S86_DecodeEffectiveAddr(&result, buffer_it, rm, mod, w);
// NOTE: Bit shifts use 'v' to indicate if shift distance should
// come from cl register otherwise bitshift by 1
if (op_decode_type >= S86_OpDecodeType_SHL_SAL && op_decode_type <= S86_OpDecodeType_RCR) {
uint8_t v = (op_code_bytes[0] & 0b0000'0010) >> 1;
if (v) {
result.src = S86_MnemonicOp_CL;
} else {
result.src = S86_MnemonicOp_Immediate;
result.immediate = 1;
}
}
} break;
// NOTE: Instruction Pattern => [0b0000'0000]
// Generally handles instructions with control bits in any position in the first byte
case S86_OpDecodeType_DECReg: /*FALLTHRU*/
case S86_OpDecodeType_INCReg: /*FALLTHRU*/
case S86_OpDecodeType_XCHGRegWithAccum: /*FALLTHRU*/
case S86_OpDecodeType_PUSHReg: /*FALLTHRU*/
case S86_OpDecodeType_POPReg: /*FALLTHRU*/
case S86_OpDecodeType_PUSHSegReg: /*FALLTHRU*/
case S86_OpDecodeType_POPSegReg: {
S86_ASSERT(op_code_size == 1);
if (op_decode_type == S86_OpDecodeType_PUSHReg ||
op_decode_type == S86_OpDecodeType_POPReg ||
op_decode_type == S86_OpDecodeType_INCReg ||
op_decode_type == S86_OpDecodeType_DECReg ||
op_decode_type == S86_OpDecodeType_XCHGRegWithAccum) {
uint8_t reg = (op_code_bytes[0] & 0b0000'0111) >> 0;
result.dest = S86_MnemonicOpFromWReg(1, reg);
} else {
S86_ASSERT(op_decode_type == S86_OpDecodeType_PUSHSegReg ||
op_decode_type == S86_OpDecodeType_POPSegReg);
uint8_t sr = (op_code_bytes[0] & 0b0001'1000) >> 3;
result.dest = S86_MnemonicOpFromSR(sr);
}
if (op_decode_type == S86_OpDecodeType_XCHGRegWithAccum) {
result.src = result.dest;
result.dest = S86_MnemonicOp_AX;
}
} break;
// NOTE: Instruction Pattern => [0b0000'000DW | 0bAABB'BCCC | DISP-LO | DISP-HI | DATA-LO | DATA-HI]
// Where, D: optional, W: optional, AA: mod, BBB: reg, CCC: r/m
case S86_OpDecodeType_ADDRegOrMemToOrFromReg: /*FALLTHRU*/
case S86_OpDecodeType_ADCRegOrMemWithRegToEither: /*FALLTHRU*/
case S86_OpDecodeType_SUBRegOrMemToOrFromReg: /*FALLTHRU*/
case S86_OpDecodeType_SBBRegOrMemAndRegToEither: /*FALLTHRU*/
case S86_OpDecodeType_ANDRegWithMemToEither: /*FALLTHRU*/
case S86_OpDecodeType_TESTRegOrMemAndReg: /*FALLTHRU*/
case S86_OpDecodeType_ORRegOrMemAndRegToEither: /*FALLTHRU*/
case S86_OpDecodeType_XORRegOrMemAndRegToEither: /*FALLTHRU*/
case S86_OpDecodeType_LEA: /*FALLTHRU*/
case S86_OpDecodeType_LDS: /*FALLTHRU*/
case S86_OpDecodeType_LES: /*FALLTHRU*/
case S86_OpDecodeType_XCHGRegOrMemWithReg: /*FALLTHRU*/
case S86_OpDecodeType_CMPRegOrMemAndReg: /*FALLTHRU*/
case S86_OpDecodeType_MOVRegOrMemToOrFromReg: /*FALLTHRU*/
case S86_OpDecodeType_MOVSegRegToRegOrMem: /*FALLTHRU*/
case S86_OpDecodeType_MOVRegOrMemToSegReg: {
// NOTE: Instruction does not have opcode bits in the 2nd byte
if (op_decode_type == S86_OpDecodeType_MOVSegRegToRegOrMem ||
op_decode_type == S86_OpDecodeType_MOVRegOrMemToSegReg) {
S86_ASSERT(op_code_size == 2);
} else {
S86_ASSERT(op_code_size == 1);
op_code_bytes[op_code_size++] = S86_BufferIteratorNextByte(buffer_it);
}
uint8_t d = 0;
uint8_t mod = (op_code_bytes[1] & 0b1100'0000) >> 6;
uint8_t rm = (op_code_bytes[1] & 0b0000'0111) >> 0;
S86_ASSERT(mod < 4);
S86_ASSERT(rm < 8);
if (op_decode_type == S86_OpDecodeType_MOVRegOrMemToSegReg ||
op_decode_type == S86_OpDecodeType_MOVSegRegToRegOrMem) {
uint8_t sr = (op_code_bytes[1] & 0b0001'1000) >> 3;
result.src = S86_MnemonicOpFromSR(sr);
result.wide = 1;
if (op_decode_type == S86_OpDecodeType_MOVRegOrMemToSegReg)
d = 1;
} else {
result.wide = (op_code_bytes[0] & 0b0000'0001) >> 0;
d = (op_code_bytes[0] & 0b0000'0010) >> 1;
if (op_decode_type == S86_OpDecodeType_XCHGRegOrMemWithReg ||
op_decode_type == S86_OpDecodeType_LEA ||
op_decode_type == S86_OpDecodeType_LDS ||
op_decode_type == S86_OpDecodeType_LES) {
d = 1; // Destintation is always the register
if (op_decode_type == S86_OpDecodeType_XCHGRegOrMemWithReg) {
if (*lock_prefix) {
// NOTE: When we XCHG, NASM complains that the
// instruction is not lockable, unless, the memory
// operand comes first. Here we flip the direction
// to ensure the memory operand is the destination.
//
// listing_0042_completionist_decode_disassembled.asm|319| warning: instruction is not lockable [-w+prefix-lock]
d = 0;
}
} else {
result.wide = 1; // Always 16 bit (load into register)
}
}
uint8_t reg = (op_code_bytes[1] & 0b0011'1000) >> 3;
result.src = S86_MnemonicOpFromWReg(result.wide, reg);
}
S86_ASSERT(result.wide < 2);
S86_ASSERT(d < 2);
if (mod == 0b11) { // NOTE: Register-to-register move
result.dest = S86_MnemonicOpFromWReg(result.wide, rm);
} else { // NOTE: Memory mode w/ effective address calculation
S86_DecodeEffectiveAddr(&result, buffer_it, rm, mod, result.wide);
if (d)
result.effective_addr = S86_EffectiveAddress_Src;
else
result.effective_addr = S86_EffectiveAddress_Dest;
}
if (d) {
S86_MnemonicOp tmp = result.src;
result.src = result.dest;
result.dest = tmp;
}
} break;
// NOTE: Instruction Pattern => [0b0000'00SW | 0bAAA00BBB | DISP-LO | DISP-HI | DATA-LO | DATA-HI]
// Where S: optional, W: optional, AAA: mod, BBB: rm
case S86_OpDecodeType_ADDImmediateToRegOrMem: /*FALLTHRU*/
case S86_OpDecodeType_ADCImmediateToRegOrMem: /*FALLTHRU*/
case S86_OpDecodeType_SUBImmediateFromRegOrMem: /*FALLTHRU*/
case S86_OpDecodeType_SBBImmediateFromRegOrMem: /*FALLTHRU*/
case S86_OpDecodeType_CMPImmediateWithRegOrMem: /*FALLTHRU*/
case S86_OpDecodeType_ANDImmediateToRegOrMem: /*FALLTHRU*/
case S86_OpDecodeType_TESTImmediateAndRegOrMem: /*FALLTHRU*/
case S86_OpDecodeType_ORImmediateToRegOrMem: /*FALLTHRU*/
case S86_OpDecodeType_XORImmediateToRegOrMem: /*FALLTHRU*/
case S86_OpDecodeType_MOVImmediateToRegOrMem: {
S86_ASSERT(op_code_size == 2);
uint8_t w = (op_code_bytes[0] & 0b0000'0001) >> 0;
uint8_t s = (op_code_bytes[0] & 0b0000'0010) >> 1;
uint8_t mod = (op_code_bytes[1] & 0b1100'0000) >> 6;
uint8_t rm = (op_code_bytes[1] & 0b0000'0111) >> 0;
S86_ASSERT(w < 2);
S86_ASSERT(mod < 4);
S86_ASSERT(rm < 8);
S86_DecodeEffectiveAddr(&result, buffer_it, rm, mod, w);
// NOTE: Parse data payload
// =============================================================
uint16_t data = S86_BufferIteratorNextByte(buffer_it);
if (w) { // 16 bit data
if ((op_decode_type == S86_OpDecodeType_ADDImmediateToRegOrMem ||
op_decode_type == S86_OpDecodeType_ADCImmediateToRegOrMem ||
op_decode_type == S86_OpDecodeType_SUBImmediateFromRegOrMem ||
op_decode_type == S86_OpDecodeType_SBBImmediateFromRegOrMem ||
op_decode_type == S86_OpDecodeType_CMPImmediateWithRegOrMem ||
op_decode_type == S86_OpDecodeType_ANDImmediateToRegOrMem ||
op_decode_type == S86_OpDecodeType_TESTImmediateAndRegOrMem ||
op_decode_type == S86_OpDecodeType_ORImmediateToRegOrMem ||
op_decode_type == S86_OpDecodeType_XORImmediateToRegOrMem) && s) {
// NOTE: Sign extend 8 bit to 16 bit
uint16_t sign_mask = 0b1000'0000;
uint8_t data_u8 = S86_CAST(uint8_t)data;
if (sign_mask & data_u8) {
data = (uint16_t)((uint8_t)~data_u8 + 1); // Convert back to 8 bit unsigned
data = ~data + 1; // Convert to 16bit signed
result.immediate_is_8bit = true;
}
} else {
uint8_t data_hi = S86_BufferIteratorNextByte(buffer_it);
data |= (uint16_t)(data_hi) << 8;
}
}
if (op_decode_type == S86_OpDecodeType_MOVImmediateToRegOrMem) {
S86_ASSERT(mod != 0b11); // NOTE: Op is IMM->Reg, register-to-register not permitted
}
// NOTE: Sign extend 16bit to 32bit
uint16_t sign_mask16 = 0b1000'0000'0000'0000;
if (data & sign_mask16) {
uint32_t data_no_sign_bit = (uint32_t)((uint16_t)~data + 1); // Convert back to 16 bit unsigned
