[PATCH v2 1/1] msvcrt: Faster memcmp().
Jan Sikorski
wine at gitlab.winehq.org
Tue Apr 26 16:24:44 CDT 2022
From: Jan Sikorski <jsikorski at codeweavers.com>
Signed-off-by: Jan Sikorski <jsikorski at codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard at winehq.org>
---
dlls/msvcrt/string.c | 55 +++++++++++++++++++++++++++++++++++++++-----
1 file changed, 49 insertions(+), 6 deletions(-)
diff --git a/dlls/msvcrt/string.c b/dlls/msvcrt/string.c
index 3b352ac0bf2..181a161481c 100644
--- a/dlls/msvcrt/string.c
+++ b/dlls/msvcrt/string.c
@@ -2675,21 +2675,64 @@ int CDECL I10_OUTPUT(MSVCRT__LDOUBLE ld80, int prec, int flag, struct _I10_OUTPU
}
#undef I10_OUTPUT_MAX_PREC
-/*********************************************************************
- * memcmp (MSVCRT.@)
- */
-int __cdecl memcmp(const void *ptr1, const void *ptr2, size_t n)
+static inline int memcmp_bytes(const void *ptr1, const void *ptr2, size_t n)
{
const unsigned char *p1, *p2;
for (p1 = ptr1, p2 = ptr2; n; n--, p1++, p2++)
{
- if (*p1 < *p2) return -1;
- if (*p1 > *p2) return 1;
+ if (*p1 != *p2)
+ return *p1 > *p2 ? 1 : -1;
}
return 0;
}
+static inline int memcmp_blocks(const void *ptr1, const void *ptr2, size_t size)
+{
+ typedef uint64_t DECLSPEC_ALIGN(1) unaligned_ui64;
+
+ const uint64_t *p1 = ptr1;
+ const unaligned_ui64 *p2 = ptr2;
+ size_t remainder = size & (sizeof(uint64_t) - 1);
+ size_t block_count = size / sizeof(uint64_t);
+
+ while (block_count)
+ {
+ if (*p1 != *p2)
+ return memcmp_bytes(p1, p2, sizeof(uint64_t));
+
+ p1++;
+ p2++;
+ block_count--;
+ }
+
+ return memcmp_bytes(p1, p2, remainder);
+}
+
+/*********************************************************************
+ * memcmp (MSVCRT.@)
+ */
+int __cdecl memcmp(const void *ptr1, const void *ptr2, size_t n)
+{
+ const unsigned char *p1 = ptr1, *p2 = ptr2;
+ size_t align;
+ int result;
+
+ if (n < sizeof(uint64_t))
+ return memcmp_bytes(p1, p2, n);
+
+ align = -(size_t)p1 & (sizeof(uint64_t) - 1);
+
+ if ((result = memcmp_bytes(p1, p2, align)))
+ return result;
+
+ p1 += align;
+ p2 += align;
+ n -= align;
+
+ return memcmp_blocks(p1, p2, n);
+}
+
#if defined(__i386__) || defined(__x86_64__)
#ifdef __i386__
--
GitLab
https://gitlab.winehq.org/wine/wine/-/merge_requests/3
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