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x86: Optimize memcmp SSE2 in memcmp.S

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New code save size (-303 bytes) and has significantly better
performance.

geometric_mean(N=20) of page cross cases New / Original: 0.634
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
This commit is contained in:
Noah Goldstein 2022-04-15 12:27:59 -05:00
parent ac0d208b54
commit 8804157ad9
8 changed files with 584 additions and 385 deletions
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902
sysdeps/x86_64/memcmp.S
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@ -18,395 +18,557 @@
#include <sysdep.h>
#ifdef USE_AS_WMEMCMP
# define PCMPEQ pcmpeqd
# define CHAR_SIZE 4
# define SIZE_OFFSET (0)
#else
# define PCMPEQ pcmpeqb
# define CHAR_SIZE 1
#endif
#ifdef USE_AS_MEMCMPEQ
# define SIZE_OFFSET (0)
# define CHECK_CMP(x, y) subl x, y
#else
# ifndef SIZE_OFFSET
# define SIZE_OFFSET (CHAR_PER_VEC * 2)
# endif
# define CHECK_CMP(x, y) cmpl x, y
#endif
#define VEC_SIZE 16
#define CHAR_PER_VEC (VEC_SIZE / CHAR_SIZE)
#ifndef MEMCMP
# define MEMCMP memcmp
#endif
.text
ENTRY (memcmp)
#ifdef __ILP32__
/* Clear the upper 32 bits. */
movl %edx, %edx
ENTRY(MEMCMP)
#ifdef USE_AS_WMEMCMP
/* Use 0xffff to test for mismatches on pmovmskb bitmask. Store
in ecx for code size. This is preferable to using `incw` as
it avoids partial register stalls on older hardware (pre
SnB). */
movl $0xffff, %ecx
#endif
test %RDX_LP, %RDX_LP
jz L(finz)
cmpq $1, %rdx
jbe L(finr1b)
subq %rdi, %rsi
movq %rdx, %r10
cmpq $32, %r10
jae L(gt32)
/* Handle small chunks and last block of less than 32 bytes. */
L(small):
testq $1, %r10
jz L(s2b)
movzbl (%rdi), %eax
movzbl (%rdi, %rsi), %edx
subq $1, %r10
je L(finz1)
addq $1, %rdi
subl %edx, %eax
jnz L(exit)
L(s2b):
testq $2, %r10
jz L(s4b)
movzwl (%rdi), %eax
movzwl (%rdi, %rsi), %edx
subq $2, %r10
#ifdef USE_AS_MEMCMPEQ
je L(finz1)
cmpq $CHAR_PER_VEC, %rdx
ja L(more_1x_vec)
#ifdef USE_AS_WMEMCMP
/* saves a byte of code keeping the fall through path n = [2, 4]
in the initial cache line. */
decl %edx
jle L(cmp_0_1)
movq (%rsi), %xmm0
movq (%rdi), %xmm1
PCMPEQ %xmm0, %xmm1
pmovmskb %xmm1, %eax
subl %ecx, %eax
jnz L(ret_nonzero_vec_start_0)
movq -4(%rsi, %rdx, CHAR_SIZE), %xmm0
movq -4(%rdi, %rdx, CHAR_SIZE), %xmm1
PCMPEQ %xmm0, %xmm1
pmovmskb %xmm1, %eax
subl %ecx, %eax
jnz L(ret_nonzero_vec_end_0_adj)
#else
je L(fin2_7)
#endif
addq $2, %rdi
cmpl %edx, %eax
#ifdef USE_AS_MEMCMPEQ
jnz L(neq_early)
#else
jnz L(fin2_7)
#endif
L(s4b):
testq $4, %r10
jz L(s8b)
movl (%rdi), %eax
movl (%rdi, %rsi), %edx
subq $4, %r10
#ifdef USE_AS_MEMCMPEQ