result.immediate = ~data_no_sign_bit + 1; // Convert to signed 32bit
} else {
result.immediate = data;
}
result.src = S86_MnemonicOp_Immediate;
} break;
// NOTE: Instruction Pattern => [0b0000'W00W | DATA-LO | DATA-HI]
case S86_OpDecodeType_ADDImmediateToAccum: /*FALLTHRU*/
case S86_OpDecodeType_ADCImmediateToAccum: /*FALLTHRU*/
case S86_OpDecodeType_SUBImmediateFromAccum: /*FALLTHRU*/
case S86_OpDecodeType_SBBImmediateFromAccum: /*FALLTHRU*/
case S86_OpDecodeType_CMPImmediateWithAccum: /*FALLTHRU*/
case S86_OpDecodeType_ANDImmediateToAccum: /*FALLTHRU*/
case S86_OpDecodeType_TESTImmediateAndAccum: /*FALLTHRU*/
case S86_OpDecodeType_ORImmediateToAccum: /*FALLTHRU*/
case S86_OpDecodeType_XORImmediateToAccum: /*FALLTHRU*/
case S86_OpDecodeType_MOVImmediateToReg: {
// NOTE: Parse opcode control bits
// =============================================================
S86_ASSERT(op_code_size == 1);
uint8_t w = 0;
if (op_decode_type == S86_OpDecodeType_ADDImmediateToAccum ||
op_decode_type == S86_OpDecodeType_ADCImmediateToAccum ||
op_decode_type == S86_OpDecodeType_SUBImmediateFromAccum ||
op_decode_type == S86_OpDecodeType_SBBImmediateFromAccum ||
op_decode_type == S86_OpDecodeType_CMPImmediateWithAccum ||
op_decode_type == S86_OpDecodeType_ANDImmediateToAccum ||
op_decode_type == S86_OpDecodeType_TESTImmediateAndAccum ||
op_decode_type == S86_OpDecodeType_ORImmediateToAccum ||
op_decode_type == S86_OpDecodeType_XORImmediateToAccum) {
w = (op_code_bytes[0] & 0b0000'0001) >> 0;
} else {
w = (op_code_bytes[0] & 0b0000'1000) >> 3;
}
// NOTE: Parse data payload
// =============================================================
uint16_t data = S86_BufferIteratorNextByte(buffer_it);
if (w) { // 16 bit data
uint8_t data_hi = S86_BufferIteratorNextByte(buffer_it);
data |= (uint16_t)(data_hi) << 8;
}
// NOTE: Disassemble
// =============================================================
result.effective_addr = S86_EffectiveAddress_Dest;
result.src = S86_MnemonicOp_Immediate;
result.wide = w;
result.src = S86_MnemonicOp_Immediate;
result.immediate = data;
if (op_decode_type == S86_OpDecodeType_MOVImmediateToReg) {
uint8_t reg = (op_code_bytes[0] & 0b0000'0111) >> 0;
result.dest = S86_MnemonicOpFromWReg(w, reg);
} else {
result.dest = result.wide ? S86_MnemonicOp_AX : S86_MnemonicOp_AL;
}
} break;
// NOTE: Instruction Pattern => [0b0000'000W | DATA-LO]
case S86_OpDecodeType_INFixedPort: /*FALLTHRU*/
case S86_OpDecodeType_INVariablePort: /*FALLTHRU*/
case S86_OpDecodeType_OUTFixedPort: /*FALLTHRU*/
case S86_OpDecodeType_OUTVariablePort: {
S86_ASSERT(op_code_size == 1);
result.wide = (op_code_bytes[0] & 0b0000'0001) >> 0;
result.dest = result.wide ? S86_MnemonicOp_AX : S86_MnemonicOp_AL;
if (op_decode_type == S86_OpDecodeType_INFixedPort ||
op_decode_type == S86_OpDecodeType_OUTFixedPort) {
result.src = S86_MnemonicOp_Immediate;
result.immediate = S86_BufferIteratorNextByte(buffer_it);
} else {
result.src = S86_MnemonicOp_DX;
}
if (op_decode_type == S86_OpDecodeType_OUTFixedPort ||
op_decode_type == S86_OpDecodeType_OUTVariablePort) {
S86_MnemonicOp tmp = result.src;
result.src = result.dest;
result.dest = tmp;
}
} break;
case S86_OpDecodeType_REP: {
S86_ASSERT(op_code_size == 1);
uint8_t string_op = S86_BufferIteratorNextByte(buffer_it);
uint8_t w_mask = 0b0000'0001;
result.rep_prefix = true;
result.wide = string_op & w_mask;
switch (string_op & ~w_mask) {
case 0b1010'0100: result.dest = S86_MnemonicOp_MOVS; break;
case 0b1010'0110: result.dest = S86_MnemonicOp_CMPS; break;
case 0b1010'1110: result.dest = S86_MnemonicOp_SCAS; break;
case 0b1010'1100: result.dest = S86_MnemonicOp_LODS; break;
case 0b1010'1010: result.dest = S86_MnemonicOp_STOS; break;
default: S86_ASSERT(!"Unhandled REP string type"); break;
}
} break;
// NOTE: Instruction Pattern => [0b0000'0000 | DATA-LO | DATA-HI]
case S86_OpDecodeType_MOVAccumToMem: /*FALLTHRU*/
case S86_OpDecodeType_MOVMemToAccum: /*FALLTHRU*/
case S86_OpDecodeType_CALLDirectInterSeg: /*FALLTHRU*/
case S86_OpDecodeType_CALLDirectWithinSeg: /*FALLTHRU*/
case S86_OpDecodeType_JMPDirectInterSeg: /*FALLTHRU*/
case S86_OpDecodeType_RETWithinSegAddImmediateToSP: /*FALLTHRU*/
case S86_OpDecodeType_INT: {
S86_ASSERT(op_code_size == 1);
uint8_t data_lo = S86_BufferIteratorNextByte(buffer_it);
uint16_t data = data_lo;
if (op_decode_type != S86_OpDecodeType_INT) {
uint8_t data_hi = S86_BufferIteratorNextByte(buffer_it);
data = S86_CAST(uint16_t)data_hi << 8 | (S86_CAST(uint16_t)data_lo);
}
if (op_decode_type == S86_OpDecodeType_CALLDirectWithinSeg) {
result.effective_addr = S86_EffectiveAddress_Dest;
result.dest = S86_MnemonicOp_BP;
result.displacement = -S86_CAST(int32_t)data;
} else if (op_decode_type == S86_OpDecodeType_RETWithinSegAddImmediateToSP) {
result.dest = S86_MnemonicOp_DirectAddress;
result.displacement = data;
} else if (op_decode_type == S86_OpDecodeType_CALLDirectInterSeg ||
op_decode_type == S86_OpDecodeType_JMPDirectInterSeg) {
uint8_t cs_lo = S86_BufferIteratorNextByte(buffer_it);
uint8_t cs_hi = S86_BufferIteratorNextByte(buffer_it);
uint16_t cs = S86_CAST(uint16_t)cs_hi << 8 | (S86_CAST(uint16_t)cs_lo);
result.displacement = (uint32_t)cs << 16 | (uint32_t)data << 0;
result.dest = S86_MnemonicOp_DirectInterSegment;
} else if (op_decode_type == S86_OpDecodeType_MOVAccumToMem) {
result.effective_addr_loads_mem = true;
result.effective_addr = S86_EffectiveAddress_Dest;
result.dest = S86_MnemonicOp_DirectAddress;
result.displacement = data;
result.src = S86_MnemonicOp_AX;
} else if (op_decode_type == S86_OpDecodeType_MOVMemToAccum) {
result.effective_addr_loads_mem = true;
result.effective_addr = S86_EffectiveAddress_Src;
result.src = S86_MnemonicOp_DirectAddress;
result.displacement = data;
result.dest = S86_MnemonicOp_AX;
} else {
result.dest = S86_MnemonicOp_Immediate;
result.immediate = data;
}
} break;
default: {
if (op_decode_type >= S86_OpDecodeType_JE_JZ && op_decode_type <= S86_OpDecodeType_JCXZ) {
S86_ASSERT(op_code_size == 1);
result.displacement = S86_CAST(int8_t)S86_BufferIteratorNextByte(buffer_it);
result.dest = S86_MnemonicOp_Jump;
} else if (op_decode_type == S86_OpDecodeType_XLAT ||
op_decode_type == S86_OpDecodeType_LAHF ||
op_decode_type == S86_OpDecodeType_SAHF ||
op_decode_type == S86_OpDecodeType_PUSHF ||
op_decode_type == S86_OpDecodeType_POPF ||
op_decode_type == S86_OpDecodeType_DAA ||
op_decode_type == S86_OpDecodeType_AAA ||
op_decode_type == S86_OpDecodeType_DAS ||
op_decode_type == S86_OpDecodeType_AAS ||
op_decode_type == S86_OpDecodeType_AAM ||
op_decode_type == S86_OpDecodeType_AAD ||
op_decode_type == S86_OpDecodeType_CBW ||
op_decode_type == S86_OpDecodeType_CWD ||
op_decode_type == S86_OpDecodeType_RETWithinSeg ||
op_decode_type == S86_OpDecodeType_INT3 ||
op_decode_type == S86_OpDecodeType_INTO ||
op_decode_type == S86_OpDecodeType_IRET ||
op_decode_type == S86_OpDecodeType_CLC ||
op_decode_type == S86_OpDecodeType_CMC ||
op_decode_type == S86_OpDecodeType_STC ||
op_decode_type == S86_OpDecodeType_CLD ||
op_decode_type == S86_OpDecodeType_STD ||
op_decode_type == S86_OpDecodeType_CLI ||
op_decode_type == S86_OpDecodeType_STI ||
op_decode_type == S86_OpDecodeType_HLT ||
op_decode_type == S86_OpDecodeType_WAIT) {
// NOTE: Mnemonic only instruction
} else if (op_decode_type == S86_OpDecodeType_LOCK) {
*lock_prefix = true;
} else if (op_decode_type == S86_OpDecodeType_SEGMENT) {
