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perfaware/part1: Support sub,cmp instructions, add untested jmp

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doyle 2023-03-17 22:34:05 +11:00 committed by committed-name
parent bcd509318c
commit f5316a08fc
1 changed files with 154 additions and 87 deletions
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241
part1/sim8086.c
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@ -76,9 +76,40 @@ typedef enum S86_InstructionType {
S86_InstructionType_MOVAccumToMem, S86_InstructionType_MOVAccumToMem,
S86_InstructionType_MOVRegOrMemToSegReg, S86_InstructionType_MOVRegOrMemToSegReg,
S86_InstructionType_MOVSegRegToRegOrMem, S86_InstructionType_MOVSegRegToRegOrMem,
S86_InstructionType_ADDRegOrMemToOrFromReg, S86_InstructionType_ADDRegOrMemToOrFromReg,
S86_InstructionType_ADDImmediateToRegOrMem, S86_InstructionType_ADDImmediateToRegOrMem,
S86_InstructionType_ADDImmediateToAccum, S86_InstructionType_ADDImmediateToAccum,
S86_InstructionType_SUBRegOrMemToOrFromReg,
S86_InstructionType_SUBImmediateFromRegOrMem,
S86_InstructionType_SUBImmediateFromAccum,
S86_InstructionType_CMPRegOrMemAndReg,
S86_InstructionType_CMPImmediateWithRegOrMem,
S86_InstructionType_CMPImmediateWithAccum,
S86_InstructionType_JE_JZ,
S86_InstructionType_JL_JNGE,
S86_InstructionType_JLE_JNG,
S86_InstructionType_JB_JNAE,
S86_InstructionType_JBE_JNA,
S86_InstructionType_JP_JPE,
S86_InstructionType_JO,
S86_InstructionType_JS,
S86_InstructionType_JNE_JNZ,
S86_InstructionType_JNL_JGE,
S86_InstructionType_JNLE_JG,
S86_InstructionType_JNB_JAE,
S86_InstructionType_JNBE_JA,
S86_InstructionType_JNP_JO,
S86_InstructionType_JNO,
S86_InstructionType_JNS,
S86_InstructionType_LOOP,
S86_InstructionType_LOOPZ_LOOPE,
S86_InstructionType_LOOPNZ_LOOPNE,
S86_InstructionType_JCZX,
S86_InstructionType_Count, S86_InstructionType_Count,
} S86_InstructionType; } S86_InstructionType;
@ -94,60 +125,9 @@ typedef struct S86_Instruction {
uint8_t op_bits0; uint8_t op_bits0;
uint8_t op_mask1; uint8_t op_mask1;
uint8_t op_bits1; uint8_t op_bits1;
S86_Str8 mnemonic;
} S86_Instruction; } S86_Instruction;
S86_Instruction const S86_INSTRUCTIONS[S86_InstructionType_Count] = {
[S86_InstructionType_MOVRegOrMemToOrFromReg] = {.op_mask0 = 0b1111'1100,
.op_bits0 = 0b1000'1000,
.op_mask1 = 0b0000'0000,
.op_bits1 = 0b0000'0000},
[S86_InstructionType_MOVImmediateToRegOrMem] = {.op_mask0 = 0b1111'1110,
.op_bits0 = 0b1100'0110,
.op_mask1 = 0b0011'1000,
.op_bits1 = 0b0000'0000},
[S86_InstructionType_MOVImmediateToReg] = {.op_mask0 = 0b1111'0000,
.op_bits0 = 0b1011'0000,
.op_mask1 = 0b0000'0000,
.op_bits1 = 0b0000'0000},
[S86_InstructionType_MOVMemToAccum] = {.op_mask0 = 0b1111'1110,
.op_bits0 = 0b1010'0000,
.op_mask1 = 0b0000'0000,
.op_bits1 = 0b0000'0000},
[S86_InstructionType_MOVAccumToMem] = {.op_mask0 = 0b1111'1110,
.op_bits0 = 0b1010'0010,
.op_mask1 = 0b0000'0000,
.op_bits1 = 0b0000'0000},
[S86_InstructionType_MOVRegOrMemToSegReg] = {.op_mask0 = 0b1111'1111,
.op_bits0 = 0b1000'1110,
.op_mask1 = 0b0010'0000,
.op_bits1 = 0b0000'0000},
[S86_InstructionType_MOVSegRegToRegOrMem] = {.op_mask0 = 0b1111'1111,
.op_bits0 = 0b1000'1100,
.op_mask1 = 0b0010'0000,
.op_bits1 = 0b0000'0000},
[S86_InstructionType_ADDRegOrMemToOrFromReg] = {.op_mask0 = 0b1111'1100,
.op_bits0 = 0b0000'0000,
.op_mask1 = 0b0000'0000,
.op_bits1 = 0b0000'0000},
[S86_InstructionType_ADDImmediateToRegOrMem] = {.op_mask0 = 0b1111'1100,
.op_bits0 = 0b1000'0000,
.op_mask1 = 0b0011'1000,
.op_bits1 = 0b0000'0000},
[S86_InstructionType_ADDImmediateToAccum] = {.op_mask0 = 0b1111'1110,
.op_bits0 = 0b0000'0100,
.op_mask1 = 0b0000'0000,
.op_bits1 = 0b0000'0000},
};
typedef struct S86_EffectiveAddressStr8 { typedef struct S86_EffectiveAddressStr8 {
char data[32]; char data[32];
size_t size; size_t size;
@ -176,12 +156,19 @@ bool S86_BufferIteratorHasMoreBytes(S86_BufferIterator it)
return result; return result;
} }
uint8_t S86_BufferIteratorNextByte(S86_BufferIterator *it) uint8_t S86_BufferIteratorPeekByte(S86_BufferIterator *it)
