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