diff options
Diffstat (limited to 'sysdeps/x86_64/multiarch/strcmp-evex.S')
| -rw-r--r-- | sysdeps/x86_64/multiarch/strcmp-evex.S | 1043 |
1 files changed, 1043 insertions, 0 deletions
diff --git a/sysdeps/x86_64/multiarch/strcmp-evex.S b/sysdeps/x86_64/multiarch/strcmp-evex.S new file mode 100644 index 0000000000..459eeed09f --- /dev/null +++ b/sysdeps/x86_64/multiarch/strcmp-evex.S @@ -0,0 +1,1043 @@ +/* strcmp/wcscmp/strncmp/wcsncmp 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 STRCMP +# define STRCMP __strcmp_evex +# endif + +# define PAGE_SIZE 4096 + +/* VEC_SIZE = Number of bytes in a ymm register */ +# define VEC_SIZE 32 + +/* Shift for dividing by (VEC_SIZE * 4). */ +# define DIVIDE_BY_VEC_4_SHIFT 7 +# if (VEC_SIZE * 4) != (1 << DIVIDE_BY_VEC_4_SHIFT) +# error (VEC_SIZE * 4) != (1 << DIVIDE_BY_VEC_4_SHIFT) +# endif + +# define VMOVU vmovdqu64 +# define VMOVA vmovdqa64 + +# ifdef USE_AS_WCSCMP +/* Compare packed dwords. */ +# define VPCMP vpcmpd +# define SHIFT_REG32 r8d +# define SHIFT_REG64 r8 +/* 1 dword char == 4 bytes. */ +# define SIZE_OF_CHAR 4 +# else +/* Compare packed bytes. */ +# define VPCMP vpcmpb +# define SHIFT_REG32 ecx +# define SHIFT_REG64 rcx +/* 1 byte char == 1 byte. */ +# define SIZE_OF_CHAR 1 +# endif + +# define XMMZERO xmm16 +# define XMM0 xmm17 +# define XMM1 xmm18 + +# define YMMZERO ymm16 +# define YMM0 ymm17 +# define YMM1 ymm18 +# define YMM2 ymm19 +# define YMM3 ymm20 +# define YMM4 ymm21 +# define YMM5 ymm22 +# define YMM6 ymm23 +# define YMM7 ymm24 + +/* Warning! + wcscmp/wcsncmp have to use SIGNED comparison for elements. + strcmp/strncmp have to use UNSIGNED comparison for elements. +*/ + +/* The main idea of the string comparison (byte or dword) using 256-bit + EVEX instructions consists of comparing (VPCMP) two ymm vectors. The + latter can be on either packed bytes or dwords depending on + USE_AS_WCSCMP. In order to check the null char, algorithm keeps the + matched bytes/dwords, requiring 5 EVEX instructions (3 VPCMP and 2 + KORD). In general, the costs of comparing VEC_SIZE bytes (32-bytes) + are 3 VPCMP and 2 KORD instructions, together with VMOVU and ktestd + instructions. Main loop (away from from page boundary) compares 4 + vectors are a time, effectively comparing 4 x VEC_SIZE bytes (128 + bytes) on each loop. + + The routine strncmp/wcsncmp (enabled by defining USE_AS_STRNCMP) logic + is the same as strcmp, except that an a maximum offset is tracked. If + the maximum offset is reached before a difference is found, zero is + returned. */ + + .section .text.evex,"ax",@progbits +ENTRY (STRCMP) +# ifdef USE_AS_STRNCMP + /* Check for simple cases (0 or 1) in offset. */ + cmp $1, %RDX_LP + je L(char0) + jb L(zero) +# ifdef USE_AS_WCSCMP + /* Convert units: from wide to byte char. */ + shl $2, %RDX_LP +# endif + /* Register %r11 tracks the maximum offset. */ + mov %RDX_LP, %R11_LP +# endif + movl %edi, %eax + xorl %edx, %edx + /* Make %XMMZERO (%YMMZERO) all zeros in this function. */ + vpxorq %XMMZERO, %XMMZERO, %XMMZERO + orl %esi, %eax + andl $(PAGE_SIZE - 1), %eax + cmpl $(PAGE_SIZE - (VEC_SIZE * 4)), %eax + jg L(cross_page) + /* Start comparing 