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| author | Wilco Dijkstra <wilco.dijkstra@arm.com> | 2023-01-11 13:51:48 +0000 |
|---|---|---|
| committer | Wilco Dijkstra <wilco.dijkstra@arm.com> | 2023-01-17 15:09:18 +0000 |
| commit | 1bbb1a2022e126f21810d3d0ebe0a975d5243e43 (patch) | |
| tree | 2e68581e051a3cd38389e118b9f1e5f4d26c7b6c | |
| parent | 00776241776e67fc666b896c1e85770f4f3ec1e1 (diff) | |
| download | glibc-1bbb1a2022e126f21810d3d0ebe0a975d5243e43.tar.gz glibc-1bbb1a2022e126f21810d3d0ebe0a975d5243e43.tar.xz glibc-1bbb1a2022e126f21810d3d0ebe0a975d5243e43.zip | |
AArch64: Improve strlen_asimd
Use shrn for the mask, merge tst+bne into cbnz, and tweak code alignment. Performance improves slightly as a result. Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
| -rw-r--r-- | sysdeps/aarch64/multiarch/strlen_asimd.S | 16 |
1 files changed, 4 insertions, 12 deletions
diff --git a/sysdeps/aarch64/multiarch/strlen_asimd.S b/sysdeps/aarch64/multiarch/strlen_asimd.S index ca6ab96ecf..490439491d 100644 --- a/sysdeps/aarch64/multiarch/strlen_asimd.S +++ b/sysdeps/aarch64/multiarch/strlen_asimd.S @@ -48,6 +48,7 @@ #define tmp x2 #define tmpw w2 #define synd x3 +#define syndw w3 #define shift x4 /* For the first 32 bytes, NUL detection works on the principle that @@ -87,7 +88,6 @@ ENTRY (__strlen_asimd) PTR_ARG (0) - and tmp1, srcin, MIN_PAGE_SIZE - 1 cmp tmp1, MIN_PAGE_SIZE - 32 b.hi L(page_cross) @@ -123,7 +123,6 @@ ENTRY (__strlen_asimd) add len, len, tmp1, lsr 3 ret - .p2align 3 /* Look for a NUL byte at offset 16..31 in the string. */ L(bytes16_31): ldp data1, data2, [srcin, 16] @@ -151,6 +150,7 @@ L(bytes16_31): add len, len, tmp1, lsr 3 ret + nop L(loop_entry): bic src, srcin, 31 @@ -166,18 +166,12 @@ L(loop): /* Low 32 bits of synd are non-zero if a NUL was found in datav1. */ cmeq maskv.16b, datav1.16b, 0 sub len, src, srcin - tst synd, 0xffffffff - b.ne 1f + cbnz syndw, 1f cmeq maskv.16b, datav2.16b, 0 add len, len, 16 1: /* Generate a bitmask and compute correct byte offset. */ -#ifdef __AARCH64EB__ - bic maskv.8h, 0xf0 -#else - bic maskv.8h, 0x0f, lsl 8 -#endif - umaxp maskv.16b, maskv.16b, maskv.16b + shrn maskv.8b, maskv.8h, 4 fmov synd, maskd #ifndef __AARCH64EB__ rbit synd, synd @@ -186,8 +180,6 @@ L(loop): add len, len, tmp, lsr 2 ret - .p2align 4 - L(page_cross): bic src, srcin, 31 mov tmpw, 0x0c03 |