{ {
S86_ASSERT(it); S86_ASSERT(it);
S86_ASSERT(S86_BufferIsValid(it->buffer)); S86_ASSERT(S86_BufferIsValid(it->buffer));
S86_ASSERT(it->index < it->buffer.size); S86_ASSERT(it->index < it->buffer.size);
uint8_t result = it->buffer.data[it->index++]; uint8_t result = it->buffer.data[it->index];
return result;
}
uint8_t S86_BufferIteratorNextByte(S86_BufferIterator *it)
{
uint8_t result = S86_BufferIteratorPeekByte(it);
it->index++;
return result; return result;
} }
@ -399,6 +386,82 @@ int main(int argc, char **argv)
REGISTER_FIELD_ENCODING[0b1][6] = S86_STR8("si"); REGISTER_FIELD_ENCODING[0b1][6] = S86_STR8("si");
REGISTER_FIELD_ENCODING[0b1][7] = S86_STR8("di"); REGISTER_FIELD_ENCODING[0b1][7] = S86_STR8("di");
S86_Instruction const S86_INSTRUCTIONS[S86_InstructionType_Count] = {
[S86_InstructionType_MOVRegOrMemToOrFromReg] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1000'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("mov")},
[S86_InstructionType_MOVImmediateToRegOrMem] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1100'0110, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("mov")},
[S86_InstructionType_MOVImmediateToReg] = {.op_mask0 = 0b1111'0000, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1011'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("mov")},
[S86_InstructionType_MOVMemToAccum] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1010'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("mov")},
[S86_InstructionType_MOVAccumToMem] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1010'0010, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("mov")},
[S86_InstructionType_MOVRegOrMemToSegReg] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0010'0000,
.op_bits0 = 0b1000'1110, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("mov")},
[S86_InstructionType_MOVSegRegToRegOrMem] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0010'0000,
.op_bits0 = 0b1000'1100, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("mov")},
[S86_InstructionType_ADDRegOrMemToOrFromReg] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0000'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("add")},
[S86_InstructionType_ADDImmediateToRegOrMem] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1000'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("add")},
[S86_InstructionType_ADDImmediateToAccum] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0000'0100, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("add")},
[S86_InstructionType_SUBRegOrMemToOrFromReg] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0010'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("sub")},
[S86_InstructionType_SUBImmediateFromRegOrMem] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1000'0000, .op_bits1 = 0b0010'1000, .mnemonic = S86_STR8("sub")},
[S86_InstructionType_SUBImmediateFromAccum] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0010'1100, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("sub")},
[S86_InstructionType_CMPRegOrMemAndReg] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0011'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("cmp")},
[S86_InstructionType_CMPImmediateWithRegOrMem] = {.op_mask0 = 0b1111'1100, .op_mask1 = 0b0011'1000,
.op_bits0 = 0b1000'0000, .op_bits1 = 0b0011'1000, .mnemonic = S86_STR8("cmp")},
[S86_InstructionType_CMPImmediateWithAccum] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0011'1100, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("cmp")},
[S86_InstructionType_JE_JZ] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'0101, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jz")},
[S86_InstructionType_JL_JNGE] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'1101, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jl")},
[S86_InstructionType_JLE_JNG] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'1110, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jle")},
