mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-22 21:10:07 +00:00
236 lines
5.3 KiB
ArmAsm
236 lines
5.3 KiB
ArmAsm
/* strlen/wcslen optimized with 256/512-bit EVEX instructions.
|
|
Copyright (C) 2021-2024 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
|
|
#include <isa-level.h>
|
|
|
|
#if ISA_SHOULD_BUILD (4)
|
|
|
|
# include <sysdep.h>
|
|
|
|
# ifdef USE_AS_WCSLEN
|
|
# define VPCMPEQ vpcmpeqd
|
|
# define VPCMPNEQ vpcmpneqd
|
|
# define VPTESTN vptestnmd
|
|
# define VPTEST vptestmd
|
|
# define VPMINU vpminud
|
|
# define CHAR_SIZE 4
|
|
# define CHAR_SIZE_SHIFT_REG(reg) sar $2, %reg
|
|
# else
|
|
# define VPCMPEQ vpcmpeqb
|
|
# define VPCMPNEQ vpcmpneqb
|
|
# define VPTESTN vptestnmb
|
|
# define VPTEST vptestmb
|
|
# define VPMINU vpminub
|
|
# define CHAR_SIZE 1
|
|
# define CHAR_SIZE_SHIFT_REG(reg)
|
|
|
|
# define REG_WIDTH VEC_SIZE
|
|
# endif
|
|
|
|
# define CHAR_PER_VEC (VEC_SIZE / CHAR_SIZE)
|
|
|
|
# include "reg-macros.h"
|
|
|
|
# if CHAR_PER_VEC == 64
|
|
|
|
# define TAIL_RETURN_LBL first_vec_x2
|
|
# define TAIL_RETURN_OFFSET (CHAR_PER_VEC * 2)
|
|
|
|
# define FALLTHROUGH_RETURN_LBL first_vec_x3
|
|
# define FALLTHROUGH_RETURN_OFFSET (CHAR_PER_VEC * 3)
|
|
|
|
# else
|
|
|
|
# define TAIL_RETURN_LBL first_vec_x3
|
|
# define TAIL_RETURN_OFFSET (CHAR_PER_VEC * 3)
|
|
|
|
# define FALLTHROUGH_RETURN_LBL first_vec_x2
|
|
# define FALLTHROUGH_RETURN_OFFSET (CHAR_PER_VEC * 2)
|
|
# endif
|
|
|
|
# define XZERO VMM_128(0)
|
|
# define VZERO VMM(0)
|
|
# define PAGE_SIZE 4096
|
|
|
|
.section SECTION(.text), "ax", @progbits
|
|
ENTRY_P2ALIGN(STRLEN, 6)
|
|
movl %edi, %eax
|
|
vpxorq %XZERO, %XZERO, %XZERO
|
|
andl $(PAGE_SIZE - 1), %eax
|
|
cmpl $(PAGE_SIZE - VEC_SIZE), %eax
|
|
ja L(cross_page_boundary)
|
|
|
|
/* Check the first VEC_SIZE bytes. Each bit in K0 represents a
|
|
null byte. */
|
|
VPCMPEQ (%rdi), %VZERO, %k0
|
|
KMOV %k0, %VRAX
|
|
test %VRAX, %VRAX
|
|
jz L(aligned_more)
|
|
bsf %VRAX, %VRAX
|
|
ret
|
|
|
|
.p2align 4,, 8
|
|
L(first_vec_x4):
|
|
bsf %VRAX, %VRAX
|
|
subl %ecx, %edi
|
|
CHAR_SIZE_SHIFT_REG (edi)
|
|
leal (CHAR_PER_VEC * 4)(%rdi, %rax), %eax
|
|
ret
|
|
|
|
|
|
|
|
/* Aligned more for strnlen compares remaining length vs 2 *
|
|
CHAR_PER_VEC, 4 * CHAR_PER_VEC, and 8 * CHAR_PER_VEC before
|
|
going to the loop. */
|
|
.p2align 4,, 10
|
|
L(aligned_more):
|
|
movq %rdi, %rcx
|
|
andq $(VEC_SIZE * -1), %rdi
|
|
L(cross_page_continue):
|
|
/* Remaining length >= 2 * CHAR_PER_VEC so do VEC0/VEC1 without
|
|
rechecking bounds. */
|
|
VPCMPEQ (VEC_SIZE * 1)(%rdi), %VZERO, %k0
|
|
KMOV %k0, %VRAX
|
|
test %VRAX, %VRAX
|
|
jnz L(first_vec_x1)
|
|
|
|
VPCMPEQ (VEC_SIZE * 2)(%rdi), %VZERO, %k0
|
|
KMOV %k0, %VRAX
|
|
