1053 lines
57 KiB
C
1053 lines
57 KiB
C
#define WIN32_MEAN_AND_LEAN
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#define NOMINMAX
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#include <Windows.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdarg.h>
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#include <stdbool.h>
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// NOTE: Macros
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// ============================================================================
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#define S86_STRINGIFY2(token) #token
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#define S86_STRINGIFY(token) S86_STRINGIFY2(token)
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#define S86_ASSERT(expr) \
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if (!(expr)) { \
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S86_PrintLnFmt("Assertion triggered [file=\"" __FILE__ ":" S86_STRINGIFY(__LINE__) "\", expr=\"" #expr "\"]"); \
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__debugbreak(); \
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} \
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#define S86_ARRAY_UCOUNT(array) sizeof((array)) / sizeof((array)[0])
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#define S86_CAST(Type) (Type)
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// NOTE: Globals
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// ============================================================================
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typedef struct S86_Globals {
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HANDLE stdout_handle;
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bool write_to_console;
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} S86_Globals;
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S86_Globals s86_globals;
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// NOTE: Strings
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// ============================================================================
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typedef struct S86_Str8 {
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char *data;
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size_t size;
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} S86_Str8;
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#define S86_STR8(string) (S86_Str8){.data = (string), .size = S86_ARRAY_UCOUNT(string) - 1 }
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#define S86_STR8_FMT(string) (int)((string).size), (string).data
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// NOTE: Buffer
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// ============================================================================
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typedef struct S86_Buffer {
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char *data;
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size_t size;
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} S86_Buffer;
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typedef struct S86_BufferIterator {
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S86_Buffer buffer;
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size_t index;
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} S86_BufferIterator;
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bool S86_BufferIsValid(S86_Buffer buffer);
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S86_BufferIterator S86_BufferIteratorInit(S86_Buffer buffer);
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bool S86_BufferIteratorHasMoreBytes(S86_BufferIterator it);
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uint8_t S86_BufferIteratorNextByte(S86_BufferIterator *it);
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// NOTE: File
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// ============================================================================
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S86_Buffer S86_FileRead(char const *file_path);
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void S86_FileFree(S86_Buffer buffer);
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// NOTE: Print
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// ============================================================================
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void S86_PrintLn(S86_Str8 string);
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void S86_PrintLnFmt(char const *fmt, ...);
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// NOTE: Sim8086
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// ============================================================================
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typedef enum S86_InstructionType {
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S86_InstructionType_MOVRegOrMemToOrFromReg,
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S86_InstructionType_MOVImmediateToRegOrMem,
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S86_InstructionType_MOVImmediateToReg,
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S86_InstructionType_MOVMemToAccum,
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S86_InstructionType_MOVAccumToMem,
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S86_InstructionType_MOVRegOrMemToSegReg,
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S86_InstructionType_MOVSegRegToRegOrMem,
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S86_InstructionType_PUSHRegOrMem,
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S86_InstructionType_PUSHReg,
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S86_InstructionType_PUSHSegReg,
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S86_InstructionType_POPRegOrMem,
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S86_InstructionType_POPReg,
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S86_InstructionType_POPSegReg,
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S86_InstructionType_XCHGRegOrMemWithReg,
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S86_InstructionType_XCHGRegWithAccum,
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S86_InstructionType_INFixedPort,
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S86_InstructionType_INVariablePort,
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S86_InstructionType_OUTFixedPort,
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S86_InstructionType_OUTVariablePort,
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S86_InstructionType_XLAT,
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S86_InstructionType_LEA,
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S86_InstructionType_LDS,
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S86_InstructionType_LES,
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S86_InstructionType_LAHF,
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S86_InstructionType_SAHF,
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S86_InstructionType_PUSHF,
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S86_InstructionType_POPF,
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S86_InstructionType_ADDRegOrMemToOrFromReg,
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S86_InstructionType_ADDImmediateToRegOrMem,
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S86_InstructionType_ADDImmediateToAccum,
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S86_InstructionType_ADCRegOrMemWithRegToEither,
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S86_InstructionType_ADCImmediateToRegOrMem,
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S86_InstructionType_ADCImmediateToAccum,
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S86_InstructionType_INCRegOrMem,
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S86_InstructionType_INCReg,
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S86_InstructionType_AAA,
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S86_InstructionType_DAA,
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S86_InstructionType_SUBRegOrMemToOrFromReg,
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S86_InstructionType_SUBImmediateFromRegOrMem,
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S86_InstructionType_SUBImmediateFromAccum,
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S86_InstructionType_SBBRegOrMemAndRegToEither,
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S86_InstructionType_SBBImmediateFromRegOrMem,
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S86_InstructionType_SBBImmediateFromAccum,
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S86_InstructionType_DECRegOrMem,
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S86_InstructionType_DECReg,
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S86_InstructionType_NEG,
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S86_InstructionType_AAS,
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S86_InstructionType_DAS,
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S86_InstructionType_MUL,
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S86_InstructionType_IMUL,
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S86_InstructionType_AAM,
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S86_InstructionType_DIV,
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S86_InstructionType_IDIV,
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S86_InstructionType_AAD,
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S86_InstructionType_CBW,
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S86_InstructionType_CWD,
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S86_InstructionType_NOT,
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S86_InstructionType_SHL_SAL,
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S86_InstructionType_SHR,
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S86_InstructionType_SAR,
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S86_InstructionType_ROL,
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S86_InstructionType_ROR,
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S86_InstructionType_RCL,
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S86_InstructionType_RCR,
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S86_InstructionType_CMPRegOrMemAndReg,
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S86_InstructionType_CMPImmediateWithRegOrMem,
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S86_InstructionType_CMPImmediateWithAccum,
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S86_InstructionType_JE_JZ,
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S86_InstructionType_JL_JNGE,
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S86_InstructionType_JLE_JNG,
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S86_InstructionType_JB_JNAE,
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S86_InstructionType_JBE_JNA,
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S86_InstructionType_JP_JPE,
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S86_InstructionType_JO,
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S86_InstructionType_JS,
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S86_InstructionType_JNE_JNZ,
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S86_InstructionType_JNL_JGE,
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S86_InstructionType_JNLE_JG,
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S86_InstructionType_JNB_JAE,
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S86_InstructionType_JNBE_JA,
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S86_InstructionType_JNP_JO,
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S86_InstructionType_JNO,
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S86_InstructionType_JNS,
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S86_InstructionType_LOOP,
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S86_InstructionType_LOOPZ_LOOPE,
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S86_InstructionType_LOOPNZ_LOOPNE,
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S86_InstructionType_JCXZ,
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S86_InstructionType_Count,
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} S86_InstructionType;
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/// Bit patterns and masks for decoding 8086 assembly. 8086 opcodes can be up
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/// to 2 bytes long and mixed with instruction specific control bits. These
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/// masks isolate the opcode bits from the bits can be checked after masking
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/// the binary instruction stream.
