vin/emu_nes
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replace bit comparisons with 0 from greater than to not equal

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They're both the same and the compiler might have already optimized it
away. It also conveys the message better in my opinion.
This commit is contained in:
Vineet K 2024-06-16 17:11:51 +05:30
parent 745496ccd1
commit 1f6e3b054c
1 changed files with 13 additions and 13 deletions
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26
cpu.c
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@ -8,7 +8,7 @@
#define STATUS_UPDATE_ZERO(r) \ #define STATUS_UPDATE_ZERO(r) \
(regs.status.zero = r == 0) (regs.status.zero = r == 0)
#define STATUS_UPDATE_NEGATIVE(r) \ #define STATUS_UPDATE_NEGATIVE(r) \
(regs.status.negative = ((r & (1 << 7)) > 0)) (regs.status.negative = ((r & (1 << 7)) != 0))
#define MEMORY_MIRROR(addr) \ #define MEMORY_MIRROR(addr) \
if (addr < 0x2000) \ if (addr < 0x2000) \
@ -197,7 +197,7 @@ adc(uint8_t arg)
regs.status.carry = sum > 0xFF; regs.status.carry = sum > 0xFF;
/* overflow flag formula: https://stackoverflow.com/a/29224684 */ /* overflow flag formula: https://stackoverflow.com/a/29224684 */
regs.status.overflow = (~(regs.a ^ arg) & (regs.a ^ sum) & 0x80) > 0; regs.status.overflow = (~(regs.a ^ arg) & (regs.a ^ sum) & 0x80) != 0;
STATUS_UPDATE_ZERO(regs.a); STATUS_UPDATE_ZERO(regs.a);
STATUS_UPDATE_NEGATIVE(regs.a); STATUS_UPDATE_NEGATIVE(regs.a);
} }
@ -262,7 +262,7 @@ static void
bit(uint8_t arg) bit(uint8_t arg)
{ {
regs.status.zero = (regs.a & arg) == 0; regs.status.zero = (regs.a & arg) == 0;
regs.status.overflow = (arg & (1 << 6)) > 0; regs.status.overflow = (arg & (1 << 6)) != 0;
STATUS_UPDATE_NEGATIVE(arg); STATUS_UPDATE_NEGATIVE(arg);
} }
@ -557,21 +557,21 @@ plp(void)
status = PULL(); status = PULL();
regs.status.carry = (status & (1 << 7)) > 0; regs.status.carry = (status & (1 << 7)) != 0;
regs.status.zero = (status & (1 << 6)) > 0; regs.status.zero = (status & (1 << 6)) != 0;
regs.status.interrupt_disable = (status & (1 << 5)) > 0; regs.status.interrupt_disable = (status & (1 << 5)) != 0;
regs.status.decimal_mode = (status & (1 << 4)) > 0; regs.status.decimal_mode = (status & (1 << 4)) != 0;
regs.status.brk = (status & (1 << 3)) > 0; regs.status.brk = (status & (1 << 3)) != 0;
regs.status.unused = (status & (1 << 2)) > 0; regs.status.unused = (status & (1 << 2)) != 0;
regs.status.overflow = (status & (1 << 1)) > 0; regs.status.overflow = (status & (1 << 1)) != 0;
regs.status.negative = (status & 1) > 0; regs.status.negative = (status & 1) != 0;
} }
static void static void
rol_acc(void) rol_acc(void)
{ {
uint8_t carry; uint8_t carry;
carry = (regs.a & (1 << 7)) > 0; carry = (regs.a & (1 << 7)) != 0;
regs.a <<= 1; regs.a <<= 1;
regs.a |= regs.status.carry; regs.a |= regs.status.carry;
@ -585,7 +585,7 @@ static void
rol(uint16_t mem) rol(uint16_t mem)
{ {
uint8_t carry, tmp; uint8_t carry, tmp;
carry = (peek(mem) & (1 << 7)) > 0; carry = (peek(mem) & (1 << 7)) != 0;
tmp = (peek(mem) << 1) | regs.status.carry; tmp = (peek(mem) << 1) | regs.status.carry;
memwrite(mem, tmp); memwrite(mem, tmp);