glibc/sysdeps/x86_64/multiarch/strlen-evex.S
H.J. Lu 1fd8c163a8 x86-64: Add ifunc-avx2.h functions with 256-bit EVEX
Update ifunc-avx2.h, strchr.c, strcmp.c, strncmp.c and wcsnlen.c to
select the function optimized with 256-bit EVEX instructions using
YMM16-YMM31 registers to avoid RTM abort with usable AVX512VL, AVX512BW
and BMI2 since VZEROUPPER isn't needed at function exit.

For strcmp/strncmp, prefer AVX2 strcmp/strncmp if Prefer_AVX2_STRCMP
is set.
2021-03-29 07:40:17 -07:00

437 lines
8.6 KiB
ArmAsm

/* strlen/strnlen/wcslen/wcsnlen optimized with 256-bit EVEX instructions.
Copyright (C) 2021 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/>. */
#if IS_IN (libc)
# include <sysdep.h>
# ifndef STRLEN
# define STRLEN __strlen_evex
# endif
# define VMOVA vmovdqa64
# ifdef USE_AS_WCSLEN
# define VPCMP vpcmpd
# define VPMINU vpminud
# define SHIFT_REG r9d
# else
# define VPCMP vpcmpb
# define VPMINU vpminub
# define SHIFT_REG ecx
# endif
# define XMMZERO xmm16
# define YMMZERO ymm16
# define YMM1 ymm17
# define YMM2 ymm18
# define YMM3 ymm19
# define YMM4 ymm20
# define YMM5 ymm21
# define YMM6 ymm22
# define VEC_SIZE 32
.section .text.evex,"ax",@progbits
ENTRY (STRLEN)
# ifdef USE_AS_STRNLEN
/* Check for zero length. */
test %RSI_LP, %RSI_LP
jz L(zero)
# ifdef USE_AS_WCSLEN
shl $2, %RSI_LP
# elif defined __ILP32__
/* Clear the upper 32 bits. */
movl %esi, %esi
# endif
mov %RSI_LP, %R8_LP
# endif
movl %edi, %ecx
movq %rdi, %rdx
vpxorq %XMMZERO, %XMMZERO, %XMMZERO
/* Check if we may cross page boundary with one vector load. */
andl $(2 * VEC_SIZE - 1), %ecx
cmpl $VEC_SIZE, %ecx
ja L(cros_page_boundary)
/* Check the first VEC_SIZE bytes. Each bit in K0 represents a
null byte. */
VPCMP $0, (%rdi), %YMMZERO, %k0
kmovd %k0, %eax
testl %eax, %eax
# ifdef USE_AS_STRNLEN
jnz L(first_vec_x0_check)
/* Adjust length and check the end of data. */
subq $VEC_SIZE, %rsi
jbe L(max)
# else
jnz L(first_vec_x0)
# endif
/* Align data for aligned loads in the loop. */
addq $VEC_SIZE, %rdi
andl $(VEC_SIZE - 1), %ecx
andq $-VEC_SIZE, %rdi
# ifdef USE_AS_STRNLEN
/* Adjust length. */
addq %rcx, %rsi
subq $(VEC_SIZE * 4), %rsi
jbe L(last_4x_vec_or_less)
# endif
jmp L(more_4x_vec)
.p2align 4
L(cros_page_boundary):
andl $(VEC_SIZE - 1), %ecx
andq $-VEC_SIZE, %rdi
# ifdef USE_AS_WCSLEN
/* NB: Divide shift count by 4 since each bit in K0 represent 4
bytes. */
movl %ecx, %SHIFT_REG
sarl $2, %SHIFT_REG
# endif
VPCMP $0, (%rdi), %YMMZERO, %k0
kmovd %k0, %eax
/* Remove the leading bytes. */
sarxl %SHIFT_REG, %eax, %eax
testl %eax, %eax
jz L(aligned_more)
tzcntl %eax, %eax
# ifdef USE_AS_WCSLEN
/* NB: Multiply wchar_t count by 4 to get the number of bytes. */
sall $2, %eax
# endif
# ifdef USE_AS_STRNLEN
/* Check the end of data. */