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///
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/// Instructions that do not have opcode bits in the 2nd byte will have the mask
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/// set to 0.
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typedef struct S86_Instruction {
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uint8_t op_mask0;
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uint8_t op_bits0;
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uint8_t op_mask1;
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uint8_t op_bits1;
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S86_Str8 mnemonic;
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} S86_Instruction;
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typedef struct S86_EffectiveAddressStr8 {
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char data[32];
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size_t size;
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} S86_EffectiveAddressStr8;
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S86_EffectiveAddressStr8 S86_EffectiveAddressCalc(S86_BufferIterator *buffer_it, uint8_t rm, uint8_t mod, uint8_t w);
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// NOTE: Implementation
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// ============================================================================
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bool S86_BufferIsValid(S86_Buffer buffer)
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{
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bool result = buffer.data && buffer.size;
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return result;
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}
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S86_BufferIterator S86_BufferIteratorInit(S86_Buffer buffer)
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{
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S86_BufferIterator result = {0};
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result.buffer = buffer;
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return result;
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}
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bool S86_BufferIteratorHasMoreBytes(S86_BufferIterator it)
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{
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bool result = S86_BufferIsValid(it.buffer) && it.index < it.buffer.size;
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return result;
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}
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uint8_t S86_BufferIteratorPeekByte(S86_BufferIterator *it)
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{
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S86_ASSERT(it);
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S86_ASSERT(S86_BufferIsValid(it->buffer));
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S86_ASSERT(it->index < it->buffer.size);
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uint8_t result = it->buffer.data[it->index];
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return result;
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}
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uint8_t S86_BufferIteratorNextByte(S86_BufferIterator *it)
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{
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uint8_t result = S86_BufferIteratorPeekByte(it);
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it->index++;
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return result;
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}
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S86_Buffer S86_FileRead(char const *file_path)
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{
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S86_Buffer result = {0};
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// NOTE: Determine file size
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// =========================================================================
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WIN32_FILE_ATTRIBUTE_DATA file_attrib_data = {0};
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if (GetFileAttributesEx(file_path, GetFileExInfoStandard, &file_attrib_data) == 0)
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return result;
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// NOTE: Open file
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// =========================================================================
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HANDLE file_handle = CreateFile(
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/*LPCSTR lpFileName*/ file_path,
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/*DWORD dwDesiredAccess*/ GENERIC_READ,
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/*DWORD dwShareMode*/ 0,
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/*LPSECURITY_ATTRIBUTES lpSecurityAttributes*/ NULL,
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/*DWORD dwCreationDisposition*/ OPEN_EXISTING,
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/*DWORD dwFlagsAndAttributes*/ 0,
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/*HANDLE hTemplateFile*/ NULL
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);
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if (file_handle == INVALID_HANDLE_VALUE)
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return result;
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// NOTE: Allocate buffer
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// =========================================================================
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uint64_t file_size = (uint64_t)file_attrib_data.nFileSizeHigh << 32 | (uint64_t)file_attrib_data.nFileSizeLow << 0;
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S86_ASSERT(file_size < (DWORD)-1);
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char *buffer = VirtualAlloc(
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/*LPVOID lpAddress*/ NULL,
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/*SIZE_T dwSize*/ file_size,
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/*DWORD flAllocationType*/ MEM_COMMIT | MEM_RESERVE,
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/*DWORD flProtect*/ PAGE_READWRITE
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);
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if (!buffer)
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goto end;
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// NOTE: Read file to buffer
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// =========================================================================
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DWORD bytes_read = 0;
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BOOL read_file_result = ReadFile(
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/*HANDLE hFile*/ file_handle,
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/*LPVOID lpBuffer*/ buffer,
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/*DWORD nNumberOfBytesToRead*/ S86_CAST(DWORD)file_size,
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/*LPDWORD lpNumberOfBytesRead*/ &bytes_read,
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/*LPOVERLAPPED lpOverlapped*/ NULL
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);
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// NOTE: Handle read result
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// =========================================================================
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if (read_file_result == 0) {
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VirtualFree(buffer, 0, MEM_RELEASE);
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} else {
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result.data = buffer;
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result.size = file_size;
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}
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end:
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CloseHandle(file_handle);
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return result;
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};
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void S86_FileFree(S86_Buffer buffer)
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{
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if (S86_BufferIsValid(buffer))
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VirtualFree(buffer.data, 0, MEM_RELEASE);
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}
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void S86_Print(S86_Str8 string)
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{
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if (s86_globals.stdout_handle == NULL) {
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s86_globals.stdout_handle = GetStdHandle(STD_OUTPUT_HANDLE);
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DWORD mode = 0;
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BOOL get_console_mode_result = GetConsoleMode(
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/*HANDLE hConsoleHandle*/ s86_globals.stdout_handle,
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/*LPDWORD lpMode*/ &mode
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);
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s86_globals.write_to_console = get_console_mode_result != 0;
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}
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S86_ASSERT(string.size < S86_CAST(DWORD)-1);
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if (s86_globals.write_to_console) {
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DWORD chars_written = 0;
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WriteConsoleA(s86_globals.stdout_handle, string.data, (DWORD)string.size, &chars_written, NULL);
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} else {
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DWORD bytes_written = 0;
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WriteFile(s86_globals.stdout_handle, string.data, (DWORD)string.size, &bytes_written, NULL);
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}
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}
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void S86_PrintFmt(char const *fmt, ...)