// NOTE: Mnemonic does not generate any assembly
S86_ASSERT(op_code_size == 1);
uint8_t sr = (op_code_bytes[0] & 0b0001'1000) >> 3;
*seg_reg = S86_MnemonicOpFromSR(sr);
} else {
S86_ASSERT(!"Unhandled instruction");
}
} break;
}
if (op_decode_type != S86_OpDecodeType_LOCK)
*lock_prefix = false;
if (op_decode_type != S86_OpDecodeType_SEGMENT)
*seg_reg = S86_MnemonicOp_Invalid;
if (result.effective_addr == S86_EffectiveAddress_Dest && result.effective_addr_loads_mem) {
result.word_byte_prefix = (result.wide || result.src >= S86_MnemonicOp_AX && result.src <= S86_MnemonicOp_BX)
? S86_WordBytePrefix_Word
: S86_WordBytePrefix_Byte;
}
if ((op_decode_type >= S86_OpDecodeType_MOVRegOrMemToOrFromReg) &&
(op_decode_type <= S86_OpDecodeType_MOVSegRegToRegOrMem)) {
if (result.src == S86_MnemonicOp_DirectAddress &&
S86_MnemonicOpIsAccumulator(result.dest)) {
result.clocks = 4;
} else if (S86_MnemonicOpIsAccumulator(result.src) &&
result.dest == S86_MnemonicOp_DirectAddress) {
result.clocks = 4;
} else if (S86_MnemonicOpIsRegister(result.src) &&
S86_MnemonicOpIsRegister(result.dest)) {
result.clocks = 2;
} else if (result.src == S86_MnemonicOp_DirectAddress &&
S86_MnemonicOpIsRegister(result.dest)) {
result.clocks = 2;
} else if (result.src == S86_MnemonicOp_Immediate &&
S86_MnemonicOpIsRegister(result.dest)) {
result.clocks = 4;
}
}
size_t buffer_end_index = buffer_it->index;
result.byte_size = S86_CAST(uint8_t)(buffer_end_index - buffer_start_index);
S86_ASSERT(result.immediate < S86_CAST(uint16_t)-1);
return result;
}
typedef struct S86_MnemonicOpToRegisterFileMap {
S86_MnemonicOp mnemonic_op; ///< Register/op that the mnemonic is using
S86_Register16 *reg; ///< Pointer to the register memory this mnemonic op is using
S86_RegisterByte byte; ///< The 'byte' that the mnemonic operates on (hi, lo or nil e.g. word)
} S86_MnemonicOpToRegisterFileMap;
char const CLI_ARG_EXEC[] = "--exec";
char const CLI_ARG_LOG_INSTRUCTION_PTR[] = "--log-instruction-ptr";
char const CLI_ARG_LOG_CYCLE_COUNTS[] = "--log-cycle-counts";
char const CLI_ARG_DUMP[] = "--dump";
#define PRINT_USAGE \
S86_PrintLnFmt("USAGE: sim8086.exe [%.*s] [%.*s] <binary asm file>", \
S86_ARRAY_UCOUNT(CLI_ARG_EXEC) - 1, \
CLI_ARG_EXEC, \
S86_ARRAY_UCOUNT(CLI_ARG_LOG_INSTRUCTION_PTR) - 1, \
CLI_ARG_LOG_INSTRUCTION_PTR, \
S86_ARRAY_UCOUNT(CLI_ARG_DUMP) - 1, \
CLI_ARG_DUMP)
int main(int argc, char **argv)
{
// NOTE: Argument handling
// =========================================================================
if (argc < 2) {
PRINT_USAGE;
return -1;
}
S86_Str8 CLI_ARG_EXEC_STR8 = (S86_Str8){(char *)CLI_ARG_EXEC, S86_ARRAY_UCOUNT(CLI_ARG_EXEC) - 1};
S86_Str8 CLI_ARG_LOG_INSTRUCTION_PTR_STR8 = (S86_Str8){(char *)CLI_ARG_LOG_INSTRUCTION_PTR, S86_ARRAY_UCOUNT(CLI_ARG_LOG_INSTRUCTION_PTR) - 1};
S86_Str8 CLI_ARG_LOG_CYCLE_COUNTS_STR8 = (S86_Str8){(char *)CLI_ARG_LOG_CYCLE_COUNTS, S86_ARRAY_UCOUNT(CLI_ARG_LOG_CYCLE_COUNTS) - 1};
S86_Str8 CLI_ARG_DUMP_STR8 = (S86_Str8){(char *)CLI_ARG_DUMP, S86_ARRAY_UCOUNT(CLI_ARG_DUMP) - 1};
bool exec_mode = false;
bool log_instruction_ptr = false;
bool log_cycle_counts = false;
bool dump = false;
S86_Str8 file_path = {0};
for (int arg_index = 1; arg_index < argc; arg_index++) {
char const *arg_cstring = argv[arg_index];
S86_Str8 arg_str8 = (S86_Str8){(char *)arg_cstring, strlen(arg_cstring)};
if (S86_Str8_Equals(arg_str8, CLI_ARG_EXEC_STR8)) {
exec_mode = true;
} else if (S86_Str8_Equals(arg_str8, CLI_ARG_LOG_INSTRUCTION_PTR_STR8)) {
log_instruction_ptr = true;
} else if (S86_Str8_Equals(arg_str8, CLI_ARG_LOG_CYCLE_COUNTS_STR8)) {
log_cycle_counts = true;
} else if (S86_Str8_Equals(arg_str8, CLI_ARG_DUMP_STR8)) {
dump = true;
} else {
if (file_path.size) {
S86_PrintLnFmt("ERROR: Only 1 ASM binary file is supported per invocation [file=\"%.*s\"]", S86_STR8_FMT(file_path));
PRINT_USAGE;
return -1;
}
file_path = arg_str8;
}
}
char const *file_name = file_path.data;
for (size_t index = file_path.size - 1; index < file_path.size; index--) {
if (file_path.data[index] == '\\' || file_path.data[index] == '/') {
file_name = file_path.data + index + 1;
break;
}
}
S86_Buffer buffer = S86_FileRead(file_path.data);
if (!S86_BufferIsValid(buffer)) {
S86_PrintLnFmt("ERROR: Failed to read file [path=\"%.*s\"]", S86_STR8_FMT(file_path));
return -1;
}
// NOTE: Sim8086
// =========================================================================
S86_OpDecode const DECODE_TABLE[] = {
[S86_OpDecodeType_MOVRegOrMemToOrFromReg] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1000'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_MOV},
[S86_OpDecodeType_MOVImmediateToRegOrMem] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1100'0110, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_MOV},
[S86_OpDecodeType_MOVImmediateToReg] = {.op_mask0 = 0b1111'0000, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1011'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_MOV},
[S86_OpDecodeType_MOVMemToAccum] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1010'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_MOV},
[S86_OpDecodeType_MOVAccumToMem] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1010'0010, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_MOV},
[S86_OpDecodeType_MOVRegOrMemToSegReg] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0010'0000,
.op_bits0 = 0b1000'1110, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_MOV},
[S86_OpDecodeType_MOVSegRegToRegOrMem] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0010'0000,
.op_bits0 = 0b1000'1100, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_MOV},
[S86_OpDecodeType_PUSHRegOrMem] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1111'1111, .op_bits1 = 0b0011'0000, .mnemonic = S86_Mnemonic_PUSH},
[S86_OpDecodeType_PUSHReg] = {.op_mask0 = 0b1111'1000, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0101'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_PUSH},
[S86_OpDecodeType_PUSHSegReg] = {.op_mask0 = 0b1110'0111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0000'0110, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_PUSH},
[S86_OpDecodeType_POPRegOrMem] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1000'1111, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_POP},
[S86_OpDecodeType_POPReg] = {.op_mask0 = 0b1111'1000, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0101'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_POP},
[S86_OpDecodeType_POPSegReg] = {.op_mask0 = 0b1110'0111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0000'0111, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_POP},
[S86_OpDecodeType_XCHGRegOrMemWithReg] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1000'0110, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_XCHG},
[S86_OpDecodeType_XCHGRegWithAccum] = {.op_mask0 = 0b1111'1000, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1001'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_XCHG},
[S86_OpDecodeType_INFixedPort] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1110'0100, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_IN},
[S86_OpDecodeType_INVariablePort] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1110'1100, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_IN},
[S86_OpDecodeType_OUTFixedPort] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1110'0110, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_OUT},