[S86_InstructionType_JB_JNAE] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'0010, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jb")},
[S86_InstructionType_JBE_JNA] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'0110, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jbe")},
[S86_InstructionType_JP_JPE] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'1010, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jp")},
[S86_InstructionType_JO] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'0000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jo")},
[S86_InstructionType_JS] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'1000, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("js")},
[S86_InstructionType_JNE_JNZ] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'0101, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jne")},
[S86_InstructionType_JNL_JGE] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'1101, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jnl")},
[S86_InstructionType_JNLE_JG] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'1111, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jnle")},
[S86_InstructionType_JNB_JAE] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'0011, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jnb")},
[S86_InstructionType_JNBE_JA] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'0111, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jnbe")},
[S86_InstructionType_JNP_JO] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'1011, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jnp")},
[S86_InstructionType_JNO] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'0001, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jno")},
[S86_InstructionType_JNS] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'1001, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jns")},
[S86_InstructionType_LOOP] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1110'0010, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("loop")},
[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_JCZX] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1110'0011, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("jczx")},
};
// NOTE: Decode assembly // NOTE: Decode assembly
// ========================================================================= // =========================================================================
S86_PrintLn(S86_STR8("bits 16")); S86_PrintLn(S86_STR8("bits 16"));
@ -431,8 +494,12 @@ int main(int argc, char **argv)
bool instruction_matched = true; bool instruction_matched = true;
if (item->op_mask1) { if (item->op_mask1) {
// TODO: This assumes the iterator is valid // TODO: This assumes the iterator is valid
op_code_bytes[op_code_size++] = S86_BufferIteratorNextByte(&buffer_it); uint8_t op_byte = S86_BufferIteratorPeekByte(&buffer_it);
instruction_matched = (op_code_bytes[op_code_size - 1] & item->op_mask1) == item->op_bits1; 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) { if (instruction_matched) {
@ -448,6 +515,8 @@ int main(int argc, char **argv)
switch (instruction_type) { switch (instruction_type) {
case S86_InstructionType_CMPRegOrMemAndReg: /*FALLTHRU*/
case S86_InstructionType_SUBRegOrMemToOrFromReg: /*FALLTHRU*/
case S86_InstructionType_ADDRegOrMemToOrFromReg: /*FALLTHRU*/ case S86_InstructionType_ADDRegOrMemToOrFromReg: /*FALLTHRU*/
case S86_InstructionType_MOVRegOrMemToOrFromReg: { case S86_InstructionType_MOVRegOrMemToOrFromReg: {
// NOTE: Instruction does not have opcode bits in the 2nd byte // NOTE: Instruction does not have opcode bits in the 2nd byte
@ -465,20 +534,12 @@ int main(int argc, char **argv)
S86_ASSERT(reg < 8); S86_ASSERT(reg < 8);
S86_ASSERT(rm < 8); S86_ASSERT(rm < 8);
S86_Str8 op = {0};
if (instruction_type == S86_InstructionType_MOVRegOrMemToOrFromReg) {
op = S86_STR8("mov");
} else {
op = S86_STR8("add");
S86_ASSERT(instruction_type == S86_InstructionType_ADDRegOrMemToOrFromReg);
}
if (mod == 0b11) { if (mod == 0b11) {
