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Diffstat (limited to 'REORG.TODO/sysdeps/powerpc/powerpc64/power8/strcpy.S')
| -rw-r--r-- | REORG.TODO/sysdeps/powerpc/powerpc64/power8/strcpy.S | 270 |
1 files changed, 270 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/powerpc/powerpc64/power8/strcpy.S b/REORG.TODO/sysdeps/powerpc/powerpc64/power8/strcpy.S new file mode 100644 index 0000000000..7f2cee4b1b --- /dev/null +++ b/REORG.TODO/sysdeps/powerpc/powerpc64/power8/strcpy.S @@ -0,0 +1,270 @@ +/* Optimized strcpy/stpcpy implementation for PowerPC64/POWER8. + Copyright (C) 2015-2017 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> + +#ifdef USE_AS_STPCPY +# ifndef STPCPY +# define FUNC_NAME __stpcpy +# else +# define FUNC_NAME STPCPY +# endif +#else +# ifndef STRCPY +# define FUNC_NAME strcpy +# else +# define FUNC_NAME STRCPY +# endif +#endif /* !USE_AS_STPCPY */ + +/* Implements the function + + char * [r3] strcpy (char *dest [r3], const char *src [r4]) + + or + + char * [r3] stpcpy (char *dest [r3], const char *src [r4]) + + if USE_AS_STPCPY is defined. + + The implementation uses unaligned doubleword access to avoid specialized + code paths depending of data alignment. Although recent powerpc64 uses + 64K as default, the page cross handling assumes minimum page size of + 4k. */ + + .machine power7 +EALIGN (FUNC_NAME, 4, 0) + li r0,0 /* Doubleword with null chars to use + with cmpb. */ + + /* Check if the [src]+15 will cross a 4K page by checking if the bit + indicating the page size changes. Basically: + + uint64_t srcin = (uint64_t)src; + uint64_t ob = srcin & 4096UL; + uint64_t nb = (srcin+15UL) & 4096UL; + if (ob ^ nb) + goto pagecross; */ + + addi r9,r4,15 + xor r9,r9,r4 + rlwinm. r9,r9,0,19,19 + bne L(pagecross) + + /* For short string (less than 16 bytes), just calculate its size as + strlen and issues a memcpy if null is found. */ + mr r7,r4 + ld r12,0(r7) /* Load doubleword from memory. */ + cmpb r10,r12,r0 /* Check for null bytes in DWORD1. */ + cmpdi cr7,r10,0 /* If r10 == 0, no null's have been found. */ + bne cr7,L(done) + + ldu r8,8(r7) + cmpb r10,r8,r0 + cmpdi cr7,r10,0 + bne cr7,L(done) + + b L(loop_before) + + .align 4 +L(pagecross): + clrrdi r7,r4,3 /* Align the address to doubleword boundary. */ + rlwinm r6,r4,3,26,28 /* Calculate padding. */ + li r5,-1 /* MASK = 0xffffffffffffffff. */ + ld r12,0(r7) /* Load doubleword from memory. */ +#ifdef __LITTLE_ENDIAN__ + sld r5,r5,r6 +#else + srd r5,r5,r6 /* MASK = MASK >> padding. */ +#endif + orc r9,r12,r5 /* Mask bits that are not part of the string. */ + cmpb r10,r9,r0 /* Check for null bytes in DWORD1. */ + cmpdi cr7,r10,0 /* If r10 == 0, no null's have been found. */ + bne cr7,L(done) + + ldu r6,8(r7) + cmpb r10,r6,r0 + cmpdi cr7,r10,0 + bne cr7,L(done) + + ld r12,0(r7) + cmpb r10,r12,r0 + cmpdi cr7,r10,0 + bne cr7,L(done) + + ldu r6,8(r7) + cmpb r10,r6,r0 + cmpdi cr7,r10,0 + bne cr7,L(done) + + /* We checked for 24 - x bytes, with x being the source alignment + (0 <= x <= 16), and no zero has been found. Start the