[S86_OpDecodeType_OUTVariablePort] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1110'1110, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_OUT},
[S86_OpDecodeType_XLAT] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1101'0111, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_XLAT},
[S86_OpDecodeType_LEA] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1000'1101, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_LEA},
[S86_OpDecodeType_LDS] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1100'0101, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_LDS},
[S86_OpDecodeType_LES] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1100'0100, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_LES},
[S86_OpDecodeType_LAHF] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1001'1111, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_LAHF},
[S86_OpDecodeType_SAHF] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1001'1110, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_SAHF},
[S86_OpDecodeType_PUSHF] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1001'1100, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_PUSHF},
[S86_OpDecodeType_POPF] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1001'1101, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_POPF},
[S86_OpDecodeType_ADDRegOrMemToOrFromReg] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0000'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_ADD},
[S86_OpDecodeType_ADDImmediateToRegOrMem] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1000'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_ADD},
[S86_OpDecodeType_ADDImmediateToAccum] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0000'0100, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_ADD},
[S86_OpDecodeType_ADCRegOrMemWithRegToEither] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0001'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_ADC},
[S86_OpDecodeType_ADCImmediateToRegOrMem] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1000'0000, .op_bits1 = 0b0001'0000, .mnemonic = S86_Mnemonic_ADC},
[S86_OpDecodeType_ADCImmediateToAccum] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0001'0100, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_ADC},
[S86_OpDecodeType_INCRegOrMem] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1111'1110, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_INC},
[S86_OpDecodeType_INCReg] = {.op_mask0 = 0b1111'1000, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0100'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_INC},
[S86_OpDecodeType_AAA] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0011'0111, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_AAA},
[S86_OpDecodeType_DAA] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0010'0111, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_DAA},
[S86_OpDecodeType_SUBRegOrMemToOrFromReg] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0010'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_SUB},
[S86_OpDecodeType_SUBImmediateFromRegOrMem] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1000'0000, .op_bits1 = 0b0010'1000, .mnemonic = S86_Mnemonic_SUB},
[S86_OpDecodeType_SUBImmediateFromAccum] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0010'1100, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_SUB},
[S86_OpDecodeType_SBBRegOrMemAndRegToEither] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0001'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_SBB},
[S86_OpDecodeType_SBBImmediateFromRegOrMem] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1000'0000, .op_bits1 = 0b0001'1000, .mnemonic = S86_Mnemonic_SBB},
[S86_OpDecodeType_SBBImmediateFromAccum] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0001'1100, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_SBB},
[S86_OpDecodeType_DECRegOrMem] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1111'1110, .op_bits1 = 0b0000'1000, .mnemonic = S86_Mnemonic_DEC},
[S86_OpDecodeType_DECReg] = {.op_mask0 = 0b1111'1000, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0100'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_DEC},
[S86_OpDecodeType_NEG] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1111'0110, .op_bits1 = 0b0001'1000, .mnemonic = S86_Mnemonic_NEG},
[S86_OpDecodeType_CMPRegOrMemAndReg] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0011'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_CMP},
[S86_OpDecodeType_CMPImmediateWithRegOrMem] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1000'0000, .op_bits1 = 0b0011'1000, .mnemonic = S86_Mnemonic_CMP},
[S86_OpDecodeType_CMPImmediateWithAccum] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0011'1100, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_CMP},
[S86_OpDecodeType_AAS] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0011'1111, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_AAS},
[S86_OpDecodeType_DAS] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0010'1111, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_DAS},
[S86_OpDecodeType_MUL] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1111'0110, .op_bits1 = 0b0010'0000, .mnemonic = S86_Mnemonic_MUL},
[S86_OpDecodeType_IMUL] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1111'0110, .op_bits1 = 0b0010'1000, .mnemonic = S86_Mnemonic_IMUL},
[S86_OpDecodeType_AAM] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b1111'1111,
.op_bits0 = 0b1101'0100, .op_bits1 = 0b0000'1010, .mnemonic = S86_Mnemonic_AAM},
[S86_OpDecodeType_DIV] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1111'0110, .op_bits1 = 0b0011'0000, .mnemonic = S86_Mnemonic_DIV},
[S86_OpDecodeType_IDIV] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1111'0110, .op_bits1 = 0b0011'1000, .mnemonic = S86_Mnemonic_IDIV},
[S86_OpDecodeType_AAD] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b1111'1111,
.op_bits0 = 0b1101'0101, .op_bits1 = 0b0000'1010, .mnemonic = S86_Mnemonic_AAD},
[S86_OpDecodeType_CBW] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1001'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_CBW},
[S86_OpDecodeType_CWD] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1001'1001, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_CWD},
[S86_OpDecodeType_NOT] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1111'0110, .op_bits1 = 0b0001'0000, .mnemonic = S86_Mnemonic_NOT},
[S86_OpDecodeType_SHL_SAL] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1101'0000, .op_bits1 = 0b0010'0000, .mnemonic = S86_Mnemonic_SHL_SAL},
[S86_OpDecodeType_SHR] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1101'0000, .op_bits1 = 0b0010'1000, .mnemonic = S86_Mnemonic_SHR},
[S86_OpDecodeType_SAR] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1101'0000, .op_bits1 = 0b0011'1000, .mnemonic = S86_Mnemonic_SAR},
[S86_OpDecodeType_ROL] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1101'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_ROL},
[S86_OpDecodeType_ROR] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1101'0000, .op_bits1 = 0b0000'1000, .mnemonic = S86_Mnemonic_ROR},
[S86_OpDecodeType_RCL] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1101'0000, .op_bits1 = 0b0001'0000, .mnemonic = S86_Mnemonic_RCL},
[S86_OpDecodeType_RCR] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1101'0000, .op_bits1 = 0b0001'1000, .mnemonic = S86_Mnemonic_RCR},