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{
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va_list args, args_copy;
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va_start(args, fmt);
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va_copy(args_copy, args);
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int string_size = vsnprintf(NULL, 0, fmt, args_copy);
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va_end(args_copy);
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char buffer[8192];
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S86_ASSERT(string_size >= 0 && string_size < S86_ARRAY_UCOUNT(buffer));
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if (string_size) {
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vsnprintf(buffer, sizeof(buffer), fmt, args);
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S86_Str8 string = {.data = buffer, .size = string_size};
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S86_Print(string);
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}
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va_end(args);
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}
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void S86_PrintLn(S86_Str8 string)
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{
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S86_Print(string);
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S86_Print(S86_STR8("\n"));
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}
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void S86_PrintLnFmt(char const *fmt, ...)
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{
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va_list args, args_copy;
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va_start(args, fmt);
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va_copy(args_copy, args);
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int string_size = vsnprintf(NULL, 0, fmt, args_copy);
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va_end(args_copy);
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char buffer[8192];
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S86_ASSERT(string_size >= 0 && string_size < S86_ARRAY_UCOUNT(buffer));
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if (string_size) {
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vsnprintf(buffer, sizeof(buffer), fmt, args);
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S86_Str8 string = {.data = buffer, .size = string_size};
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S86_PrintLn(string);
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}
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va_end(args);
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}
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S86_Str8 REGISTER_FIELD_ENCODING[2][8];
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S86_EffectiveAddressStr8 S86_EffectiveAddressCalc(S86_BufferIterator *buffer_it, uint8_t rm, uint8_t mod, uint8_t w)
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{
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// NOTE: Calculate displacement
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// =========================================================================
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bool direct_address = mod == 0b00 && rm == 0b110;
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int16_t displacement = 0;
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if (mod == 0b10 || direct_address) { // Mem mode 16 bit displacement
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uint8_t disp_lo = S86_BufferIteratorNextByte(buffer_it);
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uint8_t disp_hi = S86_BufferIteratorNextByte(buffer_it);
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displacement = (int16_t)((uint16_t)disp_lo << 0 | (uint16_t)disp_hi << 8);
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} else if (mod == 0b01) { // Mem mode 8 bit displacement
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displacement = (int8_t)S86_BufferIteratorNextByte(buffer_it);
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} else {
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S86_ASSERT(mod == 0b00 || mod == 0b11 /*Mem mode (no displacement)*/);
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}
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S86_EffectiveAddressStr8 result = {0};
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if (mod == 0b11) {
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S86_Str8 register_field = REGISTER_FIELD_ENCODING[w][rm];
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memcpy(result.data, register_field.data, register_field.size);
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result.size = register_field.size;
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} else {
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// NOTE: Effective address calculation w/ displacement
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// =========================================================================
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result.data[result.size++] = '[';
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if (direct_address) {
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result.size += snprintf(result.data + result.size,
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sizeof(result.data) - result.size,
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"%s%d",
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displacement >= 0 ? "" : "-", displacement >= 0 ? displacement : -displacement);
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} else {
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S86_Str8 base_calc = {0};
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switch (rm) {
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case 0b000: base_calc = S86_STR8("bx + si"); break;
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case 0b001: base_calc = S86_STR8("bx + di"); break;
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case 0b010: base_calc = S86_STR8("bp + si"); break;
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case 0b011: base_calc = S86_STR8("bp + di"); break;
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case 0b100: base_calc = S86_STR8("si"); break;
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case 0b101: base_calc = S86_STR8("di"); break;
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case 0b110: base_calc = S86_STR8("bp"); break;
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case 0b111: base_calc = S86_STR8("bx"); break;
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default: S86_ASSERT(!"Invalid rm value, must be 3 bits"); break;
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}
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memcpy(result.data + result.size, base_calc.data, base_calc.size);
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result.size += S86_CAST(int)base_calc.size;
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if ((mod == 0b01 || mod == 0b10) && displacement) {
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result.size += snprintf(result.data + result.size,
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sizeof(result.data) - result.size,
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" %c %d",
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displacement >= 0 ? '+' : '-', displacement >= 0 ? displacement : -displacement);
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}
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}
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result.data[result.size++] = ']';
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}
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S86_ASSERT(result.size < S86_ARRAY_UCOUNT(result.data));
|
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return result;
|
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}
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|
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int main(int argc, char **argv)
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{
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// NOTE: Argument handling
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// =========================================================================
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if (argc != 2) {
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S86_PrintLn(S86_STR8("usage: sim8086.exe <binary asm file>"));
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return -1;
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}
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char const *file_path = argv[1];
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S86_Buffer buffer = S86_FileRead(file_path);
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if (!S86_BufferIsValid(buffer)) {
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S86_PrintLnFmt("File read failed [path=\"%s\"]", argv[1], buffer.size);
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return -1;
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}
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// NOTE: Sim8086
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// =========================================================================
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// Mapping from a 'reg' encoding to the register name.
