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glibc/sysdeps/powerpc/powerpc32/power7/memcmp.S

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/* Optimized memcmp implementation for POWER7/PowerPC32.
Copyright (C) 2010-2016 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
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
/* int [r3] memcmp (const char *s1 [r3],
const char *s2 [r4],
size_t size [r5]) */
.machine power7
EALIGN (memcmp, 4, 0)
CALL_MCOUNT
#define rRTN r3
#define rSTR1 r3 /* first string arg */
#define rSTR2 r4 /* second string arg */
#define rN r5 /* max string length */
#define rWORD1 r6 /* current word in s1 */
#define rWORD2 r7 /* current word in s2 */
#define rWORD3 r8 /* next word in s1 */
#define rWORD4 r9 /* next word in s2 */
#define rWORD5 r10 /* next word in s1 */
#define rWORD6 r11 /* next word in s2 */
#define rWORD7 r30 /* next word in s1 */
#define rWORD8 r31 /* next word in s2 */
xor r0, rSTR2, rSTR1
cmplwi cr6, rN, 0
cmplwi cr1, rN, 12
clrlwi. r0, r0, 30
clrlwi r12, rSTR1, 30
cmplwi cr5, r12, 0
beq- cr6, L(zeroLength)
dcbt 0, rSTR1
dcbt 0, rSTR2
/* If less than 8 bytes or not aligned, use the unaligned
byte loop. */
blt cr1, L(bytealigned)
stwu 1, -64(r1)
cfi_adjust_cfa_offset(64)
stw rWORD8, 48(r1)
cfi_offset(rWORD8, (48-64))
stw rWORD7, 44(r1)
cfi_offset(rWORD7, (44-64))
bne L(unaligned)
/* At this point we know both strings have the same alignment and the
compare length is at least 8 bytes. r12 contains the low order
2 bits of rSTR1 and cr5 contains the result of the logical compare
of r12 to 0. If r12 == 0 then we are already word
aligned and can perform the word aligned loop.
Otherwise we know the two strings have the same alignment (but not
yet word aligned). So we force the string addresses to the next lower
word boundary and special case this first word using shift left to
eliminate bits preceding the first byte. Since we want to join the
normal (word aligned) compare loop, starting at the second word,
we need to adjust the length (rN) and special case the loop
versioning for the first word. This ensures that the loop count is
correct and the first word (shifted) is in the expected register pair. */
.align 4
L(samealignment):
clrrwi rSTR1, rSTR1, 2
clrrwi rSTR2, rSTR2, 2
beq cr5, L(Waligned)
add rN, rN, r12
slwi rWORD6, r12, 3
srwi r0, rN, 4 /* Divide by 16 */
andi. r12, rN, 12 /* Get the word remainder */
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD1, 0, rSTR1
lwbrx rWORD2, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD1, 0(rSTR1)
lwz rWORD2, 0(rSTR2)
#endif
cmplwi cr1, r12, 8
cmplwi cr7, rN, 16
clrlwi rN, rN, 30
beq L(dPs4)
mtctr r0
bgt cr1, L(dPs3)
beq cr1, L(dPs2)
/* Remainder is 4 */
.align 3
L(dsP1):
slw rWORD5, rWORD1, rWORD6
slw rWORD6, rWORD2, rWORD6
cmplw cr5, rWORD5, rWORD6
blt cr7, L(dP1x)
/* Do something useful in this cycle since we have to branch anyway. */
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD1, 0, rSTR1
lwbrx rWORD2, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD1, 4(rSTR1)
lwz rWORD2, 4(rSTR2)
#endif
cmplw cr7, rWORD1, rWORD2
b L(dP1e)
/* Remainder is 8 */
.align 4
L(dPs2):
slw rWORD5, rWORD1, rWORD6
slw rWORD6, rWORD2, rWORD6
cmplw cr6, rWORD5, rWORD6
blt cr7, L(dP2x)
/* Do something useful in this cycle since we have to branch anyway. */
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD7, 0, rSTR1
lwbrx rWORD8, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD7, 4(rSTR1)
lwz rWORD8, 4(rSTR2)
#endif
cmplw cr5, rWORD7, rWORD8
b L(dP2e)
/* Remainder is 12 */
.align 4
L(dPs3):
slw rWORD3, rWORD1, rWORD6
slw rWORD4, rWORD2, rWORD6
cmplw cr1, rWORD3, rWORD4
b L(dP3e)
/* Count is a multiple of 16, remainder is 0 */
.align 4
L(dPs4):
mtctr r0
slw rWORD1, rWORD1, rWORD6
slw rWORD2, rWORD2, rWORD6
cmplw cr7, rWORD1, rWORD2
b L(dP4e)
/* At this point we know both strings are word aligned and the
compare length is at least 8 bytes. */
.align 4
L(Waligned):
andi. r12, rN, 12 /* Get the word remainder */
srwi r0, rN, 4 /* Divide by 16 */
cmplwi cr1, r12, 8
cmplwi cr7, rN, 16
clrlwi rN, rN, 30
beq L(dP4)
bgt cr1, L(dP3)
beq cr1, L(dP2)
/* Remainder is 4 */
.align 4
L(dP1):
mtctr r0
/* Normally we'd use rWORD7/rWORD8 here, but since we might exit early
(8-15 byte compare), we want to use only volatile registers. This
means we can avoid restoring non-volatile registers since we did not
