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I used these shell commands: ../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright (cd ../glibc && git commit -am"[this commit message]") and then ignored the output, which consisted lines saying "FOO: warning: copyright statement not found" for each of 7061 files FOO. I then removed trailing white space from math/tgmath.h, support/tst-support-open-dev-null-range.c, and sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following obscure pre-commit check failure diagnostics from Savannah. I don't know why I run into these diagnostics whereas others evidently do not. remote: *** 912-#endif remote: *** 913: remote: *** 914- remote: *** error: lines with trailing whitespace found ... remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
240 lines
6.5 KiB
ArmAsm
240 lines
6.5 KiB
ArmAsm
/* __memcmpeq optimized with EVEX.
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Copyright (C) 2017-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#if IS_IN (libc)
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/* __memcmpeq is implemented as:
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1. Use ymm vector compares when possible. The only case where
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vector compares is not possible for when size < VEC_SIZE
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and loading from either s1 or s2 would cause a page cross.
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2. Use xmm vector compare when size >= 8 bytes.
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3. Optimistically compare up to first 4 * VEC_SIZE one at a
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to check for early mismatches. Only do this if its guranteed the
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work is not wasted.
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4. If size is 8 * VEC_SIZE or less, unroll the loop.
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5. Compare 4 * VEC_SIZE at a time with the aligned first memory
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area.
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6. Use 2 vector compares when size is 2 * VEC_SIZE or less.
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7. Use 4 vector compares when size is 4 * VEC_SIZE or less.
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8. Use 8 vector compares when size is 8 * VEC_SIZE or less. */
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# include <sysdep.h>
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# ifndef MEMCMPEQ
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# define MEMCMPEQ __memcmpeq_evex
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# endif
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# define VMOVU_MASK vmovdqu8
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# define VMOVU vmovdqu64
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# define VPCMP vpcmpub
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# define VPTEST vptestmb
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# define VEC_SIZE 32
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# define PAGE_SIZE 4096
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# define YMM0 ymm16
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# define YMM1 ymm17
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# define YMM2 ymm18
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# define YMM3 ymm19
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# define YMM4 ymm20
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# define YMM5 ymm21
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# define YMM6 ymm22
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.section .text.evex, "ax", @progbits
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ENTRY_P2ALIGN (MEMCMPEQ, 6)
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# ifdef __ILP32__
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/* Clear the upper 32 bits. */
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movl %edx, %edx
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# endif
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cmp $VEC_SIZE, %RDX_LP
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/* Fall through for [0, VEC_SIZE] as its the hottest. */
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ja L(more_1x_vec)
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/* Create mask of bytes that are guranteed to be valid because
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of length (edx). Using masked movs allows us to skip checks for
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page crosses/zero size. */
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movl $-1, %ecx
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bzhil %edx, %ecx, %ecx
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kmovd %ecx, %k2
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/* Use masked loads as VEC_SIZE could page cross where length
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(edx) would not. */
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VMOVU_MASK (%rsi), %YMM2{%k2}
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VPCMP $4,(%rdi), %YMM2, %k1{%k2}
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kmovd %k1, %eax
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ret
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L(last_1x_vec):
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VMOVU -(VEC_SIZE * 1)(%rsi, %rdx), %YMM1
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VPCMP $4, -(VEC_SIZE * 1)(%rdi, %rdx), %YMM1, %k1
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kmovd %k1, %eax
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L(return_neq0):
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ret
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.p2align 4
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L(more_1x_vec):
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/* From VEC + 1 to 2 * VEC. */
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VMOVU (%rsi), %YMM1
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/* Use compare not equals to directly check for mismatch. */
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VPCMP $4,(%rdi), %YMM1, %k1
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kmovd %k1, %eax
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testl %eax, %eax
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jnz L(return_neq0)
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cmpq $(VEC_SIZE * 2), %rdx
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jbe L(last_1x_vec)
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/* Check second VEC no matter what. */
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VMOVU VEC_SIZE(%rsi), %YMM2
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VPCMP $4, VEC_SIZE(%rdi), %YMM2, %k1
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kmovd %k1, %eax
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testl %eax, %eax
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jnz L(return_neq0)
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/* Less than 4 * VEC. */
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cmpq $(VEC_SIZE * 4), %rdx
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jbe L(last_2x_vec)
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/* Check third and fourth VEC no matter what. */
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VMOVU (VEC_SIZE * 2)(%rsi), %YMM3
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VPCMP $4,(VEC_SIZE * 2)(%rdi), %YMM3, %k1
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kmovd %k1, %eax
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testl %eax, %eax
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jnz L(return_neq0)
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VMOVU (VEC_SIZE * 3)(%rsi), %YMM4