// NOTE: Register-to-register move // NOTE: Register-to-register move
// ========================================================= // =========================================================
S86_Str8 src_op = REGISTER_FIELD_ENCODING[w][d ? rm : reg]; S86_Str8 src_op = REGISTER_FIELD_ENCODING[w][d ? rm : reg];
S86_Str8 dest_op = REGISTER_FIELD_ENCODING[w][d ? reg : rm]; S86_Str8 dest_op = REGISTER_FIELD_ENCODING[w][d ? reg : rm];
S86_PrintLnFmt("%.*s %.*s, %.*s", S86_STR8_FMT(op), S86_STR8_FMT(dest_op), S86_STR8_FMT(src_op)); S86_PrintLnFmt("%.*s %.*s, %.*s", S86_STR8_FMT(instruction->mnemonic), S86_STR8_FMT(dest_op), S86_STR8_FMT(src_op));
} else { } else {
// NOTE: Memory mode w/ effective address calculation // NOTE: Memory mode w/ effective address calculation
// ========================================================= // =========================================================
@ -486,10 +547,12 @@ int main(int argc, char **argv)
S86_Str8 addr = { .data = effective_address.data, .size = effective_address.size }; S86_Str8 addr = { .data = effective_address.data, .size = effective_address.size };
S86_Str8 dest_op = d ? REGISTER_FIELD_ENCODING[w][reg] : addr; S86_Str8 dest_op = d ? REGISTER_FIELD_ENCODING[w][reg] : addr;
S86_Str8 src_op = d ? addr : REGISTER_FIELD_ENCODING[w][reg]; S86_Str8 src_op = d ? addr : REGISTER_FIELD_ENCODING[w][reg];
S86_PrintLnFmt("%.*s %.*s, %.*s", S86_STR8_FMT(op), S86_STR8_FMT(dest_op), S86_STR8_FMT(src_op)); S86_PrintLnFmt("%.*s %.*s, %.*s", S86_STR8_FMT(instruction->mnemonic), S86_STR8_FMT(dest_op), S86_STR8_FMT(src_op));
} }
} break; } break;
case S86_InstructionType_CMPImmediateWithRegOrMem: /*FALLTHRU*/
case S86_InstructionType_SUBImmediateFromRegOrMem: /*FALLTHRU*/
case S86_InstructionType_ADDImmediateToRegOrMem: /*FALLTHRU*/ case S86_InstructionType_ADDImmediateToRegOrMem: /*FALLTHRU*/
case S86_InstructionType_MOVImmediateToRegOrMem: { case S86_InstructionType_MOVImmediateToRegOrMem: {
S86_ASSERT(op_code_size == 2); S86_ASSERT(op_code_size == 2);
@ -508,7 +571,9 @@ int main(int argc, char **argv)
uint16_t data = S86_BufferIteratorNextByte(&buffer_it); uint16_t data = S86_BufferIteratorNextByte(&buffer_it);
bool sign_extend_8bit_data = false; bool sign_extend_8bit_data = false;
if (w) { // 16 bit data if (w) { // 16 bit data
if (instruction_type == S86_InstructionType_ADDImmediateToRegOrMem && s) { if ((instruction_type == S86_InstructionType_ADDImmediateToRegOrMem ||
instruction_type == S86_InstructionType_SUBImmediateFromRegOrMem ||
instruction_type == S86_InstructionType_CMPImmediateWithRegOrMem) && s) {
sign_extend_8bit_data = true; sign_extend_8bit_data = true;
} else { } else {
uint8_t data_hi = S86_BufferIteratorNextByte(&buffer_it); uint8_t data_hi = S86_BufferIteratorNextByte(&buffer_it);
@ -516,35 +581,34 @@ int main(int argc, char **argv)
} }
} }
S86_Str8 op = {0};
if (instruction_type == S86_InstructionType_MOVImmediateToRegOrMem) { if (instruction_type == S86_InstructionType_MOVImmediateToRegOrMem) {
S86_ASSERT(mod != 0b11); // NOTE: Op is IMM->Reg, register-to-register not permitted S86_ASSERT(mod != 0b11); // NOTE: Op is IMM->Reg, register-to-register not permitted
op = S86_STR8("mov");
} else {
S86_ASSERT(instruction_type == S86_InstructionType_ADDImmediateToRegOrMem);
op = S86_STR8("add");
} }
// NOTE: Disassemble // NOTE: Disassemble
// ========================================================= // =========================================================
if (instruction_type == S86_InstructionType_MOVImmediateToRegOrMem) { if (instruction_type == S86_InstructionType_MOVImmediateToRegOrMem) {
S86_PrintLnFmt("%.*s %.*s, %s %u", S86_STR8_FMT(op), effective_address.size, effective_address.data, w ? "word" : "byte", data); S86_PrintLnFmt("%.*s %.*s, %s %u", S86_STR8_FMT(instruction->mnemonic), effective_address.size, effective_address.data, w ? "word" : "byte", data);
} else { } else {
if (sign_extend_8bit_data) { if (sign_extend_8bit_data) {