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REGISTER_FIELD_ENCODING[0b0][0] = S86_STR8("al");
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REGISTER_FIELD_ENCODING[0b0][1] = S86_STR8("cl");
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REGISTER_FIELD_ENCODING[0b0][2] = S86_STR8("dl");
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REGISTER_FIELD_ENCODING[0b0][3] = S86_STR8("bl");
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REGISTER_FIELD_ENCODING[0b0][4] = S86_STR8("ah");
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REGISTER_FIELD_ENCODING[0b0][5] = S86_STR8("ch");
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REGISTER_FIELD_ENCODING[0b0][6] = S86_STR8("dh");
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REGISTER_FIELD_ENCODING[0b0][7] = S86_STR8("bh");
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REGISTER_FIELD_ENCODING[0b1][0] = S86_STR8("ax");
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REGISTER_FIELD_ENCODING[0b1][1] = S86_STR8("cx");
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REGISTER_FIELD_ENCODING[0b1][2] = S86_STR8("dx");
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REGISTER_FIELD_ENCODING[0b1][3] = S86_STR8("bx");
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REGISTER_FIELD_ENCODING[0b1][4] = S86_STR8("sp");
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REGISTER_FIELD_ENCODING[0b1][5] = S86_STR8("bp");
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REGISTER_FIELD_ENCODING[0b1][6] = S86_STR8("si");
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REGISTER_FIELD_ENCODING[0b1][7] = S86_STR8("di");
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S86_Instruction const S86_INSTRUCTIONS[] = {
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[S86_InstructionType_MOVRegOrMemToOrFromReg] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b1000'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("mov")},
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[S86_InstructionType_MOVImmediateToRegOrMem] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1100'0110, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("mov")},
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[S86_InstructionType_MOVImmediateToReg] = {.op_mask0 = 0b1111'0000, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b1011'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("mov")},
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[S86_InstructionType_MOVMemToAccum] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b1010'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("mov")},
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[S86_InstructionType_MOVAccumToMem] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b1010'0010, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("mov")},
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[S86_InstructionType_MOVRegOrMemToSegReg] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0010'0000,
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.op_bits0 = 0b1000'1110, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("mov")},
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[S86_InstructionType_MOVSegRegToRegOrMem] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0010'0000,
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.op_bits0 = 0b1000'1100, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("mov")},
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[S86_InstructionType_PUSHRegOrMem] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1111'1111, .op_bits1 = 0b0011'0000, .mnemonic = S86_STR8("push")},
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[S86_InstructionType_PUSHReg] = {.op_mask0 = 0b1111'1000, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0101'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("push")},
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[S86_InstructionType_PUSHSegReg] = {.op_mask0 = 0b1110'0111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0000'0110, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("push")},
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[S86_InstructionType_POPRegOrMem] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1000'1111, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("pop")},
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[S86_InstructionType_POPReg] = {.op_mask0 = 0b1111'1000, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0101'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("pop")},
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[S86_InstructionType_POPSegReg] = {.op_mask0 = 0b1110'0111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0000'0111, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("pop")},
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[S86_InstructionType_XCHGRegOrMemWithReg] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b1000'0110, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("xchg")},
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[S86_InstructionType_XCHGRegWithAccum] = {.op_mask0 = 0b1111'1000, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b1001'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("xchg")},
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[S86_InstructionType_INFixedPort] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b1110'0100, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("in")},
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[S86_InstructionType_INVariablePort] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b1110'1100, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("in")},
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[S86_InstructionType_OUTFixedPort] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b1110'0110, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("out")},
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[S86_InstructionType_OUTVariablePort] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b1110'1110, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("out")},
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[S86_InstructionType_XLAT] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b1101'0111, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("xlat")},
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[S86_InstructionType_LEA] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b1000'1101, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("lea")},
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[S86_InstructionType_LDS] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b1100'0101, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("lds")},
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[S86_InstructionType_LES] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b1100'0100, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("les")},
