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Diffstat (limited to 'REORG.TODO/sysdeps/powerpc/powerpc32/power7/memchr.S')
| -rw-r--r-- | REORG.TODO/sysdeps/powerpc/powerpc32/power7/memchr.S | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/powerpc/powerpc32/power7/memchr.S b/REORG.TODO/sysdeps/powerpc/powerpc32/power7/memchr.S new file mode 100644 index 0000000000..9ce8507a82 --- /dev/null +++ b/REORG.TODO/sysdeps/powerpc/powerpc32/power7/memchr.S @@ -0,0 +1,193 @@ +/* Optimized memchr implementation for PowerPC32/POWER7 using cmpb insn. + Copyright (C) 2010-2017 Free Software Foundation, Inc. + Contributed by Luis Machado <luisgpm@br.ibm.com>. + 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> + +/* int [r3] memchr (char *s [r3], int byte [r4], int size [r5]) */ + .machine power7 +ENTRY (__memchr) + CALL_MCOUNT + dcbt 0,r3 + clrrwi r8,r3,2 + insrwi r4,r4,8,16 /* Replicate byte to word. */ + + /* Calculate the last acceptable address and check for possible + addition overflow by using satured math: + r7 = r3 + r5 + r7 |= -(r7 < x) */ + add r7,r3,r5 + subfc r6,r3,r7 + subfe r9,r9,r9 + or r7,r7,r9 + + insrwi r4,r4,16,0 + cmplwi r5,16 + li r9, -1 + rlwinm r6,r3,3,27,28 /* Calculate padding. */ + addi r7,r7,-1 +#ifdef __LITTLE_ENDIAN__ + slw r9,r9,r6 +#else + srw r9,r9,r6 +#endif + ble L(small_range) + + lwz r12,0(r8) /* Load word from memory. */ + cmpb r3,r12,r4 /* Check for BYTEs in WORD1. */ + and r3,r3,r9 + clrlwi r5,r7,30 /* Byte count - 1 in last word. */ + clrrwi r7,r7,2 /* Address of last word. */ + cmplwi cr7,r3,0 /* If r3 == 0, no BYTEs have been found. */ + bne cr7,L(done) + + mtcrf 0x01,r8 + /* Are we now aligned to a doubleword boundary? If so, skip to + the main loop. Otherwise, go through the alignment code. */ + bt 29,L(loop_setup) + + /* Handle WORD2 of pair. */ + lwzu r12,4(r8) + cmpb r3,r12,r4 + cmplwi cr7,r3,0 + bne cr7,L(done) + +L(loop_setup): + /* The last word we want to read in the loop below is the one + containing the last byte of the string, ie. the word at + (s + size - 1) & ~3, or r7. The first word read is at + r8 + 4, we read 2 * cnt words, so the last word read will + be at r8 + 4 + 8 * cnt - 4. Solving for cnt gives + cnt = (r7 - r8) / 8 */ + sub r6,r7,r8 + srwi r6,r6,3 /* Number of loop iterations. */ + mtctr r6 /* Setup the counter. */ + + /* Main loop to look for BYTE in the string. Since + it's a small loop (8 instructions), align it to 32-bytes. */ + .align 5 +L(loop): + /* Load two words, compare and merge in a + single register for speed. This is an attempt + to speed up the byte-checking process for bigger strings. */ + lwz r12,4(r8) + lwzu r11,8(r8) + cmpb r3,r12,r4 + cmpb r9,r11,r4 + or r6,r9,r3 /* Merge everything in one word. */ + cmplwi cr7,r6,0 + bne cr7,L(found) + bdnz L(loop) + + /* We may have one more dword to read. */ + cmplw r8,r7 + beqlr + + lwzu r12,4(r8) + cmpb r3,r12,r4 + cmplwi cr6,r3,0 + bne cr6,L(done) + blr + + .align 4 +L(found): + /* OK, one (or both) of the words contains BYTE. Check + the first word and decrement the address in case the first + word really contains BYTE. */ + cmplwi cr6,r3,0 + addi r8,r8,-4 + bne cr6,L(done) + + /* BYTE must be in the second word. Adjust the address + again and move the result of cmpb to r3 so we can calculate the + pointer. */ + + mr r3,r9 + addi r8,r8,4 + + /* r3 has the output of the cmpb instruction, that is, it contains + 0xff in the same position as BYTE in the original + word from the string. Use that to calculate the pointer. + We need to make sure BYTE is *before* the end of the range. */ +L(done): +#ifdef __LITTLE_ENDIAN__ + addi r0,r3,-1 + andc r0,r0,r3 + popcntw r0,r0 /* Count trailing zeros. */ +#else + cntlzw r0,r3 /* Count leading zeros before the match. */ +#endif + cmplw r8,r7 /* Are we on the last word? */ + srwi r0,r0,3 /* Convert leading/trailing zeros to bytes. */ + add r3,r8,r0 + cmplw cr7,r0,r5 /* If on the last dword, check byte offset. */ + bnelr + blelr cr7 + li r3,0 + blr + + .align 4 +L(null): + li r3,0 + blr + +/* Deals with size <= 16. */ + .align 4 +L(small_range): + cmplwi r5,0 + beq L(null) + lwz r12,0(r8) /* Load word from memory. */ + cmpb r3,r12,r4 /* Check for BYTE in DWORD1. */ + and r3,r3,r9 + cmplwi cr7,r3,0 + clrlwi r5,r7,30 /* Byte count - 1 in last word. */ + clrrwi r7,r7,2 /* Address of last word. */ + cmplw r8,r7 /* Are we done already? */ + bne cr7,L(done) + beqlr + + lwzu r12,4(r8) + cmpb r3,r12,r4 + cmplwi cr6,r3,0 + cmplw r8,r7 + bne cr6,L(done) + beqlr + + lwzu r12,4(r8) + cmpb r3,r12,r4 + cmplwi cr6,r3,0 + cmplw r8,r7 + bne cr6,L(done) + beqlr + + lwzu r12,4(r8) + cmpb r3,r12,r4 + cmplwi cr6,r3,0 + cmplw r8,r7 + bne cr6,L(done) + beqlr + + lwzu r12,4(r8) + cmpb r3,r12,r4 + cmplwi cr6,r3,0 + bne cr6,L(done) + blr + +END (__memchr) +weak_alias (__memchr, memchr) +libc_hidden_builtin_def (memchr) |