S86_PrintLnFmt("%.*s %.*s, %d", S86_STR8_FMT(op), effective_address.size, effective_address.data, (int16_t)data); S86_PrintLnFmt("%.*s %.*s, %d", S86_STR8_FMT(instruction->mnemonic), effective_address.size, effective_address.data, (int16_t)data);
} else { } else {
S86_PrintLnFmt("%.*s %.*s, %u", S86_STR8_FMT(op), effective_address.size, effective_address.data, data); S86_PrintLnFmt("%.*s %.*s, %u", S86_STR8_FMT(instruction->mnemonic), effective_address.size, effective_address.data, data);
} }
} }
} break; } break;
case S86_InstructionType_CMPImmediateWithAccum: /*FALLTHRU*/
case S86_InstructionType_SUBImmediateFromAccum: /*FALLTHRU*/
case S86_InstructionType_ADDImmediateToAccum: /*FALLTHRU*/ case S86_InstructionType_ADDImmediateToAccum: /*FALLTHRU*/
case S86_InstructionType_MOVImmediateToReg: { case S86_InstructionType_MOVImmediateToReg: {
// NOTE: Parse opcode control bits // NOTE: Parse opcode control bits
// ============================================================= // =============================================================
S86_ASSERT(op_code_size == 1); S86_ASSERT(op_code_size == 1);
uint8_t w = 0; uint8_t w = 0;
if (instruction_type == S86_InstructionType_ADDImmediateToAccum) { if (instruction_type == S86_InstructionType_ADDImmediateToAccum ||
instruction_type == S86_InstructionType_SUBImmediateFromAccum ||
instruction_type == S86_InstructionType_CMPImmediateWithAccum) {
w = (op_code_bytes[0] & 0b0000'0001) >> 0; w = (op_code_bytes[0] & 0b0000'0001) >> 0;
} else { } else {
w = (op_code_bytes[0] & 0b0000'1000) >> 3; w = (op_code_bytes[0] & 0b0000'1000) >> 3;
@ -561,14 +625,13 @@ int main(int argc, char **argv)
// NOTE: Disassemble // NOTE: Disassemble
// ============================================================= // =============================================================
S86_Str8 op = {0};
S86_Str8 dest_register = {0}; S86_Str8 dest_register = {0};
if (instruction_type == S86_InstructionType_MOVImmediateToReg) { if (instruction_type == S86_InstructionType_MOVImmediateToReg) {
op = S86_STR8("mov");
dest_register = REGISTER_FIELD_ENCODING[w][reg]; dest_register = REGISTER_FIELD_ENCODING[w][reg];
} else { } else {
S86_ASSERT(instruction_type == S86_InstructionType_ADDImmediateToAccum); S86_ASSERT(instruction_type == S86_InstructionType_ADDImmediateToAccum ||
op = S86_STR8("add"); instruction_type == S86_InstructionType_SUBImmediateFromAccum ||
instruction_type == S86_InstructionType_CMPImmediateWithAccum);
if (w) { if (w) {
dest_register = S86_STR8("ax"); dest_register = S86_STR8("ax");
} else { } else {
@ -577,7 +640,7 @@ int main(int argc, char **argv)
} }
} }
S86_PrintLnFmt("%.*s %.*s, %d", S86_STR8_FMT(op), S86_STR8_FMT(dest_register), (int16_t)data); S86_PrintLnFmt("%.*s %.*s, %d", S86_STR8_FMT(instruction->mnemonic), S86_STR8_FMT(dest_register), (int16_t)data);
} break; } break;
case S86_InstructionType_MOVAccumToMem: /*FALLTHRU*/ case S86_InstructionType_MOVAccumToMem: /*FALLTHRU*/
@ -589,18 +652,22 @@ int main(int argc, char **argv)
S86_Str8 fmt = {0}; S86_Str8 fmt = {0};
if (instruction_type == S86_InstructionType_MOVAccumToMem) { if (instruction_type == S86_InstructionType_MOVAccumToMem) {
fmt = S86_STR8("mov [%u], ax"); fmt = S86_STR8("%.*s [%u], ax");
} else { } else {
S86_ASSERT(instruction_type == S86_InstructionType_MOVMemToAccum); S86_ASSERT(instruction_type == S86_InstructionType_MOVMemToAccum);
fmt = S86_STR8("mov ax, [%u]"); fmt = S86_STR8("%.*s ax, [%u]");
} }
S86_PrintLnFmt(fmt.data, addr); S86_PrintLnFmt(fmt.data, S86_STR8_FMT(instruction->mnemonic), addr);
} break; } break;
case S86_InstructionType_MOVRegOrMemToSegReg: /*FALLTHRU*/
case S86_InstructionType_MOVSegRegToRegOrMem: /*FALLTHRU*/
default: { default: {
S86_ASSERT(!"Unhandled instruction"); if (instruction_type >= S86_InstructionType_JE_JZ && instruction_type <= S86_InstructionType_JCZX) {
S86_ASSERT(op_code_size == 1);
int8_t jump_offset = S86_CAST(int8_t)S86_BufferIteratorNextByte(&buffer_it);
S86_PrintLnFmt("%.*s %d", S86_STR8_FMT(instruction->mnemonic), jump_offset);
} else {
S86_ASSERT(!"Unhandled instruction");
}
} break; } break;
} }
} }