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[S86_InstructionType_LAHF] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b1001'1111, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("lahf")},
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[S86_InstructionType_SAHF] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b1001'1110, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("sahf")},
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[S86_InstructionType_PUSHF] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b1001'1100, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("pushf")},
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[S86_InstructionType_POPF] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b1001'1101, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("popf")},
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[S86_InstructionType_ADDRegOrMemToOrFromReg] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0000'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("add")},
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[S86_InstructionType_ADDImmediateToRegOrMem] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1000'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("add")},
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[S86_InstructionType_ADDImmediateToAccum] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0000'0100, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("add")},
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[S86_InstructionType_ADCRegOrMemWithRegToEither] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0001'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("adc")},
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[S86_InstructionType_ADCImmediateToRegOrMem] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1000'0000, .op_bits1 = 0b0001'0000, .mnemonic = S86_STR8("adc")},
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[S86_InstructionType_ADCImmediateToAccum] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0001'0100, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("adc")},
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[S86_InstructionType_INCRegOrMem] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1111'1110, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("inc")},
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[S86_InstructionType_INCReg] = {.op_mask0 = 0b1111'1000, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0100'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("inc")},
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[S86_InstructionType_AAA] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0011'0111, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("aaa")},
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[S86_InstructionType_DAA] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0010'0111, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("daa")},
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[S86_InstructionType_SUBRegOrMemToOrFromReg] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0010'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("sub")},
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[S86_InstructionType_SUBImmediateFromRegOrMem] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1000'0000, .op_bits1 = 0b0010'1000, .mnemonic = S86_STR8("sub")},
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[S86_InstructionType_SUBImmediateFromAccum] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0010'1100, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("sub")},
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[S86_InstructionType_SBBRegOrMemAndRegToEither] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0001'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("sbb")},
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[S86_InstructionType_SBBImmediateFromRegOrMem] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1000'0000, .op_bits1 = 0b0001'1000, .mnemonic = S86_STR8("sbb")},
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[S86_InstructionType_SBBImmediateFromAccum] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0001'1100, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("sbb")},
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[S86_InstructionType_DECRegOrMem] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1111'1110, .op_bits1 = 0b0000'1000, .mnemonic = S86_STR8("dec")},
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[S86_InstructionType_DECReg] = {.op_mask0 = 0b1111'1000, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0100'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("dec")},
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[S86_InstructionType_NEG] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1111'0110, .op_bits1 = 0b0001'1000, .mnemonic = S86_STR8("neg")},
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[S86_InstructionType_CMPRegOrMemAndReg] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0011'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("cmp")},
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[S86_InstructionType_CMPImmediateWithRegOrMem] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1000'0000, .op_bits1 = 0b0011'1000, .mnemonic = S86_STR8("cmp")},
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[S86_InstructionType_CMPImmediateWithAccum] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0011'1100, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("cmp")},
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[S86_InstructionType_AAS] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0011'1111, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("aas")},
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[S86_InstructionType_DAS] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0010'1111, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("das")},
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[S86_InstructionType_MUL] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1111'0110, .op_bits1 = 0b0010'0000, .mnemonic = S86_STR8("mul")},
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[S86_InstructionType_IMUL] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1111'0110, .op_bits1 = 0b0010'1000, .mnemonic = S86_STR8("imul")},
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[S86_InstructionType_AAM] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b1111'1111,
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.op_bits0 = 0b1101'0100, .op_bits1 = 0b0000'1010, .mnemonic = S86_STR8("aam")},
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[S86_InstructionType_DIV] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1111'0110, .op_bits1 = 0b0011'0000, .mnemonic = S86_STR8("div")},
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[S86_InstructionType_IDIV] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1111'0110, .op_bits1 = 0b0011'1000, .mnemonic = S86_STR8("idiv")},