[S86_OpDecodeType_ANDRegWithMemToEither] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0010'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_AND},
[S86_OpDecodeType_ANDImmediateToRegOrMem] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1000'0000, .op_bits1 = 0b0010'0000, .mnemonic = S86_Mnemonic_AND},
[S86_OpDecodeType_ANDImmediateToAccum] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0010'0100, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_AND},
[S86_OpDecodeType_TESTRegOrMemAndReg] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1000'0100, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_TEST},
[S86_OpDecodeType_TESTImmediateAndRegOrMem] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1111'0110, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_TEST},
[S86_OpDecodeType_TESTImmediateAndAccum] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1010'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_TEST},
[S86_OpDecodeType_ORRegOrMemAndRegToEither] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0000'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_OR},
[S86_OpDecodeType_ORImmediateToRegOrMem] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1000'0000, .op_bits1 = 0b0000'1000, .mnemonic = S86_Mnemonic_OR},
[S86_OpDecodeType_ORImmediateToAccum] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0000'1100, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_OR},
[S86_OpDecodeType_XORRegOrMemAndRegToEither] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0011'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_XOR},
[S86_OpDecodeType_XORImmediateToRegOrMem] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1000'0000, .op_bits1 = 0b0011'0000, .mnemonic = S86_Mnemonic_XOR},
[S86_OpDecodeType_XORImmediateToAccum] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0011'0100, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_XOR},
[S86_OpDecodeType_REP] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1111'0010, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_REP},
[S86_OpDecodeType_CALLDirectWithinSeg] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1110'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_CALL},
[S86_OpDecodeType_CALLIndirectWithinSeg] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1111'1111, .op_bits1 = 0b0001'0000, .mnemonic = S86_Mnemonic_CALL},
[S86_OpDecodeType_CALLDirectInterSeg] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1001'1010, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_CALL},
[S86_OpDecodeType_CALLIndirectInterSeg] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1111'1111, .op_bits1 = 0b0001'1000, .mnemonic = S86_Mnemonic_CALL},
[S86_OpDecodeType_JMPDirectWithinSeg] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1110'1001, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_JMP},
[S86_OpDecodeType_JMPDirectWithinSegShort] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1110'1011, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_JMP},
[S86_OpDecodeType_JMPIndirectWithinSeg] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1111'1111, .op_bits1 = 0b0010'0000, .mnemonic = S86_Mnemonic_JMP},
[S86_OpDecodeType_JMPDirectInterSeg] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1110'1010, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_JMP},
[S86_OpDecodeType_JMPIndirectInterSeg] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1111'1111, .op_bits1 = 0b0010'1000, .mnemonic = S86_Mnemonic_JMP},
[S86_OpDecodeType_RETWithinSeg] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1100'0011, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_RET},
[S86_OpDecodeType_RETWithinSegAddImmediateToSP] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1100'0010, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_RET},
[S86_OpDecodeType_RETInterSeg] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1100'1011, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_RET},
[S86_OpDecodeType_RETInterSegAddImmediateToSP] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1100'1010, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_RET},
[S86_OpDecodeType_JE_JZ] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'0100, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_JE_JZ},
[S86_OpDecodeType_JL_JNGE] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'1100, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_JL_JNGE},
[S86_OpDecodeType_JLE_JNG] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'1110, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_JLE_JNG},
[S86_OpDecodeType_JB_JNAE] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'0010, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_JB_JNAE},
[S86_OpDecodeType_JBE_JNA] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'0110, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_JBE_JNA},
[S86_OpDecodeType_JP_JPE] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'1010, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_JP_JPE},
[S86_OpDecodeType_JO] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_JO},
[S86_OpDecodeType_JS] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_JS},
[S86_OpDecodeType_JNE_JNZ] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'0101, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_JNE_JNZ},
[S86_OpDecodeType_JNL_JGE] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'1101, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_JNL_JGE},
[S86_OpDecodeType_JNLE_JG] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'1111, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_JNLE_JG},
[S86_OpDecodeType_JNB_JAE] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'0011, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_JNB_JAE},
[S86_OpDecodeType_JNBE_JA] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'0111, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_JNBE_JA},
[S86_OpDecodeType_JNP_JO] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'1011, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_JNP_JO},
[S86_OpDecodeType_JNO] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'0001, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_JNO},
[S86_OpDecodeType_JNS] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'1001, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_JNS},
[S86_OpDecodeType_LOOP] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1110'0010, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_LOOP},
[S86_OpDecodeType_LOOPZ_LOOPE] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1110'0001, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_LOOPZ_LOOPE},
[S86_OpDecodeType_LOOPNZ_LOOPNE] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1110'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_LOOPNZ_LOOPNE},
[S86_OpDecodeType_JCXZ] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1110'0011, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_JCXZ},
[S86_OpDecodeType_INT] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1100'1101, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_INT},
[S86_OpDecodeType_INT3] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1100'1100, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_INT3},
[S86_OpDecodeType_INTO] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1100'1110, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_INTO},