4 vectors. */ + VMOVU (%rdi), %YMM0 + VMOVU (%rsi), %YMM1 + + /* Each bit in K0 represents a mismatch in YMM0 and YMM1. */ + VPCMP $4, %YMM0, %YMM1, %k0 + + /* Check for NULL in YMM0. */ + VPCMP $0, %YMMZERO, %YMM0, %k1 + /* Check for NULL in YMM1. */ + VPCMP $0, %YMMZERO, %YMM1, %k2 + /* Each bit in K1 represents a NULL in YMM0 or YMM1. */ + kord %k1, %k2, %k1 + + /* Each bit in K1 represents: + 1. A mismatch in YMM0 and YMM1. Or + 2. A NULL in YMM0 or YMM1. + */ + kord %k0, %k1, %k1 + + ktestd %k1, %k1 + je L(next_3_vectors) + kmovd %k1, %ecx + tzcntl %ecx, %edx +# ifdef USE_AS_WCSCMP + /* NB: Multiply wchar_t count by 4 to get the number of bytes. */ + sall $2, %edx +# endif +# ifdef USE_AS_STRNCMP + /* Return 0 if the mismatched index (%rdx) is after the maximum + offset (%r11). */ + cmpq %r11, %rdx + jae L(zero) +# endif +# ifdef USE_AS_WCSCMP + xorl %eax, %eax + movl (%rdi, %rdx), %ecx + cmpl (%rsi, %rdx), %ecx + je L(return) +L(wcscmp_return): + setl %al + negl %eax + orl $1, %eax +L(return): +# else + movzbl (%rdi, %rdx), %eax + movzbl (%rsi, %rdx), %edx + subl %edx, %eax +# endif + ret + + .p2align 4 +L(return_vec_size): + kmovd %k1, %ecx + tzcntl %ecx, %edx +# ifdef USE_AS_WCSCMP + /* NB: Multiply wchar_t count by 4 to get the number of bytes. */ + sall $2, %edx +# endif +# ifdef USE_AS_STRNCMP + /* Return 0 if the mismatched index (%rdx + VEC_SIZE) is after + the maximum offset (%r11). */ + addq $VEC_SIZE, %rdx + cmpq %r11, %rdx + jae L(zero) +# ifdef USE_AS_WCSCMP + xorl %eax, %eax + movl (%rdi, %rdx), %ecx + cmpl (%rsi, %rdx), %ecx + jne L(wcscmp_return) +# else + movzbl (%rdi, %rdx), %eax + movzbl (%rsi, %rdx), %edx + subl %edx, %eax +# endif +# else +# ifdef USE_AS_WCSCMP + xorl %eax, %eax + movl VEC_SIZE(%rdi, %rdx), %ecx + cmpl VEC_SIZE(%rsi, %rdx), %ecx + jne L(wcscmp_return) +# else + movzbl VEC_SIZE(%rdi, %rdx), %eax + movzbl VEC_SIZE(%rsi, %rdx), %edx + subl %edx, %eax +# endif +# endif + ret + + .p2align 4 +L(return_2_vec_size): + kmovd %k1, %ecx + tzcntl %ecx, %edx +# ifdef USE_AS_WCSCMP + /* NB: Multiply wchar_t count by 4 to get the number of bytes. */ + sall $2, %edx +# endif +# ifdef USE_AS_STRNCMP + /* Return 0 if the mismatched index (%rdx + 2 * VEC_SIZE) is + after the maximum offset (%r11). */ + addq $(VEC_SIZE * 2), %rdx + cmpq %r11, %rdx + jae L(zero) +# ifdef USE_AS_WCSCMP + xorl %eax, %eax + movl (%rdi, %rdx), %ecx + cmpl (%rsi, %rdx), %ecx + jne L(wcscmp_return) +# else + movzbl (%rdi, %rdx), %eax + movzbl (%rsi, %rdx), %edx + subl %edx, %eax +# endif +# else +# ifdef USE_AS_WCSCMP + xorl %eax, %eax + movl (VEC_SIZE * 2)(%rdi, %rdx), %ecx + cmpl (VEC_SIZE * 2)(%rsi, %rdx), %ecx + jne L(wcscmp_return) +# else + movzbl (VEC_SIZE * 2)(%rdi, %rdx), %eax + movzbl (VEC_SIZE * 2)(%rsi, %rdx), %edx + subl %edx, %eax +# endif +# endif + ret + + .p2align 4 +L(return_3_vec_size): + kmovd %k1, %ecx + tzcntl %ecx, %edx +# ifdef USE_AS_WCSCMP + /* NB: Multiply wchar_t count by 4 to get the number of bytes. */ + sall $2, %edx +# endif +# ifdef USE_AS_STRNCMP + /* Return 0 if the mismatched index (%rdx + 3 * VEC_SIZE) is + after the maximum offset (%r11). */ + addq $(VEC_SIZE * 3), %rdx + cmpq %r11, %rdx + jae L(zero) +# ifdef USE_AS_WCSCMP + xorl %eax, %eax + movl (%rdi, %rdx), %ecx + cmpl (%rsi, %rdx), %ecx + jne L(wcscmp_return) +# else + movzbl (%rdi, %rdx), %eax + movzbl (%rsi, %rdx), %edx + subl %edx, %eax +# endif +# else +# ifdef USE_AS_WCSCMP + xorl %eax, %eax + movl (VEC_SIZE * 3)(%rdi, %rdx), %ecx + cmpl (VEC_SIZE * 3)(%rsi, %rdx), %ecx + jne L(wcscmp_return) +# else + movzbl (VEC_SIZE * 3)(%rdi, %rdx), %eax + movzbl (VEC_SIZE * 3)(%rsi, %rdx), %edx + subl %edx, %eax +# endif +# endif + ret + + .p2align 4 +L(next_3_vectors): + VMOVU VEC_SIZE(%rdi), %YMM0 + VMOVU VEC_SIZE(%rsi), %YMM1 + /* Each bit in K0 represents a mismatch in YMM0 and YMM1. */ + VPCMP $4, %YMM0, %YMM1, %k0 + VPCMP $0, %YMMZERO, %YMM0, %k1 + VPCMP $0, %YMMZERO, %YMM1, %k2 + /* Each bit in K1 represents a NULL in YMM0 or YMM1. */ + kord %k1, %k2, %k1 + /* Each bit in K1 represents a NULL or a mismatch. */ + kord %k0, %k1, %k1 + ktestd %k1, %k1 + jne L(return_vec_size) + + VMOVU (VEC_SIZE * 2)(%rdi), %YMM2 + VMOVU (VEC_SIZE * 3)(%rdi), %YMM3 + VMOVU (VEC_SIZE * 2)(%rsi), %YMM4 + VMOVU (VEC_SIZE * 3)(%rsi), %YMM5 + + /* Each bit in K0 represents a mismatch in YMM2 and YMM4. */ + VPCMP $4, %YMM2, %YMM4, %k0 + VPCMP $0, %YMMZERO, %YMM2, %k1 + VPCMP $0, %YMMZERO, %YMM4, %k2 + /* Each bit in K1 represents a NULL in YMM2 or YMM4. */ + kord %k1, %k2, %k1 + /* Each bit in K1 represents a NULL or a mismatch. */ + kord %k0, %k1, %k1 + ktestd %k1, %k1 + jne L(return_2_vec_size) + + /* Each bit in K0 represents a mismatch in YMM3 and YMM5. */ + VPCMP $4, %YMM3, %YMM5, %k0 + VPCMP $0, %YMMZERO, %YMM3, %k1 + VPCMP $0, %YMMZERO, %YMM5, %k2 + /* Each bit in K1 represents a NULL in YMM3 or YMM5. */ + kord %k1, %k2, %k1 + /* Each bit in K1 represents a NULL or a mismatch. */ + kord %k0, %k1, %k1 + ktestd %k1, %k1 + jne L(return_3_vec_size) +L(main_loop_header): + leaq (VEC_SIZE * 4)(%rdi), %rdx + movl $PAGE_SIZE, %ecx + /* Align load via RAX. */ + andq $-(VEC_SIZE * 4), %rdx + subq %rdi, %rdx + leaq (%rdi, %rdx), %rax +# ifdef USE_AS_STRNCMP + /* Starting from this point, the maximum offset, or simply the + 'offset', DECREASES by the same amount when base pointers are + moved forward. Return 0 when: + 1) On match: offset <= the matched vector index. + 2) On mistmach, offset is before the mistmatched index. + */ + subq %rdx, %r11 + jbe L(zero) +# endif + addq %rsi, %rdx + movq %rdx, %rsi + andl $(PAGE_SIZE - 1), %esi + /* Number of bytes before page crossing. */ + subq %rsi, %rcx + /* Number of VEC_SIZE * 4 blocks before page crossing. */ + shrq $DIVIDE_BY_VEC_4_SHIFT, %rcx + /* ESI: Number of VEC_SIZE * 4 blocks before page crossing. */ + movl %ecx, %esi + jmp L(loop_start) + + .p2align 4 +L(loop): +# ifdef USE_AS_STRNCMP + /* Base pointers are moved forward by 4 * VEC_SIZE. Decrease + the maximum offset (%r11) by the same amount. */ + subq $(VEC_SIZE * 4), %r11 + jbe L(zero) +# endif + addq $(VEC_SIZE * 4), %rax + addq $(VEC_SIZE * 4), %rdx +L(loop_start): + testl %esi, %esi + leal -1(%esi), %esi + je L(loop_cross_page) +L(back_to_loop): + /* Main loop, comparing 4 vectors are a time. */ + VMOVA (%rax), %YMM0 + VMOVA