573 lines
14 KiB
ArmAsm
573 lines
14 KiB
ArmAsm
/* memchr/wmemchr optimized with 256-bit EVEX instructions.
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Copyright (C) 2021-2022 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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#include <isa-level.h>
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#include <sysdep.h>
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#if ISA_SHOULD_BUILD (4)
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# ifndef MEMCHR
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# define MEMCHR __memchr_evex
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# endif
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# ifdef USE_AS_WMEMCHR
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# define VPBROADCAST vpbroadcastd
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# define VPMINU vpminud
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# define VPCMP vpcmpd
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# define VPCMPEQ vpcmpeqd
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# define CHAR_SIZE 4
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# else
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# define VPBROADCAST vpbroadcastb
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# define VPMINU vpminub
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# define VPCMP vpcmpb
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# define VPCMPEQ vpcmpeqb
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# define CHAR_SIZE 1
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# endif
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/* In the 4x loop the RTM and non-RTM versions have data pointer
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off by VEC_SIZE * 4 with RTM version being VEC_SIZE * 4 greater.
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This is represented by BASE_OFFSET. As well because the RTM
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version uses vpcmp which stores a bit per element compared where
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the non-RTM version uses vpcmpeq which stores a bit per byte
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compared RET_SCALE of CHAR_SIZE is only relevant for the RTM
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version. */
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# ifdef USE_IN_RTM
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# define VZEROUPPER
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# define BASE_OFFSET (VEC_SIZE * 4)
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# define RET_SCALE CHAR_SIZE
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# else
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# define VZEROUPPER vzeroupper
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# define BASE_OFFSET 0
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# define RET_SCALE 1
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# endif
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/* In the return from 4x loop memchr and rawmemchr versions have
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data pointers off by VEC_SIZE * 4 with memchr version being
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VEC_SIZE * 4 greater. */
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# ifdef USE_AS_RAWMEMCHR
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# define RET_OFFSET (BASE_OFFSET - (VEC_SIZE * 4))
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# define RAW_PTR_REG rcx
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# define ALGN_PTR_REG rdi
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# else
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# define RET_OFFSET BASE_OFFSET
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# define RAW_PTR_REG rdi
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# define ALGN_PTR_REG rcx
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# endif
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# define XMMZERO xmm23
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# define YMMZERO ymm23
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# define XMMMATCH xmm16
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# define YMMMATCH 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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# ifndef SECTION
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# define SECTION(p) p##.evex
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# endif
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# define VEC_SIZE 32
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# define CHAR_PER_VEC (VEC_SIZE / CHAR_SIZE)
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# define PAGE_SIZE 4096
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.section SECTION(.text),"ax",@progbits
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ENTRY_P2ALIGN (MEMCHR, 6)
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# ifndef USE_AS_RAWMEMCHR
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/* Check for zero length. */
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test %RDX_LP, %RDX_LP
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jz L(zero)
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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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# endif
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/* Broadcast CHAR to YMMMATCH. */
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VPBROADCAST %esi, %YMMMATCH
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/* Check if we may cross page boundary with one vector load. */
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movl %edi, %eax
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andl $(PAGE_SIZE - 1), %eax
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cmpl $(PAGE_SIZE - VEC_SIZE), %eax
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ja L(cross_page_boundary)
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/* Check the first VEC_SIZE bytes. */
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VPCMP $0, (%rdi), %YMMMATCH, %k0
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kmovd %k0, %eax
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# ifndef USE_AS_RAWMEMCHR
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/* If length < CHAR_PER_VEC handle special. */
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cmpq $CHAR_PER_VEC, %rdx
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jbe L(first_vec_x0)
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# endif
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testl %eax, %eax
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jz L(aligned_more)
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tzcntl %eax, %eax
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# ifdef USE_AS_WMEMCHR
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/* NB: Multiply bytes by CHAR_SIZE to get the wchar_t count. */
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leaq (%rdi, %rax, CHAR_SIZE), %rax
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# else
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addq %rdi, %rax
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# endif
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ret
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# ifndef USE_AS_RAWMEMCHR
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L(zero):
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xorl %eax, %eax
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ret
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.p2align 4
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L(first_vec_x0):
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/* Check if first match was before length. NB: tzcnt has false data-
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dependency on destination. eax already had a data-dependency on esi
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so this should have no affect here. */
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tzcntl %eax, %esi
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# ifdef USE_AS_WMEMCHR
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leaq (%rdi, %rsi, CHAR_SIZE), %rdi
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# else
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addq %rsi, %rdi
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# endif
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xorl %eax, %eax
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cmpl %esi, %edx