[S86_OpDecodeType_IRET] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1100'1111, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_IRET},
[S86_OpDecodeType_CLC] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1111'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_CLC},
[S86_OpDecodeType_CMC] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1111'0101, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_CMC},
[S86_OpDecodeType_STC] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1111'1001, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_STC},
[S86_OpDecodeType_CLD] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1111'1100, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_CLD},
[S86_OpDecodeType_STD] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1111'1101, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_STD},
[S86_OpDecodeType_CLI] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1111'1010, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_CLI},
[S86_OpDecodeType_STI] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1111'1011, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_STI},
[S86_OpDecodeType_HLT] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1111'0100, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_HLT},
[S86_OpDecodeType_WAIT] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1001'1011, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_WAIT},
[S86_OpDecodeType_LOCK] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1111'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_LOCK},
[S86_OpDecodeType_SEGMENT] = {.op_mask0 = 0b1110'0111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0010'0110, .op_bits1 = 0b0000'0000, .mnemonic = S86_Mnemonic_SEGMENT},
};
// NOTE: Decode assembly
// =========================================================================
if (exec_mode) {
if (log_cycle_counts) { // NOTE: Print disclaimer + header
S86_PrintLn(S86_STR8("**************"));
S86_PrintLn(S86_STR8("**** 8086 ****"));
S86_PrintLn(S86_STR8("**************"));
S86_PrintLn(S86_STR8(""));
S86_PrintLn(S86_STR8("WARNING: Clocks reported by this utility are strictly from the 8086 manual."));
S86_PrintLn(S86_STR8("They will be inaccurate, both because the manual clocks are estimates, and because"));
S86_PrintLn(S86_STR8("some of the entries in the manual look highly suspicious and are probably typos."));
S86_PrintLn(S86_STR8(""));
}
S86_PrintLnFmt("--- test\\%s execution ---", file_name);
} else {
S86_PrintLn(S86_STR8("bits 16"));
}
uint32_t const S86_MEMORY_SIZE = 1024 * 1024;
S86_RegisterFile register_file = {0};
uint8_t *memory = VirtualAlloc(0, S86_MEMORY_SIZE, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
memcpy(memory, buffer.data, buffer.size);
S86_MnemonicOpToRegisterFileMap mnemonic_op_to_register_file_map[] = {
{.mnemonic_op = S86_MnemonicOp_AX, .reg = &register_file.reg.file.ax, .byte = S86_RegisterByte_Nil},
{.mnemonic_op = S86_MnemonicOp_AL, .reg = &register_file.reg.file.ax, .byte = S86_RegisterByte_Lo},
{.mnemonic_op = S86_MnemonicOp_AH, .reg = &register_file.reg.file.ax, .byte = S86_RegisterByte_Hi},
{.mnemonic_op = S86_MnemonicOp_CX, .reg = &register_file.reg.file.cx, .byte = S86_RegisterByte_Nil},
{.mnemonic_op = S86_MnemonicOp_CL, .reg = &register_file.reg.file.cx, .byte = S86_RegisterByte_Lo},
{.mnemonic_op = S86_MnemonicOp_CH, .reg = &register_file.reg.file.cx, .byte = S86_RegisterByte_Lo},
{.mnemonic_op = S86_MnemonicOp_DX, .reg = &register_file.reg.file.dx, .byte = S86_RegisterByte_Nil},
{.mnemonic_op = S86_MnemonicOp_DL, .reg = &register_file.reg.file.dx, .byte = S86_RegisterByte_Lo},
{.mnemonic_op = S86_MnemonicOp_DH, .reg = &register_file.reg.file.dx, .byte = S86_RegisterByte_Hi},
{.mnemonic_op = S86_MnemonicOp_BX, .reg = &register_file.reg.file.bx, .byte = S86_RegisterByte_Nil},
{.mnemonic_op = S86_MnemonicOp_BL, .reg = &register_file.reg.file.bx, .byte = S86_RegisterByte_Lo},
{.mnemonic_op = S86_MnemonicOp_BH, .reg = &register_file.reg.file.bx, .byte = S86_RegisterByte_Hi},
{.mnemonic_op = S86_MnemonicOp_SP, .reg = &register_file.reg.file.sp, .byte = S86_RegisterByte_Nil},
{.mnemonic_op = S86_MnemonicOp_BP, .reg = &register_file.reg.file.bp, .byte = S86_RegisterByte_Nil},
{.mnemonic_op = S86_MnemonicOp_SI, .reg = &register_file.reg.file.si, .byte = S86_RegisterByte_Nil},
{.mnemonic_op = S86_MnemonicOp_DI, .reg = &register_file.reg.file.di, .byte = S86_RegisterByte_Nil},
{.mnemonic_op = S86_MnemonicOp_ES, .reg = &register_file.reg.file.es, .byte = S86_RegisterByte_Nil},
{.mnemonic_op = S86_MnemonicOp_CS, .reg = &register_file.reg.file.cs, .byte = S86_RegisterByte_Nil},
{.mnemonic_op = S86_MnemonicOp_SS, .reg = &register_file.reg.file.ss, .byte = S86_RegisterByte_Nil},
{.mnemonic_op = S86_MnemonicOp_DS, .reg = &register_file.reg.file.ds, .byte = S86_RegisterByte_Nil},
{.mnemonic_op = S86_MnemonicOp_BX_SI, .reg = &register_file.reg.file.bx, .byte = S86_RegisterByte_Nil},
{.mnemonic_op = S86_MnemonicOp_BX_DI, .reg = &register_file.reg.file.bx, .byte = S86_RegisterByte_Nil},
{.mnemonic_op = S86_MnemonicOp_BP_SI, .reg = &register_file.reg.file.bp, .byte = S86_RegisterByte_Nil},
{.mnemonic_op = S86_MnemonicOp_BP_DI, .reg = &register_file.reg.file.bp, .byte = S86_RegisterByte_Nil},
};
// NOTE: Execute the assembly
// =========================================================================
S86_Buffer instruction_buffer = {0};
instruction_buffer.data = (char *)&memory[register_file.instruction_ptr];
instruction_buffer.size = buffer.size;
S86_BufferIterator instruction_it = S86_BufferIteratorInit(instruction_buffer);
uint32_t clocks_counter = 0;
bool lock_prefix = false;
S86_MnemonicOp seg_reg = S86_CAST(S86_MnemonicOp)0;
for (uint16_t prev_ip = 0; register_file.instruction_ptr < buffer.size; prev_ip = register_file.instruction_ptr) {
instruction_it.index = register_file.instruction_ptr;
S86_Opcode opcode = S86_DecodeOpcode(&instruction_it, DECODE_TABLE, S86_ARRAY_UCOUNT(DECODE_TABLE), &lock_prefix, &seg_reg);
S86_PrintOpcode(opcode);
register_file.instruction_ptr += opcode.byte_size;
if (opcode.mnemonic == S86_Mnemonic_LOCK || opcode.mnemonic == S86_Mnemonic_SEGMENT)
continue;
if (!exec_mode) {
S86_Print(S86_STR8("\n"));
continue;
}
// NOTE: Simulate instruction ==============================================================
S86_RegisterFile prev_register_file = register_file;
switch (opcode.mnemonic) {
case S86_Mnemonic_PUSH: /*FALLTHRU*/
case S86_Mnemonic_POP: /*FALLTHRU*/
case S86_Mnemonic_XCHG: /*FALLTHRU*/
case S86_Mnemonic_IN: /*FALLTHRU*/
case S86_Mnemonic_OUT: /*FALLTHRU*/
case S86_Mnemonic_XLAT: /*FALLTHRU*/
case S86_Mnemonic_LEA: /*FALLTHRU*/
case S86_Mnemonic_LDS: /*FALLTHRU*/
case S86_Mnemonic_LES: /*FALLTHRU*/
case S86_Mnemonic_LAHF: /*FALLTHRU*/
case S86_Mnemonic_SAHF: /*FALLTHRU*/
case S86_Mnemonic_PUSHF: /*FALLTHRU*/
case S86_Mnemonic_POPF: /*FALLTHRU*/
case S86_Mnemonic_ADC: /*FALLTHRU*/
case S86_Mnemonic_INC: /*FALLTHRU*/
case S86_Mnemonic_AAA: /*FALLTHRU*/
case S86_Mnemonic_DAA: /*FALLTHRU*/
case S86_Mnemonic_SBB: /*FALLTHRU*/
case S86_Mnemonic_DEC: /*FALLTHRU*/
case S86_Mnemonic_NEG: /*FALLTHRU*/
case S86_Mnemonic_AAS: /*FALLTHRU*/
case S86_Mnemonic_DAS: /*FALLTHRU*/
case S86_Mnemonic_MUL: /*FALLTHRU*/
case S86_Mnemonic_IMUL: /*FALLTHRU*/
case S86_Mnemonic_AAM: /*FALLTHRU*/
