108 lines
2.9 KiB
ArmAsm
108 lines
2.9 KiB
ArmAsm
/* Optimized strcpy implementation for PowerPC476.
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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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/* strcpy
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Register Use
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r3:destination and return address
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r4:source address
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r10:temp destination address
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Implementation description
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Loop by checking 2 words at a time, with dlmzb. Check if there is a null
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in the 2 words. If there is a null jump to end checking to determine
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where in the last 8 bytes it is. Copy the appropriate bytes of the last
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8 according to the null position. */
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EALIGN (strcpy, 5, 0)
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neg r7,r4
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subi r4,r4,1
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clrlwi. r8,r7,29
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subi r10,r3,1
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beq L(pre_word8_loop)
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mtctr r8
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L(loop):
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lbzu r5,0x01(r4)
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cmpi cr5,r5,0x0
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stbu r5,0x01(r10)
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beq cr5,L(end_strcpy)
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bdnz L(loop)
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L(pre_word8_loop):
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subi r4,r4,3
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subi r10,r10,3
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L(word8_loop):
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lwzu r5,0x04(r4)
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lwzu r6,0x04(r4)
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dlmzb. r11,r5,r6
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bne L(byte_copy)
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stwu r5,0x04(r10)
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stwu r6,0x04(r10)
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lwzu r5,0x04(r4)
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lwzu r6,0x04(r4)
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dlmzb. r11,r5,r6
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bne L(byte_copy)
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stwu r5,0x04(r10)
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stwu r6,0x04(r10)
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lwzu r5,0x04(r4)
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lwzu r6,0x04(r4)
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dlmzb. r11,r5,r6
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bne L(byte_copy)
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stwu r5,0x04(r10)
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stwu r6,0x04(r10)
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lwzu r5,0x04(r4)
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lwzu r6,0x04(r4)
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dlmzb. r11,r5,r6
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bne L(byte_copy)
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stwu r5,0x04(r10)
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stwu r6,0x04(r10)
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b L(word8_loop)
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L(last_bytes_copy):
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stwu r5,0x04(r10)
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subi r11,r11,4
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mtctr r11
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addi r10,r10,3
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subi r4,r4,1
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L(last_bytes_copy_loop):
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lbzu r5,0x01(r4)
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stbu r5,0x01(r10)
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bdnz L(last_bytes_copy_loop)
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blr
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L(byte_copy):
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blt L(last_bytes_copy)
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mtctr r11
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addi r10,r10,3
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subi r4,r4,5
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L(last_bytes_copy_loop2):
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lbzu r5,0x01(r4)
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stbu r5,0x01(r10)
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bdnz L(last_bytes_copy_loop2)
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L(end_strcpy):
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blr
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END (strcpy)
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libc_hidden_builtin_def (strcpy)
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