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Fix NEC BCD instructions (#15)

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This commit is contained in:
Cacodemon345
2022-09-09 00:26:05 +06:00
committed by GitHub
parent 25b2e16a27
commit c2cc656103
1 changed files with 13 additions and 21 deletions
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34
src/cpu/808x.c
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@@ -2049,24 +2049,22 @@ execx86(int cycs)
wait(5, 0); wait(5, 0);
for (i = 0; i < ((nibbles_count / 2) + odd); i++) { for (i = 0; i < ((nibbles_count / 2) + odd); i++) {
wait(19, 0); wait(19, 0);
uint8_t destcmp = read_mem_b((es) + DI + i);
for (nibble = 0; nibble < 2; nibble++) { for (nibble = 0; nibble < 2; nibble++) {
uint8_t destbyte = read_mem_b((es) + DI + i) >> (nibble ? 4 : 0); uint8_t destbyte = destcmp >> (nibble ? 4 : 0);
uint8_t srcbyte = read_mem_b(srcseg + SI + i) >> (nibble ? 4 : 0); uint8_t srcbyte = read_mem_b(srcseg + SI + i) >> (nibble ? 4 : 0);
destbyte &= 0xF; destbyte &= 0xF;
srcbyte &= 0xF; srcbyte &= 0xF;
uint8_t nibble_result = destbyte + srcbyte + carry; uint8_t nibble_result = (i == (nibbles_count / 2) && nibble == 1) ? (destbyte + carry) : ((uint8_t)(destbyte)) + ((uint8_t)(srcbyte)) + ((uint32_t)carry);
carry = 0; carry = 0;
while (nibble_result >= 10) { while (nibble_result >= 10) {
nibble_result -= 10; nibble_result -= 10;
carry++; carry++;
} }
if (zero != 0) zero = (nibble_result == 0); if (zero != 0 || (i == (nibbles_count / 2) && nibble == 1)) zero = (nibble_result == 0);
write_mem_b((es) + DI + i, (read_mem_b((es) + DI + i) & (nibble ? 0x0F : 0xF0)) | (nibble_result << (4 * nibble))); destcmp = ((destcmp & (nibble ? 0x0F : 0xF0)) | (nibble_result << (4 * nibble)));
if (i == ((nibbles_count / 2)) && odd && nibble == 0) {
zero = ((read_mem_b((es) + DI + i) & 0xF0) == 0);
break;
}
} }
write_mem_b(es + DI + i, destcmp);
} }
set_cf(!!carry); set_cf(!!carry);
set_zf(!!zero); set_zf(!!zero);
@@ -2084,24 +2082,22 @@ execx86(int cycs)
wait(5, 0); wait(5, 0);
for (i = 0; i < ((nibbles_count / 2) + odd); i++) { for (i = 0; i < ((nibbles_count / 2) + odd); i++) {
wait(19, 0); wait(19, 0);
uint8_t destcmp = read_mem_b((es) + DI + i);
for (nibble = 0; nibble < 2; nibble++) { for (nibble = 0; nibble < 2; nibble++) {
uint8_t destbyte = read_mem_b((es) + DI + i) >> (nibble ? 4 : 0); uint8_t destbyte = destcmp >> (nibble ? 4 : 0);
uint8_t srcbyte = read_mem_b(srcseg + SI + i) >> (nibble ? 4 : 0); uint8_t srcbyte = read_mem_b(srcseg + SI + i) >> (nibble ? 4 : 0);
destbyte &= 0xF; destbyte &= 0xF;
srcbyte &= 0xF; srcbyte &= 0xF;
int8_t nibble_result = ((int8_t)(destbyte)) - ((int8_t)(srcbyte)) - ((int8_t)carry); int8_t nibble_result = (i == (nibbles_count / 2) && nibble == 1) ? ((int8_t)destbyte - (int8_t)carry) : ((int8_t)(destbyte)) - ((int8_t)(srcbyte)) - ((int8_t)carry);
carry = 0; carry = 0;
while (nibble_result < 0) { while (nibble_result < 0) {
nibble_result += 10; nibble_result += 10;
carry++; carry++;
} }
if (zero != 0) zero = (nibble_result == 0); if (zero != 0 || (i == (nibbles_count / 2) && nibble == 1)) zero = (nibble_result == 0);
write_mem_b((es) + DI + i, (read_mem_b((es) + DI + i) & (nibble ? 0x0F : 0xF0)) | (nibble_result << (4 * nibble))); destcmp = ((destcmp & (nibble ? 0x0F : 0xF0)) | (nibble_result << (4 * nibble)));
if (i == ((nibbles_count / 2)) && odd && nibble == 0) {
zero = ((read_mem_b((es) + DI + i) & 0xF0) == 0);
break;
}
} }
write_mem_b(es + DI + i, destcmp);
} }
set_cf(!!carry); set_cf(!!carry);
set_zf(!!zero); set_zf(!!zero);
@@ -2131,12 +2127,8 @@ execx86(int cycs)
nibble_result += 10; nibble_result += 10;
carry++; carry++;
} }
if (zero != 0) zero = (nibble_result == 0); if (zero != 0 || (i == (nibbles_count / 2) && nibble == 1)) zero = (nibble_result == 0);
destcmp = ((destcmp & (nibble ? 0x0F : 0xF0)) | (nibble_result << (4 * nibble))); destcmp = ((destcmp & (nibble ? 0x0F : 0xF0)) | (nibble_result << (4 * nibble)));
if (i == ((nibbles_count / 2)) && odd && nibble == 0) {
zero = ((destcmp & 0xF0) == 0);
break;
}
} }
} }
set_cf(!!carry); set_cf(!!carry);