387 lines
6.0 KiB
ArmAsm
387 lines
6.0 KiB
ArmAsm
/* Optimized memset implementation for PowerPC64/POWER7.
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Copyright (C) 2010-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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/* void * [r3] memset (void *s [r3], int c [r4], size_t n [r5]));
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Returns 's'. */
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#ifndef MEMSET
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# define MEMSET memset
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#endif
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.machine power7
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ENTRY_TOCLESS (MEMSET, 5)
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CALL_MCOUNT 3
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L(_memset):
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cmpldi cr7,5,31
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cmpldi cr6,5,8
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mr 10,3
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/* Replicate byte to word. */
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insrdi 4,4,8,48
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insrdi 4,4,16,32
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ble cr6,L(small) /* If length <= 8, use short copy code. */
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neg 0,3
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ble cr7,L(medium) /* If length < 32, use medium copy code. */
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andi. 11,10,7 /* Check alignment of SRC. */
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insrdi 4,4,32,0 /* Replicate word to double word. */
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mr 12,5
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beq L(big_aligned)
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clrldi 0,0,61
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mtocrf 0x01,0
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subf 5,0,5
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/* Get DST aligned to 8 bytes. */
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1: bf 31,2f
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stb 4,0(10)
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addi 10,10,1
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2: bf 30,4f
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sth 4,0(10)
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addi 10,10,2
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4: bf 29,L(big_aligned)
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stw 4,0(10)
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addi 10,10,4
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.align 4
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L(big_aligned):
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cmpldi cr5,5,255
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li 0,32
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dcbtst 0,10
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cmpldi cr6,4,0
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srdi 9,5,3 /* Number of full doublewords remaining. */
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crand 27,26,21
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mtocrf 0x01,9
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bt 27,L(huge)
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/* From this point on, we'll copy 32+ bytes and the value
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isn't 0 (so we can't use dcbz). */
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srdi 8,5,5
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clrldi 11,5,61
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cmpldi cr6,11,0
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cmpldi cr1,9,4
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mtctr 8
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/* Copy 1~3 doublewords so the main loop starts
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at a multiple of 32 bytes. */
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bf 30,1f
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std 4,0(10)
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std 4,8(10)
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addi 10,10,16
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bf 31,L(big_loop)
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std 4,0(10)
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addi 10,10,8
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mr 12,10
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blt cr1,L(tail_bytes)
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b L(big_loop)
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.align 4
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1: /* Copy 1 doubleword. */
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bf 31,L(big_loop)
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std 4,0(10)
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addi 10,10,8
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/* Main aligned copy loop. Copies 32-bytes at a time and
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ping-pong through r10 and r12 to avoid AGEN delays. */
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.align 4
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L(big_loop):
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addi 12,10,32
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std 4,0(10)
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std 4,8(10)
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std 4,16(10)
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std 4,24(10)
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bdz L(tail_bytes)
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addi 10,10,64
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std 4,0(12)
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std 4,8(12)
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std 4,16(12)
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std 4,24(12)
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bdnz L(big_loop)
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mr 12,10
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b L(tail_bytes)
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.align 4
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L(tail_bytes):
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/* Check for tail bytes. */
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beqlr cr6
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clrldi 0,5,61
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mtocrf 0x01,0
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/* At this point we have a tail of 0-7 bytes and we know that the
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destination is doubleword-aligned. */
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4: /* Copy 4 bytes. */
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bf 29,2f
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stw 4,0(12)
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addi 12,12,4
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2: /* Copy 2 bytes. */
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bf 30,1f
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sth 4,0(12)
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addi 12,12,2
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1: /* Copy 1 byte. */
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bflr 31
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stb 4,0(12)
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blr
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/* Special case when value is 0 and we have a long length to deal
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with. Use dcbz to zero out 128-bytes at a time. Before using
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dcbz though, we need to get the destination 128-bytes aligned. */
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.align 4
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L(huge):
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andi. 11,10,127
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neg 0,10
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beq L(huge_aligned)
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clrldi 0,0,57
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subf 5,0,5
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srdi 0,0,3
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mtocrf 0x01,0
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/* Get DST aligned to 128 bytes. */
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8: bf 28,4f
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std 4,0(10)
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std 4,8(10)
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std 4,16(10)
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std 4,24(10)
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std 4,32(10)
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std 4,40(10)
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std 4,48(10)
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std 4,56(10)
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addi 10,10,64
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.align 4
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4: bf 29,2f
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std 4,0(10)
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std 4,8(10)
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std 4,16(10)
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std 4,24(10)
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addi 10,10,32
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.align 4
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2: bf 30,1f
