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dtoa.c: Extract macro to update 5powers Bigint cache atomically

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Nobuyoshi Nakada 2025-09-10 00:26:56 +09:00
parent 0887d82406
commit d0c966adcd
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GPG Key ID: 3582D74E1FEE4465
1 changed files with 17 additions and 28 deletions
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45
missing/dtoa.c
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@ -815,29 +815,30 @@ static Bigint *
pow5mult(Bigint *b, int k)
{
Bigint *b1, *p5, *p51;
Bigint *p5tmp;
int i;
static const int p05[3] = { 5, 25, 125 };
if ((i = k & 3) != 0)
b = multadd(b, p05[i-1], 0);
#define b_cache(var, addr, new_expr) \
if ((var = addr) != 0) {} else { \
Bigint *tmp = 0; \
ACQUIRE_DTOA_LOCK(1); \
if (!(var = addr) && (var = (new_expr)) != 0) { \
var->next = 0; \
tmp = ATOMIC_PTR_CAS(addr, NULL, var); \
} \
FREE_DTOA_LOCK(1); \
if (UNLIKELY(tmp)) { \
Bfree(var); \
var = tmp; \
} \
}
if (!(k >>= 2))
return b;
if (!(p5 = p5s)) {
/* first time */
ACQUIRE_DTOA_LOCK(1);
if (!(p5 = p5s)) {
p5 = i2b(625);
p5->next = 0;
p5tmp = ATOMIC_PTR_CAS(p5s, NULL, p5);
if (UNLIKELY(p5tmp)) {
Bfree(p5);
p5 = p5tmp;
}
}
FREE_DTOA_LOCK(1);
}
/* first time */
b_cache(p5, p5s, i2b(625));
for (;;) {
if (k & 1) {
b1 = mult(b, p5);
@ -846,19 +847,7 @@ pow5mult(Bigint *b, int k)
}
if (!(k >>= 1))
break;
if (!(p51 = p5->next)) {
ACQUIRE_DTOA_LOCK(1);
if (!(p51 = p5->next)) {
p51 = mult(p5,p5);
p51->next = 0;
p5tmp = ATOMIC_PTR_CAS(p5->next, NULL, p51);
if (UNLIKELY(p5tmp)) {
Bfree(p51);
p51 = p5tmp;
}
}
FREE_DTOA_LOCK(1);
}
b_cache(p51, p5->next, mult(p5, p5));
p5 = p51;
}
return b;