change any on the early exit path. The key here is the non-early
exit path only cares about the condition code (cr5), not about which
register pair was used. */
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD5, 0, rSTR1
lwbrx rWORD6, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD5, 0(rSTR1)
lwz rWORD6, 0(rSTR2)
#endif
cmplw cr5, rWORD5, rWORD6
blt cr7, L(dP1x)
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD1, 0, rSTR1
lwbrx rWORD2, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD1, 4(rSTR1)
lwz rWORD2, 4(rSTR2)
#endif
cmplw cr7, rWORD1, rWORD2
L(dP1e):
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD3, 0, rSTR1
lwbrx rWORD4, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD3, 8(rSTR1)
lwz rWORD4, 8(rSTR2)
#endif
cmplw cr1, rWORD3, rWORD4
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD5, 0, rSTR1
lwbrx rWORD6, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD5, 12(rSTR1)
lwz rWORD6, 12(rSTR2)
#endif
cmplw cr6, rWORD5, rWORD6
bne cr5, L(dLcr5x)
bne cr7, L(dLcr7x)
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD7, 0, rSTR1
lwbrx rWORD8, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwzu rWORD7, 16(rSTR1)
lwzu rWORD8, 16(rSTR2)
#endif
bne cr1, L(dLcr1)
cmplw cr5, rWORD7, rWORD8
bdnz L(dLoop)
bne cr6, L(dLcr6)
lwz rWORD7, 44(r1)
lwz rWORD8, 48(r1)
.align 3
L(dP1x):
slwi. r12, rN, 3
bne cr5, L(dLcr5x)
subfic rN, r12, 32 /* Shift count is 32 - (rN * 8). */
addi r1, r1, 64
cfi_adjust_cfa_offset(-64)
bne L(d00)
li rRTN, 0
blr
/* Remainder is 8 */
.align 4
cfi_adjust_cfa_offset(64)
L(dP2):
mtctr r0
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD5, 0, rSTR1
lwbrx rWORD6, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD5, 0(rSTR1)
lwz rWORD6, 0(rSTR2)
#endif
cmplw cr6, rWORD5, rWORD6
blt cr7, L(dP2x)
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD7, 0, rSTR1
lwbrx rWORD8, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD7, 4(rSTR1)
lwz rWORD8, 4(rSTR2)
#endif
cmplw cr5, rWORD7, rWORD8
L(dP2e):
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD1, 0, rSTR1
lwbrx rWORD2, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD1, 8(rSTR1)
lwz rWORD2, 8(rSTR2)
#endif
cmplw cr7, rWORD1, rWORD2
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD3, 0, rSTR1
lwbrx rWORD4, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD3, 12(rSTR1)
lwz rWORD4, 12(rSTR2)
#endif
cmplw cr1, rWORD3, rWORD4
#ifndef __LITTLE_ENDIAN__
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#endif
bne cr6, L(dLcr6)
bne cr5, L(dLcr5)
b L(dLoop2)
/* Again we are on a early exit path (16-23 byte compare), we want to
only use volatile registers and avoid restoring non-volatile
registers. */
.align 4
L(dP2x):
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD3, 0, rSTR1
lwbrx rWORD4, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD3, 4(rSTR1)
lwz rWORD4, 4(rSTR2)
#endif
cmplw cr1, rWORD3, rWORD4
slwi. r12, rN, 3
bne cr6, L(dLcr6x)
#ifndef __LITTLE_ENDIAN__
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#endif
bne cr1, L(dLcr1x)
subfic rN, r12, 32 /* Shift count is 32 - (rN * 8). */
addi r1, r1, 64
cfi_adjust_cfa_offset(-64)
bne L(d00)
li rRTN, 0
blr
/* Remainder is 12 */
.align 4
cfi_adjust_cfa_offset(64)
L(dP3):
mtctr r0
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD3, 0, rSTR1
lwbrx rWORD4, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD3, 0(rSTR1)
lwz rWORD4, 0(rSTR2)
#endif
cmplw cr1, rWORD3, rWORD4
L(dP3e):
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD5, 0, rSTR1
lwbrx rWORD6, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD5, 4(rSTR1)
lwz rWORD6, 4(rSTR2)
#endif
cmplw cr6, rWORD5, rWORD6
blt cr7, L(dP3x)
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD7, 0, rSTR1
lwbrx rWORD8, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD7, 8(rSTR1)
lwz rWORD8, 8(rSTR2)
#endif
cmplw cr5, rWORD7, rWORD8
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD1, 0, rSTR1
lwbrx rWORD2, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD1, 12(rSTR1)
lwz rWORD2, 12(rSTR2)
#endif
cmplw cr7, rWORD1, rWORD2
#ifndef __LITTLE_ENDIAN__
addi rSTR1, rSTR1, 8
addi rSTR2, rSTR2, 8
#endif
bne cr1, L(dLcr1)
bne cr6, L(dLcr6)
b L(dLoop1)
/* Again we are on a early exit path (24-31 byte compare), we want to
only use volatile registers and avoid restoring non-volatile
registers. */
.align 4
L(dP3x):
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD1, 0, rSTR1