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cmovg %rdi, %rax
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ret
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# endif
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.p2align 4
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L(cross_page_boundary):
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/* Save pointer before aligning as its original value is
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necessary for computer return address if byte is found or
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adjusting length if it is not and this is memchr. */
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movq %rdi, %rcx
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/* Align data to VEC_SIZE. ALGN_PTR_REG is rcx for memchr and rdi
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for rawmemchr. */
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andq $-VEC_SIZE, %ALGN_PTR_REG
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VPCMP $0, (%ALGN_PTR_REG), %YMMMATCH, %k0
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kmovd %k0, %r8d
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# ifdef USE_AS_WMEMCHR
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/* NB: Divide shift count by 4 since each bit in K0 represent 4
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bytes. */
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sarl $2, %eax
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# endif
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# ifndef USE_AS_RAWMEMCHR
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movl $(PAGE_SIZE / CHAR_SIZE), %esi
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subl %eax, %esi
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# endif
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# ifdef USE_AS_WMEMCHR
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andl $(CHAR_PER_VEC - 1), %eax
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# endif
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/* Remove the leading bytes. */
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sarxl %eax, %r8d, %eax
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# ifndef USE_AS_RAWMEMCHR
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/* Check the end of data. */
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cmpq %rsi, %rdx
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jbe L(first_vec_x0)
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# endif
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testl %eax, %eax
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jz L(cross_page_continue)
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tzcntl %eax, %eax
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# ifdef USE_AS_WMEMCHR
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/* NB: Multiply bytes by CHAR_SIZE to get the wchar_t count. */
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leaq (%RAW_PTR_REG, %rax, CHAR_SIZE), %rax
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# else
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addq %RAW_PTR_REG, %rax
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# endif
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ret
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.p2align 4
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L(first_vec_x1):
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tzcntl %eax, %eax
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leaq VEC_SIZE(%rdi, %rax, CHAR_SIZE), %rax
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ret
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.p2align 4
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L(first_vec_x2):
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tzcntl %eax, %eax
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leaq (VEC_SIZE * 2)(%rdi, %rax, CHAR_SIZE), %rax
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ret
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.p2align 4
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L(first_vec_x3):
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tzcntl %eax, %eax
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leaq (VEC_SIZE * 3)(%rdi, %rax, CHAR_SIZE), %rax
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ret
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.p2align 4
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L(first_vec_x4):
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tzcntl %eax, %eax
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leaq (VEC_SIZE * 4)(%rdi, %rax, CHAR_SIZE), %rax
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ret
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.p2align 5
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L(aligned_more):
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/* Check the first 4 * VEC_SIZE. Only one VEC_SIZE at a time
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since data is only aligned to VEC_SIZE. */
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# ifndef USE_AS_RAWMEMCHR
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/* Align data to VEC_SIZE. */
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L(cross_page_continue):
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xorl %ecx, %ecx
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subl %edi, %ecx
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andq $-VEC_SIZE, %rdi
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/* esi is for adjusting length to see if near the end. */
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leal (VEC_SIZE * 5)(%rdi, %rcx), %esi
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# ifdef USE_AS_WMEMCHR
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/* NB: Divide bytes by 4 to get the wchar_t count. */
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sarl $2, %esi
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# endif
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# else
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andq $-VEC_SIZE, %rdi
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L(cross_page_continue):
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# endif
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/* Load first VEC regardless. */
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VPCMP $0, (VEC_SIZE)(%rdi), %YMMMATCH, %k0
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kmovd %k0, %eax
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# ifndef USE_AS_RAWMEMCHR
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/* Adjust length. If near end handle specially. */
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subq %rsi, %rdx
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jbe L(last_4x_vec_or_less)
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# endif
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testl %eax, %eax
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jnz L(first_vec_x1)
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VPCMP $0, (VEC_SIZE * 2)(%rdi), %YMMMATCH, %k0
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kmovd %k0, %eax
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testl %eax, %eax
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jnz L(first_vec_x2)
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VPCMP $0, (VEC_SIZE * 3)(%rdi), %YMMMATCH, %k0
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kmovd %k0, %eax
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testl %eax, %eax
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jnz L(first_vec_x3)
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VPCMP $0, (VEC_SIZE * 4)(%rdi), %YMMMATCH, %k0
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kmovd %k0, %eax
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testl %eax, %eax
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jnz L(first_vec_x4)
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# ifndef USE_AS_RAWMEMCHR
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/* Check if at last CHAR_PER_VEC * 4 length. */
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subq $(CHAR_PER_VEC * 4), %rdx
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jbe L(last_4x_vec_or_less_cmpeq)
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/* +VEC_SIZE if USE_IN_RTM otherwise +VEC_SIZE * 5. */
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addq $(VEC_SIZE + (VEC_SIZE * 4 - BASE_OFFSET)), %rdi
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/* Align data to VEC_SIZE * 4 for the loop and readjust length.