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VPCMP $4,(VEC_SIZE * 3)(%rdi), %YMM4, %k1
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kmovd %k1, %eax
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testl %eax, %eax
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jnz L(return_neq0)
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/* Go to 4x VEC loop. */
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cmpq $(VEC_SIZE * 8), %rdx
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ja L(more_8x_vec)
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/* Handle remainder of size = 4 * VEC + 1 to 8 * VEC without any
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branches. */
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VMOVU -(VEC_SIZE * 4)(%rsi, %rdx), %YMM1
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VMOVU -(VEC_SIZE * 3)(%rsi, %rdx), %YMM2
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addq %rdx, %rdi
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/* Wait to load from s1 until addressed adjust due to
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unlamination. */
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/* vpxor will be all 0s if s1 and s2 are equal. Otherwise it
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will have some 1s. */
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vpxorq -(VEC_SIZE * 4)(%rdi), %YMM1, %YMM1
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/* Ternary logic to xor -(VEC_SIZE * 3)(%rdi) with YMM2 while
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oring with YMM1. Result is stored in YMM1. */
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vpternlogd $0xde, -(VEC_SIZE * 3)(%rdi), %YMM1, %YMM2
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VMOVU -(VEC_SIZE * 2)(%rsi, %rdx), %YMM3
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vpxorq -(VEC_SIZE * 2)(%rdi), %YMM3, %YMM3
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/* Or together YMM1, YMM2, and YMM3 into YMM3. */
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VMOVU -(VEC_SIZE)(%rsi, %rdx), %YMM4
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vpxorq -(VEC_SIZE)(%rdi), %YMM4, %YMM4
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/* Or together YMM2, YMM3, and YMM4 into YMM4. */
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vpternlogd $0xfe, %YMM2, %YMM3, %YMM4
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/* Compare YMM4 with 0. If any 1s s1 and s2 don't match. */
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VPTEST %YMM4, %YMM4, %k1
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kmovd %k1, %eax
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ret
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.p2align 4
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L(more_8x_vec):
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/* Set end of s1 in rdx. */
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leaq -(VEC_SIZE * 4)(%rdi, %rdx), %rdx
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/* rsi stores s2 - s1. This allows loop to only update one
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pointer. */
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subq %rdi, %rsi
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/* Align s1 pointer. */
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andq $-VEC_SIZE, %rdi
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/* Adjust because first 4x vec where check already. */
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subq $-(VEC_SIZE * 4), %rdi
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.p2align 4
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L(loop_4x_vec):
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VMOVU (%rsi, %rdi), %YMM1
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vpxorq (%rdi), %YMM1, %YMM1
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VMOVU VEC_SIZE(%rsi, %rdi), %YMM2
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vpternlogd $0xde,(VEC_SIZE)(%rdi), %YMM1, %YMM2
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VMOVU (VEC_SIZE * 2)(%rsi, %rdi), %YMM3
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vpxorq (VEC_SIZE * 2)(%rdi), %YMM3, %YMM3
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VMOVU (VEC_SIZE * 3)(%rsi, %rdi), %YMM4
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vpxorq (VEC_SIZE * 3)(%rdi), %YMM4, %YMM4
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vpternlogd $0xfe, %YMM2, %YMM3, %YMM4
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VPTEST %YMM4, %YMM4, %k1
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kmovd %k1, %eax
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testl %eax, %eax
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jnz L(return_neq2)
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subq $-(VEC_SIZE * 4), %rdi
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cmpq %rdx, %rdi
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jb L(loop_4x_vec)
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subq %rdx, %rdi
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VMOVU (VEC_SIZE * 3)(%rsi, %rdx), %YMM4
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vpxorq (VEC_SIZE * 3)(%rdx), %YMM4, %YMM4
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/* rdi has 4 * VEC_SIZE - remaining length. */
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cmpl $(VEC_SIZE * 3), %edi
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jae L(8x_last_1x_vec)
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/* Load regardless of branch. */
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VMOVU (VEC_SIZE * 2)(%rsi, %rdx), %YMM3
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/* Ternary logic to xor (VEC_SIZE * 2)(%rdx) with YMM3 while
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oring with YMM4. Result is stored in YMM4. */
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vpternlogd $0xf6,(VEC_SIZE * 2)(%rdx), %YMM3, %YMM4
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cmpl $(VEC_SIZE * 2), %edi
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jae L(8x_last_2x_vec)
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VMOVU VEC_SIZE(%rsi, %rdx), %YMM2
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vpxorq VEC_SIZE(%rdx), %YMM2, %YMM2
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VMOVU (%rsi, %rdx), %YMM1
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vpxorq (%rdx), %YMM1, %YMM1
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vpternlogd $0xfe, %YMM1, %YMM2, %YMM4
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L(8x_last_1x_vec):
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L(8x_last_2x_vec):
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VPTEST %YMM4, %YMM4, %k1
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kmovd %k1, %eax
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L(return_neq2):
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ret
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.p2align 4,, 8
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L(last_2x_vec):
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VMOVU -(VEC_SIZE * 2)(%rsi, %rdx), %YMM1
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vpxorq -(VEC_SIZE * 2)(%rdi, %rdx), %YMM1, %YMM1
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VMOVU -(VEC_SIZE * 1)(%rsi, %rdx), %YMM2
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vpternlogd $0xde, -(VEC_SIZE * 1)(%rdi, %rdx), %YMM1, %YMM2
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VPTEST %YMM2, %YMM2, %k1
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kmovd %k1, %eax
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ret
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/* 1 Bytes from next cache line. */
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END (MEMCMPEQ)
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#endif
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