lwbrx rWORD2, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD1, 8(rSTR1)
lwz rWORD2, 8(rSTR2)
#endif
cmplw cr7, rWORD1, rWORD2
slwi. r12, rN, 3
bne cr1, L(dLcr1x)
#ifndef __LITTLE_ENDIAN__
addi rSTR1, rSTR1, 8
addi rSTR2, rSTR2, 8
#endif
bne cr6, L(dLcr6x)
subfic rN, r12, 32 /* Shift count is 32 - (rN * 8). */
bne cr7, L(dLcr7x)
addi r1, r1, 64
cfi_adjust_cfa_offset(-64)
bne L(d00)
li rRTN, 0
blr
/* Count is a multiple of 16, remainder is 0 */
.align 4
cfi_adjust_cfa_offset(64)
L(dP4):
mtctr r0
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD1, 0, rSTR1
lwbrx rWORD2, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD1, 0(rSTR1)
lwz rWORD2, 0(rSTR2)
#endif
cmplw cr7, rWORD1, rWORD2
L(dP4e):
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD3, 0, rSTR1
lwbrx rWORD4, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD3, 4(rSTR1)
lwz rWORD4, 4(rSTR2)
#endif
cmplw cr1, rWORD3, rWORD4
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD5, 0, rSTR1
lwbrx rWORD6, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD5, 8(rSTR1)
lwz rWORD6, 8(rSTR2)
#endif
cmplw cr6, rWORD5, rWORD6
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD7, 0, rSTR1
lwbrx rWORD8, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwzu rWORD7, 12(rSTR1)
lwzu rWORD8, 12(rSTR2)
#endif
cmplw cr5, rWORD7, rWORD8
bne cr7, L(dLcr7)
bne cr1, L(dLcr1)
bdz- L(d24) /* Adjust CTR as we start with +4 */
/* This is the primary loop */
.align 4
L(dLoop):
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD1, 0, rSTR1
lwbrx rWORD2, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD1, 4(rSTR1)
lwz rWORD2, 4(rSTR2)
#endif
cmplw cr1, rWORD3, rWORD4
bne cr6, L(dLcr6)
L(dLoop1):
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD3, 0, rSTR1
lwbrx rWORD4, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD3, 8(rSTR1)
lwz rWORD4, 8(rSTR2)
#endif
cmplw cr6, rWORD5, rWORD6
bne cr5, L(dLcr5)
L(dLoop2):
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD5, 0, rSTR1
lwbrx rWORD6, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD5, 12(rSTR1)
lwz rWORD6, 12(rSTR2)
#endif
cmplw cr5, rWORD7, rWORD8
bne cr7, L(dLcr7)
L(dLoop3):
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD7, 0, rSTR1
lwbrx rWORD8, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwzu rWORD7, 16(rSTR1)
lwzu rWORD8, 16(rSTR2)
#endif
bne cr1, L(dLcr1)
cmplw cr7, rWORD1, rWORD2
bdnz L(dLoop)
L(dL4):
cmplw cr1, rWORD3, rWORD4
bne cr6, L(dLcr6)
cmplw cr6, rWORD5, rWORD6
bne cr5, L(dLcr5)
cmplw cr5, rWORD7, rWORD8
L(d44):
bne cr7, L(dLcr7)
L(d34):
bne cr1, L(dLcr1)
L(d24):
bne cr6, L(dLcr6)
L(d14):
slwi. r12, rN, 3
bne cr5, L(dLcr5)
L(d04):
lwz rWORD7, 44(r1)
lwz rWORD8, 48(r1)
addi r1, r1, 64
cfi_adjust_cfa_offset(-64)
subfic rN, r12, 32 /* Shift count is 32 - (rN * 8). */
beq L(zeroLength)
/* At this point we have a remainder of 1 to 3 bytes to compare. Since
we are aligned it is safe to load the whole word, and use
shift right to eliminate bits beyond the compare length. */
L(d00):
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD1, 0, rSTR1
lwbrx rWORD2, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD1, 4(rSTR1)
lwz rWORD2, 4(rSTR2)
#endif
srw rWORD1, rWORD1, rN
srw rWORD2, rWORD2, rN
sub rRTN, rWORD1, rWORD2
blr
.align 4
cfi_adjust_cfa_offset(64)
L(dLcr7):
lwz rWORD7, 44(r1)
lwz rWORD8, 48(r1)
L(dLcr7x):
li rRTN, 1
addi r1, r1, 64
cfi_adjust_cfa_offset(-64)
bgtlr cr7
li rRTN, -1
blr
.align 4
cfi_adjust_cfa_offset(64)
L(dLcr1):
lwz rWORD7, 44(r1)
lwz rWORD8, 48(r1)
L(dLcr1x):
li rRTN, 1
addi r1, r1, 64
cfi_adjust_cfa_offset(-64)
bgtlr cr1
li rRTN, -1
blr
.align 4
cfi_adjust_cfa_offset(64)
L(dLcr6):
lwz rWORD7, 44(r1)
lwz rWORD8, 48(r1)
L(dLcr6x):
li rRTN, 1
addi r1, r1, 64
cfi_adjust_cfa_offset(-64)
bgtlr cr6
li rRTN, -1
blr
.align 4
cfi_adjust_cfa_offset(64)
L(dLcr5):
lwz rWORD7, 44(r1)
lwz rWORD8, 48(r1)
L(dLcr5x):
li rRTN, 1
addi r1, r1, 64
cfi_adjust_cfa_offset(-64)
bgtlr cr5
li rRTN, -1
blr
.align 4
L(bytealigned):
mtctr rN
/* We need to prime this loop. This loop is swing modulo scheduled
to avoid pipe delays. The dependent instruction latencies (load to
compare to conditional branch) is 2 to 3 cycles. In this loop each
dispatch group ends in a branch and takes 1 cycle. Effectively
the first iteration of the loop only serves to load operands and
branches based on compares are delayed until the next loop.