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[S86_InstructionType_AAD] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b1111'1111,
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.op_bits0 = 0b1101'0101, .op_bits1 = 0b0000'1010, .mnemonic = S86_STR8("aad")},
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[S86_InstructionType_CBW] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b1001'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("cbw")},
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[S86_InstructionType_CWD] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b1001'1001, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("cwd")},
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[S86_InstructionType_NOT] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1111'0110, .op_bits1 = 0b0001'0000, .mnemonic = S86_STR8("not")},
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[S86_InstructionType_SHL_SAL] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1101'0000, .op_bits1 = 0b0010'0000, .mnemonic = S86_STR8("shl")},
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[S86_InstructionType_SHR] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1101'0000, .op_bits1 = 0b0010'1000, .mnemonic = S86_STR8("shr")},
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[S86_InstructionType_SAR] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1101'0000, .op_bits1 = 0b0011'1000, .mnemonic = S86_STR8("sar")},
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[S86_InstructionType_ROL] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1101'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("rol")},
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[S86_InstructionType_ROR] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1101'0000, .op_bits1 = 0b0000'1000, .mnemonic = S86_STR8("ror")},
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[S86_InstructionType_RCL] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1101'0000, .op_bits1 = 0b0001'0000, .mnemonic = S86_STR8("rcl")},
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[S86_InstructionType_RCR] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
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.op_bits0 = 0b1101'0000, .op_bits1 = 0b0001'1000, .mnemonic = S86_STR8("rcr")},
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[S86_InstructionType_JE_JZ] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0111'0100, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("je")},
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[S86_InstructionType_JL_JNGE] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0111'1100, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jl")},
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[S86_InstructionType_JLE_JNG] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0111'1110, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jle")},
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[S86_InstructionType_JB_JNAE] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0111'0010, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jb")},
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[S86_InstructionType_JBE_JNA] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0111'0110, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jbe")},
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[S86_InstructionType_JP_JPE] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0111'1010, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jp")},
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[S86_InstructionType_JO] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0111'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jo")},
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[S86_InstructionType_JS] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0111'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("js")},
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[S86_InstructionType_JNE_JNZ] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0111'0101, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jnz")},
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[S86_InstructionType_JNL_JGE] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0111'1101, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jnl")},
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[S86_InstructionType_JNLE_JG] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0111'1111, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jg")},
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[S86_InstructionType_JNB_JAE] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0111'0011, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jnb")},
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[S86_InstructionType_JNBE_JA] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0111'0111, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("ja")},
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[S86_InstructionType_JNP_JO] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0111'1011, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jnp")},
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[S86_InstructionType_JNO] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0111'0001, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jno")},
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[S86_InstructionType_JNS] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b0111'1001, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jns")},
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[S86_InstructionType_LOOP] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
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.op_bits0 = 0b1110'0010, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("loop")},
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[S86_InstructionType_LOOPZ_LOOPE] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
|
|
.op_bits0 = 0b1110'0001, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("loopz")},
|
|
[S86_InstructionType_LOOPNZ_LOOPNE] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
|
|
.op_bits0 = 0b1110'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("loopnz")},
|
|
[S86_InstructionType_JCXZ] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
|
|
.op_bits0 = 0b1110'0011, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jcxz")},
|
|
};
|
|
|
|
S86_Str8 SEGMENT_REGISTER_NAME[] = {
|
|
[0b00] = S86_STR8("es"),
|
|
[0b01] = S86_STR8("cs"),
|
|
[0b10] = S86_STR8("ss"),
|
|
[0b11] = S86_STR8("ds"),
|
|
};
|
|
|
|
// NOTE: Decode assembly
|
|
// =========================================================================
|
|
S86_PrintLn(S86_STR8("bits 16"));
|
|
S86_BufferIterator buffer_it = S86_BufferIteratorInit(buffer);
|
|
while (S86_BufferIteratorHasMoreBytes(buffer_it)) {
|
|
|
|
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_InstructionType instruction_type = S86_InstructionType_Count;