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*/
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# ifdef USE_AS_WMEMCHR
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movl %edi, %ecx
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andq $-(4 * VEC_SIZE), %rdi
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subl %edi, %ecx
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/* NB: Divide bytes by 4 to get the wchar_t count. */
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sarl $2, %ecx
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addq %rcx, %rdx
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# else
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addq %rdi, %rdx
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andq $-(4 * VEC_SIZE), %rdi
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subq %rdi, %rdx
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# endif
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# else
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addq $(VEC_SIZE + (VEC_SIZE * 4 - BASE_OFFSET)), %rdi
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andq $-(4 * VEC_SIZE), %rdi
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# endif
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# ifdef USE_IN_RTM
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vpxorq %XMMZERO, %XMMZERO, %XMMZERO
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# else
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/* copy ymmmatch to ymm0 so we can use vpcmpeq which is not
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encodable with EVEX registers (ymm16-ymm31). */
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vmovdqa64 %YMMMATCH, %ymm0
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# endif
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/* Compare 4 * VEC at a time forward. */
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.p2align 4
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L(loop_4x_vec):
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/* Two versions of the loop. One that does not require
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vzeroupper by not using ymm0-ymm15 and another does that require
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vzeroupper because it uses ymm0-ymm15. The reason why ymm0-ymm15
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is used at all is because there is no EVEX encoding vpcmpeq and
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with vpcmpeq this loop can be performed more efficiently. The
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non-vzeroupper version is safe for RTM while the vzeroupper
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version should be prefered if RTM are not supported. */
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# ifdef USE_IN_RTM
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/* It would be possible to save some instructions using 4x VPCMP
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but bottleneck on port 5 makes it not woth it. */
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VPCMP $4, (VEC_SIZE * 4)(%rdi), %YMMMATCH, %k1
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/* xor will set bytes match esi to zero. */
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vpxorq (VEC_SIZE * 5)(%rdi), %YMMMATCH, %YMM2
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vpxorq (VEC_SIZE * 6)(%rdi), %YMMMATCH, %YMM3
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VPCMP $0, (VEC_SIZE * 7)(%rdi), %YMMMATCH, %k3
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/* Reduce VEC2 / VEC3 with min and VEC1 with zero mask. */
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VPMINU %YMM2, %YMM3, %YMM3{%k1}{z}
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VPCMP $0, %YMM3, %YMMZERO, %k2
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# else
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/* Since vptern can only take 3x vectors fastest to do 1 vec
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seperately with EVEX vpcmp. */
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# ifdef USE_AS_WMEMCHR
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/* vptern can only accept masks for epi32/epi64 so can only save
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instruction using not equals mask on vptern with wmemchr. */
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VPCMP $4, (%rdi), %YMMMATCH, %k1
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# else
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VPCMP $0, (%rdi), %YMMMATCH, %k1
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# endif
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/* Compare 3x with vpcmpeq and or them all together with vptern.
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*/
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VPCMPEQ VEC_SIZE(%rdi), %ymm0, %ymm2
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VPCMPEQ (VEC_SIZE * 2)(%rdi), %ymm0, %ymm3
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VPCMPEQ (VEC_SIZE * 3)(%rdi), %ymm0, %ymm4
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# ifdef USE_AS_WMEMCHR
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/* This takes the not of or between ymm2, ymm3, ymm4 as well as
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combines result from VEC0 with zero mask. */
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vpternlogd $1, %ymm2, %ymm3, %ymm4{%k1}{z}
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vpmovmskb %ymm4, %ecx
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# else
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/* 254 is mask for oring ymm2, ymm3, ymm4 into ymm4. */
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vpternlogd $254, %ymm2, %ymm3, %ymm4
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vpmovmskb %ymm4, %ecx
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kmovd %k1, %eax
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# endif
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# endif
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# ifdef USE_AS_RAWMEMCHR
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subq $-(VEC_SIZE * 4), %rdi
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# endif
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# ifdef USE_IN_RTM
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kortestd %k2, %k3
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# else
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# ifdef USE_AS_WMEMCHR
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/* ecx contains not of matches. All 1s means no matches. incl will
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overflow and set zeroflag if that is the case. */
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incl %ecx
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# else
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/* If either VEC1 (eax) or VEC2-VEC4 (ecx) are not zero. Adding
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to ecx is not an issue because if eax is non-zero it will be
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used for returning the match. If it is zero the add does
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nothing. */
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addq %rax, %rcx
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# endif
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# endif
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# ifdef USE_AS_RAWMEMCHR
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jz L(loop_4x_vec)
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# else
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jnz L(loop_4x_vec_end)
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subq $-(VEC_SIZE * 4), %rdi
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subq $(CHAR_PER_VEC * 4), %rdx
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ja L(loop_4x_vec)
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/* Fall through into less than 4 remaining vectors of length case.