So we must precondition some registers and condition codes so that
we don't exit the loop early on the first iteration. */
lbz rWORD1, 0(rSTR1)
lbz rWORD2, 0(rSTR2)
bdz L(b11)
cmplw cr7, rWORD1, rWORD2
lbz rWORD3, 1(rSTR1)
lbz rWORD4, 1(rSTR2)
bdz L(b12)
cmplw cr1, rWORD3, rWORD4
lbzu rWORD5, 2(rSTR1)
lbzu rWORD6, 2(rSTR2)
bdz L(b13)
.align 4
L(bLoop):
lbzu rWORD1, 1(rSTR1)
lbzu rWORD2, 1(rSTR2)
bne cr7, L(bLcr7)
cmplw cr6, rWORD5, rWORD6
bdz L(b3i)
lbzu rWORD3, 1(rSTR1)
lbzu rWORD4, 1(rSTR2)
bne cr1, L(bLcr1)
cmplw cr7, rWORD1, rWORD2
bdz L(b2i)
lbzu rWORD5, 1(rSTR1)
lbzu rWORD6, 1(rSTR2)
bne cr6, L(bLcr6)
cmplw cr1, rWORD3, rWORD4
bdnz L(bLoop)
/* We speculatively loading bytes before we have tested the previous
bytes. But we must avoid overrunning the length (in the ctr) to
prevent these speculative loads from causing a segfault. In this
case the loop will exit early (before the all pending bytes are
tested. In this case we must complete the pending operations
before returning. */
L(b1i):
bne cr7, L(bLcr7)
bne cr1, L(bLcr1)
b L(bx56)
.align 4
L(b2i):
bne cr6, L(bLcr6)
bne cr7, L(bLcr7)
b L(bx34)
.align 4
L(b3i):
bne cr1, L(bLcr1)
bne cr6, L(bLcr6)
b L(bx12)
.align 4
L(bLcr7):
li rRTN, 1
bgtlr cr7
li rRTN, -1
blr
L(bLcr1):
li rRTN, 1
bgtlr cr1
li rRTN, -1
blr
L(bLcr6):
li rRTN, 1
bgtlr cr6
li rRTN, -1
blr
L(b13):
bne cr7, L(bx12)
bne cr1, L(bx34)
L(bx56):
sub rRTN, rWORD5, rWORD6
blr
nop
L(b12):
bne cr7, L(bx12)
L(bx34):
sub rRTN, rWORD3, rWORD4
blr
L(b11):
L(bx12):
sub rRTN, rWORD1, rWORD2
blr
.align 4
L(zeroLength):
li rRTN, 0
blr
.align 4
/* At this point we know the strings have different alignment and the
compare length is at least 8 bytes. r12 contains the low order
2 bits of rSTR1 and cr5 contains the result of the logical compare
of r12 to 0. If r12 == 0 then rStr1 is word aligned and can
perform the Wunaligned loop.
Otherwise we know that rSTR1 is not already word aligned yet.