je L(finz1)
#else
je L(fin2_7)
#endif
addq $4, %rdi
cmpl %edx, %eax
#ifdef USE_AS_MEMCMPEQ
jnz L(neq_early)
#else
jnz L(fin2_7)
#endif
L(s8b):
testq $8, %r10
jz L(s16b)
movq (%rdi), %rax
movq (%rdi, %rsi), %rdx
subq $8, %r10
#ifdef USE_AS_MEMCMPEQ
je L(sub_return8)
#else
je L(fin2_7)
#endif
addq $8, %rdi
cmpq %rdx, %rax
#ifdef USE_AS_MEMCMPEQ
jnz L(neq_early)
#else
jnz L(fin2_7)
#endif
L(s16b):
movdqu (%rdi), %xmm1
movdqu (%rdi, %rsi), %xmm0
pcmpeqb %xmm0, %xmm1
#ifdef USE_AS_MEMCMPEQ
pmovmskb %xmm1, %eax
subl $0xffff, %eax
cmpl $8, %edx
ja L(cmp_9_16)
cmpl $4, %edx
jb L(cmp_0_3)
# ifdef USE_AS_MEMCMPEQ
movl (%rsi), %eax
subl (%rdi), %eax
movl -4(%rsi, %rdx), %esi
subl -4(%rdi, %rdx), %esi
orl %esi, %eax
ret
#else
pmovmskb %xmm1, %edx
xorl %eax, %eax
subl $0xffff, %edx
jz L(finz)
bsfl %edx, %ecx
leaq (%rdi, %rcx), %rcx
movzbl (%rcx), %eax
movzbl (%rsi, %rcx), %edx
jmp L(finz1)
#endif
.p2align 4,, 4
L(finr1b):
movzbl (%rdi), %eax
movzbl (%rsi), %edx
L(finz1):
subl %edx, %eax
L(exit):
ret
#ifdef USE_AS_MEMCMPEQ
.p2align 4,, 4
L(sub_return8):
subq %rdx, %rax
movl %eax, %edx
shrq $32, %rax
orl %edx, %eax
ret
#else
.p2align 4,, 4
L(fin2_7):
cmpq %rdx, %rax
jz L(finz)
movq %rax, %r11
subq %rdx, %r11
bsfq %r11, %rcx
sarq $3, %rcx
salq $3, %rcx
sarq %cl, %rax
movzbl %al, %eax
sarq %cl, %rdx
movzbl %dl, %edx
subl %edx, %eax
ret
#endif
.p2align 4,, 4
L(finz):
# else
/* Combine comparisons for lo and hi 4-byte comparisons. */
movl -4(%rsi, %rdx), %ecx
movl -4(%rdi, %rdx), %eax
shlq $32, %rcx
shlq $32, %rax
movl (%rsi), %esi
movl (%rdi), %edi
orq %rsi, %rcx
orq %rdi, %rax
/* Only compute proper return if not-equal. */
cmpq %rcx, %rax
jnz L(ret_nonzero)
xorl %eax, %eax
ret
#ifdef USE_AS_MEMCMPEQ
.p2align 4,, 4
L(neq_early):
movl $1, %eax
# endif
.p2align 4,, 10
L(cmp_9_16):
# ifdef USE_AS_MEMCMPEQ
movq (%rsi), %rax
subq (%rdi), %rax
movq -8(%rsi, %rdx), %rcx
subq -8(%rdi, %rdx), %rcx
orq %rcx, %rax
/* Convert 64 bit -> 32 bit boolean (we should have made the ABI
return long). */
setnz %cl
movzbl %cl, %eax
# else
movq (%rsi), %rcx
movq (%rdi), %rax
/* Only compute proper return if not-equal. */
cmpq %rcx, %rax
jnz L(ret_nonzero)
movq -8(%rsi, %rdx, CHAR_SIZE), %rcx
movq -8(%rdi, %rdx, CHAR_SIZE), %rax
/* Only compute proper return if not-equal. */
cmpq %rcx, %rax
jnz L(ret_nonzero)
xorl %eax, %eax
# endif
#endif
ret
.p2align 4,, 8
L(cmp_0_1):
/* Flag set by earlier comparison against 1. */
jne L(cmp_0_0)
#ifdef USE_AS_WMEMCMP
movl (%rdi), %ecx
xorl %edx, %edx
cmpl (%rsi), %ecx
je L(cmp_0_0)
setg %dl
leal -1(%rdx, %rdx), %eax
#else
movzbl (%rdi), %eax
movzbl (%rsi), %ecx
subl %ecx, %eax
#endif
ret