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*/
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VPCMP $0, BASE_OFFSET(%rdi), %YMMMATCH, %k0
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addq $(BASE_OFFSET - VEC_SIZE), %rdi
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kmovd %k0, %eax
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VZEROUPPER
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L(last_4x_vec_or_less):
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/* Check if first VEC contained match. */
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testl %eax, %eax
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jnz L(first_vec_x1_check)
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/* If remaining length > CHAR_PER_VEC * 2. */
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addl $(CHAR_PER_VEC * 2), %edx
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jg L(last_4x_vec)
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L(last_2x_vec):
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/* If remaining length < CHAR_PER_VEC. */
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addl $CHAR_PER_VEC, %edx
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jle L(zero_end)
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/* Check VEC2 and compare any match with remaining length. */
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VPCMP $0, (VEC_SIZE * 2)(%rdi), %YMMMATCH, %k0
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kmovd %k0, %eax
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tzcntl %eax, %eax
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cmpl %eax, %edx
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jbe L(set_zero_end)
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leaq (VEC_SIZE * 2)(%rdi, %rax, CHAR_SIZE), %rax
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L(zero_end):
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ret
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L(set_zero_end):
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xorl %eax, %eax
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ret
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.p2align 4
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L(first_vec_x1_check):
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/* eax must be non-zero. Use bsfl to save code size. */
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bsfl %eax, %eax
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/* Adjust length. */
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subl $-(CHAR_PER_VEC * 4), %edx
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/* Check if match within remaining length. */
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cmpl %eax, %edx
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jbe L(set_zero_end)
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/* NB: Multiply bytes by CHAR_SIZE to get the wchar_t count. */
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leaq VEC_SIZE(%rdi, %rax, CHAR_SIZE), %rax
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ret
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.p2align 4
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L(loop_4x_vec_end):
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# endif
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/* rawmemchr will fall through into this if match was found in
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loop. */
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# if defined USE_IN_RTM || defined USE_AS_WMEMCHR
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/* k1 has not of matches with VEC1. */
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kmovd %k1, %eax
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# ifdef USE_AS_WMEMCHR
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subl $((1 << CHAR_PER_VEC) - 1), %eax
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# else
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incl %eax
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# endif
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# else
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/* eax already has matches for VEC1. */
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testl %eax, %eax
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# endif
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jnz L(last_vec_x1_return)
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# ifdef USE_IN_RTM