test %VRAX, %VRAX
|
|
jnz L(first_vec_x2)
|
|
|
|
VPCMPEQ (VEC_SIZE * 3)(%rdi), %VZERO, %k0
|
|
KMOV %k0, %VRAX
|
|
test %VRAX, %VRAX
|
|
jnz L(first_vec_x3)
|
|
|
|
VPCMPEQ (VEC_SIZE * 4)(%rdi), %VZERO, %k0
|
|
KMOV %k0, %VRAX
|
|
test %VRAX, %VRAX
|
|
jnz L(first_vec_x4)
|
|
|
|
subq $(VEC_SIZE * -1), %rdi
|
|
|
|
# if CHAR_PER_VEC == 64
|
|
/* No partial register stalls on processors that we use evex512
|
|
on and this saves code size. */
|
|
xorb %dil, %dil
|
|
# else
|
|
andq $-(VEC_SIZE * 4), %rdi
|
|
# endif
|
|
|
|
|
|
|
|
/* Compare 4 * VEC at a time forward. */
|
|
.p2align 4
|
|
L(loop_4x_vec):
|
|
VMOVA (VEC_SIZE * 4)(%rdi), %VMM(1)
|
|
VPMINU (VEC_SIZE * 5)(%rdi), %VMM(1), %VMM(2)
|
|
VMOVA (VEC_SIZE * 6)(%rdi), %VMM(3)
|
|
VPMINU (VEC_SIZE * 7)(%rdi), %VMM(3), %VMM(4)
|
|
VPTESTN %VMM(2), %VMM(2), %k0
|
|
VPTESTN %VMM(4), %VMM(4), %k2
|
|
|
|
subq $-(VEC_SIZE * 4), %rdi
|
|
KORTEST %k0, %k2
|
|
jz L(loop_4x_vec)
|
|
|
|
VPTESTN %VMM(1), %VMM(1), %k1
|
|
KMOV %k1, %VRAX
|
|
test %VRAX, %VRAX
|
|
jnz L(first_vec_x0)
|
|
|
|
KMOV %k0, %VRAX
|
|
test %VRAX, %VRAX
|
|
jnz L(first_vec_x1)
|
|
|
|
VPTESTN %VMM(3), %VMM(3), %k0
|
|
|
|
# if CHAR_PER_VEC == 64
|
|
KMOV %k0, %VRAX
|
|
test %VRAX, %VRAX
|
|
jnz L(first_vec_x2)
|
|
KMOV %k2, %VRAX
|
|
# else
|
|
/* We can only combine last 2x VEC masks if CHAR_PER_VEC <= 32. */
|
|
kmovd %k2, %edx
|
|
kmovd %k0, %eax
|
|
salq $CHAR_PER_VEC, %rdx
|
|
orq %rdx, %rax
|
|
# endif
|
|
|
|
/* first_vec_x3 for strlen-ZMM and first_vec_x2 for strlen-YMM. */
|
|
.p2align 4,, 2
|
|
L(FALLTHROUGH_RETURN_LBL):
|
|
bsfq %rax, %rax
|
|
subq %rcx, %rdi
|
|
CHAR_SIZE_SHIFT_REG (rdi)
|
|
leaq (FALLTHROUGH_RETURN_OFFSET)(%rdi, %rax), %rax
|
|
ret
|
|
|
|
.p2align 4,, 8
|
|
L(first_vec_x0):
|
|
bsf %VRAX, %VRAX
|
|
sub %rcx, %rdi
|
|
CHAR_SIZE_SHIFT_REG (rdi)
|
|
addq %rdi, %rax
|
|
ret
|
|
|
|
.p2align 4,, 10
|
|
L(first_vec_x1):
|
|
bsf %VRAX, %VRAX
|
|
sub %rcx, %rdi
|
|
CHAR_SIZE_SHIFT_REG (rdi)
|
|
leaq (CHAR_PER_VEC)(%rdi, %rax), %rax
|
|
ret
|
|
|
|
.p2align 4,, 10
|
|
/* first_vec_x2 for strlen-ZMM and first_vec_x3 for strlen-YMM. */
|
|
L(TAIL_RETURN_LBL):
|
|
bsf %VRAX, %VRAX
|
|
sub %VRCX, %VRDI
|
|
CHAR_SIZE_SHIFT_REG (VRDI)
|
|
lea (TAIL_RETURN_OFFSET)(%rdi, %rax), %VRAX
|
|
ret
|
|
|
|
.p2align 4,, 8
|
|
L(cross_page_boundary):
|
|
movq %rdi, %rcx
|
|
/* Align data to VEC_SIZE. */
|
|
andq $-VEC_SIZE, %rdi
|
|
|
|
VPCMPEQ (%rdi), %VZERO, %k0
|
|
|
|
KMOV %k0, %VRAX
|
|
# ifdef USE_AS_WCSLEN
|
|
movl %ecx, %edx
|
|
shrl $2, %edx
|
|
andl $(CHAR_PER_VEC - 1), %edx
|
|
shrx %edx, %eax, %eax
|
|
testl %eax, %eax
|
|
# else
|
|
shr %cl, %VRAX
|
|
# endif
|
|
jz L(cross_page_continue)
|
|
bsf %VRAX, %VRAX
|
|
ret
|
|
|
|
END(STRLEN)
|
|
#endif
|