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std 4,0(10)
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std 4,8(10)
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addi 10,10,16
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.align 4
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1: bf 31,L(huge_aligned)
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std 4,0(10)
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addi 10,10,8
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L(huge_aligned):
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srdi 8,5,7
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clrldi 11,5,57
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cmpldi cr6,11,0
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mtctr 8
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.align 4
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L(huge_loop):
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dcbz 0,10
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addi 10,10,128
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bdnz L(huge_loop)
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/* Check how many bytes are still left. */
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beqlr cr6
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subf 9,3,10
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subf 5,9,12
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srdi 8,5,3
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cmpldi cr6,8,0
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mtocrf 0x01,8
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/* We have a tail o 1~127 bytes. Copy up to 15 doublewords for
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speed. We'll handle the resulting tail bytes later. */
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beq cr6,L(tail)
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8: bf 28,4f
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std 4,0(10)
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std 4,8(10)
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std 4,16(10)
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std 4,24(10)
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std 4,32(10)
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std 4,40(10)
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std 4,48(10)
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std 4,56(10)
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addi 10,10,64
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.align 4
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4: bf 29,2f
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std 4,0(10)
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std 4,8(10)
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std 4,16(10)
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std 4,24(10)
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addi 10,10,32
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.align 4
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2: bf 30,1f
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std 4,0(10)
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std 4,8(10)
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addi 10,10,16
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.align 4
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1: bf 31,L(tail)
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std 4,0(10)
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addi 10,10,8
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/* Handle the rest of the tail bytes here. */
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L(tail):
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mtocrf 0x01,5
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.align 4
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4: bf 29,2f
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stw 4,0(10)
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addi 10,10,4
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.align 4
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2: bf 30,1f
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sth 4,0(10)
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addi 10,10,2
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.align 4
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1: bflr 31
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stb 4,0(10)
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blr
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/* Expanded tree to copy tail bytes without increments. */
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.align 4
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L(copy_tail):
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bf 29,L(FXX)
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stw 4,0(10)
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bf 30,L(TFX)
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sth 4,4(10)
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bflr 31
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stb 4,6(10)
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blr
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.align 4
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L(FXX): bf 30,L(FFX)
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sth 4,0(10)
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bflr 31
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stb 4,2(10)
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blr
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.align 4
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L(TFX): bflr 31
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stb 4,4(10)
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blr
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.align 4
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L(FFX): bflr 31
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stb 4,0(10)
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blr
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/* Handle copies of 9~31 bytes. */
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.align 4
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L(medium):
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/* At least 9 bytes to go. */
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andi. 11,10,3
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clrldi 0,0,62
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beq L(medium_aligned)
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/* Force 4-bytes alignment for DST. */
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mtocrf 0x01,0
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subf 5,0,5
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1: /* Copy 1 byte. */
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bf 31,2f
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stb 4,0(10)
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addi 10,10,1
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2: /* Copy 2 bytes. */
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bf 30,L(medium_aligned)
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sth 4,0(10)
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addi 10,10,2
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.align 4
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L(medium_aligned):
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/* At least 6 bytes to go, and DST is word-aligned. */
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cmpldi cr1,5,16
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mtocrf 0x01,5
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blt cr1,8f
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/* Copy 16 bytes. */
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stw 4,0(10)
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stw 4,4(10)
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stw 4,8(10)
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stw 4,12(10)
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addi 10,10,16
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8: /* Copy 8 bytes. */
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bf 28,4f
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stw 4,0(10)
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stw 4,4(10)
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addi 10,10,8
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4: /* Copy 4 bytes. */
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bf 29,2f
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stw 4,0(10)
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addi 10,10,4
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2: /* Copy 2-3 bytes. */
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bf 30,1f
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sth 4,0(10)
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addi 10,10,2
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1: /* Copy 1 byte. */
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bflr 31
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stb 4,0(10)
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blr
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/* Handles copies of 0~8 bytes. */
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.align 4
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L(small):
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mtocrf 0x01,5
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bne cr6,L(copy_tail)
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stw 4,0(10)
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stw 4,4(10)
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blr
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END_GEN_TB (MEMSET,TB_TOCLESS)
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libc_hidden_builtin_def (memset)
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