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perfaware/part1: Correctly print P/Z flags

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This commit is contained in:
doyle 2023-04-16 14:23:55 +10:00
parent b5fd6cb4a8
commit 9c9a505464
2 changed files with 67 additions and 37 deletions
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89
part1/sim8086.c
View File

@ -1,3 +1,13 @@
#define WIN32_MEAN_AND_LEAN
#define NOMINMAX
#include <Windows.h>
#include <immintrin.h>
#include <stdint.h>
#include <stdio.h>
#include <stdarg.h>
#include <stdbool.h>
#include "sim8086_stdlib.h"
#include "sim8086.h"
@ -16,11 +26,15 @@ typedef union S86_Register16 {
uint8_t bytes[S86_RegisterByte_Count];
} S86_Register16;
typedef struct S86_RegisterFileFlags {
bool zero;
bool sign;
bool parity;
bool overflow;
} S86_RegisterFileFlags;
typedef struct S86_RegisterFile {
bool zero_flag;
bool sign_flag;
bool parity_flag;
bool overflow_flag;
S86_RegisterFileFlags flags;
S86_Register16 ax;
S86_Register16 bx;
@ -38,6 +52,15 @@ typedef struct S86_RegisterFile {
S86_Register16 ds;
} S86_RegisterFile;
bool S86_RegisterFileFlagsEq(S86_RegisterFileFlags lhs, S86_RegisterFileFlags rhs)
{
bool result = lhs.sign == rhs.sign &&
lhs.zero == rhs.zero &&
lhs.parity == rhs.parity &&
lhs.overflow == rhs.overflow;
return result;
}
S86_Str8 S86_MnemonicStr8(S86_Mnemonic type)
{
S86_Str8 result = {0};
@ -1207,8 +1230,7 @@ int main(int argc, char **argv)
continue;
}
bool prev_sign_flag = register_file.sign_flag;
bool prev_zero_flag = register_file.zero_flag;
S86_RegisterFileFlags prev_flags = register_file.flags;
switch (opcode.mnemonic) {
case S86_Mnemonic_PUSH: /*FALLTHRU*/
case S86_Mnemonic_POP: /*FALLTHRU*/
@ -1366,33 +1388,44 @@ int main(int argc, char **argv)
dest.word += S86_CAST(uint16_t)(src_map->reg->word * sign);
}
int bit_count = _mm_popcnt_u32(S86_CAST(uint32_t)dest.bytes[S86_RegisterByte_Lo]);
register_file.flags.parity = (bit_count % 2 == 0);
S86_Str8 dest_reg16 = S86_MnemonicOpStr8(dest_map->mnemonic_op_reg16);
register_file.sign_flag = dest_map->reg->word & (byte_op ? 0b0000'0000'1000'0000 : 0b1000'0000'0000'0000);
register_file.flags.sign = dest_map->reg->word & (byte_op ? 0b0000'0000'1000'0000 : 0b1000'0000'0000'0000);
if (opcode.mnemonic == S86_Mnemonic_CMP) {
S86_PrintFmt(" ; ");
} else {
if (opcode.mnemonic == S86_Mnemonic_SUB)
register_file.zero_flag = byte_op ? dest.bytes[dest_map->byte] == 0 : dest.word == 0;
register_file.flags.zero = byte_op ? dest.bytes[dest_map->byte] == 0 : dest.word == 0;
S86_PrintFmt(" ; %.*s:0x%x->0x%x ", S86_STR8_FMT(dest_reg16), prev_dest16, dest.word);
*dest_map->reg = dest;
}
} break;
}
if (register_file.sign_flag != prev_sign_flag) {
if (register_file.sign_flag) {
S86_PrintFmt("flags:->S ");
} else {
S86_PrintFmt("flags:S-> ");
}
}
if (!S86_RegisterFileFlagsEq(register_file.flags, prev_flags)) {
S86_PrintFmt("flags:");
if (prev_flags.parity && !register_file.flags.parity)
S86_PrintFmt("P");
if (prev_flags.zero && !register_file.flags.zero)
S86_PrintFmt("Z");
if (prev_flags.sign && !register_file.flags.sign)
S86_PrintFmt("S");
if (prev_flags.overflow && !register_file.flags.overflow)
S86_PrintFmt("O");
if (register_file.zero_flag != prev_zero_flag) {
if (register_file.zero_flag) {
S86_PrintFmt("flags:->PZ ");
} else {
S86_PrintFmt("flags:PZ-> ");
}
S86_PrintFmt("->");
if (!prev_flags.parity && register_file.flags.parity)
S86_PrintFmt("P");
if (!prev_flags.zero && register_file.flags.zero)
S86_PrintFmt("Z");
if (!prev_flags.sign && register_file.flags.sign)
S86_PrintFmt("S");
if (!prev_flags.overflow && register_file.flags.overflow)
S86_PrintFmt("O");
S86_PrintFmt(" ");
}
S86_Print(S86_STR8("\n"));
}
@ -1421,12 +1454,18 @@ int main(int argc, char **argv)
S86_PrintLnFmt(" ss: 0x%04x (%u)", register_file.ss, register_file.ss);
if (register_file.ds.word)
S86_PrintLnFmt(" ds: 0x%04x (%u)", register_file.ds, register_file.ds);
if (register_file.zero_flag || register_file.sign_flag) {
S86_RegisterFileFlags nil_flags = {0};
if (!S86_RegisterFileFlagsEq(register_file.flags, nil_flags)) {
S86_PrintFmt(" flags: ");
if (register_file.zero_flag)
S86_PrintFmt(" PZ");
if (register_file.sign_flag)
if (register_file.flags.parity)
S86_PrintFmt("P");
if (register_file.flags.zero)
S86_PrintFmt("Z");
if (register_file.flags.sign)
S86_PrintFmt("S");
if (register_file.flags.overflow)
S86_PrintFmt("O");
S86_Print(S86_STR8("\n"));
}
S86_Print(S86_STR8("\n"));

9
part1/sim8086_stdlib.h
View File

@ -1,12 +1,3 @@
#define WIN32_MEAN_AND_LEAN
#define NOMINMAX
#include <Windows.h>
#include <stdint.h>
#include <stdio.h>
#include <stdarg.h>
#include <stdbool.h>
// NOTE: Macros
// ============================================================================
#define S86_STRINGIFY2(token) #token