So we can force the string addresses to the next lower word
boundary and special case this first word using shift left to
eliminate bits preceding the first byte. Since we want to join the
normal (Wualigned) compare loop, starting at the second word,
we need to adjust the length (rN) and special case the loop
versioning for the first W. This ensures that the loop count is
correct and the first W (shifted) is in the expected resister pair. */
#define rSHL r29 /* Unaligned shift left count. */
#define rSHR r28 /* Unaligned shift right count. */
#define rWORD8_SHIFT r27 /* Left rotation temp for rWORD2. */
#define rWORD2_SHIFT r26 /* Left rotation temp for rWORD4. */
#define rWORD4_SHIFT r25 /* Left rotation temp for rWORD6. */
#define rWORD6_SHIFT r24 /* Left rotation temp for rWORD8. */
cfi_adjust_cfa_offset(64)
L(unaligned):
stw rSHL, 40(r1)
cfi_offset(rSHL, (40-64))
clrlwi rSHL, rSTR2, 30
stw rSHR, 36(r1)
cfi_offset(rSHR, (36-64))
beq cr5, L(Wunaligned)
stw rWORD8_SHIFT, 32(r1)
cfi_offset(rWORD8_SHIFT, (32-64))
/* Adjust the logical start of rSTR2 to compensate for the extra bits
in the 1st rSTR1 W. */
sub rWORD8_SHIFT, rSTR2, r12
/* But do not attempt to address the W before that W that contains
the actual start of rSTR2. */
clrrwi rSTR2, rSTR2, 2
stw rWORD2_SHIFT, 28(r1)
cfi_offset(rWORD2_SHIFT, (28-64))
/* Compute the left/right shift counts for the unaligned rSTR2,
compensating for the logical (W aligned) start of rSTR1. */
clrlwi rSHL, rWORD8_SHIFT, 30
clrrwi rSTR1, rSTR1, 2
stw rWORD4_SHIFT, 24(r1)
cfi_offset(rWORD4_SHIFT, (24-64))
slwi rSHL, rSHL, 3
cmplw cr5, rWORD8_SHIFT, rSTR2
add rN, rN, r12
slwi rWORD6, r12, 3
stw rWORD6_SHIFT, 20(r1)
cfi_offset(rWORD6_SHIFT, (20-64))
subfic rSHR, rSHL, 32
srwi r0, rN, 4 /* Divide by 16 */
andi. r12, rN, 12 /* Get the W remainder */
/* We normally need to load 2 Ws to start the unaligned rSTR2, but in
this special case those bits may be discarded anyway. Also we
must avoid loading a W where none of the bits are part of rSTR2 as
this may cross a page boundary and cause a page fault. */
li rWORD8, 0
blt cr5, L(dus0)
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD8, 0, rSTR2
addi rSTR2, rSTR2, 4
#else
lwz rWORD8, 0(rSTR2)
addi rSTR2, rSTR2, 4
#endif
slw rWORD8, rWORD8, rSHL
L(dus0):
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD1, 0, rSTR1
lwbrx rWORD2, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD1, 0(rSTR1)
lwz rWORD2, 0(rSTR2)
#endif
cmplwi cr1, r12, 8
cmplwi cr7, rN, 16
srw r12, rWORD2, rSHR
clrlwi rN, rN, 30
beq L(duPs4)
mtctr r0
or rWORD8, r12, rWORD8
bgt cr1, L(duPs3)
beq cr1, L(duPs2)
/* Remainder is 4 */
.align 4
L(dusP1):
slw rWORD8_SHIFT, rWORD2, rSHL
slw rWORD7, rWORD1, rWORD6
slw rWORD8, rWORD8, rWORD6
bge cr7, L(duP1e)
/* At this point we exit early with the first word compare
complete and remainder of 0 to 3 bytes. See L(du14) for details on
how we handle the remaining bytes. */
cmplw cr5, rWORD7, rWORD8
slwi. rN, rN, 3
bne cr5, L(duLcr5)
cmplw cr7, rN, rSHR
beq L(duZeroReturn)
li r0, 0
ble cr7, L(dutrim)
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD2, 0, rSTR2
addi rSTR2, rSTR2, 4
#else
lwz rWORD2, 4(rSTR2)
#endif
srw r0, rWORD2, rSHR
b L(dutrim)
/* Remainder is 8 */
.align 4
L(duPs2):
slw rWORD6_SHIFT, rWORD2, rSHL
slw rWORD5, rWORD1, rWORD6
slw rWORD6, rWORD8, rWORD6
b L(duP2e)
/* Remainder is 12 */
.align 4
L(duPs3):
slw rWORD4_SHIFT, rWORD2, rSHL
slw rWORD3, rWORD1, rWORD6
slw rWORD4, rWORD8, rWORD6
b L(duP3e)
/* Count is a multiple of 16, remainder is 0 */
.align 4
L(duPs4):
mtctr r0
or rWORD8, r12, rWORD8
slw rWORD2_SHIFT, rWORD2, rSHL
slw rWORD1, rWORD1, rWORD6
slw rWORD2, rWORD8, rWORD6