VEC_SIZE(%rax), %YMM2 + VMOVA (VEC_SIZE * 2)(%rax), %YMM4 + VMOVA (VEC_SIZE * 3)(%rax), %YMM6 + VMOVU (%rdx), %YMM1 + VMOVU VEC_SIZE(%rdx), %YMM3 + VMOVU (VEC_SIZE * 2)(%rdx), %YMM5 + VMOVU (VEC_SIZE * 3)(%rdx), %YMM7 + + VPCMP $4, %YMM0, %YMM1, %k0 + VPCMP $0, %YMMZERO, %YMM0, %k1 + VPCMP $0, %YMMZERO, %YMM1, %k2 + kord %k1, %k2, %k1 + /* Each bit in K4 represents a NULL or a mismatch in YMM0 and + YMM1. */ + kord %k0, %k1, %k4 + + VPCMP $4, %YMM2, %YMM3, %k0 + VPCMP $0, %YMMZERO, %YMM2, %k1 + VPCMP $0, %YMMZERO, %YMM3, %k2 + kord %k1, %k2, %k1 + /* Each bit in K5 represents a NULL or a mismatch in YMM2 and + YMM3. */ + kord %k0, %k1, %k5 + + VPCMP $4, %YMM4, %YMM5, %k0 + VPCMP $0, %YMMZERO, %YMM4, %k1 + VPCMP $0, %YMMZERO, %YMM5, %k2 + kord %k1, %k2, %k1 + /* Each bit in K6 represents a NULL or a mismatch in YMM4 and + YMM5. */ + kord %k0, %k1, %k6 + + VPCMP $4, %YMM6, %YMM7, %k0 + VPCMP $0, %YMMZERO, %YMM6, %k1 + VPCMP $0, %YMMZERO, %YMM7, %k2 + kord %k1, %k2, %k1 + /* Each bit in K7 represents a NULL or a mismatch in YMM6 and + YMM7. */ + kord %k0, %k1, %k7 + + kord %k4, %k5, %k0 + kord %k6, %k7, %k1 + + /* Test each mask (32 bits) individually because for VEC_SIZE + == 32 is not possible to OR the four masks and keep all bits + in a 64-bit integer register, differing from SSE2 strcmp + where ORing is possible. */ + kortestd %k0, %k1 + je L(loop) + ktestd %k4, %k4 + je L(test_vec) + kmovd %k4, %edi + tzcntl %edi, %ecx +# ifdef USE_AS_WCSCMP + /* NB: Multiply wchar_t count by 4 to get the number of bytes. */ + sall $2, %ecx +# endif +# ifdef USE_AS_STRNCMP + cmpq %rcx, %r11 + jbe L(zero) +# ifdef USE_AS_WCSCMP + movq %rax, %rsi + xorl %eax, %eax + movl (%rsi, %rcx), %edi + cmpl (%rdx, %rcx), %edi + jne L(wcscmp_return) +# else + movzbl (%rax, %rcx), %eax + movzbl (%rdx, %rcx), %edx + subl %edx, %eax +# endif +# else +# ifdef USE_AS_WCSCMP + movq %rax, %rsi + xorl %eax, %eax + movl (%rsi, %rcx), %edi + cmpl (%rdx, %rcx), %edi + jne L(wcscmp_return) +# else + movzbl (%rax, %rcx), %eax + movzbl (%rdx, %rcx), %edx + subl %edx, %eax +# endif +# endif + ret + + .p2align 4 +L(test_vec): +# ifdef USE_AS_STRNCMP + /* The first vector matched. Return 0 if the maximum offset + (%r11) <= VEC_SIZE. */ + cmpq $VEC_SIZE, %r11 + jbe L(zero) +# endif + ktestd %k5, %k5 + je L(test_2_vec) + kmovd %k5, %ecx + tzcntl %ecx, %edi +# ifdef USE_AS_WCSCMP + /* NB: Multiply wchar_t count by 4 to get the number of bytes. */ + sall $2, %edi +# endif +# ifdef USE_AS_STRNCMP + addq $VEC_SIZE, %rdi + cmpq %rdi, %r11 + jbe L(zero) +# ifdef USE_AS_WCSCMP + movq %rax, %rsi + xorl %eax, %eax + movl (%rsi, %rdi), %ecx + cmpl (%rdx, %rdi), %ecx + jne L(wcscmp_return) +# else + movzbl (%rax, %rdi), %eax + movzbl (%rdx, %rdi), %edx + subl %edx, %eax +# endif +# else +# ifdef USE_AS_WCSCMP + movq %rax, %rsi + xorl %eax, %eax + movl VEC_SIZE(%rsi, %rdi), %ecx + cmpl VEC_SIZE(%rdx, %rdi), %ecx + jne L(wcscmp_return) +# else + movzbl VEC_SIZE(%rax, %rdi), %eax + movzbl VEC_SIZE(%rdx, %rdi), %edx + subl %edx, %eax +# endif +# endif + ret + + .p2align 4 +L(test_2_vec): +# ifdef USE_AS_STRNCMP + /* The first 2 vectors matched. Return 0 if the maximum