|
|
S86_Instruction const *instruction = NULL;
|
|
for (size_t instruction_index = 0;
|
|
instruction_type == S86_InstructionType_Count && instruction_index < S86_ARRAY_UCOUNT(S86_INSTRUCTIONS);
|
|
instruction_index++)
|
|
{
|
|
S86_Instruction const *item = S86_INSTRUCTIONS + instruction_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 instruction_matched = true;
|
|
if (item->op_mask1) {
|
|
// TODO: This assumes the iterator is valid
|
|
uint8_t op_byte = S86_BufferIteratorPeekByte(&buffer_it);
|
|
instruction_matched = (op_byte & item->op_mask1) == item->op_bits1;
|
|
if (instruction_matched) {
|
|
op_code_bytes[op_code_size++] = op_byte;
|
|
S86_BufferIteratorNextByte(&buffer_it);
|
|
}
|
|
}
|
|
|
|
if (instruction_matched) {
|
|
instruction_type = instruction_index;
|
|
instruction = item;
|
|
}
|
|
}
|
|
|
|
// NOTE: Disassemble bytes to assembly mnemonics
|
|
// =================================================================
|
|
S86_ASSERT(op_code_size > 0 && op_code_size <= S86_ARRAY_UCOUNT(op_code_bytes));
|
|
S86_ASSERT(instruction_type != S86_InstructionType_Count && "Unknown instruction");
|
|
|
|
S86_Print(instruction->mnemonic);
|
|
switch (instruction_type) {
|
|
|
|
case S86_InstructionType_NOT: /*FALLTHRU*/
|
|
case S86_InstructionType_SHL_SAL: /*FALLTHRU*/
|
|
case S86_InstructionType_SHR: /*FALLTHRU*/
|
|
case S86_InstructionType_SAR: /*FALLTHRU*/
|
|
case S86_InstructionType_ROL: /*FALLTHRU*/
|
|
case S86_InstructionType_ROR: /*FALLTHRU*/
|
|
case S86_InstructionType_RCL: /*FALLTHRU*/
|
|
case S86_InstructionType_RCR: /*FALLTHRU*/
|
|
case S86_InstructionType_MUL: /*FALLTHRU*/
|
|
case S86_InstructionType_IMUL: /*FALLTHRU*/
|
|
case S86_InstructionType_DIV: /*FALLTHRU*/
|
|
case S86_InstructionType_IDIV: /*FALLTHRU*/
|
|
case S86_InstructionType_INCRegOrMem: /*FALLTHRU*/
|
|
case S86_InstructionType_DECRegOrMem: /*FALLTHRU*/
|
|
case S86_InstructionType_NEG: /*FALLTHRU*/
|
|
case S86_InstructionType_POPRegOrMem: /*FALLTHRU*/
|
|
case S86_InstructionType_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 (instruction_type == S86_InstructionType_INCRegOrMem ||
|
|
instruction_type == S86_InstructionType_DECRegOrMem ||
|
|
instruction_type == S86_InstructionType_NEG ||
|
|
instruction_type == S86_InstructionType_MUL ||
|
|
instruction_type == S86_InstructionType_MUL ||
|
|
instruction_type == S86_InstructionType_IMUL ||
|
|
instruction_type == S86_InstructionType_DIV ||
|
|
instruction_type == S86_InstructionType_IDIV ||
|
|
(instruction_type >= S86_InstructionType_NOT &&
|
|
instruction_type <= S86_InstructionType_RCR)) {
|
|
w = op_code_bytes[0] & 0b0000'0001;
|
|
}
|
|
|
|
S86_EffectiveAddressStr8 effective_address = S86_EffectiveAddressCalc(&buffer_it, rm, mod, w);
|
|
if (effective_address.data[0] == '[')
|
|
S86_PrintFmt(" %s", w ? "word" : "byte");
|
|
S86_PrintFmt(" %.*s", S86_STR8_FMT(effective_address));
|
|
|
|
// NOTE: Bit shifts use 'v' to indicate if shift distance should
|
|
// come from cl register otherwise bitshift by 1
|
|
if (instruction_type >= S86_InstructionType_SHL_SAL && instruction_type <= S86_InstructionType_RCR) {
|
|
uint8_t v = (op_code_bytes[0] & 0b0000'0010) >> 1;
|
|
S86_PrintFmt(", %s", v ? "cl" : "1");
|
|
}
|
|
|
|
S86_Print(S86_STR8("\n"));
|
|
} break;
|
|
|
|
case S86_InstructionType_DECReg: /*FALLTHRU*/
|
|
case S86_InstructionType_INCReg: /*FALLTHRU*/
|
|
case S86_InstructionType_XCHGRegWithAccum: /*FALLTHRU*/
|
|
case S86_InstructionType_PUSHReg: /*FALLTHRU*/
|
|
case S86_InstructionType_POPReg: /*FALLTHRU*/
|
|
case S86_InstructionType_PUSHSegReg: /*FALLTHRU*/
|
|
case S86_InstructionType_POPSegReg: {
|
|
S86_ASSERT(op_code_size == 1);
|
|
S86_Str8 reg_name = {0};
|
|
if (instruction_type == S86_InstructionType_PUSHReg ||
|
|
instruction_type == S86_InstructionType_POPReg ||
|
|
instruction_type == S86_InstructionType_INCReg ||
|
|
instruction_type == S86_InstructionType_DECReg ||
|
|
instruction_type == S86_InstructionType_XCHGRegWithAccum) {
|
|
uint8_t reg = (op_code_bytes[0] & 0b0000'0111) >> 0;
|
|
reg_name = REGISTER_FIELD_ENCODING[/*w*/1][reg];
|
|
} else {
|
|
S86_ASSERT(instruction_type == S86_InstructionType_PUSHSegReg ||
|
|
instruction_type == S86_InstructionType_POPSegReg);
|
|
uint8_t sr = (op_code_bytes[0] & 0b0001'1000) >> 3;
|
|
reg_name = SEGMENT_REGISTER_NAME[sr];
|
|
}
|
|
|
|
if (instruction_type == S86_InstructionType_XCHGRegWithAccum)
|
|
S86_Print(S86_STR8(" ax,"));
|
|
|
|
S86_PrintLnFmt(" %.*s", S86_STR8_FMT(reg_name));
|
|
} break;
|
|
|
|
case S86_InstructionType_ADDRegOrMemToOrFromReg: /*FALLTHRU*/
|
|
case S86_InstructionType_ADCRegOrMemWithRegToEither: /*FALLTHRU*/
|
|
case S86_InstructionType_SUBRegOrMemToOrFromReg: /*FALLTHRU*/
|
|
case S86_InstructionType_SBBRegOrMemAndRegToEither: /*FALLTHRU*/
|
|
case S86_InstructionType_LEA: /*FALLTHRU*/
|
|
case S86_InstructionType_LDS: /*FALLTHRU*/
|
|
case S86_InstructionType_LES: /*FALLTHRU*/
|
|
case S86_InstructionType_XCHGRegOrMemWithReg: /*FALLTHRU*/
|
|
case S86_InstructionType_CMPRegOrMemAndReg: /*FALLTHRU*/
|
|
case S86_InstructionType_MOVRegOrMemToOrFromReg: {
|
|
// NOTE: Instruction does not have opcode bits in the 2nd byte
|
|
S86_ASSERT(op_code_size == 1);
|
|
op_code_bytes[op_code_size++] = S86_BufferIteratorNextByte(&buffer_it);
|
|
|
|
uint8_t w = (op_code_bytes[0] & 0b0000'0001) >> 0;
|
|
uint8_t d = (op_code_bytes[0] & 0b0000'0010) >> 1;
|
|
if (instruction_type == S86_InstructionType_XCHGRegOrMemWithReg ||
|
|
instruction_type == S86_InstructionType_LEA ||
|
|
instruction_type == S86_InstructionType_LDS ||
|
|
instruction_type == S86_InstructionType_LES) {
|
|
if (instruction_type == S86_InstructionType_XCHGRegOrMemWithReg) {
|
|
d = 0; // Destination is always the memory address
|
|
} else {
|
|
d = 1; // Destination is always the register
|
|
w = 1; // Always 16 bit (load into register)
|
|
}
|
|
}
|
|
|
|
uint8_t mod = (op_code_bytes[1] & 0b1100'0000) >> 6;
|
|
uint8_t reg = (op_code_bytes[1] & 0b0011'1000) >> 3;
|
|
uint8_t rm = (op_code_bytes[1] & 0b0000'0111) >> 0;
|
|
S86_ASSERT(d < 2);
|
|
S86_ASSERT(w < 2);
|
|
S86_ASSERT(mod < 4);
|
|
S86_ASSERT(reg < 8);
|
|
S86_ASSERT(rm < 8);
|
|
|
|
if (mod == 0b11) {
|
|
// NOTE: Register-to-register move
|
|
// =========================================================
|
|
S86_Str8 src_op = REGISTER_FIELD_ENCODING[w][d ? rm : reg];
|
|
S86_Str8 dest_op = REGISTER_FIELD_ENCODING[w][d ? reg : rm];
|
|
S86_PrintLnFmt(" %.*s, %.*s", S86_STR8_FMT(dest_op), S86_STR8_FMT(src_op));
|
|
} else {
|
|
// NOTE: Memory mode w/ effective address calculation
|
|
// =========================================================
|
|
S86_EffectiveAddressStr8 effective_address = S86_EffectiveAddressCalc(&buffer_it, rm, mod, w);
|
|
S86_Str8 addr = { .data = effective_address.data, .size = effective_address.size };
|
|
S86_Str8 dest_op = d ? REGISTER_FIELD_ENCODING[w][reg] : addr;
|
|
S86_Str8 src_op = d ? addr : REGISTER_FIELD_ENCODING[w][reg];
|
|
S86_PrintLnFmt(" %.*s, %.*s", S86_STR8_FMT(dest_op), S86_STR8_FMT(src_op));
