x86-64: Improve EVEX strcmp with masked load

In strcmp-evex.S, to compare 2 32-byte strings, replace

        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)

with

        VMOVU   (%rdi, %rdx), %YMM0
        VPTESTM %YMM0, %YMM0, %k2
        /* Each bit cleared in K1 represents a mismatch or a null CHAR
           in YMM0 and 32 bytes at (%rsi, %rdx).  */
        VPCMP   $0, (%rsi, %rdx), %YMM0, %k1{%k2}
        kmovd   %k1, %ecx
        incl    %ecx
        jne     L(last_vector)

It makes EVEX strcmp faster than AVX2 strcmp by up to 40% on Tiger Lake
and Ice Lake.

Co-Authored-By: Noah Goldstein <goldstein.w.n@gmail.com>
This commit is contained in:
H.J. Lu 2021-10-29 12:40:20 -07:00
parent 79d0fc6539
commit c46e9afb2d

View File

@ -41,6 +41,8 @@
# ifdef USE_AS_WCSCMP
/* Compare packed dwords. */
# define VPCMP vpcmpd
# define VPMINU vpminud
# define VPTESTM vptestmd
# define SHIFT_REG32 r8d
# define SHIFT_REG64 r8
/* 1 dword char == 4 bytes. */
@ -48,6 +50,8 @@
# else
/* Compare packed bytes. */
# define VPCMP vpcmpb
# define VPMINU vpminub
# define VPTESTM vptestmb
# define SHIFT_REG32 ecx
# define SHIFT_REG64 rcx
/* 1 byte char == 1 byte. */
@ -67,6 +71,9 @@
# define YMM5 ymm22
# define YMM6 ymm23
# define YMM7 ymm24
# define YMM8 ymm25
# define YMM9 ymm26
# define YMM10 ymm27
/* Warning!
wcscmp/wcsncmp have to use SIGNED comparison for elements.
@ -76,7 +83,7 @@
/* 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
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
@ -113,27 +120,21 @@ ENTRY (STRCMP)
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
/* Each bit set in K2 represents a non-null CHAR in YMM0. */
VPTESTM %YMM0, %YMM0, %k2
/* 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 cleared in K1 represents a mismatch or a null CHAR
in YMM0 and 32 bytes at (%rsi). */
VPCMP $0, (%rsi), %YMM0, %k1{%k2}
/* 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
# ifdef USE_AS_WCSCMP
subl $0xff, %ecx
# else
incl %ecx
# endif
je L(next_3_vectors)
tzcntl %ecx, %edx
# ifdef USE_AS_WCSCMP
/* NB: Multiply wchar_t count by 4 to get the number of bytes. */
@ -162,9 +163,7 @@ L(return):
# 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. */
@ -200,9 +199,7 @@ L(return_vec_size):
# 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. */
@ -238,9 +235,7 @@ L(return_2_vec_size):
# 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. */
@ -279,43 +274,45 @@ L(return_3_vec_size):
.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
/* Each bit set in K2 represents a non-null CHAR in YMM0. */
VPTESTM %YMM0, %YMM0, %k2
/* Each bit cleared in K1 represents a mismatch or a null CHAR
in YMM0 and 32 bytes at VEC_SIZE(%rsi). */
VPCMP $0, VEC_SIZE(%rsi), %YMM0, %k1{%k2}
kmovd %k1, %ecx
# ifdef USE_AS_WCSCMP
subl $0xff, %ecx
# else
incl %ecx
# endif
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
VMOVU (VEC_SIZE * 2)(%rdi), %YMM0
/* Each bit set in K2 represents a non-null CHAR in YMM0. */
VPTESTM %YMM0, %YMM0, %k2