case S86_Mnemonic_DIV: /*FALLTHRU*/
case S86_Mnemonic_IDIV: /*FALLTHRU*/
case S86_Mnemonic_AAD: /*FALLTHRU*/
case S86_Mnemonic_CBW: /*FALLTHRU*/
case S86_Mnemonic_CWD: /*FALLTHRU*/
case S86_Mnemonic_NOT: /*FALLTHRU*/
case S86_Mnemonic_SHL_SAL: /*FALLTHRU*/
case S86_Mnemonic_SHR: /*FALLTHRU*/
case S86_Mnemonic_SAR: /*FALLTHRU*/
case S86_Mnemonic_ROL: /*FALLTHRU*/
case S86_Mnemonic_ROR: /*FALLTHRU*/
case S86_Mnemonic_RCL: /*FALLTHRU*/
case S86_Mnemonic_RCR: /*FALLTHRU*/
case S86_Mnemonic_AND: /*FALLTHRU*/
case S86_Mnemonic_TEST: /*FALLTHRU*/
case S86_Mnemonic_OR: /*FALLTHRU*/
case S86_Mnemonic_XOR: /*FALLTHRU*/
case S86_Mnemonic_REP: /*FALLTHRU*/
case S86_Mnemonic_CALL: /*FALLTHRU*/
case S86_Mnemonic_JMP: /*FALLTHRU*/
case S86_Mnemonic_RET: /*FALLTHRU*/
case S86_Mnemonic_JL_JNGE: /*FALLTHRU*/
case S86_Mnemonic_JLE_JNG: /*FALLTHRU*/
case S86_Mnemonic_JBE_JNA: /*FALLTHRU*/
case S86_Mnemonic_JO: /*FALLTHRU*/
case S86_Mnemonic_JS: /*FALLTHRU*/
case S86_Mnemonic_JNL_JGE: /*FALLTHRU*/
case S86_Mnemonic_JNLE_JG: /*FALLTHRU*/
case S86_Mnemonic_JNB_JAE: /*FALLTHRU*/
case S86_Mnemonic_JNBE_JA: /*FALLTHRU*/
case S86_Mnemonic_JNP_JO: /*FALLTHRU*/
case S86_Mnemonic_JNO: /*FALLTHRU*/
case S86_Mnemonic_JNS: /*FALLTHRU*/
case S86_Mnemonic_LOOPZ_LOOPE: /*FALLTHRU*/
case S86_Mnemonic_JCXZ: /*FALLTHRU*/
case S86_Mnemonic_INT: /*FALLTHRU*/
case S86_Mnemonic_INT3: /*FALLTHRU*/
case S86_Mnemonic_INTO: /*FALLTHRU*/
case S86_Mnemonic_IRET: /*FALLTHRU*/
case S86_Mnemonic_CLC: /*FALLTHRU*/
case S86_Mnemonic_CMC: /*FALLTHRU*/
case S86_Mnemonic_STC: /*FALLTHRU*/
case S86_Mnemonic_CLD: /*FALLTHRU*/
case S86_Mnemonic_STD: /*FALLTHRU*/
case S86_Mnemonic_CLI: /*FALLTHRU*/
case S86_Mnemonic_STI: /*FALLTHRU*/
case S86_Mnemonic_HLT: /*FALLTHRU*/
case S86_Mnemonic_WAIT: /*FALLTHRU*/
case S86_Mnemonic_LOCK: /*FALLTHRU*/
case S86_Mnemonic_SEGMENT: break;
case S86_Mnemonic_MOV: {
uint16_t src = 0;
bool byte_op = opcode.dest >= S86_MnemonicOp_AL && opcode.dest <= S86_MnemonicOp_BH;
if (opcode.src == S86_MnemonicOp_Immediate) {
if (byte_op) {
S86_ASSERT(opcode.immediate < S86_CAST(uint8_t)-1);
src = S86_CAST(uint8_t)opcode.immediate;
} else {
src = S86_CAST(uint16_t)opcode.immediate;
}
} else if (opcode.src == S86_MnemonicOp_DirectAddress) {
S86_ASSERT(opcode.displacement >= 0);
src = memory[opcode.displacement];
} else {
S86_MnemonicOpToRegisterFileMap const *src_map = NULL;
for (size_t index = 0; !src_map && index < S86_ARRAY_UCOUNT(mnemonic_op_to_register_file_map); index++) {
S86_MnemonicOpToRegisterFileMap const *item = mnemonic_op_to_register_file_map + index;
if (item->mnemonic_op == opcode.src)
src_map = item;
}
if (src_map->mnemonic_op >= S86_MnemonicOp_BX_SI &&
src_map->mnemonic_op <= S86_MnemonicOp_BP_DI) {
uint16_t address = 0;
if (src_map->mnemonic_op == S86_MnemonicOp_BX_SI) {
address = src_map->reg->word + register_file.reg.file.si.word;
} else if (src_map->mnemonic_op == S86_MnemonicOp_BX_DI) {
address = src_map->reg->word + register_file.reg.file.di.word;
} else if (src_map->mnemonic_op == S86_MnemonicOp_BP_SI) {
address = src_map->reg->word + register_file.reg.file.si.word;
} else if (src_map->mnemonic_op == S86_MnemonicOp_BP_DI) {
address = src_map->reg->word + register_file.reg.file.di.word;
} else {
S86_ASSERT(!"Invalid code path");
}
src = *(uint16_t *)&memory[address];
} else {
src = byte_op ? src_map->reg->bytes[src_map->byte] : src_map->reg->word;
}
}
uint8_t *dest_lo = NULL;
uint8_t *dest_hi = NULL;
if (opcode.dest == S86_MnemonicOp_DirectAddress) {
// NOTE: The 8086 doesn't support load to store directly
// memory to memory afaict
S86_ASSERT(opcode.dest != opcode.src);
S86_ASSERT(opcode.displacement >= 0);
dest_lo = memory + opcode.displacement;
dest_hi = byte_op ? NULL : memory + (opcode.displacement + 1);
} else {
S86_MnemonicOpToRegisterFileMap const *dest_map = NULL;
for (size_t index = 0; !dest_map && index < S86_ARRAY_UCOUNT(mnemonic_op_to_register_file_map); index++) {
S86_MnemonicOpToRegisterFileMap const *item = mnemonic_op_to_register_file_map + index;
if (item->mnemonic_op == opcode.dest)
dest_map = item;
}
S86_ASSERT(dest_map);
// NOTE: Effective address means we're store/load from memory
// The opcode value is the address.
if (opcode.effective_addr == S86_EffectiveAddress_Dest && opcode.effective_addr_loads_mem) {
uint16_t address = dest_map->reg->word + S86_CAST(uint16_t)opcode.displacement;
if (dest_map->mnemonic_op == S86_MnemonicOp_BX_SI) {
address = dest_map->reg->word + register_file.reg.file.si.word;
} else if (dest_map->mnemonic_op == S86_MnemonicOp_BX_DI) {
address = dest_map->reg->word + register_file.reg.file.di.word;
} else if (dest_map->mnemonic_op == S86_MnemonicOp_BP_SI) {
address = dest_map->reg->word + register_file.reg.file.si.word;
} else if (dest_map->mnemonic_op == S86_MnemonicOp_BP_DI) {
address = dest_map->reg->word + register_file.reg.file.di.word;
}
dest_lo = memory + address;
dest_hi = byte_op ? NULL : memory + (address + 1);
} else {
if (byte_op) {
dest_lo = &dest_map->reg->bytes[dest_map->byte];
} else {
dest_lo = &dest_map->reg->bytes[0];
dest_hi = &dest_map->reg->bytes[1];
}
}
}
if (dest_lo)
*dest_lo = S86_CAST(uint8_t)(src >> 0);
if (dest_hi)
*dest_hi = S86_CAST(uint8_t)(src >> 8);
} break;
case S86_Mnemonic_ADD: /*FALLTHRU*/
case S86_Mnemonic_SUB: /*FALLTHRU*/
case S86_Mnemonic_CMP: {
S86_MnemonicOpToRegisterFileMap *dest_map = NULL;
for (size_t index = 0; !dest_map && index < S86_ARRAY_UCOUNT(mnemonic_op_to_register_file_map); index++) {
S86_MnemonicOpToRegisterFileMap *item = mnemonic_op_to_register_file_map + index;
if (item->mnemonic_op == opcode.dest)
dest_map = item;
}
S86_ASSERT(dest_map);
bool subtract = opcode.mnemonic != S86_Mnemonic_ADD;
S86_Register16 dest = *dest_map->reg;
bool byte_op = opcode.dest >= S86_MnemonicOp_AL && opcode.dest <= S86_MnemonicOp_BH;
uint16_t src = 0;
if (opcode.src == S86_MnemonicOp_Immediate) {
if (byte_op) {
S86_ASSERT(opcode.immediate < S86_CAST(uint8_t)-1);
src = S86_CAST(uint8_t)opcode.immediate;
} else {
S86_ASSERT(opcode.immediate < S86_CAST(uint16_t)-1);
src = S86_CAST(uint16_t)opcode.immediate;
}
} else if (opcode.src == S86_MnemonicOp_DirectAddress) {
S86_ASSERT(opcode.displacement >= 0);
src = memory[opcode.displacement];
} else {
S86_MnemonicOpToRegisterFileMap const *src_map = NULL;
for (size_t index = 0; !src_map && index < S86_ARRAY_UCOUNT(mnemonic_op_to_register_file_map); index++) {
S86_MnemonicOpToRegisterFileMap const *item = mnemonic_op_to_register_file_map + index;
if (item->mnemonic_op == opcode.src)
src_map = item;
}
if (src_map->mnemonic_op >= S86_MnemonicOp_BX_SI &&
src_map->mnemonic_op <= S86_MnemonicOp_BP_DI) {
uint16_t address = 0;
if (src_map->mnemonic_op == S86_MnemonicOp_BX_SI) {
address = src_map->reg->word + register_file.reg.file.si.word;
} else if (src_map->mnemonic_op == S86_MnemonicOp_BX_DI) {
address = src_map->reg->word + register_file.reg.file.di.word;
} else if (src_map->mnemonic_op == S86_MnemonicOp_BP_SI) {
address = src_map->reg->word + register_file.reg.file.si.word;
} else if (src_map->mnemonic_op == S86_MnemonicOp_BP_DI) {
address = src_map->reg->word + register_file.reg.file.di.word;
} else {
S86_ASSERT(!"Invalid code path");
}
src = *(uint16_t *)&memory[address];
} else {
src = byte_op ? src_map->reg->bytes[src_map->byte] : src_map->reg->word;
}
}
// NOTE: Overflow if the sign masks were initially the same,
// but, after the operation the sign masked changed.