/* Fits in aligning bytes. */
L(cmp_0_0):
xorl %eax, %eax
ret
#ifdef USE_AS_WMEMCMP
.p2align 4
L(ret_nonzero_vec_start_0):
bsfl %eax, %eax
movl (%rdi, %rax), %ecx
xorl %edx, %edx
cmpl (%rsi, %rax), %ecx
/* NB: no partial register stall here because xorl zero idiom
above. */
setg %dl
leal -1(%rdx, %rdx), %eax
ret
#else
# ifndef USE_AS_MEMCMPEQ
.p2align 4,, 14
L(ret_nonzero):
/* Need to bswap to get proper return without branch. */
bswapq %rcx
bswapq %rax
subq %rcx, %rax
sbbl %eax, %eax
orl $1, %eax
ret
# endif
.p2align 4
L(cmp_0_3):
# ifdef USE_AS_MEMCMPEQ
/* No reason to add to dependency chain on rdx. Saving a the
bytes here doesn't change number of fetch blocks. */
cmpl $1, %edx
jbe L(cmp_0_1)
# else
/* We need the code size to prevent taking an extra fetch block.
*/
decl %edx
jle L(cmp_0_1)
# endif
movzwl (%rsi), %ecx
movzwl (%rdi), %eax
# ifdef USE_AS_MEMCMPEQ
subl %ecx, %eax
movzbl -1(%rsi, %rdx), %esi
movzbl -1(%rdi, %rdx), %edi
subl %edi, %esi
orl %esi, %eax
# else
bswapl %ecx
bswapl %eax
/* Implicit right shift by one. We just need to displace the
sign bits. */
shrl %ecx
shrl %eax
/* Eat a partial register stall here. Saves code stopping
L(cmp_0_3) from bleeding into the next fetch block and saves
an ALU. */
movb (%rsi, %rdx), %cl
movzbl (%rdi, %rdx), %edi
orl %edi, %eax
subl %ecx, %eax
# endif
ret
#endif
/* For blocks bigger than 32 bytes
1. Advance one of the addr pointer to be 16B aligned.
2. Treat the case of both addr pointers aligned to 16B
separately to avoid movdqu.
3. Handle any blocks of greater than 64 consecutive bytes with
unrolling to reduce branches.
4. At least one addr pointer is 16B aligned, use memory version
of pcmbeqb.
*/
.p2align 4,, 4
L(gt32):
movq %rdx, %r11
addq %rdi, %r11
movq %rdi, %r8
andq $15, %r8
jz L(16am)
/* Both pointers may be misaligned. */
movdqu (%rdi), %xmm1
movdqu (%rdi, %rsi), %xmm0
pcmpeqb %xmm0, %xmm1
pmovmskb %xmm1, %edx
subl $0xffff, %edx
jnz L(neq)
neg %r8
leaq 16(%rdi, %r8), %rdi
L(16am):
/* Handle two 16B aligned pointers separately. */
testq $15, %rsi
jz L(ATR)
testq $16, %rdi
jz L(A32)
movdqu (%rdi, %rsi), %xmm0
pcmpeqb (%rdi), %xmm0
pmovmskb %xmm0, %edx
subl $0xffff, %edx
jnz L(neq)
addq $16, %rdi
L(A32):
movq %r11, %r10
andq $-32, %r10
cmpq %r10, %rdi
jae L(mt16)
/* Pre-unroll to be ready for unrolled 64B loop. */
testq $32, %rdi
jz L(A64)
movdqu (%rdi,%rsi), %xmm0
pcmpeqb (%rdi), %xmm0
pmovmskb %xmm0, %edx
subl $0xffff, %edx
jnz L(neq)
addq $16, %rdi
movdqu (%rdi,%rsi), %xmm0
pcmpeqb (%rdi), %xmm0
pmovmskb %xmm0, %edx
subl $0xffff, %edx
jnz L(neq)
addq $16, %rdi
L(A64):
movq %r11, %r10
andq $-64, %r10
cmpq %r10, %rdi
jae L(mt32)
L(A64main):
