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Immediate to register/memory conditionals condensed

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This commit is contained in:
Joseph Ferano 2024-01-15 12:42:54 +07:00
parent 5b2542b0dd
commit 08753ea330
1 changed files with 8 additions and 25 deletions
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33
decode.c
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@ -145,9 +145,9 @@ int main(int argc, char** argv)
}
else
{
bool is_direct_addr = mod == 0 && rm == 0b110;
// This is a trick because mod == 1 and mod == 2 will displace one and two bytes
// respectively but mod == 3 wraps to 0 since it doesn't displace
bool is_direct_addr = mod == 0 && rm == 0b110;
int bytes_to_read = is_direct_addr ? 2 : mod % 3;
bytes_read = fread(buf, sizeof(char), bytes_to_read, f);
char* eac_name = is_direct_addr ? "" : get_eac_registers(rm);
@ -166,8 +166,8 @@ int main(int argc, char** argv)
// Immediate to register/memory
else if ((inst & ~0x1) == (char)0b11000110)
{
char w = inst & 0b00000001;
bytes_read = fread(buf, sizeof(char), 1, f);
char w = inst & 0b00000001;
char mod = (buf[0] & 0b11000000) >> 6;
char rm = (buf[0] & 0b00000111);
int bytes_to_read = 1;
@ -176,28 +176,11 @@ int main(int argc, char** argv)
bytes_to_read += mod % 3;
bytes_read = fread(buf, sizeof(char), bytes_to_read, f);
char *eac_name = get_eac_registers(rm);
char *data_ptr = (char*)buf + (char)bytes_to_read - (w == 0 ? 1 : 2);
i16 data = w == 0 ? data_ptr[0] : (i16)data_ptr[1] << 8 | data_ptr[0];
char *word = w == 0 ? "byte" : "word";
char disp_str[16];
if (mod > 0 && mod < 3)
{
if (mod == 1)
{
sprintf(disp_str, " + %d", buf[1]);
}
else
{
i16 disp = (i16)buf[1] << 8 | buf[0];
sprintf(disp_str, " + %d", disp);
}
}
else
{
disp_str[0] = '\0';
}
printf("mov [%s%s], %s %d ;w %d mod %d rm %d", eac_name, disp_str, word, data, w, mod, rm);
i16 data = get_data(buf + (char)bytes_to_read - (w == 0 ? 1 : 2), w);
char *word_str = w == 0 ? "byte" : "word";
char disp_str[16] = {'\0'};
if (mod % 3 > 1) sprintf(disp_str, " + %d", get_data(buf, (mod % 3) - 1));
printf("mov [%s%s], %s %d ;3", eac_name, disp_str, word_str, data);
}
// Immediate to register
else if ((inst & ~0xF) == (char)0b10110000)
@ -206,7 +189,7 @@ int main(int argc, char** argv)
Register reg = registers[(size_t)inst & 0b00000111];
char bytes_to_read = w == 1 ? 2 : 1;
bytes_read = fread(buf, sizeof(char), bytes_to_read, f);
printf("mov %s, %hd ; Immediate to register", reg_name(reg, w), get_data(buf, w));
printf("mov %s, %hd ;4", reg_name(reg, w), get_data(buf, w));
}
// Memory to accumulator
else if ((inst & ~0x1) == (char)0b10100000)