b L(duP4e)
/* At this point we know rSTR1 is word aligned and the
compare length is at least 8 bytes. */
.align 4
L(Wunaligned):
stw rWORD8_SHIFT, 32(r1)
cfi_offset(rWORD8_SHIFT, (32-64))
clrrwi rSTR2, rSTR2, 2
stw rWORD2_SHIFT, 28(r1)
cfi_offset(rWORD2_SHIFT, (28-64))
srwi r0, rN, 4 /* Divide by 16 */
stw rWORD4_SHIFT, 24(r1)
cfi_offset(rWORD4_SHIFT, (24-64))
andi. r12, rN, 12 /* Get the W remainder */
stw rWORD6_SHIFT, 20(r1)
cfi_offset(rWORD6_SHIFT, (20-64))
slwi rSHL, rSHL, 3
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD6, 0, rSTR2
addi rSTR2, rSTR2, 4
lwbrx rWORD8, 0, rSTR2
addi rSTR2, rSTR2, 4
#else
lwz rWORD6, 0(rSTR2)
lwzu rWORD8, 4(rSTR2)
#endif
cmplwi cr1, r12, 8
cmplwi cr7, rN, 16
clrlwi rN, rN, 30
subfic rSHR, rSHL, 32
slw rWORD6_SHIFT, rWORD6, rSHL
beq L(duP4)
mtctr r0
bgt cr1, L(duP3)
beq cr1, L(duP2)
/* Remainder is 4 */
.align 4
L(duP1):
srw r12, rWORD8, rSHR
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD7, 0, rSTR1
addi rSTR1, rSTR1, 4
#else
lwz rWORD7, 0(rSTR1)
#endif
slw rWORD8_SHIFT, rWORD8, rSHL
or rWORD8, r12, rWORD6_SHIFT
blt cr7, L(duP1x)
L(duP1e):
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD1, 0, rSTR1
lwbrx rWORD2, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD1, 4(rSTR1)
lwz rWORD2, 4(rSTR2)
#endif
cmplw cr5, rWORD7, rWORD8
srw r0, rWORD2, rSHR
slw rWORD2_SHIFT, rWORD2, rSHL
or rWORD2, r0, rWORD8_SHIFT
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD3, 0, rSTR1
lwbrx rWORD4, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD3, 8(rSTR1)
lwz rWORD4, 8(rSTR2)
#endif
cmplw cr7, rWORD1, rWORD2
srw r12, rWORD4, rSHR
slw rWORD4_SHIFT, rWORD4, rSHL
bne cr5, L(duLcr5)
or rWORD4, r12, rWORD2_SHIFT
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD5, 0, rSTR1
lwbrx rWORD6, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD5, 12(rSTR1)
lwz rWORD6, 12(rSTR2)
#endif
cmplw cr1, rWORD3, rWORD4
srw r0, rWORD6, rSHR
slw rWORD6_SHIFT, rWORD6, rSHL
bne cr7, L(duLcr7)
or rWORD6, r0, rWORD4_SHIFT
cmplw cr6, rWORD5, rWORD6
b L(duLoop3)
.align 4
/* At this point we exit early with the first word compare
complete and remainder of 0 to 3 bytes. See L(du14) for details on
how we handle the remaining bytes. */
L(duP1x):
cmplw cr5, rWORD7, rWORD8
slwi. rN, rN, 3
bne cr5, L(duLcr5)
cmplw cr7, rN, rSHR
beq L(duZeroReturn)
li r0, 0
ble cr7, L(dutrim)
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD2, 0, rSTR2
addi rSTR2, rSTR2, 4
#else
lwz rWORD2, 8(rSTR2)
#endif
srw r0, rWORD2, rSHR
b L(dutrim)
/* Remainder is 8 */
.align 4
L(duP2):
srw r0, rWORD8, rSHR
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD5, 0, rSTR1
addi rSTR1, rSTR1, 4
#else
lwz rWORD5, 0(rSTR1)
#endif
or rWORD6, r0, rWORD6_SHIFT
slw rWORD6_SHIFT, rWORD8, rSHL
L(duP2e):
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD7, 0, rSTR1
lwbrx rWORD8, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD7, 4(rSTR1)
lwz rWORD8, 4(rSTR2)
#endif
cmplw cr6, rWORD5, rWORD6
srw r12, rWORD8, rSHR
slw rWORD8_SHIFT, rWORD8, rSHL
or rWORD8, r12, rWORD6_SHIFT
blt cr7, L(duP2x)
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD1, 0, rSTR1
lwbrx rWORD2, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD1, 8(rSTR1)
lwz rWORD2, 8(rSTR2)
#endif
cmplw cr5, rWORD7, rWORD8
bne cr6, L(duLcr6)
srw r0, rWORD2, rSHR
slw rWORD2_SHIFT, rWORD2, rSHL
or rWORD2, r0, rWORD8_SHIFT
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD3, 0, rSTR1
lwbrx rWORD4, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD3, 12(rSTR1)
lwz rWORD4, 12(rSTR2)
#endif
cmplw cr7, rWORD1, rWORD2
bne cr5, L(duLcr5)
srw r12, rWORD4, rSHR
slw rWORD4_SHIFT, rWORD4, rSHL
or rWORD4, r12, rWORD2_SHIFT