movdqu (%rdi,%rsi), %xmm0
pcmpeqb (%rdi), %xmm0
pmovmskb %xmm0, %edx
subl $0xffff, %edx
jnz L(neq)
addq $16, %rdi
movdqu (%rdi,%rsi), %xmm0
pcmpeqb (%rdi), %xmm0
pmovmskb %xmm0, %edx
subl $0xffff, %edx
jnz L(neq)
addq $16, %rdi
movdqu (%rdi,%rsi), %xmm0
pcmpeqb (%rdi), %xmm0
pmovmskb %xmm0, %edx
subl $0xffff, %edx
jnz L(neq)
addq $16, %rdi
movdqu (%rdi,%rsi), %xmm0
pcmpeqb (%rdi), %xmm0
pmovmskb %xmm0, %edx
subl $0xffff, %edx
jnz L(neq)
addq $16, %rdi
cmpq %rdi, %r10
jne L(A64main)
L(mt32):
movq %r11, %r10
andq $-32, %r10
cmpq %r10, %rdi
jae L(mt16)
L(A32main):
movdqu (%rdi,%rsi), %xmm0
pcmpeqb (%rdi), %xmm0
pmovmskb %xmm0, %edx
subl $0xffff, %edx
jnz L(neq)
addq $16, %rdi
movdqu (%rdi,%rsi), %xmm0
pcmpeqb (%rdi), %xmm0
pmovmskb %xmm0, %edx
subl $0xffff, %edx
jnz L(neq)
addq $16, %rdi
cmpq %rdi, %r10
jne L(A32main)
L(mt16):
subq %rdi, %r11
je L(finz)
movq %r11, %r10
jmp L(small)
.p2align 4,, 4
L(neq):
#ifdef USE_AS_MEMCMPEQ
movl $1, %eax
ret
.p2align 5
L(more_1x_vec):
#ifndef USE_AS_WMEMCMP
/* Use 0xffff to test for mismatches on pmovmskb bitmask. Store
in ecx for code size. This is preferable to using `incw` as
it avoids partial register stalls on older hardware (pre
SnB). */
movl $0xffff, %ecx
#endif
movups (%rsi), %xmm0
movups (%rdi), %xmm1
PCMPEQ %xmm0, %xmm1
pmovmskb %xmm1, %eax
subl %ecx, %eax
jnz L(ret_nonzero_vec_start_0)
#if SIZE_OFFSET == 0
cmpq $(CHAR_PER_VEC * 2), %rdx
#else
/* Offset rdx. Saves just enough code size to keep the
L(last_2x_vec) case and the non-zero return in a single
cache line. */
subq $(CHAR_PER_VEC * 2), %rdx
#endif
ja L(more_2x_vec)
movups (VEC_SIZE * -1 + SIZE_OFFSET)(%rsi, %rdx, CHAR_SIZE), %xmm0
movups (VEC_SIZE * -1 + SIZE_OFFSET)(%rdi, %rdx, CHAR_SIZE), %xmm1
PCMPEQ %xmm0, %xmm1
pmovmskb %xmm1, %eax
subl %ecx, %eax
#ifndef USE_AS_MEMCMPEQ
/* Don't use `incw ax` as machines this code runs on are liable
to have partial register stall. */
jnz L(ret_nonzero_vec_end_0)
#else
/* Various return targets for memcmpeq. Will always be hot in
Icache and get short encoding. */
L(ret_nonzero_vec_start_1):
L(ret_nonzero_vec_start_0):
L(ret_nonzero_vec_end_0):
#endif
ret
#ifndef USE_AS_MEMCMPEQ
# ifdef USE_AS_WMEMCMP
.p2align 4
L(ret_nonzero_vec_end_0_adj):
addl $3, %edx
# else
.p2align 4,, 8
# endif
L(ret_nonzero_vec_end_0):
bsfl %eax, %eax
# ifdef USE_AS_WMEMCMP
leal (%rax, %rdx, CHAR_SIZE), %eax
movl (VEC_SIZE * -1 + SIZE_OFFSET)(%rdi, %rax), %ecx
xorl %edx, %edx
cmpl (VEC_SIZE * -1 + SIZE_OFFSET)(%rsi, %rax), %ecx
/* NB: no partial register stall here because xorl zero idiom
above. */
setg %dl
leal -1(%rdx, %rdx), %eax
# else
addl %edx, %eax