|
|
}
|
|
} break;
|
|
|
|
case S86_InstructionType_ADDImmediateToRegOrMem: /*FALLTHRU*/
|
|
case S86_InstructionType_ADCImmediateToRegOrMem: /*FALLTHRU*/
|
|
case S86_InstructionType_SUBImmediateFromRegOrMem: /*FALLTHRU*/
|
|
case S86_InstructionType_SBBImmediateFromRegOrMem: /*FALLTHRU*/
|
|
case S86_InstructionType_CMPImmediateWithRegOrMem: /*FALLTHRU*/
|
|
case S86_InstructionType_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_EffectiveAddressStr8 effective_address = S86_EffectiveAddressCalc(&buffer_it, rm, mod, w);
|
|
|
|
// NOTE: Parse data payload
|
|
// =============================================================
|
|
uint16_t data = S86_BufferIteratorNextByte(&buffer_it);
|
|
bool sign_extend_8bit_data = false;
|
|
if (w) { // 16 bit data
|
|
if ((instruction_type == S86_InstructionType_ADDImmediateToRegOrMem ||
|
|
instruction_type == S86_InstructionType_ADCImmediateToRegOrMem ||
|
|
instruction_type == S86_InstructionType_SUBImmediateFromRegOrMem ||
|
|
instruction_type == S86_InstructionType_SBBImmediateFromRegOrMem ||
|
|
instruction_type == S86_InstructionType_CMPImmediateWithRegOrMem) && s) {
|
|
sign_extend_8bit_data = true;
|
|
} else {
|
|
uint8_t data_hi = S86_BufferIteratorNextByte(&buffer_it);
|
|
data |= (uint16_t)(data_hi) << 8;
|
|
}
|
|
}
|
|
|
|
if (instruction_type == S86_InstructionType_MOVImmediateToRegOrMem) {
|
|
S86_ASSERT(mod != 0b11); // NOTE: Op is IMM->Reg, register-to-register not permitted
|
|
}
|
|
|
|
// NOTE: Disassemble
|
|
// =========================================================
|
|
if (instruction_type == S86_InstructionType_MOVImmediateToRegOrMem) {
|
|
S86_PrintLnFmt(" %.*s, %s %u", effective_address.size, effective_address.data, w ? "word" : "byte", data);
|
|
} else {
|
|
if (effective_address.data[0] == '[')
|
|
S86_PrintFmt(" %s", w ? "word" : "byte", S86_STR8_FMT(effective_address));
|
|
|
|
S86_PrintFmt(" %.*s, ", S86_STR8_FMT(effective_address));
|
|
if (sign_extend_8bit_data)
|
|
S86_PrintLnFmt("%d", (int16_t)data);
|
|
else
|
|
S86_PrintLnFmt("%u", data);
|
|
}
|
|
} break;
|
|
|
|
case S86_InstructionType_ADDImmediateToAccum: /*FALLTHRU*/
|
|
case S86_InstructionType_ADCImmediateToAccum: /*FALLTHRU*/
|
|
case S86_InstructionType_SUBImmediateFromAccum: /*FALLTHRU*/
|
|
case S86_InstructionType_SBBImmediateFromAccum: /*FALLTHRU*/
|
|
case S86_InstructionType_CMPImmediateWithAccum: /*FALLTHRU*/
|
|
case S86_InstructionType_MOVImmediateToReg: {
|
|
// NOTE: Parse opcode control bits
|
|
// =============================================================
|
|
S86_ASSERT(op_code_size == 1);
|
|
uint8_t w = 0;
|
|
if (instruction_type == S86_InstructionType_ADDImmediateToAccum ||
|
|
instruction_type == S86_InstructionType_ADCImmediateToAccum ||
|
|
instruction_type == S86_InstructionType_SUBImmediateFromAccum ||
|
|
instruction_type == S86_InstructionType_SBBImmediateFromAccum ||
|
|
instruction_type == S86_InstructionType_CMPImmediateWithAccum) {
|
|
w = (op_code_bytes[0] & 0b0000'0001) >> 0;
|
|
} else {
|
|
w = (op_code_bytes[0] & 0b0000'1000) >> 3;
|
|
}
|
|
uint8_t reg = (op_code_bytes[0] & 0b0000'0111) >> 0;
|
|
|
|
// 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
|
|
// =============================================================
|
|
S86_Str8 dest_register = {0};
|
|
if (instruction_type == S86_InstructionType_MOVImmediateToReg) {
|
|
dest_register = REGISTER_FIELD_ENCODING[w][reg];
|
|
} else {
|
|
S86_ASSERT(instruction_type == S86_InstructionType_ADDImmediateToAccum ||
|
|
instruction_type == S86_InstructionType_ADCImmediateToAccum ||
|
|
instruction_type == S86_InstructionType_SUBImmediateFromAccum ||
|
|
instruction_type == S86_InstructionType_SBBImmediateFromAccum ||
|
|
instruction_type == S86_InstructionType_CMPImmediateWithAccum);
|
|
if (w) {
|
|
dest_register = S86_STR8("ax");
|
|
} else {
|
|
data = (uint16_t)(int8_t)data; // Sign extension
|
|
dest_register = S86_STR8("al");
|
|
}
|
|
}
|
|
|
|
S86_PrintLnFmt(" %.*s, %d", S86_STR8_FMT(dest_register), (int16_t)data);
|
|
} break;
|
|
|
|
case S86_InstructionType_INFixedPort: /*FALLTHRU*/
|
|
case S86_InstructionType_INVariablePort: /*FALLTHRU*/
|
|
case S86_InstructionType_OUTFixedPort: /*FALLTHRU*/
|
|
case S86_InstructionType_OUTVariablePort: {
|
|
S86_ASSERT(op_code_size == 1);
|
|
uint8_t w = (op_code_bytes[0] & 0b0000'0001) >> 0;
|
|
S86_Str8 accum_name = w ? S86_STR8("ax") : S86_STR8("al");
|
|
bool is_in = instruction_type == S86_InstructionType_INFixedPort ||
|
|
instruction_type == S86_InstructionType_INVariablePort;
|
|
|
|
char data_val[8] = {0};
|
|
if (instruction_type == S86_InstructionType_INFixedPort ||
|
|
instruction_type == S86_InstructionType_OUTFixedPort) {
|
|
uint8_t data = S86_BufferIteratorNextByte(&buffer_it);
|
|
snprintf(data_val, sizeof(data_val), "%d", data);
|
|
} else {
|
|
data_val[0] = 'd';
|
|
data_val[1] = 'x';
|
|
}
|
|
|
|
if (is_in)
|
|
S86_PrintLnFmt(" %.*s, %s", S86_STR8_FMT(accum_name), data_val);
|
|
else
|
|
S86_PrintLnFmt(" %s, %.*s", data_val, S86_STR8_FMT(accum_name));
|
|
} break;
|
|
|
|
case S86_InstructionType_MOVAccumToMem: /*FALLTHRU*/
|
|
case S86_InstructionType_MOVMemToAccum: {
|
|
S86_ASSERT(op_code_size == 1);
|
|
uint16_t addr_lo = S86_BufferIteratorNextByte(&buffer_it);
|
|
uint16_t addr_hi = S86_BufferIteratorNextByte(&buffer_it);
|
|
uint16_t addr = (addr_hi << 8) | (addr_lo << 0);
|
|
|
|
S86_Str8 fmt = {0};
|
|
if (instruction_type == S86_InstructionType_MOVAccumToMem) {
|
|
fmt = S86_STR8(" [%u], ax");
|
|
} else {
|
|
S86_ASSERT(instruction_type == S86_InstructionType_MOVMemToAccum);
|
|
fmt = S86_STR8(" ax, [%u]");
|
|
}
|
|
S86_PrintLnFmt(fmt.data, addr);
|
|
} break;
|
|
|
|
default: {
|
|
if (instruction_type >= S86_InstructionType_JE_JZ && instruction_type <= S86_InstructionType_JCXZ) {
|
|
S86_ASSERT(op_code_size == 1);
|
|
int8_t jump_offset = S86_CAST(int8_t)S86_BufferIteratorNextByte(&buffer_it);
|
|
char sign = 0;
|
|
if (jump_offset > 0) {
|
|
sign = '+';
|
|
} else {
|
|
jump_offset *= -1;
|
|
sign = '-';
|
|
}
|
|
S86_PrintLnFmt(" $+2%c%d", sign, jump_offset);
|
|
} else if (instruction_type == S86_InstructionType_XLAT ||
|
|
instruction_type == S86_InstructionType_LAHF ||
|
|
instruction_type == S86_InstructionType_SAHF ||
|
|
instruction_type == S86_InstructionType_PUSHF ||
|
|
instruction_type == S86_InstructionType_POPF ||
|
|
instruction_type == S86_InstructionType_DAA ||
|
|
instruction_type == S86_InstructionType_AAA ||
|
|
instruction_type == S86_InstructionType_DAS ||
|
|
instruction_type == S86_InstructionType_AAS ||
|
|
instruction_type == S86_InstructionType_AAM ||
|
|
instruction_type == S86_InstructionType_AAD ||
|
|
instruction_type == S86_InstructionType_CBW ||
|
|
instruction_type == S86_InstructionType_CWD) {
|
|
// NOTE: Mnemonic instruction only, already printed
|
|
S86_Print(S86_STR8("\n"));
|
|
} else {
|
|
S86_Print(S86_STR8("\n"));
|
|
S86_ASSERT(!"Unhandled instruction");
|
|
}
|
|
} break;
|
|
}
|
|
}
|
|
}
|