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Make more progress on aarch64

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This commit is contained in:
Justine Tunney 2023-05-03 00:00:09 -07:00
parent 135080fd3e
commit aef9a69a60
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GPG key ID: BE714B4575D6E328
42 changed files with 563 additions and 387 deletions
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38
libc/str/strchr.c
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@ -55,6 +55,35 @@ noasan static inline const char *strchr_sse(const char *s, unsigned char c) {
}
#endif
static noasan inline const char *strchr_x64(const char *p, uint64_t c) {
unsigned a, b;
uint64_t w, x, y;
for (c *= 0x0101010101010101;; p += 8) {
w = (uint64_t)(255 & p[7]) << 070 | (uint64_t)(255 & p[6]) << 060 |
(uint64_t)(255 & p[5]) << 050 | (uint64_t)(255 & p[4]) << 040 |
(uint64_t)(255 & p[3]) << 030 | (uint64_t)(255 & p[2]) << 020 |
(uint64_t)(255 & p[1]) << 010 | (uint64_t)(255 & p[0]) << 000;
if ((x = ~(w ^ c) & ((w ^ c) - 0x0101010101010101) & 0x8080808080808080) |
(y = ~w & (w - 0x0101010101010101) & 0x8080808080808080)) {
if (x) {
a = __builtin_ctzll(x);
if (y) {
b = __builtin_ctzll(y);
if (a <= b) {
return p + (a >> 3);
} else {
return 0;
}
} else {
return p + (a >> 3);
}
} else {
return 0;
}
}
}
}
/**
* Returns pointer to first instance of character.
*
@ -77,6 +106,13 @@ char *strchr(const char *s, int c) {
_unassert(!r || *r || !(c & 255));
return (char *)r;
#else
return strchr_pure(s, c);
char *r;
for (c &= 255; (uintptr_t)s & 7; ++s) {
if ((*s & 255) == c) return s;
if (!*s) return NULL;
}
r = strchr_x64(s, c);
_unassert(!r || *r || !c);
return r;
#endif
}