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275 lines
6.1 KiB
ArmAsm
275 lines
6.1 KiB
ArmAsm
/* Optimized strcpy/stpcpy implementation for PowerPC64/POWER7.
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Copyright (C) 2013-2014 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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/* Implements the function
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char * [r3] strcpy (char *dest [r3], const char *src [r4])
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or
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char * [r3] strcpy (char *dest [r3], const char *src [r4])
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if USE_AS_STPCPY is defined. It tries to use aligned memory accesses
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when possible using the following algorithm:
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if (((((uintptr_t)dst & 0x7UL) == 0) && ((uintptr_t)src & 0x7UL) == 0))
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goto aligned_doubleword_copy;
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if (((((uintptr_t)dst & 0x3UL) == 0) && ((uintptr_t)src & 0x3UL) == 0))
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goto aligned_word_copy;
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if (((uintptr_t)dst & 0x7UL) == ((uintptr_t)src & 0x7UL))
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goto same_alignment;
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goto unaligned;
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The aligned comparison are made using cmpb instructions. */
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#ifdef USE_AS_STPCPY
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# define FUNC_NAME __stpcpy
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#else
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# define FUNC_NAME strcpy
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#endif
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.machine power7
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EALIGN (FUNC_NAME, 4, 0)
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CALL_MCOUNT 2
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#define rTMP r0
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#ifdef USE_AS_STPCPY
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#define rRTN r3 /* pointer to previous word/doubleword in dest */
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#else
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#define rRTN r12 /* pointer to previous word/doubleword in dest */
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#endif
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#define rSRC r4 /* pointer to previous word/doubleword in src */
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#define rMASK r5 /* mask 0xffffffff | 0xffffffffffffffff */
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#define rWORD r6 /* current word from src */
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#define rALT r7 /* alternate word from src */
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#define rRTNAL r8 /* alignment of return pointer */
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#define rSRCAL r9 /* alignment of source pointer */
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#define rALCNT r10 /* bytes to read to reach 8 bytes alignment */
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#define rSUBAL r11 /* doubleword minus unaligned displacement */
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#ifndef USE_AS_STPCPY
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/* Save the dst pointer to use as return value. */
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mr rRTN, r3
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#endif
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or rTMP, rSRC, rRTN
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clrldi. rTMP, rTMP, 61
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bne L(check_word_alignment)
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b L(aligned_doubleword_copy)
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L(same_alignment):
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/* Src and dst with same alignment: align both to doubleword. */
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mr rALCNT, rRTN
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lbz rWORD, 0(rSRC)
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subfic rSUBAL, rRTNAL, 8
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addi rRTN, rRTN, 1
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addi rSRC, rSRC, 1
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cmpdi cr7, rWORD, 0
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stb rWORD, 0(rALCNT)
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beq cr7, L(s2)
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add rALCNT, rALCNT, rSUBAL
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subf rALCNT, rRTN, rALCNT
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addi rALCNT, rALCNT, 1
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mtctr rALCNT
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b L(s1)
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.align 4
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L(s0):
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addi rSRC, rSRC, 1
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lbz rWORD, -1(rSRC)
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cmpdi cr7, rWORD, 0
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stb rWORD, -1(rALCNT)
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beqlr cr7
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mr rRTN, rALCNT
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L(s1):
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addi rALCNT, rRTN,1
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bdnz L(s0)
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b L(aligned_doubleword_copy)
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.align 4
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L(s2):
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mr rRTN, rALCNT
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blr
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/* For doubleword aligned memory, operate using doubleword load and stores. */
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.align 4
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L(aligned_doubleword_copy):
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li rMASK, 0
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addi rRTN, rRTN, -8
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ld rWORD, 0(rSRC)
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b L(g2)
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.align 4
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L(g0): ldu rALT, 8(rSRC)
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stdu rWORD, 8(rRTN)
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cmpb rTMP, rALT, rMASK
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cmpdi rTMP, 0
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bne L(g1)
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ldu rWORD, 8(rSRC)
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stdu rALT, 8(rRTN)
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L(g2): cmpb rTMP, rWORD, rMASK
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cmpdi rTMP, 0 /* If rTMP is 0, no null's have been found. */
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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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extrdi. rTMP, rALT, 8, 56
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stbu rALT, 8(rRTN)
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beqlr-
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extrdi. rTMP, rALT, 8, 48
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stbu rTMP, 1(rRTN)
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beqlr-
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extrdi. rTMP, rALT, 8, 40
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stbu rTMP, 1(rRTN)
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beqlr-
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extrdi. rTMP, rALT, 8, 32
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stbu rTMP, 1(rRTN)