/* Each bit cleared in K1 represents a mismatch or a null CHAR
in YMM0 and 32 bytes at (VEC_SIZE * 2)(%rsi). */
VPCMP $0, (VEC_SIZE * 2)(%rsi), %YMM0, %k1{%k2}
kmovd %k1, %ecx
# ifdef USE_AS_WCSCMP
subl $0xff, %ecx
# else
incl %ecx
# endif
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
VMOVU (VEC_SIZE * 3)(%rdi), %YMM0
/* Each bit set in K2 represents a non-null CHAR in YMM0. */
VPTESTM %YMM0, %YMM0, %k2
/* Each bit cleared in K1 represents a mismatch or a null CHAR
in YMM0 and 32 bytes at (VEC_SIZE * 2)(%rsi). */
VPCMP $0, (VEC_SIZE * 3)(%rsi), %YMM0, %k1{%k2}
kmovd %k1, %ecx
# ifdef USE_AS_WCSCMP
subl $0xff, %ecx
# else
incl %ecx
# endif
jne L(return_3_vec_size)
L(main_loop_header):
leaq (VEC_SIZE * 4)(%rdi), %rdx
@ -365,56 +362,51 @@ L(back_to_loop):
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
VPMINU %YMM0, %YMM2, %YMM8
VPMINU %YMM4, %YMM6, %YMM9
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
/* A zero CHAR in YMM8 means that there is a null CHAR. */
VPMINU %YMM8, %YMM9, %YMM8
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
/* Each bit set in K1 represents a non-null CHAR in YMM8. */
VPTESTM %YMM8, %YMM8, %k1
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
/* (YMM ^ YMM): A non-zero CHAR represents a mismatch. */
vpxorq (%rdx), %YMM0, %YMM1
vpxorq VEC_SIZE(%rdx), %YMM2, %YMM3
vpxorq (VEC_SIZE * 2)(%rdx), %YMM4, %YMM5
vpxorq (VEC_SIZE * 3)(%rdx), %YMM6, %YMM7
kord %k4, %k5, %k0
kord %k6, %k7, %k1
vporq %YMM1, %YMM3, %YMM9
vporq %YMM5, %YMM7, %YMM10
/* 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
/* A non-zero CHAR in YMM9 represents a mismatch. */
vporq %YMM9, %YMM10, %YMM9
/* Each bit cleared in K0 represents a mismatch or a null CHAR. */
VPCMP $0, %YMMZERO, %YMM9, %k0{%k1}
kmovd %k0, %ecx
# ifdef USE_AS_WCSCMP
subl $0xff, %ecx
# else
incl %ecx
# endif
je L(loop)
/* Each bit set in K1 represents a non-null CHAR in YMM0. */
VPTESTM %YMM0, %YMM0, %k1
/* Each bit cleared in K0 represents a mismatch or a null CHAR
in YMM0 and (%rdx). */
VPCMP $0, %YMMZERO, %YMM1, %k0{%k1}
kmovd %k0, %ecx
# ifdef USE_AS_WCSCMP
subl $0xff, %ecx
# else
incl %ecx
# endif
je L(test_vec)
kmovd %k4, %edi
tzcntl %edi, %ecx
tzcntl %ecx, %ecx
# ifdef USE_AS_WCSCMP
/* NB: Multiply wchar_t count by 4 to get the number of bytes. */
sall $2, %ecx
@ -456,9 +448,18 @@ L(test_vec):
cmpq $VEC_SIZE, %r11
jbe L(zero)
# endif
ktestd %k5, %k5
/* Each bit set in K1 represents a non-null CHAR in YMM2. */
VPTESTM %YMM2, %YMM2, %k1
/* Each bit cleared in K0 represents a mismatch or a null CHAR
in YMM2 and VEC_SIZE(%rdx). */
VPCMP $0, %YMMZERO, %YMM3, %k0{%k1}
kmovd %k0, %ecx
# ifdef USE_AS_WCSCMP
subl $0xff, %ecx
# else
incl %ecx
# endif
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. */
@ -502,9 +503,18 @@ L(test_2_vec):
cmpq $(VEC_SIZE * 2), %r11
jbe L(zero)
# endif
ktestd %k6, %k6
/* Each bit set in K1 represents a non-null CHAR in YMM4. */
VPTESTM %YMM4, %YMM4, %k1
/* Each bit cleared in K0 represents a mismatch or a null CHAR
