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string.c (search_nonascii): simplify fallback implementation by SWAR

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This commit is contained in:
Yukihiro "Matz" Matsumoto
2024-04-02 19:50:13 +09:00
parent 898d1ff11e
commit aa28f48c3b
1 changed files with 12 additions and 43 deletions
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src/string.c
+12 -43
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@@ -338,56 +338,25 @@ search_nonascii(const char *p, const char *e)
#else
#ifdef MRB_64BIT
# define NONASCII_MASK 0x8080808080808080ULL
#else /* MRB_32BIT */
# define NONASCII_MASK 0x80808080UL
#endif
static const char*
search_nonascii(const char *p, const char *e)
{
if (e - p >= sizeof(void*)) {
#if ALIGNED_WORD_ACCESS
if ((uintptr_t)p % sizeof(void*)) {
int l = sizeof(void*) - (uintptr_t)p % sizeof(void*);
p += l;
switch (l) {
#ifdef MRB_64BIT
case 7: if (p[-7]&0x80) return p-7;
case 6: if (p[-6]&0x80) return p-6;
case 5: if (p[-5]&0x80) return p-5;
case 4: if (p[-4]&0x80) return p-4;
#endif
case 3: if (p[-3]&0x80) return p-3;
case 2: if (p[-2]&0x80) return p-2;
case 1: if (p[-1]&0x80) return p-1;
case 0: break;
}
}
#endif
ptrdiff_t byte_len = e - p;
const uintptr_t *s = (uintptr_t*)p;
const uintptr_t *t = (uintptr_t*)(e - (sizeof(void*)-1));
const char *be = p + sizeof(bitint) * (byte_len / sizeof(bitint));
for (; p < be; p+=sizeof(bitint)) {
bitint t0;
for (;s < t; s++) {
if (*s & NONASCII_MASK) {
p = (const char*)s;
if (NOASCII(p[0])) return p+0;
if (NOASCII(p[1])) return p+1;
if (NOASCII(p[2])) return p+2;
if (NOASCII(p[3])) return p+3;
#ifdef MRB_64BIT
if (NOASCII(p[4])) return p+4;
if (NOASCII(p[5])) return p+5;
if (NOASCII(p[6])) return p+6;
if (NOASCII(p[7])) return p+7;
#endif
}
memcpy(&t0, p, sizeof(bitint));
const bitint t1 = t0 & (MASK1*0x80);
if (t1) {
e = p + sizeof(bitint)-1;
byte_len = sizeof(bitint)-1;
break;
}
}
switch (e - p) {
default:
switch (byte_len % sizeof(bitint)) {
#ifdef MRB_64BIT
case 7: if (e[-7]&0x80) return e-7;
case 6: if (e[-6]&0x80) return e-6;