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beqlr-
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extrdi. rTMP, rALT, 8, 24
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stbu rTMP, 1(rRTN)
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beqlr-
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extrdi. rTMP, rALT, 8, 16
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stbu rTMP, 1(rRTN)
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beqlr-
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extrdi. rTMP, rALT, 8, 8
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stbu rTMP, 1(rRTN)
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beqlr-
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extrdi rTMP, rALT, 8, 0
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stbu rTMP, 1(rRTN)
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#else
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extrdi. rTMP, rALT, 8, 0
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stbu rTMP, 8(rRTN)
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beqlr
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extrdi. rTMP, rALT, 8, 8
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stbu rTMP, 1(rRTN)
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beqlr
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extrdi. rTMP, rALT, 8, 16
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stbu rTMP, 1(rRTN)
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beqlr
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extrdi. rTMP, rALT, 8, 24
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stbu rTMP, 1(rRTN)
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beqlr
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extrdi. rTMP, rALT, 8, 32
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stbu rTMP, 1(rRTN)
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beqlr
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extrdi. rTMP, rALT, 8, 40
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stbu rTMP, 1(rRTN)
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beqlr
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extrdi. rTMP, rALT, 8, 48
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stbu rTMP, 1(rRTN)
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beqlr
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stbu rALT, 1(rRTN)
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#endif
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blr
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L(check_word_alignment):
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clrldi. rTMP, rTMP, 62
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beq L(aligned_word_copy)
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rldicl rRTNAL, rRTN, 0, 61
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rldicl rSRCAL, rSRC, 0, 61
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cmpld cr7, rSRCAL, rRTNAL
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beq cr7, L(same_alignment)
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b L(unaligned)
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/* For word aligned memory, operate using word load and stores. */
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.align 4
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L(aligned_word_copy):
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li rMASK, 0
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addi rRTN, rRTN, -4
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lwz rWORD, 0(rSRC)
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b L(g5)
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.align 4
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L(g3): lwzu rALT, 4(rSRC)
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stwu rWORD, 4(rRTN)
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cmpb rTMP, rALT, rMASK
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cmpwi rTMP, 0
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bne L(g4)
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lwzu rWORD, 4(rSRC)
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stwu rALT, 4(rRTN)
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L(g5): cmpb rTMP, rWORD, rMASK
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cmpwi rTMP, 0 /* If rTMP is 0, no null in word. */
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beq L(g3)
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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(g4):
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#ifdef __LITTLE_ENDIAN__
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rlwinm. rTMP, rALT, 0, 24, 31
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stbu rALT, 4(rRTN)
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beqlr-
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rlwinm. rTMP, rALT, 24, 24, 31
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stbu rTMP, 1(rRTN)
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beqlr-
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rlwinm. rTMP, rALT, 16, 24, 31
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stbu rTMP, 1(rRTN)
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beqlr-
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rlwinm rTMP, rALT, 8, 24, 31
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stbu rTMP, 1(rRTN)
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#else
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rlwinm. rTMP, rALT, 8, 24, 31
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stbu rTMP, 4(rRTN)
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beqlr
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rlwinm. rTMP, rALT, 16, 24, 31
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stbu rTMP, 1(rRTN)
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beqlr
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rlwinm. rTMP, rALT, 24, 24, 31
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stbu rTMP, 1(rRTN)
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beqlr
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stbu rALT, 1(rRTN)
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#endif
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blr
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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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L(unaligned):
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lbz rWORD, 0(rSRC)
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addi rRTN, rRTN, -1
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cmpdi rWORD, 0
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beq L(u2)
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.align 5
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L(u0): lbzu rALT, 1(rSRC)
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stbu rWORD, 1(rRTN)
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cmpdi rALT, 0
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beq L(u1)
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lbzu rWORD, 1(rSRC)
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stbu rALT, 1(rRTN)
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cmpdi rWORD, 0
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beq L(u2)
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lbzu rALT, 1(rSRC)
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stbu rWORD, 1(rRTN)
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cmpdi rALT, 0
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beq L(u1)
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lbzu rWORD, 1(rSRC)
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stbu rALT, 1(rRTN)
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cmpdi rWORD, 0
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bne L(u0)
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L(u2): stbu rWORD, 1(rRTN)
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blr
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L(u1): stbu rALT, 1(rRTN)
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blr
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END (FUNC_NAME)
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#ifndef USE_AS_STPCPY
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libc_hidden_builtin_def (strcpy)
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#endif
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