in YMM4 and (VEC_SIZE * 2)(%rdx). */
VPCMP $0, %YMMZERO, %YMM5, %k0{%k1}
kmovd %k0, %ecx
# ifdef USE_AS_WCSCMP
subl $0xff, %ecx
# else
incl %ecx
# endif
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. */
@ -548,8 +558,18 @@ L(test_3_vec):
cmpq $(VEC_SIZE * 3), %r11
jbe L(zero)
# endif
kmovd %k7, %esi
tzcntl %esi, %ecx
/* Each bit set in K1 represents a non-null CHAR in YMM6. */
VPTESTM %YMM6, %YMM6, %k1
/* Each bit cleared in K0 represents a mismatch or a null CHAR
in YMM6 and (VEC_SIZE * 3)(%rdx). */
VPCMP $0, %YMMZERO, %YMM7, %k0{%k1}
kmovd %k0, %ecx
# ifdef USE_AS_WCSCMP
subl $0xff, %ecx
# else
incl %ecx
# endif
tzcntl %ecx, %ecx
# ifdef USE_AS_WCSCMP
/* NB: Multiply wchar_t count by 4 to get the number of bytes. */
sall $2, %ecx
@ -605,39 +625,51 @@ L(loop_cross_page):
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
/* Each bit set in K2 represents a non-null CHAR in YMM2. */
VPTESTM %YMM2, %YMM2, %k2
/* Each bit cleared in K1 represents a mismatch or a null CHAR
in YMM2 and 32 bytes at (%rdx, %r10). */
VPCMP $0, (%rdx, %r10), %YMM2, %k1{%k2}
kmovd %k1, %r9d
/* Don't use subl since it is the lower 16/32 bits of RDI
below. */
notl %r9d
# ifdef USE_AS_WCSCMP
/* Only last 8 bits are valid. */
andl $0xff, %r9d
# endif
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
/* Each bit set in K4 represents a non-null CHAR in YMM3. */
VPTESTM %YMM3, %YMM3, %k4
/* Each bit cleared in K3 represents a mismatch or a null CHAR
in YMM3 and 32 bytes at VEC_SIZE(%rdx, %r10). */
VPCMP $0, VEC_SIZE(%rdx, %r10), %YMM3, %k3{%k4}
kmovd %k3, %edi
# ifdef USE_AS_WCSCMP
/* Don't use subl since it is the upper 8 bits of EDI below. */
notl %edi
andl $0xff, %edi
# else
incl %edi
# endif
# ifdef USE_AS_WCSCMP
/* NB: Each bit in K1/K3 represents 4-byte element. */
kshiftlw $8, %k3, %k2
/* NB: Each bit in EDI/R9D represents 4-byte element. */
sall $8, %edi
/* 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
/* Each bit in EDI represents a null CHAR or a mismatch. */
orl %r9d, %edi
# else
salq $32, %rdi
/* Each bit in RDI represents a null CHAR or a mismatch. */
orq %r9, %rdi
# endif
/* Since ECX < VEC_SIZE * 2, simply skip the first ECX bytes. */
shrxq %SHIFT_REG64, %rdi, %rdi
@ -682,35 +714,45 @@ 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
VPTESTM %YMM0, %YMM0, %k2
/* Each bit cleared in K1 represents a mismatch or a null CHAR
in YMM0 and 32 bytes at (VEC_SIZE * 2)(%rdx, %r10). */
VPCMP $0, (VEC_SIZE * 2)(%rdx, %r10), %YMM0, %k1{%k2}
kmovd %k1, %r9d
/* Don't use subl since it is the lower 16/32 bits of RDI
below. */
notl %r9d
# ifdef USE_AS_WCSCMP
/* NB: Each bit in K1/K3 represents 4-byte element. */
kshiftlw $8, %k3, %k2
# else
kshiftlq $32, %k3, %k2
/* Only last 8 bits are valid. */
andl $0xff, %r9d
# endif
/* Each bit in K1 represents a NULL or a mismatch. */
korq %k1, %k2, %k1
kmovq %k1, %rdi
VPTESTM %YMM1, %YMM1, %k4
/* Each bit cleared in K3 represents a mismatch or a null CHAR
