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perfaware/part1: Add support for REP

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doyle 2023-03-19 16:50:58 +11:00
parent 0ec809a22f
commit 21d98ec223
1 changed files with 24 additions and 0 deletions
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24
part1/sim8086.c
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@ -171,6 +171,8 @@ typedef enum S86_InstructionType {
S86_InstructionType_XORImmediateToRegOrMem,
S86_InstructionType_XORImmediateToAccum,
S86_InstructionType_REP,
S86_InstructionType_JE_JZ,
S86_InstructionType_JL_JNGE,
S86_InstructionType_JLE_JNG,
@ -674,6 +676,9 @@ int main(int argc, char **argv)
[S86_InstructionType_XORImmediateToAccum] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0011'0100, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("xor")},
[S86_InstructionType_REP] = {.op_mask0 = 0b1111'1110, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b1111'0010, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("rep")},
[S86_InstructionType_JE_JZ] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
.op_bits0 = 0b0111'0100, .op_bits1 = 0b0000'0000, .mnemonic = S86_STR8("je")},
[S86_InstructionType_JL_JNGE] = {.op_mask0 = 0b1111'1111, .op_mask1 = 0b0000'0000,
@ -1074,6 +1079,25 @@ int main(int argc, char **argv)
S86_PrintLnFmt(fmt.data, addr);
} break;
case S86_InstructionType_REP: {
S86_ASSERT(op_code_size == 1);
uint8_t string_op = S86_BufferIteratorNextByte(&buffer_it);
uint8_t w_mask = 0b0000'0001;
uint8_t w = string_op & w_mask;
S86_Str8 string_type = {0};
switch (string_op & ~w_mask) {
case 0b1010'0100: string_type = S86_STR8("movs"); break;
case 0b1010'0110: string_type = S86_STR8("cmps"); break;
case 0b1010'1110: string_type = S86_STR8("scas"); break;
case 0b1010'1100: string_type = S86_STR8("lods"); break;
case 0b1010'1010: string_type = S86_STR8("stos"); break;
default: S86_ASSERT(!"Unhandled REP string type"); break;
}
S86_PrintLnFmt(" %.*s%c", S86_STR8_FMT(string_type), w ? 'w' : 'b');
} break;
default: {
if (instruction_type >= S86_InstructionType_JE_JZ && instruction_type <= S86_InstructionType_JCXZ) {
S86_ASSERT(op_code_size == 1);