movzbl (VEC_SIZE * -1 + SIZE_OFFSET)(%rsi, %rax), %ecx
movzbl (VEC_SIZE * -1 + SIZE_OFFSET)(%rdi, %rax), %eax
subl %ecx, %eax
# endif
ret
# ifndef USE_AS_WMEMCMP
.p2align 4,, 10
L(ret_nonzero_vec_start_0):
bsfl %eax, %eax
movzbl (%rsi, %rax), %ecx
movzbl (%rdi, %rax), %eax
subl %ecx, %eax
ret
# endif
#else
bsfl %edx, %ecx
movzbl (%rdi, %rcx), %eax
addq %rdi, %rsi
movzbl (%rsi,%rcx), %edx
jmp L(finz1)
#endif
.p2align 4,, 4
L(ATR):
movq %r11, %r10
andq $-32, %r10
cmpq %r10, %rdi
jae L(mt16)
testq $16, %rdi
jz L(ATR32)
.p2align 5
L(more_2x_vec):
movups (VEC_SIZE * 1)(%rsi), %xmm0
movups (VEC_SIZE * 1)(%rdi), %xmm1
PCMPEQ %xmm0, %xmm1
pmovmskb %xmm1, %eax
subl %ecx, %eax
jnz L(ret_nonzero_vec_start_1)
movdqa (%rdi,%rsi), %xmm0
pcmpeqb (%rdi), %xmm0
pmovmskb %xmm0, %edx
subl $0xffff, %edx
jnz L(neq)
addq $16, %rdi
cmpq %rdi, %r10
je L(mt16)
cmpq $(CHAR_PER_VEC * 4 - SIZE_OFFSET), %rdx
jbe L(last_2x_vec)
L(ATR32):
movq %r11, %r10
andq $-64, %r10
testq $32, %rdi
jz L(ATR64)
cmpq $(CHAR_PER_VEC * 8 - SIZE_OFFSET), %rdx
ja L(more_8x_vec)
movdqa (%rdi,%rsi), %xmm0
pcmpeqb (%rdi), %xmm0
pmovmskb %xmm0, %edx
subl $0xffff, %edx
jnz L(neq)
addq $16, %rdi
/* Do comparisons for [65, 96] and [97, 128] 2x VEC at a time.
This can harm performance if non-zero return in [65, 80] or
[97, 112] but helps performance otherwise. Generally zero-
return is hotter. */
movups (VEC_SIZE * 2)(%rsi), %xmm0
movups (VEC_SIZE * 2)(%rdi), %xmm1
PCMPEQ %xmm0, %xmm1
movups (VEC_SIZE * 3)(%rsi), %xmm2
movups (VEC_SIZE * 3)(%rdi), %xmm3
PCMPEQ %xmm2, %xmm3
pand %xmm1, %xmm3
movdqa (%rdi,%rsi), %xmm0
pcmpeqb (%rdi), %xmm0
pmovmskb %xmm0, %edx
subl $0xffff, %edx
jnz L(neq)
addq $16, %rdi
pmovmskb %xmm3, %eax
CHECK_CMP (%ecx, %eax)
jnz L(ret_nonzero_vec_start_2_3)
L(ATR64):
cmpq %rdi, %r10
je L(mt32)
cmpl $(CHAR_PER_VEC * 6 - SIZE_OFFSET), %edx
jbe L(last_2x_vec)
L(ATR64main):
movdqa (%rdi,%rsi), %xmm0
pcmpeqb (%rdi), %xmm0
pmovmskb %xmm0, %edx
subl $0xffff, %edx
jnz L(neq)
addq $16, %rdi
movdqa (%rdi,%rsi), %xmm0
pcmpeqb (%rdi), %xmm0
pmovmskb %xmm0, %edx
subl $0xffff, %edx
jnz L(neq)
addq $16, %rdi
movdqa (%rdi,%rsi), %xmm0
pcmpeqb (%rdi), %xmm0
pmovmskb %xmm0, %edx
subl $0xffff, %edx
jnz L(neq)
addq $16, %rdi
movdqa (%rdi,%rsi), %xmm0
pcmpeqb (%rdi), %xmm0
pmovmskb %xmm0, %edx
subl $0xffff, %edx
jnz L(neq)
addq $16, %rdi
cmpq %rdi, %r10
jne L(ATR64main)
movq %r11, %r10
andq $-32, %r10
cmpq %r10, %rdi
jae L(mt16)
L(ATR32res):
movdqa (%rdi,%rsi), %xmm0
pcmpeqb (%rdi), %xmm0
pmovmskb %xmm0, %edx
subl $0xffff, %edx
jnz L(neq)
addq $16, %rdi
movdqa (%rdi,%rsi), %xmm0
pcmpeqb (%rdi), %xmm0
pmovmskb %xmm0, %edx
subl $0xffff, %edx
jnz L(neq)
addq $16, %rdi
cmpq %r10, %rdi