#ifndef __LITTLE_ENDIAN__
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#endif
cmplw cr1, rWORD3, rWORD4
b L(duLoop2)
.align 4
L(duP2x):
cmplw cr5, rWORD7, rWORD8
#ifndef __LITTLE_ENDIAN__
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#endif
bne cr6, L(duLcr6)
slwi. rN, rN, 3
bne cr5, L(duLcr5)
cmplw cr7, rN, rSHR
beq L(duZeroReturn)
li r0, 0
ble cr7, L(dutrim)
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD2, 0, rSTR2
addi rSTR2, rSTR2, 4
#else
lwz rWORD2, 4(rSTR2)
#endif
srw r0, rWORD2, rSHR
b L(dutrim)
/* Remainder is 12 */
.align 4
L(duP3):
srw r12, rWORD8, rSHR
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD3, 0, rSTR1
addi rSTR1, rSTR1, 4
#else
lwz rWORD3, 0(rSTR1)
#endif
slw rWORD4_SHIFT, rWORD8, rSHL
or rWORD4, r12, rWORD6_SHIFT
L(duP3e):
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD5, 0, rSTR1
lwbrx rWORD6, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD5, 4(rSTR1)
lwz rWORD6, 4(rSTR2)
#endif
cmplw cr1, rWORD3, rWORD4
srw r0, rWORD6, rSHR
slw rWORD6_SHIFT, rWORD6, rSHL
or rWORD6, r0, rWORD4_SHIFT
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD7, 0, rSTR1
lwbrx rWORD8, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD7, 8(rSTR1)
lwz rWORD8, 8(rSTR2)
#endif
cmplw cr6, rWORD5, rWORD6
bne cr1, L(duLcr1)
srw r12, rWORD8, rSHR
slw rWORD8_SHIFT, rWORD8, rSHL
or rWORD8, r12, rWORD6_SHIFT
blt cr7, L(duP3x)
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD1, 0, rSTR1
lwbrx rWORD2, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD1, 12(rSTR1)
lwz rWORD2, 12(rSTR2)
#endif
cmplw cr5, rWORD7, rWORD8
bne cr6, L(duLcr6)
srw r0, rWORD2, rSHR
slw rWORD2_SHIFT, rWORD2, rSHL
or rWORD2, r0, rWORD8_SHIFT
#ifndef __LITTLE_ENDIAN__
addi rSTR1, rSTR1, 8
addi rSTR2, rSTR2, 8
#endif
cmplw cr7, rWORD1, rWORD2
b L(duLoop1)
.align 4
L(duP3x):
#ifndef __LITTLE_ENDIAN__
addi rSTR1, rSTR1, 8
addi rSTR2, rSTR2, 8
#endif
#if 0
/* Huh? We've already branched on cr1! */
bne cr1, L(duLcr1)
#endif
cmplw cr5, rWORD7, rWORD8
bne cr6, L(duLcr6)
slwi. rN, rN, 3
bne cr5, L(duLcr5)
cmplw cr7, rN, rSHR
beq L(duZeroReturn)
li r0, 0
ble cr7, L(dutrim)
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD2, 0, rSTR2
addi rSTR2, rSTR2, 4
#else
lwz rWORD2, 4(rSTR2)
#endif
srw r0, rWORD2, rSHR
b L(dutrim)
/* Count is a multiple of 16, remainder is 0 */
.align 4
L(duP4):
mtctr r0
srw r0, rWORD8, rSHR
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD1, 0, rSTR1
addi rSTR1, rSTR1, 4
#else
lwz rWORD1, 0(rSTR1)
#endif
slw rWORD2_SHIFT, rWORD8, rSHL
or rWORD2, r0, rWORD6_SHIFT
L(duP4e):
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD3, 0, rSTR1
lwbrx rWORD4, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD3, 4(rSTR1)
lwz rWORD4, 4(rSTR2)
#endif
cmplw cr7, rWORD1, rWORD2
srw r12, rWORD4, rSHR
slw rWORD4_SHIFT, rWORD4, rSHL
or rWORD4, r12, rWORD2_SHIFT
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD5, 0, rSTR1
lwbrx rWORD6, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD5, 8(rSTR1)
lwz rWORD6, 8(rSTR2)
#endif
cmplw cr1, rWORD3, rWORD4
bne cr7, L(duLcr7)
srw r0, rWORD6, rSHR
slw rWORD6_SHIFT, rWORD6, rSHL
or rWORD6, r0, rWORD4_SHIFT
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD7, 0, rSTR1
lwbrx rWORD8, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwzu rWORD7, 12(rSTR1)
lwzu rWORD8, 12(rSTR2)
#endif
cmplw cr6, rWORD5, rWORD6
bne cr1, L(duLcr1)
srw r12, rWORD8, rSHR
slw rWORD8_SHIFT, rWORD8, rSHL
or rWORD8, r12, rWORD6_SHIFT
cmplw cr5, rWORD7, rWORD8
bdz L(du24) /* Adjust CTR as we start with +4 */
/* This is the primary loop */
.align 4
L(duLoop):
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD1, 0, rSTR1