cmpq %rax, %rsi
jbe L(max)
# endif
addq %rdi, %rax
addq %rcx, %rax
subq %rdx, %rax
# ifdef USE_AS_WCSLEN
shrq $2, %rax
# endif
ret
.p2align 4
L(aligned_more):
# ifdef USE_AS_STRNLEN
/* "rcx" is less than VEC_SIZE. Calculate "rdx + rcx - VEC_SIZE"
with "rdx - (VEC_SIZE - rcx)" instead of "(rdx + rcx) - VEC_SIZE"
to void possible addition overflow. */
negq %rcx
addq $VEC_SIZE, %rcx
/* Check the end of data. */
subq %rcx, %rsi
jbe L(max)
# endif
addq $VEC_SIZE, %rdi
# ifdef USE_AS_STRNLEN
subq $(VEC_SIZE * 4), %rsi
jbe L(last_4x_vec_or_less)
# endif
L(more_4x_vec):
/* Check the first 4 * VEC_SIZE. Only one VEC_SIZE at a time
since data is only aligned to VEC_SIZE. */
VPCMP $0, (%rdi), %YMMZERO, %k0
kmovd %k0, %eax
testl %eax, %eax
jnz L(first_vec_x0)
VPCMP $0, VEC_SIZE(%rdi), %YMMZERO, %k0
kmovd %k0, %eax
testl %eax, %eax
jnz L(first_vec_x1)
VPCMP $0, (VEC_SIZE * 2)(%rdi), %YMMZERO, %k0
kmovd %k0, %eax
testl %eax, %eax
jnz L(first_vec_x2)
VPCMP $0, (VEC_SIZE * 3)(%rdi), %YMMZERO, %k0
kmovd %k0, %eax
testl %eax, %eax
jnz L(first_vec_x3)
addq $(VEC_SIZE * 4), %rdi
# ifdef USE_AS_STRNLEN
subq $(VEC_SIZE * 4), %rsi
jbe L(last_4x_vec_or_less)
# endif
/* Align data to 4 * VEC_SIZE. */
movq %rdi, %rcx
andl $(4 * VEC_SIZE - 1), %ecx
andq $-(4 * VEC_SIZE), %rdi
# ifdef USE_AS_STRNLEN
/* Adjust length. */
addq %rcx, %rsi
# endif
.p2align 4
L(loop_4x_vec):
/* Compare 4 * VEC at a time forward. */
VMOVA (%rdi), %YMM1
VMOVA VEC_SIZE(%rdi), %YMM2
VMOVA (VEC_SIZE * 2)(%rdi), %YMM3
VMOVA (VEC_SIZE * 3)(%rdi), %YMM4
VPMINU %YMM1, %YMM2, %YMM5
VPMINU %YMM3, %YMM4, %YMM6
VPMINU %YMM5, %YMM6, %YMM5
VPCMP $0, %YMM5, %YMMZERO, %k0
ktestd %k0, %k0
jnz L(4x_vec_end)
addq $(VEC_SIZE * 4), %rdi
# ifndef USE_AS_STRNLEN
jmp L(loop_4x_vec)
# else
subq $(VEC_SIZE * 4), %rsi
ja L(loop_4x_vec)
L(last_4x_vec_or_less):
/* Less than 4 * VEC and aligned to VEC_SIZE. */
addl $(VEC_SIZE * 2), %esi
jle L(last_2x_vec)
VPCMP $0, (%rdi), %YMMZERO, %k0
kmovd %k0, %eax
testl %eax, %eax
jnz L(first_vec_x0)
VPCMP $0, VEC_SIZE(%rdi), %YMMZERO, %k0
kmovd %k0, %eax
testl %eax, %eax
jnz L(first_vec_x1)
VPCMP $0, (VEC_SIZE * 2)(%rdi), %YMMZERO, %k0
kmovd %k0, %eax
testl %eax, %eax
jnz L(first_vec_x2_check)
subl $VEC_SIZE, %esi
jle L(max)
VPCMP $0, (VEC_SIZE * 3)(%rdi), %YMMZERO, %k0
kmovd %k0, %eax
testl %eax, %eax
jnz L(first_vec_x3_check)
movq %r8, %rax
# ifdef USE_AS_WCSLEN
shrq $2, %rax
# endif
ret
.p2align 4
L(last_2x_vec):
addl $(VEC_SIZE * 2), %esi
VPCMP $0, (%rdi), %YMMZERO, %k0
kmovd %k0, %eax
testl %eax, %eax
jnz L(first_vec_x0_check)
subl $VEC_SIZE, %esi
jle L(max)
VPCMP $0, VEC_SIZE(%rdi), %YMMZERO, %k0
kmovd %k0, %eax
testl %eax, %eax
jnz L(first_vec_x1_check)
movq %r8, %rax
# ifdef USE_AS_WCSLEN
shrq $2, %rax
# endif
ret