jne L(ATR32res)
subq %rdi, %r11
je L(finz)
movq %r11, %r10
jmp L(small)
/* Align to 16byte to improve instruction fetch. */
.p2align 4,, 4
END(memcmp)
movups (VEC_SIZE * 4)(%rsi), %xmm0
movups (VEC_SIZE * 4)(%rdi), %xmm1
PCMPEQ %xmm0, %xmm1
movups (VEC_SIZE * 5)(%rsi), %xmm2
movups (VEC_SIZE * 5)(%rdi), %xmm3
PCMPEQ %xmm2, %xmm3
pand %xmm1, %xmm3
pmovmskb %xmm3, %eax
CHECK_CMP (%ecx, %eax)
#ifdef USE_AS_MEMCMPEQ
libc_hidden_def (memcmp)
jz L(last_2x_vec)
ret
#else
# undef bcmp
weak_alias (memcmp, bcmp)
libc_hidden_builtin_def (memcmp)
jnz L(ret_nonzero_vec_start_4_5)
#endif
.p2align 4
L(last_2x_vec):
movups (VEC_SIZE * -2 + SIZE_OFFSET)(%rsi, %rdx, CHAR_SIZE), %xmm0
movups (VEC_SIZE * -2 + SIZE_OFFSET)(%rdi, %rdx, CHAR_SIZE), %xmm1
PCMPEQ %xmm0, %xmm1
movups (VEC_SIZE * -1 + SIZE_OFFSET)(%rsi, %rdx, CHAR_SIZE), %xmm2
movups (VEC_SIZE * -1 + SIZE_OFFSET)(%rdi, %rdx, CHAR_SIZE), %xmm3
PCMPEQ %xmm2, %xmm3
pand %xmm1, %xmm3
pmovmskb %xmm3, %eax
subl %ecx, %eax
#ifdef USE_AS_MEMCMPEQ
/* Various return targets for memcmpeq. Will always be hot in
Icache and get short encoding. */
L(ret_nonzero_vec_start_2_3):
L(ret_nonzero_vec_start_4_5):
ret
#else
jnz L(ret_nonzero_vec_end_1)
ret
.p2align 4,, 8
L(ret_nonzero_vec_end_1):
pmovmskb %xmm1, %ecx
/* High 16 bits of eax guranteed to be all ones. Rotate them in
to we can do `or + not` with just `xor`. */
rorl $16, %eax
xorl %ecx, %eax
/* Partial register stall. */
bsfl %eax, %eax
# ifdef USE_AS_WMEMCMP
leal (%rax, %rdx, CHAR_SIZE), %eax
movl (VEC_SIZE * -2 + SIZE_OFFSET)(%rdi, %rax), %ecx
xorl %edx, %edx
cmpl (VEC_SIZE * -2 + SIZE_OFFSET)(%rsi, %rax), %ecx
/* NB: no partial register stall here because xorl zero idiom
above. */
setg %dl
leal -1(%rdx, %rdx), %eax
# else
addl %edx, %eax
movzbl (VEC_SIZE * -2 + SIZE_OFFSET)(%rsi, %rax), %ecx
movzbl (VEC_SIZE * -2 + SIZE_OFFSET)(%rdi, %rax), %eax
subl %ecx, %eax
# endif
ret
.p2align 4
L(ret_nonzero_vec_start_4_5):
pmovmskb %xmm1, %edx
sall $16, %eax
leal 1(%rax, %rdx), %eax
bsfl %eax, %eax
# ifdef USE_AS_WMEMCMP
movl (VEC_SIZE * 4)(%rdi, %rax), %ecx
xorl %edx, %edx
cmpl (VEC_SIZE * 4)(%rsi, %rax), %ecx
/* NB: no partial register stall here because xorl zero idiom
above. */
setg %dl
leal -1(%rdx, %rdx), %eax
# else
movzbl (VEC_SIZE * 4)(%rsi, %rax), %ecx
movzbl (VEC_SIZE * 4)(%rdi, %rax), %eax
subl %ecx, %eax
# endif
ret
.p2align 4,, 8
L(ret_nonzero_vec_start_1):
bsfl %eax, %eax
# ifdef USE_AS_WMEMCMP
movl (VEC_SIZE * 1)(%rdi, %rax), %ecx
xorl %edx, %edx
cmpl (VEC_SIZE * 1)(%rsi, %rax), %ecx
/* NB: no partial register stall here because xorl zero idiom
above. */
setg %dl
leal -1(%rdx, %rdx), %eax