lwbrx rWORD2, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD1, 4(rSTR1)
lwz rWORD2, 4(rSTR2)
#endif
cmplw cr1, rWORD3, rWORD4
bne cr6, L(duLcr6)
srw r0, rWORD2, rSHR
slw rWORD2_SHIFT, rWORD2, rSHL
or rWORD2, r0, rWORD8_SHIFT
L(duLoop1):
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD3, 0, rSTR1
lwbrx rWORD4, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD3, 8(rSTR1)
lwz rWORD4, 8(rSTR2)
#endif
cmplw cr6, rWORD5, rWORD6
bne cr5, L(duLcr5)
srw r12, rWORD4, rSHR
slw rWORD4_SHIFT, rWORD4, rSHL
or rWORD4, r12, rWORD2_SHIFT
L(duLoop2):
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD5, 0, rSTR1
lwbrx rWORD6, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwz rWORD5, 12(rSTR1)
lwz rWORD6, 12(rSTR2)
#endif
cmplw cr5, rWORD7, rWORD8
bne cr7, L(duLcr7)
srw r0, rWORD6, rSHR
slw rWORD6_SHIFT, rWORD6, rSHL
or rWORD6, r0, rWORD4_SHIFT
L(duLoop3):
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD7, 0, rSTR1
lwbrx rWORD8, 0, rSTR2
addi rSTR1, rSTR1, 4
addi rSTR2, rSTR2, 4
#else
lwzu rWORD7, 16(rSTR1)
lwzu rWORD8, 16(rSTR2)
#endif
cmplw cr7, rWORD1, rWORD2
bne cr1, L(duLcr1)
srw r12, rWORD8, rSHR
slw rWORD8_SHIFT, rWORD8, rSHL
or rWORD8, r12, rWORD6_SHIFT
bdnz L(duLoop)
L(duL4):
#if 0
/* Huh? We've already branched on cr1! */
bne cr1, L(duLcr1)
#endif
cmplw cr1, rWORD3, rWORD4
bne cr6, L(duLcr6)
cmplw cr6, rWORD5, rWORD6
bne cr5, L(duLcr5)
cmplw cr5, rWORD7, rWORD8
L(du44):
bne cr7, L(duLcr7)
L(du34):
bne cr1, L(duLcr1)
L(du24):
bne cr6, L(duLcr6)
L(du14):
slwi. rN, rN, 3
bne cr5, L(duLcr5)
/* At this point we have a remainder of 1 to 3 bytes to compare. We use
shift right to eliminate bits beyond the compare length.
This allows the use of word subtract to compute the final result.
However it may not be safe to load rWORD2 which may be beyond the
string length. So we compare the bit length of the remainder to
the right shift count (rSHR). If the bit count is less than or equal
we do not need to load rWORD2 (all significant bits are already in
rWORD8_SHIFT). */
cmplw cr7, rN, rSHR
beq L(duZeroReturn)
li r0, 0
ble cr7, L(dutrim)
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD2, 0, rSTR2
addi rSTR2, rSTR2, 4
#else
lwz rWORD2, 4(rSTR2)
#endif
srw r0, rWORD2, rSHR
.align 4
L(dutrim):
#ifdef __LITTLE_ENDIAN__
lwbrx rWORD1, 0, rSTR1
#else
lwz rWORD1, 4(rSTR1)
#endif
lwz rWORD8, 48(r1)
subfic rN, rN, 32 /* Shift count is 32 - (rN * 8). */
or rWORD2, r0, rWORD8_SHIFT
lwz rWORD7, 44(r1)
lwz rSHL, 40(r1)
srw rWORD1, rWORD1, rN
srw rWORD2, rWORD2, rN
lwz rSHR, 36(r1)
lwz rWORD8_SHIFT, 32(r1)
sub rRTN, rWORD1, rWORD2
b L(dureturn26)
.align 4
L(duLcr7):
lwz rWORD8, 48(r1)
lwz rWORD7, 44(r1)
li rRTN, 1
bgt cr7, L(dureturn29)
lwz rSHL, 40(r1)
lwz rSHR, 36(r1)
li rRTN, -1
b L(dureturn27)
.align 4
L(duLcr1):
lwz rWORD8, 48(r1)
lwz rWORD7, 44(r1)
li rRTN, 1
bgt cr1, L(dureturn29)
lwz rSHL, 40(r1)
lwz rSHR, 36(r1)
li rRTN, -1
b L(dureturn27)
.align 4
L(duLcr6):
lwz rWORD8, 48(r1)
lwz rWORD7, 44(r1)
li rRTN, 1
bgt cr6, L(dureturn29)
lwz rSHL, 40(r1)
lwz rSHR, 36(r1)
li rRTN, -1
b L(dureturn27)
.align 4
L(duLcr5):
lwz rWORD8, 48(r1)
lwz rWORD7, 44(r1)
li rRTN, 1
bgt cr5, L(dureturn29)
lwz rSHL, 40(r1)
lwz rSHR, 36(r1)
li rRTN, -1
b L(dureturn27)
.align 3
L(duZeroReturn):
li rRTN, 0
.align 4
L(dureturn):
lwz rWORD8, 48(r1)
lwz rWORD7, 44(r1)
L(dureturn29):
lwz rSHL, 40(r1)
lwz rSHR, 36(r1)
L(dureturn27):
lwz rWORD8_SHIFT, 32(r1)
L(dureturn26):
lwz rWORD2_SHIFT, 28(r1)
L(dureturn25):
lwz rWORD4_SHIFT, 24(r1)
lwz rWORD6_SHIFT, 20(r1)
addi r1, r1, 64
cfi_adjust_cfa_offset(-64)
blr
END (memcmp)
libc_hidden_builtin_def (memcmp)
weak_alias (memcmp, bcmp)
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