in YMM1 and 32 bytes at (VEC_SIZE * 3)(%rdx, %r10). */
VPCMP $0, (VEC_SIZE * 3)(%rdx, %r10), %YMM1, %k3{%k4}
kmovd %k3, %edi
# ifdef USE_AS_WCSCMP
/* Don't use subl since it is the upper 8 bits of EDI below. */
notl %edi
andl $0xff, %edi
# else
incl %edi
# endif
# ifdef USE_AS_WCSCMP
/* NB: Each bit in EDI/R9D represents 4-byte element. */
sall $8, %edi
/* Each bit in EDI represents a null CHAR or a mismatch. */
orl %r9d, %edi
# else
salq $32, %rdi
/* Each bit in RDI represents a null CHAR or a mismatch. */
orq %r9, %rdi
# endif
xorl %r8d, %r8d
/* If ECX > VEC_SIZE * 2, skip ECX - (VEC_SIZE * 2) bytes. */
@ -719,12 +761,15 @@ L(loop_cross_page_2_vec):
/* 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
/* NB: Divide shift count by 4 since each bit in RDI represent 4
bytes. */
sarl $2, %ecx
# endif
/* Skip ECX bytes. */
shrl %cl, %edi
# else
/* Skip ECX bytes. */
shrq %cl, %rdi
# endif
1:
/* Before jumping back to the loop, set ESI to the number of
VEC_SIZE * 4 blocks before page crossing. */
@ -808,7 +853,7 @@ L(cross_page_loop):
movzbl (%rdi, %rdx), %eax
movzbl (%rsi, %rdx), %ecx
# endif
/* Check null char. */
/* Check null CHAR. */
testl %eax, %eax
jne L(cross_page_loop)
/* Since %eax == 0, subtract is OK for both SIGNED and UNSIGNED
@ -891,18 +936,17 @@ L(cross_page):
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
VPTESTM %YMM0, %YMM0, %k2
/* Each bit cleared in K1 represents a mismatch or a null CHAR
in YMM0 and 32 bytes at (%rsi, %rdx). */
VPCMP $0, (%rsi, %rdx), %YMM0, %k1{%k2}
kmovd %k1, %ecx
testl %ecx, %ecx
# ifdef USE_AS_WCSCMP
subl $0xff, %ecx
# else
incl %ecx
# endif
jne L(last_vector)
addl $VEC_SIZE, %edx
@ -921,18 +965,17 @@ L(cross_page_1_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
VPTESTM %YMM0, %YMM0, %k2
/* Each bit cleared in K1 represents a mismatch or a null CHAR
in XMM0 and 16 bytes at (%rsi, %rdx). */
VPCMP $0, (%rsi, %rdx), %XMM0, %k1{%k2}
kmovd %k1, %ecx
# ifdef USE_AS_WCSCMP
subl $0xf, %ecx
# else
subl $0xffff, %ecx
# endif
jne L(last_vector)
addl $16, %edx
@ -955,25 +998,16 @@ L(cross_page_1_xmm):
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
VPTESTM %YMM0, %YMM0, %k2
/* Each bit cleared in K1 represents a mismatch or a null CHAR
in XMM0 and XMM1. */
VPCMP $0, %XMM1, %XMM0, %k1{%k2}
kmovb %k1, %ecx
# ifdef USE_AS_WCSCMP
/* Only last 2 bits are valid. */
andl $0x3, %ecx
subl $0x3, %ecx
# else
/* Only last 8 bits are valid. */
andl $0xff, %ecx
subl $0xff, %ecx
# endif
testl %ecx, %ecx
jne L(last_vector)
addl $8, %edx
@ -992,25 +1026,16 @@ L(cross_page_8bytes):
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
VPTESTM %YMM0, %YMM0, %k2
/* Each bit cleared in K1 represents a mismatch or a null CHAR
in XMM0 and XMM1. */
VPCMP $0, %XMM1, %XMM0, %k1{%k2}
kmovd %k1, %ecx
# ifdef USE_AS_WCSCMP
/* Only the last bit is valid. */
andl $0x1, %ecx
subl $0x1, %ecx
# else
/* Only last 4 bits are valid. */
andl $0xf, %ecx
subl $0xf, %ecx
# endif
testl %ecx, %ecx
jne L(last_vector)
addl $4, %edx