# else
movzbl (VEC_SIZE * 1)(%rsi, %rax), %ecx
movzbl (VEC_SIZE * 1)(%rdi, %rax), %eax
subl %ecx, %eax
# endif
ret
#endif
.p2align 4
L(more_8x_vec):
subq %rdi, %rsi
leaq (VEC_SIZE * -6 + SIZE_OFFSET)(%rdi, %rdx, CHAR_SIZE), %rdx
andq $(VEC_SIZE * -1), %rdi
addq %rdi, %rsi
.p2align 4
L(loop_4x):
movups (VEC_SIZE * 2)(%rsi), %xmm0
movups (VEC_SIZE * 3)(%rsi), %xmm1
PCMPEQ (VEC_SIZE * 2)(%rdi), %xmm0
PCMPEQ (VEC_SIZE * 3)(%rdi), %xmm1
movups (VEC_SIZE * 4)(%rsi), %xmm2
movups (VEC_SIZE * 5)(%rsi), %xmm3
PCMPEQ (VEC_SIZE * 4)(%rdi), %xmm2
PCMPEQ (VEC_SIZE * 5)(%rdi), %xmm3
pand %xmm0, %xmm1
pand %xmm2, %xmm3
pand %xmm1, %xmm3
pmovmskb %xmm3, %eax
subl %ecx, %eax
jnz L(ret_nonzero_loop)
addq $(VEC_SIZE * 4), %rdi
addq $(VEC_SIZE * 4), %rsi
cmpq %rdi, %rdx
ja L(loop_4x)
/* Get remaining length in edx. */
subl %edi, %edx
/* Restore offset so we can reuse L(last_2x_vec). */
addl $(VEC_SIZE * 6 - SIZE_OFFSET), %edx
#ifdef USE_AS_WMEMCMP
shrl $2, %edx
#endif
cmpl $(CHAR_PER_VEC * 4 - SIZE_OFFSET), %edx
jbe L(last_2x_vec)
movups (VEC_SIZE * 2)(%rsi), %xmm0
movups (VEC_SIZE * 2)(%rdi), %xmm1
PCMPEQ %xmm0, %xmm1
movups (VEC_SIZE * 3)(%rsi), %xmm2
movups (VEC_SIZE * 3)(%rdi), %xmm3
PCMPEQ %xmm2, %xmm3
pand %xmm1, %xmm3
pmovmskb %xmm3, %eax
CHECK_CMP (%ecx, %eax)
jz L(last_2x_vec)
#ifdef USE_AS_MEMCMPEQ
L(ret_nonzero_loop):
ret
#else
.p2align 4
L(ret_nonzero_vec_start_2_3):
pmovmskb %xmm1, %edx
sall $16, %eax
leal 1(%rax, %rdx), %eax
bsfl %eax, %eax
# ifdef USE_AS_WMEMCMP
movl (VEC_SIZE * 2)(%rdi, %rax), %ecx
xorl %edx, %edx
cmpl (VEC_SIZE * 2)(%rsi, %rax), %ecx
/* NB: no partial register stall here because xorl zero idiom
above. */
setg %dl
leal -1(%rdx, %rdx), %eax
# else
movzbl (VEC_SIZE * 2)(%rsi, %rax), %ecx
movzbl (VEC_SIZE * 2)(%rdi, %rax), %eax
subl %ecx, %eax
# endif
ret
.p2align 4
L(ret_nonzero_loop):
pmovmskb %xmm0, %ecx
pmovmskb %xmm1, %edx
sall $(VEC_SIZE * 1), %edx
leal 1(%rcx, %rdx), %edx
pmovmskb %xmm2, %ecx
/* High 16 bits of eax guranteed to be all ones. Rotate them in
to we can do `or + not` with just `xor`. */
rorl $16, %eax
xorl %ecx, %eax
salq $32, %rax
orq %rdx, %rax
bsfq %rax, %rax
# ifdef USE_AS_WMEMCMP
movl (VEC_SIZE * 2)(%rdi, %rax), %ecx
xorl %edx, %edx
cmpl (VEC_SIZE * 2)(%rsi, %rax), %ecx
/* NB: no partial register stall here because xorl zero idiom
above. */
setg %dl
leal -1(%rdx, %rdx), %eax
# else
movzbl (VEC_SIZE * 2)(%rsi, %rax), %ecx
movzbl (VEC_SIZE * 2)(%rdi, %rax), %eax
subl %ecx, %eax
# endif
ret
#endif
END(MEMCMP)
#ifndef USE_AS_WMEMCMP
# ifdef USE_AS_MEMCMPEQ
libc_hidden_def (MEMCMP)
# else
# undef bcmp
weak_alias (MEMCMP, bcmp)
libc_hidden_builtin_def (MEMCMP)
# endif
#endif

