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118 lines
2.9 KiB
ArmAsm
118 lines
2.9 KiB
ArmAsm
/* Optimized strcpy implementation for PowerPC.
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Copyright (C) 1997-2017 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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<http://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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/* See strlen.s for comments on how the end-of-string testing works. */
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/* char * [r3] strcpy (char *dest [r3], const char *src [r4]) */
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EALIGN (strcpy, 4, 0)
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#define rTMP r0
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#define rRTN r3 /* incoming DEST arg preserved as result */
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#define rSRC r4 /* pointer to previous word in src */
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#define rDEST r5 /* pointer to previous word in dest */
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#define rWORD r6 /* current word from src */
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#define rFEFE r7 /* constant 0xfefefeff (-0x01010101) */
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#define r7F7F r8 /* constant 0x7f7f7f7f */
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#define rNEG r9 /* ~(word in s1 | 0x7f7f7f7f) */
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#define rALT r10 /* alternate word from src */
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or rTMP, rSRC, rRTN
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clrlwi. rTMP, rTMP, 30
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addi rDEST, rRTN, -4
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bne L(unaligned)
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lis rFEFE, -0x101
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lis r7F7F, 0x7f7f
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lwz rWORD, 0(rSRC)
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addi rFEFE, rFEFE, -0x101
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addi r7F7F, r7F7F, 0x7f7f
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b L(g2)
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L(g0): lwzu rALT, 4(rSRC)
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stwu rWORD, 4(rDEST)
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add rTMP, rFEFE, rALT
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nor rNEG, r7F7F, rALT
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and. rTMP, rTMP, rNEG
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bne- L(g1)
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lwzu rWORD, 4(rSRC)
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stwu rALT, 4(rDEST)
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L(g2): add rTMP, rFEFE, rWORD
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nor rNEG, r7F7F, rWORD
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and. rTMP, rTMP, rNEG
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beq+ L(g0)
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mr rALT, rWORD
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/* We've hit the end of the string. Do the rest byte-by-byte. */
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L(g1):
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#ifdef __LITTLE_ENDIAN__
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rlwinm. rTMP, rALT, 0, 24, 31
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stb rALT, 4(rDEST)
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beqlr-
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rlwinm. rTMP, rALT, 24, 24, 31
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stb rTMP, 5(rDEST)
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beqlr-
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rlwinm. rTMP, rALT, 16, 24, 31
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stb rTMP, 6(rDEST)
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beqlr-
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rlwinm rTMP, rALT, 8, 24, 31
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stb rTMP, 7(rDEST)
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blr
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#else
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rlwinm. rTMP, rALT, 8, 24, 31
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stb rTMP, 4(rDEST)
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beqlr-
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rlwinm. rTMP, rALT, 16, 24, 31
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stb rTMP, 5(rDEST)
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beqlr-
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rlwinm. rTMP, rALT, 24, 24, 31
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stb rTMP, 6(rDEST)
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beqlr-
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stb rALT, 7(rDEST)
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blr
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#endif
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/* Oh well. In this case, we just do a byte-by-byte copy. */
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.align 4
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nop
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L(unaligned):
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lbz rWORD, 0(rSRC)
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addi rDEST, rRTN, -1
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cmpwi rWORD, 0
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beq- L(u2)
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L(u0): lbzu rALT, 1(rSRC)
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stbu rWORD, 1(rDEST)
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cmpwi rALT, 0
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beq- L(u1)
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nop /* Let 601 load start of loop. */
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lbzu rWORD, 1(rSRC)
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stbu rALT, 1(rDEST)
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cmpwi rWORD, 0
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bne+ L(u0)
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L(u2): stb rWORD, 1(rDEST)
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blr
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L(u1): stb rALT, 1(rDEST)
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blr
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END (strcpy)
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libc_hidden_builtin_def (strcpy)
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