loop + copy with doubleword aligned address. */ + mr r7,r4 + ld r12, 0(r7) + ldu r8, 8(r7) + +L(loop_before): + /* Save the two doublewords readed from source and align the source + to 16 bytes for the loop. */ + mr r11,r3 + std r12,0(r11) + std r8,8(r11) + addi r11,r11,16 + rldicl r9,r4,0,60 + subf r7,r9,r7 + subf r11,r9,r11 + b L(loop_start) + + .align 5 +L(loop): + std r12, 0(r11) + std r6, 8(r11) + addi r11,r11,16 +L(loop_start): + /* Load two doublewords, compare and merge in a + single register for speed. This is an attempt + to speed up the null-checking process for bigger strings. */ + + ld r12, 8(r7) + ldu r6, 16(r7) + cmpb r10,r12,r0 + cmpb r9,r6,r0 + or r8,r9,r10 /* Merge everything in one doubleword. */ + cmpdi cr7,r8,0 + beq cr7,L(loop) + + + /* OK, one (or both) of the doublewords contains a null byte. Check + the first doubleword and decrement the address in case the first + doubleword really contains a null byte. */ + + addi r4,r7,-8 + cmpdi cr6,r10,0 + addi r7,r7,-8 + bne cr6,L(done2) + + /* The null byte must be in the second doubleword. Adjust the address + again and move the result of cmpb to r10 so we can calculate the + length. */ + + mr r10,r9 + addi r7,r7,8 + b L(done2) + + /* r10 has the output of the cmpb instruction, that is, it contains + 0xff in the same position as the null byte in the original + doubleword from the string. Use that to calculate the length. */ +L(done): + mr r11,r3 +L(done2): +#ifdef __LITTLE_ENDIAN__ + addi r9, r10, -1 /* Form a mask from trailing zeros. */ + andc r9, r9, r10 + popcntd r6, r9 /* Count the bits in the mask. */ +#else + cntlzd r6,r10 /* Count leading zeros before the match. */ +#endif + subf r5,r4,r7 + srdi r6,r6,3 /* Convert leading/trailing zeros to bytes. */ + add r8,r5,r6 /* Compute final length. */ +#ifdef USE_AS_STPCPY + /* stpcpy returns the dest address plus the size not counting the + final '\0'. */ + add r3,r11,r8 +#endif + addi r8,r8,1 /* Final '/0'. */ + + cmpldi cr6,r8,8 + mtocrf 0x01,r8 + ble cr6,L(copy_LE_8) + + cmpldi cr1,r8,16 + blt cr1,8f + + /* Handle copies of 0~31 bytes. */ + .align 4 +L(copy_LT_32): + /* At least 6 bytes to go. */ + blt cr1,8f + + /* Copy 16 bytes. */ + ld r6,0(r4) + ld r8,8(r4) + addi r4,r4,16 + std r6,0(r11) + std r8,8(r11) + addi r11,r11,16 +8: /* Copy 8 bytes. */ + bf 28,L(tail4) + ld r6,0(r4) + addi r4,r4,8 + std r6,0(r11) + addi r11,r11,8 + + .align 4 +/* Copies 4~7 bytes. */ +L(tail4): + bf 29,L(tail2) + lwz r6,0(r4) + stw r6,0(r11) + bf 30,L(tail5) + lhz r7,4(r4) + sth r7,4(r11) + bflr 31 + lbz r8,6(r4) + stb r8,6(r11) + blr + + .align 4 +/* Copies 2~3 bytes. */ +L(tail2): + bf 30,1f + lhz r6,0(r4) + sth r6,0(r11) + bflr 31 + lbz r7,2(r4) + stb r7,2(r11) + blr + + .align 4 +L(tail5): + bf 31,1f + lbz r6,4(r4) + stb r6,4(r11) + blr + + .align 4 +1: + bflr 31 + lbz r6,0(r4) + stb r6,0(r11) + blr + +/* Handles copies of 0~8 bytes. */ + .align 4 +L(copy_LE_8): + bne cr6,L(tail4) + ld r6,0(r4) + std r6,0(r11) + blr +END (FUNC_NAME) + +#ifndef USE_AS_STPCPY +libc_hidden_builtin_def (strcpy) +#endif |