uint8_t const sign_mask8 = 0b1000'0000;
uint16_t const sign_mask16 = 0b1000'0000'0000'0000;
if (byte_op) {
uint8_t src_u8 = S86_CAST(uint8_t)src;
if (subtract)
src_u8 = ~src_u8 + 1;
uint8_t dest_u8 = dest.bytes[dest_map->byte];
uint8_t new_dest_u8 = dest_u8 + src_u8;
// NOTE: Overflow check
bool initially_matching_sign_masks = (dest_u8 & sign_mask8) == (src_u8 & sign_mask8);
bool sign_masks_changed = (dest_u8 & sign_mask8) != (new_dest_u8 & sign_mask8);
register_file.flags.overflow = initially_matching_sign_masks && sign_masks_changed;
// NOTE: Carry check
register_file.flags.carry = subtract ? new_dest_u8 > dest_u8 : new_dest_u8 < dest_u8;
// NOTE: Auxiliary carry check
uint8_t dest_u8_nibble_lo = dest_u8 & 0b0000'1111 >> 0;
uint8_t dest_u8_nibble_hi = dest_u8 & 0b1111'0000 >> 4;
uint8_t new_dest_u8_nibble_lo = new_dest_u8 & 0b0000'1111 >> 0;
uint8_t new_dest_u8_nibble_hi = new_dest_u8 & 0b1111'0000 >> 4;
register_file.flags.auxiliary_carry = subtract ? new_dest_u8_nibble_hi > dest_u8_nibble_hi
: new_dest_u8_nibble_lo < dest_u8_nibble_lo;
// NOTE: Sign check
register_file.flags.sign = new_dest_u8 & 0b1000'0000;
// NOTE: Update the register
dest.bytes[dest_map->byte] = new_dest_u8;
} else {
if (subtract)
src = ~src + 1;
S86_Register16 new_dest = {0};
new_dest.word = dest.word + src;
// NOTE: Overflow check
bool initially_matching_sign_masks = (dest.word & sign_mask16) == (src & sign_mask16);
bool sign_masks_changed = (dest.word & sign_mask16) != (new_dest.word & sign_mask16);
register_file.flags.overflow = initially_matching_sign_masks && sign_masks_changed;
// NOTE: Auxiliary carry check
uint8_t dest_lo_nibble_lo = dest.bytes[S86_RegisterByte_Lo] & 0b0000'1111 >> 0;
uint8_t dest_lo_nibble_hi = dest.bytes[S86_RegisterByte_Lo] & 0b1111'0000 >> 4;
uint8_t new_dest_lo_nibble_lo = new_dest.bytes[S86_RegisterByte_Lo] & 0b0000'1111 >> 0;
uint8_t new_dest_lo_nibble_hi = new_dest.bytes[S86_RegisterByte_Lo] & 0b1111'0000 >> 4;
register_file.flags.auxiliary_carry = subtract ? new_dest_lo_nibble_hi > dest_lo_nibble_hi
: new_dest_lo_nibble_lo < dest_lo_nibble_lo;
// NOTE: Carry check
register_file.flags.carry = subtract ? new_dest.word > dest.word : new_dest.word < dest.word;
// NOTE: Sign check
register_file.flags.sign = new_dest.word & 0b1000'0000'0000'0000;
// NOTE: Update the register
dest.word = new_dest.word;
}
int lo_bit_count = _mm_popcnt_u32(S86_CAST(uint32_t)dest.bytes[S86_RegisterByte_Lo]);
register_file.flags.parity = lo_bit_count % 2 == 0;
register_file.flags.zero = byte_op ? dest.bytes[dest_map->byte] == 0 : dest.word == 0;
if (opcode.mnemonic != S86_Mnemonic_CMP)
*dest_map->reg = dest;
} break;
case S86_Mnemonic_JNE_JNZ: {
if (!register_file.flags.zero)
register_file.instruction_ptr += S86_CAST(int16_t)opcode.displacement;
} break;
case S86_Mnemonic_JE_JZ: {
if (register_file.flags.zero)
register_file.instruction_ptr += S86_CAST(int16_t)opcode.displacement;
} break;
case S86_Mnemonic_JP_JPE: {
if (register_file.flags.parity)
register_file.instruction_ptr += S86_CAST(int16_t)opcode.displacement;
} break;
case S86_Mnemonic_JB_JNAE: {
if (register_file.flags.carry)
register_file.instruction_ptr += S86_CAST(int16_t)opcode.displacement;
} break;
case S86_Mnemonic_LOOP: {
register_file.reg.file.cx.word -= 1;
if (register_file.reg.file.cx.word != 0)
register_file.instruction_ptr += S86_CAST(int16_t)opcode.displacement;
} break;
case S86_Mnemonic_LOOPNZ_LOOPNE: {
register_file.reg.file.cx.word -= 1;
if (register_file.reg.file.cx.word != 0 && !register_file.flags.zero)
register_file.instruction_ptr += S86_CAST(int16_t)opcode.displacement;
} break;
}
clocks_counter += opcode.clocks;
// NOTE: Printing ==========================================================================
S86_PrintFmt(" ; ");
// NOTE: Clocks
if (log_cycle_counts) {
S86_PrintFmt("Clocks: +%u = %u |", opcode.clocks, clocks_counter);
}
// NOTE: Registers
for (size_t index = 0; index < S86_RegisterFileRegArray_Count; index++) {
if (register_file.reg.array[index].word != prev_register_file.reg.array[index].word) {
S86_Str8 label = S86_RegisterFileRegArrayStr8(index);
S86_PrintFmt("%.*s:0x%x->0x%x ",
S86_STR8_FMT(label),
prev_register_file.reg.array[index].word,
register_file.reg.array[index].word);
// NOTE: In 8086, instructions can only change one register at a
// time. Once we find the first delta in the register file, we
// exit.
break;
}
}
// NOTE: Instruction Pointer
if (log_instruction_ptr)
S86_PrintFmt("ip:0x%x->0x%x ", prev_ip, register_file.instruction_ptr);
// NOTE: Flags
if (!S86_RegisterFileFlagsEq(register_file.flags, prev_register_file.flags)) {
S86_PrintFmt("flags:");
if (prev_register_file.flags.carry)
S86_PrintFmt("C");
if (prev_register_file.flags.parity)
S86_PrintFmt("P");
if (prev_register_file.flags.auxiliary_carry)
S86_PrintFmt("A");
if (prev_register_file.flags.zero)
S86_PrintFmt("Z");
if (prev_register_file.flags.sign)
S86_PrintFmt("S");
if (prev_register_file.flags.overflow)
S86_PrintFmt("O");
S86_PrintFmt("->");
if (register_file.flags.carry)
S86_PrintFmt("C");
if (register_file.flags.parity)
S86_PrintFmt("P");
if (register_file.flags.auxiliary_carry)
S86_PrintFmt("A");
if (register_file.flags.zero)
S86_PrintFmt("Z");
if (register_file.flags.sign)
S86_PrintFmt("S");
if (register_file.flags.overflow)
S86_PrintFmt("O");
S86_PrintFmt(" ");
}
S86_Print(S86_STR8("\n"));
}
if (exec_mode) {
S86_PrintLn(S86_STR8("\nFinal registers:"));
if (register_file.reg.file.ax.word)
S86_PrintLnFmt(" ax: 0x%04x (%u)", register_file.reg.file.ax.word, register_file.reg.file.ax.word);
if (register_file.reg.file.bx.word)
S86_PrintLnFmt(" bx: 0x%04x (%u)", register_file.reg.file.bx.word, register_file.reg.file.bx.word);
if (register_file.reg.file.cx.word)
S86_PrintLnFmt(" cx: 0x%04x (%u)", register_file.reg.file.cx.word, register_file.reg.file.cx.word);
if (register_file.reg.file.dx.word)
S86_PrintLnFmt(" dx: 0x%04x (%u)", register_file.reg.file.dx.word, register_file.reg.file.dx.word);
if (register_file.reg.file.sp.word)
S86_PrintLnFmt(" sp: 0x%04x (%u)", register_file.reg.file.sp.word, register_file.reg.file.sp.word);
if (register_file.reg.file.bp.word)
S86_PrintLnFmt(" bp: 0x%04x (%u)", register_file.reg.file.bp.word, register_file.reg.file.bp.word);
if (register_file.reg.file.si.word)
S86_PrintLnFmt(" si: 0x%04x (%u)", register_file.reg.file.si.word, register_file.reg.file.si.word);
if (register_file.reg.file.di.word)
S86_PrintLnFmt(" di: 0x%04x (%u)", register_file.reg.file.di.word, register_file.reg.file.di.word);
if (register_file.reg.file.es.word)
S86_PrintLnFmt(" es: 0x%04x (%u)", register_file.reg.file.es.word, register_file.reg.file.es.word);
if (register_file.reg.file.ss.word)
S86_PrintLnFmt(" ss: 0x%04x (%u)", register_file.reg.file.ss.word, register_file.reg.file.ss.word);
if (register_file.reg.file.ds.word)
S86_PrintLnFmt(" ds: 0x%04x (%u)", register_file.reg.file.ds.word, register_file.reg.file.ds.word);
if (log_instruction_ptr)
S86_PrintLnFmt(" ip: 0x%04x (%u)", register_file.instruction_ptr, register_file.instruction_ptr);
S86_RegisterFileFlags nil_flags = {0};
if (!S86_RegisterFileFlagsEq(register_file.flags, nil_flags)) {
S86_PrintFmt(" flags: ");
if (register_file.flags.carry)
S86_PrintFmt("C");
if (register_file.flags.parity)
S86_PrintFmt("P");
if (register_file.flags.auxiliary_carry)
S86_PrintFmt("A");
if (register_file.flags.zero)
S86_PrintFmt("Z");
if (register_file.flags.sign)
S86_PrintFmt("S");
if (register_file.flags.overflow)
S86_PrintFmt("O");
S86_Print(S86_STR8("\n"));
}
S86_Print(S86_STR8("\n"));
}
if (dump) {
char buf[1024];
snprintf(buf, sizeof(buf), "%s_mem_dump.data", file_name);
S86_FileWrite(buf, memory, S86_MEMORY_SIZE);
}
}
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