.p2align 4
L(first_vec_x0_check):
tzcntl %eax, %eax
# ifdef USE_AS_WCSLEN
/* NB: Multiply wchar_t count by 4 to get the number of bytes. */
sall $2, %eax
# endif
/* Check the end of data. */
cmpq %rax, %rsi
jbe L(max)
addq %rdi, %rax
subq %rdx, %rax
# ifdef USE_AS_WCSLEN
shrq $2, %rax
# endif
ret
.p2align 4
L(first_vec_x1_check):
tzcntl %eax, %eax
# ifdef USE_AS_WCSLEN
/* NB: Multiply wchar_t count by 4 to get the number of bytes. */
sall $2, %eax
# endif
/* Check the end of data. */
cmpq %rax, %rsi
jbe L(max)
addq $VEC_SIZE, %rax
addq %rdi, %rax
subq %rdx, %rax
# ifdef USE_AS_WCSLEN
shrq $2, %rax
# endif
ret
.p2align 4
L(first_vec_x2_check):
tzcntl %eax, %eax
# ifdef USE_AS_WCSLEN
/* NB: Multiply wchar_t count by 4 to get the number of bytes. */
sall $2, %eax
# endif
/* Check the end of data. */
cmpq %rax, %rsi
jbe L(max)
addq $(VEC_SIZE * 2), %rax
addq %rdi, %rax
subq %rdx, %rax
# ifdef USE_AS_WCSLEN
shrq $2, %rax
# endif
ret
.p2align 4
L(first_vec_x3_check):
tzcntl %eax, %eax
# ifdef USE_AS_WCSLEN
/* NB: Multiply wchar_t count by 4 to get the number of bytes. */
sall $2, %eax
# endif
/* Check the end of data. */
cmpq %rax, %rsi
jbe L(max)
addq $(VEC_SIZE * 3), %rax
addq %rdi, %rax
subq %rdx, %rax
# ifdef USE_AS_WCSLEN
shrq $2, %rax
# endif
ret
.p2align 4
L(max):
movq %r8, %rax
# ifdef USE_AS_WCSLEN
shrq $2, %rax
# endif
ret
.p2align 4
L(zero):
xorl %eax, %eax
ret
# endif
.p2align 4
L(first_vec_x0):
tzcntl %eax, %eax
# ifdef USE_AS_WCSLEN
/* NB: Multiply wchar_t count by 4 to get the number of bytes. */
sall $2, %eax
# endif
addq %rdi, %rax
subq %rdx, %rax
# ifdef USE_AS_WCSLEN
shrq $2, %rax
# endif
ret
.p2align 4
L(first_vec_x1):
tzcntl %eax, %eax
# ifdef USE_AS_WCSLEN
/* NB: Multiply wchar_t count by 4 to get the number of bytes. */
sall $2, %eax
# endif
addq $VEC_SIZE, %rax
addq %rdi, %rax
subq %rdx, %rax
# ifdef USE_AS_WCSLEN
shrq $2, %rax
# endif
ret
.p2align 4
L(first_vec_x2):
tzcntl %eax, %eax
# ifdef USE_AS_WCSLEN
/* NB: Multiply wchar_t count by 4 to get the number of bytes. */
sall $2, %eax
# endif
addq $(VEC_SIZE * 2), %rax
addq %rdi, %rax
subq %rdx, %rax
# ifdef USE_AS_WCSLEN
shrq $2, %rax
# endif
ret
.p2align 4
L(4x_vec_end):
VPCMP $0, %YMM1, %YMMZERO, %k0
kmovd %k0, %eax
testl %eax, %eax
jnz L(first_vec_x0)
VPCMP $0, %YMM2, %YMMZERO, %k1
kmovd %k1, %eax
testl %eax, %eax
jnz L(first_vec_x1)
VPCMP $0, %YMM3, %YMMZERO, %k2
kmovd %k2, %eax
testl %eax, %eax
jnz L(first_vec_x2)
VPCMP $0, %YMM4, %YMMZERO, %k3
kmovd %k3, %eax
L(first_vec_x3):
tzcntl %eax, %eax
# ifdef USE_AS_WCSLEN
/* NB: Multiply wchar_t count by 4 to get the number of bytes. */
sall $2, %eax
# endif
addq $(VEC_SIZE * 3), %rax
addq %rdi, %rax
subq %rdx, %rax
# ifdef USE_AS_WCSLEN
shrq $2, %rax
# endif
ret
END (STRLEN)
#endif