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| author | Will Newton <will.newton@linaro.org> | 2013-08-07 14:15:52 +0100 |
|---|---|---|
| committer | Will Newton <will.newton@linaro.org> | 2013-09-16 17:55:28 +0100 |
| commit | cd90698b541046c22544c2c057a4676368fd1d7f (patch) | |
| tree | 152f00ad520b5c8e106f821044f3b589da2a7872 | |
| parent | f06dd27b0c61ea8905103c9391f0900fa896bd74 (diff) | |
| download | glibc-cd90698b541046c22544c2c057a4676368fd1d7f.tar.gz glibc-cd90698b541046c22544c2c057a4676368fd1d7f.tar.xz glibc-cd90698b541046c22544c2c057a4676368fd1d7f.zip | |
ARM: Improve armv7 memcpy performance.
Only enter the aligned copy loop with buffers that can be 8-byte aligned. This improves performance slightly on Cortex-A9 and Cortex-A15 cores for large copies with buffers that are 4-byte aligned but not 8-byte aligned. ports/ChangeLog.arm: 2013-09-16 Will Newton <will.newton@linaro.org> * sysdeps/arm/armv7/multiarch/memcpy_impl.S: Tighten check on entry to aligned copy loop to improve performance.
| -rw-r--r-- | ports/ChangeLog.arm | 5 | ||||
| -rw-r--r-- | ports/sysdeps/arm/armv7/multiarch/memcpy_impl.S | 11 |
2 files changed, 10 insertions, 6 deletions
diff --git a/ports/ChangeLog.arm b/ports/ChangeLog.arm index 8ef09b1161..35f6f7765c 100644 --- a/ports/ChangeLog.arm +++ b/ports/ChangeLog.arm @@ -1,3 +1,8 @@ +2013-09-16 Will Newton <will.newton@linaro.org> + + * sysdeps/arm/armv7/multiarch/memcpy_impl.S: Tighten check + on entry to aligned copy loop to improve performance. + 2013-08-30 Roland McGrath <roland@hack.frob.com> * sysdeps/arm/armv6t2/strlen.S: Use sfi_pld and sfi_breg macros. diff --git a/ports/sysdeps/arm/armv7/multiarch/memcpy_impl.S b/ports/sysdeps/arm/armv7/multiarch/memcpy_impl.S index 3decad60bc..ad43a3db5a 100644 --- a/ports/sysdeps/arm/armv7/multiarch/memcpy_impl.S +++ b/ports/sysdeps/arm/armv7/multiarch/memcpy_impl.S @@ -24,7 +24,6 @@ ARMv6 (ARMv7-a if using Neon) ARM state Unaligned accesses - LDRD/STRD support unaligned word accesses */ @@ -369,8 +368,8 @@ ENTRY(memcpy) cfi_adjust_cfa_offset (FRAME_SIZE) cfi_rel_offset (tmp2, 0) cfi_remember_state - and tmp2, src, #3 - and tmp1, dst, #3 + and tmp2, src, #7 + and tmp1, dst, #7 cmp tmp1, tmp2 bne .Lcpy_notaligned @@ -381,9 +380,9 @@ ENTRY(memcpy) vmov.f32 s0, s0 #endif - /* SRC and DST have the same mutual 32-bit alignment, but we may + /* SRC and DST have the same mutual 64-bit alignment, but we may still need to pre-copy some bytes to get to natural alignment. - We bring DST into full 64-bit alignment. */ + We bring SRC and DST into full 64-bit alignment. */ lsls tmp2, dst, #29 beq 1f rsbs tmp2, tmp2, #0 @@ -515,7 +514,7 @@ ENTRY(memcpy) .Ltail63aligned: /* Count in tmp2. */ /* Copy up to 7 d-words of data. Similar to Ltail63unaligned, but - we know that the src and dest are 32-bit aligned so we can use + we know that the src and dest are 64-bit aligned so we can use LDRD/STRD to improve efficiency. */ /* TMP2 is now negative, but we don't care about that. The bottom six bits still tell us how many bytes are left to copy. */ |