2
sysdeps/x86_64/memcmpeq.S
View File

@ -16,6 +16,6 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#define memcmp __memcmpeq
#define MEMCMP __memcmpeq
#define USE_AS_MEMCMPEQ 1
#include "multiarch/memcmp-sse2.S"

2
sysdeps/x86_64/multiarch/Makefile
View File

@ -162,8 +162,8 @@ sysdep_routines += \
wmemchr-sse2 \
wmemcmp-avx2-movbe \
wmemcmp-avx2-movbe-rtm \
wmemcmp-c \
wmemcmp-evex-movbe \
wmemcmp-sse2 \
wmemcmp-sse4 \
# sysdep_routines
endif

4
sysdeps/x86_64/multiarch/memcmp-sse2.S
View File

@ -17,8 +17,8 @@
<https://www.gnu.org/licenses/>. */
#if IS_IN (libc)
# ifndef memcmp
# define memcmp __memcmp_sse2
# ifndef MEMCMP
# define MEMCMP __memcmp_sse2
# endif
# ifdef SHARED

4
sysdeps/x86_64/multiarch/memcmpeq-sse2.S
View File

@ -17,9 +17,9 @@
<https://www.gnu.org/licenses/>. */
#if IS_IN (libc)
# define memcmp __memcmpeq_sse2
# define MEMCMP __memcmpeq_sse2
#else
# define memcmp __memcmpeq
# define MEMCMP __memcmpeq
#endif
#define USE_AS_MEMCMPEQ 1
#include "memcmp-sse2.S"

9
sysdeps/x86_64/multiarch/wmemcmp-c.c
View File

@ -1,9 +0,0 @@
#if IS_IN (libc)
# include <wchar.h>
# define WMEMCMP __wmemcmp_sse2
extern __typeof (wmemcmp) __wmemcmp_sse2;
#endif
#include "wcsmbs/wmemcmp.c"

25
sysdeps/x86_64/multiarch/wmemcmp-sse2.S Normal file
View File

@ -0,0 +1,25 @@
/* wmemcmp optimized with SSE2.
Copyright (C) 2022 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)
# define MEMCMP __wmemcmp_sse2
#else
# define MEMCMP wmemcmp
#endif
#define USE_AS_WMEMCMP 1
#include "memcmp-sse2.S"

21
sysdeps/x86_64/wmemcmp.S Normal file
View File

@ -0,0 +1,21 @@
/* wmemcmp optimized with SSE2.
Copyright (C) 2022 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/>. */
#define MEMCMP wmemcmp
#define USE_AS_WMEMCMP 1
#include "multiarch/memcmp-sse2.S"