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VPCMP $0, %YMM2, %YMMZERO, %k0
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kmovd %k0, %eax
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# else
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vpmovmskb %ymm2, %eax
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# endif
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testl %eax, %eax
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jnz L(last_vec_x2_return)
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# ifdef USE_IN_RTM
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kmovd %k2, %eax
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testl %eax, %eax
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jnz L(last_vec_x3_return)
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kmovd %k3, %eax
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tzcntl %eax, %eax
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leaq (VEC_SIZE * 3 + RET_OFFSET)(%rdi, %rax, CHAR_SIZE), %rax
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# else
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vpmovmskb %ymm3, %eax
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/* Combine matches in VEC3 (eax) with matches in VEC4 (ecx). */
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salq $VEC_SIZE, %rcx
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orq %rcx, %rax
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tzcntq %rax, %rax
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leaq (VEC_SIZE * 2 + RET_OFFSET)(%rdi, %rax), %rax
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VZEROUPPER
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# endif
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ret
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.p2align 4,, 10
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L(last_vec_x1_return):
|
|
tzcntl %eax, %eax
|
|
# if defined USE_AS_WMEMCHR || RET_OFFSET != 0
|
|
/* NB: Multiply bytes by CHAR_SIZE to get the wchar_t count. */
|
|
leaq RET_OFFSET(%rdi, %rax, CHAR_SIZE), %rax
|
|
# else
|
|
addq %rdi, %rax
|
|
# endif
|
|
VZEROUPPER
|
|
ret
|
|
|
|
.p2align 4
|
|
L(last_vec_x2_return):
|
|
tzcntl %eax, %eax
|
|
/* NB: Multiply bytes by RET_SCALE to get the wchar_t count
|
|
if relevant (RET_SCALE = CHAR_SIZE if USE_AS_WMEMCHAR and
|
|
USE_IN_RTM are both defined. Otherwise RET_SCALE = 1. */
|
|
leaq (VEC_SIZE + RET_OFFSET)(%rdi, %rax, RET_SCALE), %rax
|
|
VZEROUPPER
|
|
ret
|
|
|
|
# ifdef USE_IN_RTM
|
|
.p2align 4
|
|
L(last_vec_x3_return):
|
|
tzcntl %eax, %eax
|
|
/* NB: Multiply bytes by CHAR_SIZE to get the wchar_t count. */
|
|
leaq (VEC_SIZE * 2 + RET_OFFSET)(%rdi, %rax, CHAR_SIZE), %rax
|
|
ret
|
|
# endif
|
|
|
|
# ifndef USE_AS_RAWMEMCHR
|
|
.p2align 4,, 5
|
|
L(last_4x_vec_or_less_cmpeq):
|
|
VPCMP $0, (VEC_SIZE * 5)(%rdi), %YMMMATCH, %k0
|
|
kmovd %k0, %eax
|
|
subq $-(VEC_SIZE * 4), %rdi
|
|
/* Check first VEC regardless. */
|
|
testl %eax, %eax
|
|
jnz L(first_vec_x1_check)
|
|
|
|
/* If remaining length <= CHAR_PER_VEC * 2. */
|
|
addl $(CHAR_PER_VEC * 2), %edx
|
|
jle L(last_2x_vec)
|
|
|
|
.p2align 4
|
|
L(last_4x_vec):
|
|
VPCMP $0, (VEC_SIZE * 2)(%rdi), %YMMMATCH, %k0
|
|
kmovd %k0, %eax
|
|
testl %eax, %eax
|
|
jnz L(last_vec_x2)
|
|
|
|
|
|
VPCMP $0, (VEC_SIZE * 3)(%rdi), %YMMMATCH, %k0
|
|
kmovd %k0, %eax
|
|
/* Create mask for possible matches within remaining length. */
|
|
# ifdef USE_AS_WMEMCHR
|
|
movl $((1 << (CHAR_PER_VEC * 2)) - 1), %ecx
|
|
bzhil %edx, %ecx, %ecx
|
|
# else
|
|
movq $-1, %rcx
|
|
bzhiq %rdx, %rcx, %rcx
|
|
# endif
|
|
/* Test matches in data against length match. */
|
|
andl %ecx, %eax
|
|
jnz L(last_vec_x3)
|
|
|
|
/* if remaining length <= CHAR_PER_VEC * 3 (Note this is after
|
|
remaining length was found to be > CHAR_PER_VEC * 2. */
|
|
subl $CHAR_PER_VEC, %edx
|
|
jbe L(zero_end2)
|
|
|
|
|
|
VPCMP $0, (VEC_SIZE * 4)(%rdi), %YMMMATCH, %k0
|
|
kmovd %k0, %eax
|
|
/* Shift remaining length mask for last VEC. */
|
|
# ifdef USE_AS_WMEMCHR
|
|
shrl $CHAR_PER_VEC, %ecx
|
|
# else
|
|
shrq $CHAR_PER_VEC, %rcx
|
|
# endif
|
|
andl %ecx, %eax
|
|
jz L(zero_end2)
|
|
bsfl %eax, %eax
|
|
leaq (VEC_SIZE * 4)(%rdi, %rax, CHAR_SIZE), %rax
|
|
L(zero_end2):
|
|
ret
|
|
|
|
L(last_vec_x2):
|
|
tzcntl %eax, %eax
|
|
leaq (VEC_SIZE * 2)(%rdi, %rax, CHAR_SIZE), %rax
|
|
ret
|
|
|
|
.p2align 4
|
|
L(last_vec_x3):
|
|
tzcntl %eax, %eax
|
|
leaq (VEC_SIZE * 3)(%rdi, %rax, CHAR_SIZE), %rax
|
|
ret
|
|
# endif
|
|
/* 7 bytes from next cache line. */
|
|
END (MEMCHR)
|
|
#endif
|