offset + (%r11) <= 2 * VEC_SIZE. */ + cmpq $(VEC_SIZE * 2), %r11 + jbe L(zero) +# endif + ktestd %k6, %k6 + je L(test_3_vec) + kmovd %k6, %ecx + tzcntl %ecx, %edi +# ifdef USE_AS_WCSCMP + /* NB: Multiply wchar_t count by 4 to get the number of bytes. */ + sall $2, %edi +# endif +# ifdef USE_AS_STRNCMP + addq $(VEC_SIZE * 2), %rdi + cmpq %rdi, %r11 + jbe L(zero) +# ifdef USE_AS_WCSCMP + movq %rax, %rsi + xorl %eax, %eax + movl (%rsi, %rdi), %ecx + cmpl (%rdx, %rdi), %ecx + jne L(wcscmp_return) +# else + movzbl (%rax, %rdi), %eax + movzbl (%rdx, %rdi), %edx + subl %edx, %eax +# endif +# else +# ifdef USE_AS_WCSCMP + movq %rax, %rsi + xorl %eax, %eax + movl (VEC_SIZE * 2)(%rsi, %rdi), %ecx + cmpl (VEC_SIZE * 2)(%rdx, %rdi), %ecx + jne L(wcscmp_return) +# else + movzbl (VEC_SIZE * 2)(%rax, %rdi), %eax + movzbl (VEC_SIZE * 2)(%rdx, %rdi), %edx + subl %edx, %eax +# endif +# endif + ret + + .p2align 4 +L(test_3_vec): +# ifdef USE_AS_STRNCMP + /* The first 3 vectors matched. Return 0 if the maximum offset + (%r11) <= 3 * VEC_SIZE. */ + cmpq $(VEC_SIZE * 3), %r11 + jbe L(zero) +# endif + kmovd %k7, %esi + tzcntl %esi, %ecx +# ifdef USE_AS_WCSCMP + /* NB: Multiply wchar_t count by 4 to get the number of bytes. */ + sall $2, %ecx +# endif +# ifdef USE_AS_STRNCMP + addq $(VEC_SIZE * 3), %rcx + cmpq %rcx, %r11 + jbe L(zero) +# ifdef USE_AS_WCSCMP + movq %rax, %rsi + xorl %eax, %eax + movl (%rsi, %rcx), %esi + cmpl (%rdx, %rcx), %esi + jne L(wcscmp_return) +# else + movzbl (%rax, %rcx), %eax + movzbl (%rdx, %rcx), %edx + subl %edx, %eax +# endif +# else +# ifdef USE_AS_WCSCMP + movq %rax, %rsi + xorl %eax, %eax + movl (VEC_SIZE * 3)(%rsi, %rcx), %esi + cmpl (VEC_SIZE * 3)(%rdx, %rcx), %esi + jne L(wcscmp_return) +# else + movzbl (VEC_SIZE * 3)(%rax, %rcx), %eax + movzbl (VEC_SIZE * 3)(%rdx, %rcx), %edx + subl %edx, %eax +# endif +# endif + ret + + .p2align 4 +L(loop_cross_page): + xorl %r10d, %r10d + movq %rdx, %rcx + /* Align load via RDX. We load the extra ECX bytes which should + be ignored. */ + andl $((VEC_SIZE * 4) - 1), %ecx + /* R10 is -RCX. */ + subq %rcx, %r10 + + /* This works only if VEC_SIZE * 2 == 64. */ +# if (VEC_SIZE * 2) != 64 +# error (VEC_SIZE * 2) != 64 +# endif + + /* Check if the first VEC_SIZE * 2 bytes should be ignored. */ + cmpl $(VEC_SIZE * 2), %ecx + jge L(loop_cross_page_2_vec) + + VMOVU (%rax, %r10), %YMM2 + VMOVU VEC_SIZE(%rax, %r10), %YMM3 + VMOVU (%rdx, %r10), %YMM4 + VMOVU VEC_SIZE(%rdx, %r10), %YMM5 + + VPCMP $4, %YMM4, %YMM2, %k0 + VPCMP $0, %YMMZERO, %YMM2, %k1 + VPCMP $0, %YMMZERO, %YMM4, %k2 + kord %k1, %k2, %k1 + /* Each bit in K1 represents a NULL or a mismatch in YMM2 and + YMM4. */ + kord %k0, %k1, %k1 + + VPCMP $4, %YMM5, %YMM3, %k3 + VPCMP $0, %YMMZERO, %YMM3, %k4 + VPCMP $0, %YMMZERO, %YMM5, %k5 + kord %k4, %k5, %k4 + /* Each bit in K3 represents a NULL or a mismatch in YMM3 and + YMM5. */ + kord %k3, %k4, %k3 + +# ifdef USE_AS_WCSCMP + /* NB: Each bit in K1/K3 represents 4-byte element. */ + kshiftlw $8, %k3, %k2 + /* NB: Divide shift count by 4 since each bit in K1 represent 4 + bytes. */ + movl %ecx, %SHIFT_REG32 + sarl $2, %SHIFT_REG32 +# else + kshiftlq $32, %k3, %k2 +# endif + + /* Each bit in K1 represents a NULL or a mismatch. */ + korq %k1, %k2, %k1 + kmovq %k1, %rdi + + /* Since ECX < VEC_SIZE * 2, simply skip the first ECX bytes. */ + shrxq %SHIFT_REG64, %rdi, %rdi + testq %rdi, %rdi + je L(loop_cross_page_2_vec) + tzcntq %rdi, %rcx +# ifdef USE_AS_WCSCMP + /* NB: Multiply wchar_t count by 4 to get the number of bytes. */ + sall $2, %ecx +# endif +# ifdef USE_AS_STRNCMP + cmpq %rcx, %r11 + jbe L(zero) +# ifdef USE_AS_WCSCMP + movq %rax, %rsi + xorl %eax, %eax + movl (%rsi, %rcx), %edi + cmpl (%rdx, %rcx), %edi + jne L(wcscmp_return) +# else + movzbl (%rax, %rcx), %eax + movzbl (%rdx, %rcx), %edx + subl %edx, %eax +# endif +# else +# ifdef USE_AS_WCSCMP + movq %rax, %rsi + xorl %eax, %eax + movl (%rsi, %rcx), %edi + cmpl (%rdx, %rcx), %edi + jne L(wcscmp_return) +# else + movzbl (%rax, %rcx), %eax + movzbl (%rdx, %rcx), %edx + subl %edx, %eax +# endif +# endif + ret + + .p2align 4 +L(loop_cross_page_2_vec): + /* The first VEC_SIZE * 2 bytes match or are ignored. */ + VMOVU (VEC_SIZE * 2)(%rax, %r10), %YMM0 + VMOVU (VEC_SIZE * 3)(%rax, %r10), %YMM1 + VMOVU (VEC_SIZE * 2)(%rdx, %r10), %YMM2 + VMOVU (VEC_SIZE * 3)(%rdx, %r10), %YMM3 + + VPCMP $4, %YMM0, %YMM2, %k0 + VPCMP $0, %YMMZERO, %YMM0, %k1 + VPCMP $0, %YMMZERO, %YMM2, %k2 + kord %k1, %k2, %k1 + /* Each bit in K1 represents a NULL or a mismatch in YMM0 and + YMM2. */ + kord %k0, %k1, %k1 + + VPCMP $4, %YMM1, %YMM3, %k3 + VPCMP $0, %YMMZERO, %YMM1, %k4 + VPCMP $0, %YMMZERO, %YMM3, %k5 + kord %k4, %k5, %k4 + /* Each bit in K3 represents a NULL or a mismatch in YMM1 and + YMM3. */ + kord %k3, %k4, %k3 + +# ifdef USE_AS_WCSCMP + /* NB: Each bit in K1/K3 represents 4-byte element. */ + kshiftlw $8, %k3, %k2 +# else + kshiftlq $32, %k3, %k2 +# endif + + /* Each bit in K1 represents a NULL or a mismatch. */ + korq %k1, %k2, %k1 + kmovq %k1, %rdi + + xorl %r8d, %r8d + /* If ECX > VEC_SIZE * 2, skip ECX - (VEC_SIZE * 2) bytes. */ + subl $(VEC_SIZE * 2), %ecx + jle 1f + /* R8 has number of bytes skipped. */ + movl %ecx, %r8d +# ifdef USE_AS_WCSCMP + /* NB: Divide shift count by 4 since each bit in K1 represent 4 + bytes. */ + sarl $2, %ecx +# endif + /* Skip ECX bytes. */ + shrq %cl, %rdi +1: + /* Before jumping back to the loop, set ESI to the number of + VEC_SIZE * 4 blocks before page crossing. */ + movl $(PAGE_SIZE / (VEC_SIZE * 4) - 1), %esi + + testq %rdi, %rdi +# ifdef USE_AS_STRNCMP + /* At this point, if %rdi value is 0, it already tested + VEC_SIZE*4+%r10 byte starting from %rax. This label + checks whether strncmp maximum offset reached or not. */ + je L(string_nbyte_offset_check) +# else + je L(back_to_loop) +# endif + tzcntq %rdi, %rcx +# ifdef USE_AS_WCSCMP + /* NB: Multiply wchar_t count by 4 to get the number of bytes. */ + sall $2, %ecx +# endif + addq %r10, %rcx + /* Adjust for number of bytes skipped. */ + addq %r8, %rcx +# ifdef USE_AS_STRNCMP + addq $(VEC_SIZE * 2), %rcx + subq %rcx, %r11 + jbe L(zero) +# ifdef USE_AS_WCSCMP + movq %rax, %rsi + xorl %eax, %eax + movl (%rsi, %rcx), %edi + cmpl (%rdx, %rcx), %edi + jne L(wcscmp_return) +# else + movzbl (%rax, %rcx), %eax + movzbl (%rdx, %rcx), %edx + subl %edx, %eax +# endif +# else +# ifdef USE_AS_WCSCMP + movq %rax, %rsi + xorl %eax, %eax + movl (VEC_SIZE * 2)(%rsi, %rcx), %edi + cmpl (VEC_SIZE * 2)(%rdx, %rcx), %edi + jne L(wcscmp_return) +# else + movzbl (VEC_SIZE * 2)(%rax, %rcx), %eax + movzbl (VEC_SIZE * 2)(%rdx, %rcx), %edx + subl %edx, %eax +# endif +# endif + ret + +# ifdef USE_AS_STRNCMP +L(string_nbyte_offset_check): + leaq (VEC_SIZE * 4)(%r10), %r10 + cmpq %r10, %r11 + jbe L(zero) + jmp L(back_to_loop) +# endif + + .p2align 4 +L(cross_page_loop): + /* Check one byte/dword at a time. */ +# ifdef USE_AS_WCSCMP + cmpl %ecx, %eax +# else + subl %ecx, %eax +# endif + jne L(different) + addl $SIZE_OF_CHAR, %edx + cmpl $(VEC_SIZE * 4), %edx + je L(main_loop_header) +# ifdef USE_AS_STRNCMP + cmpq %r11, %rdx + jae L(zero) +# endif +# ifdef USE_AS_WCSCMP + movl (%rdi, %rdx), %eax + movl (%rsi, %rdx), %ecx +# else + movzbl (%rdi, %rdx), %eax + movzbl (%rsi, %rdx), %ecx +# endif + /* Check null char. */ + testl %eax, %eax + jne L(cross_page_loop) + /* Since %eax == 0, subtract is OK for both SIGNED and UNSIGNED + comparisons. */ + subl %ecx, %eax +# ifndef USE_AS_WCSCMP +L(different): +# endif + ret + +# ifdef USE_AS_WCSCMP + .p2align 4 +L(different): + /* Use movl to avoid modifying EFLAGS. */ + movl $0, %eax + setl %al + negl %eax + orl $1, %eax + ret +# endif + +# ifdef USE_AS_STRNCMP + .p2align 4 +L(zero): + xorl %eax, %eax + ret + + .p2align 4 +L(char0): +# ifdef USE_AS_WCSCMP + xorl %eax, %eax + movl (%rdi), %ecx + cmpl (%rsi), %ecx + jne L(wcscmp_return) +# else + movzbl (%rsi), %ecx + movzbl (%rdi), %eax + subl %ecx, %eax +# endif + ret +# endif + + .p2align 4 +L(last_vector): + addq %rdx, %rdi + addq %rdx, %rsi +# ifdef USE_AS_STRNCMP + subq %rdx, %r11 +# endif + tzcntl %ecx, %edx +# ifdef USE_AS_WCSCMP + /* NB: Multiply wchar_t count by 4 to get the number of bytes. */ + sall $2, %edx +# endif +# ifdef USE_AS_STRNCMP + cmpq %r11, %rdx + jae L(zero) +# endif +# ifdef USE_AS_WCSCMP + xorl %eax, %eax + movl (%rdi, %rdx), %ecx + cmpl (%rsi, %rdx), %ecx + jne L(wcscmp_return) +# else + movzbl (%rdi, %rdx), %eax + movzbl (%rsi, %rdx), %edx + subl %edx, %eax +# endif + ret + + /* Comparing on page boundary region requires special treatment: + It must done one vector at the time, starting with the wider + ymm vector if possible, if not, with xmm. If fetching 16 bytes + (xmm) still passes the boundary, byte comparison must be done. + */ + .p2align 4 +L(cross_page): + /* Try one ymm vector at a time. */ + cmpl $(PAGE_SIZE - VEC_SIZE), %eax + jg L(cross_page_1_vector) +L(loop_1_vector): + VMOVU (%rdi, %rdx), %YMM0 + VMOVU (%rsi, %rdx), %YMM1 + + /* Each bit in K0 represents a mismatch in YMM0 and YMM1. */ + VPCMP $4, %YMM0, %YMM1, %k0 + VPCMP $0, %YMMZERO, %YMM0, %k1 + VPCMP $0, %YMMZERO, %YMM1, %k2 + /* Each bit in K1 represents a NULL in YMM0 or YMM1. */ + kord %k1, %k2, %k1 + /* Each bit in K1 represents a NULL or a mismatch. */ + kord %k0, %k1, %k1 + kmovd %k1, %ecx + testl %ecx, %ecx + jne L(last_vector) + + addl $VEC_SIZE, %edx + + addl $VEC_SIZE, %eax +# ifdef USE_AS_STRNCMP + /* Return 0 if the current offset (%rdx) >= the maximum offset + (%r11). */ + cmpq %r11, %rdx + jae L(zero) +# endif + cmpl $(PAGE_SIZE - VEC_SIZE), %eax + jle L(loop_1_vector) +L(cross_page_1_vector): + /* Less than 32 bytes to check, try one xmm vector. */ + cmpl $(PAGE_SIZE - 16), %eax + jg L(cross_page_1_xmm) + VMOVU (%rdi, %rdx), %XMM0 + VMOVU (%rsi, %rdx), %XMM1 + + /* Each bit in K0 represents a mismatch in XMM0 and XMM1. */ + VPCMP $4, %XMM0, %XMM1, %k0 + VPCMP $0, %XMMZERO, %XMM0, %k1 + VPCMP $0, %XMMZERO, %XMM1, %k2 + /* Each bit in K1 represents a NULL in XMM0 or XMM1. */ + korw %k1, %k2, %k1 + /* Each bit in K1 represents a NULL or a mismatch. */ + korw %k0, %k1, %k1 + kmovw %k1, %ecx + testl %ecx, %ecx + jne L(last_vector) + + addl $16, %edx +# ifndef USE_AS_WCSCMP + addl $16, %eax +# endif +# ifdef USE_AS_STRNCMP + /* Return 0 if the current offset (%rdx) >= the maximum offset + (%r11). */ + cmpq %r11, %rdx + jae L(zero) +# endif + +L(cross_page_1_xmm): +# ifndef USE_AS_WCSCMP + /* Less than 16 bytes to check, try 8 byte vector. NB: No need + for wcscmp nor wcsncmp since wide char is 4 bytes. */ + cmpl $(PAGE_SIZE - 8), %eax + jg L(cross_page_8bytes) + vmovq (%rdi, %rdx), %XMM0 + vmovq (%rsi, %rdx), %XMM1 + + /* Each bit in K0 represents a mismatch in XMM0 and XMM1. */ + VPCMP $4, %XMM0, %XMM1, %k0 + VPCMP $0, %XMMZERO, %XMM0, %k1 + VPCMP $0, %XMMZERO, %XMM1, %k2 + /* Each bit in K1 represents a NULL in XMM0 or XMM1. */ + kord %k1, %k2, %k1 + /* Each bit in K1 represents a NULL or a mismatch. */ + kord %k0, %k1, %k1 + kmovd %k1, %ecx + +# ifdef USE_AS_WCSCMP + /* Only last 2 bits are valid. */ + andl $0x3, %ecx +# else + /* Only last 8 bits are valid. */ + andl $0xff, %ecx +# endif + + testl %ecx, %ecx + jne L(last_vector) + + addl $8, %edx + addl $8, %eax +# ifdef USE_AS_STRNCMP + /* Return 0 if the current offset (%rdx) >= the maximum offset + (%r11). */ + cmpq %r11, %rdx + jae L(zero) +# endif + +L(cross_page_8bytes): + /* Less than 8 bytes to check, try 4 byte vector. */ + cmpl $(PAGE_SIZE - 4), %eax + jg L(cross_page_4bytes) + vmovd (%rdi, %rdx), %XMM0 + vmovd (%rsi, %rdx), %XMM1 + + /* Each bit in K0 represents a mismatch in XMM0 and XMM1. */ + VPCMP $4, %XMM0, %XMM1, %k0 + VPCMP $0, %XMMZERO, %XMM0, %k1 + VPCMP $0, %XMMZERO, %XMM1, %k2 + /* Each bit in K1 represents a NULL in XMM0 or XMM1. */ + kord %k1, %k2, %k1 + /* Each bit in K1 represents a NULL or a mismatch. */ + kord %k0, %k1, %k1 + kmovd %k1, %ecx + +# ifdef USE_AS_WCSCMP + /* Only the last bit is valid. */ + andl $0x1, %ecx +# else + /* Only last 4 bits are valid. */ + andl $0xf, %ecx +# endif + + testl %ecx, %ecx + jne L(last_vector) + + addl $4, %edx +# ifdef USE_AS_STRNCMP + /* Return 0 if the current offset (%rdx) >= the maximum offset + (%r11). */ + cmpq %r11, %rdx + jae L(zero) +# endif + +L(cross_page_4bytes): +# endif + /* Less than 4 bytes to check, try one byte/dword at a time. */ +# ifdef USE_AS_STRNCMP + cmpq %r11, %rdx + jae L(zero) +# endif +# ifdef USE_AS_WCSCMP + movl (%rdi, %rdx), %eax + movl (%rsi, %rdx), %ecx +# else + movzbl (%rdi, %rdx), %eax + movzbl (%rsi, %rdx), %ecx +# endif + testl %eax, %eax + jne L(cross_page_loop) + subl %ecx, %eax + ret +END (STRCMP) +#endif |