diff options
author | Joseph Myers <joseph@codesourcery.com> | 2014-02-08 01:49:39 +0000 |
---|---|---|
committer | Joseph Myers <joseph@codesourcery.com> | 2014-02-08 01:49:39 +0000 |
commit | c6bfe5c4d756913297db03f55e42016d1c48918c (patch) | |
tree | 898d2910ef903f46b596ad54e519ed4495357766 /sysdeps/arm/armv6/strrchr.S | |
parent | 852fa2dd3aa1a687780e27300df9eb0bdc433863 (diff) | |
download | glibc-c6bfe5c4d756913297db03f55e42016d1c48918c.tar.gz glibc-c6bfe5c4d756913297db03f55e42016d1c48918c.tar.xz glibc-c6bfe5c4d756913297db03f55e42016d1c48918c.zip |
Move arm from ports to libc.
I've moved the ARM port from ports to the main sysdeps hierarchy. Beyond the README update, the move of the files was simply git mv ports/sysdeps/arm sysdeps/arm git mv ports/sysdeps/unix/arm sysdeps/unix/arm git mv ports/sysdeps/unix/sysv/linux/arm sysdeps/unix/sysv/linux/arm and in addition to the ChangeLog entries here, I put a note at the top of ports/ChangeLog.arm similar to that at the top of ChangeLog.powerpc. There is deliberately no NEWS change, as I think it makes the most sense to put in a general note above all ports having moved if we can achieve that for 2.20. Tested that disassembly of installed shared libraries for arm is the same before and after this patch, except for data (not instructions) in ld.so (there are assertions in sysdeps/arm/dl-machine.h, and the path by which that file is found, and so by which it appears in the assertion message, changes as a result of the move). * sysdeps/arm: Move directory from ports/sysdeps/arm. * sysdeps/unix/arm: Move directory from ports/sysdeps/unix/arm. * sysdeps/unix/sysv/linux/arm: Move directory from ports/sysdeps/unix/sysv/linux/arm. * README: Update listing for arm-*-linux-gnueabi. ports/ChangeLog.arm: * sysdeps/arm: Move directory to ../sysdeps/arm. * sysdeps/unix/arm: Move directory to ../sysdeps.arm. * sysdeps/unix/sysv/linux/arm: Move directory to ../sysdeps/unix/sysv/linux/arm.
Diffstat (limited to 'sysdeps/arm/armv6/strrchr.S')
-rw-r--r-- | sysdeps/arm/armv6/strrchr.S | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/sysdeps/arm/armv6/strrchr.S b/sysdeps/arm/armv6/strrchr.S new file mode 100644 index 0000000000..a1e753c11b --- /dev/null +++ b/sysdeps/arm/armv6/strrchr.S @@ -0,0 +1,131 @@ +/* strrchr -- find the last occurence of C in a nul-terminated string + 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> + + .syntax unified + .text + +ENTRY (strrchr) + @ r0 = start of string + @ r1 = character to match + @ returns NULL for no match, or a pointer to the match + + mov r3, r0 + mov r0, #0 + uxtb r1, r1 + + @ Loop a few times until we're aligned. + tst r3, #7 + beq 2f +1: sfi_breg r3, \ + ldrb r2, [\B], #1 + cmp r2, r1 @ Find the character + it eq + subeq r0, r3, #1 + cmp r2, #0 @ Find EOS + it eq + bxeq lr + tst r3, #7 @ Find the aligment point + bne 1b + + @ So now we're aligned. Now we actually need a stack frame. +2: push { r4, r5, r6, r7 } + cfi_adjust_cfa_offset (16) + cfi_rel_offset (r4, 0) + cfi_rel_offset (r5, 4) + cfi_rel_offset (r6, 8) + cfi_rel_offset (r7, 12) + + orr r1, r1, r1, lsl #8 @ Replicate C to all bytes +#ifdef ARCH_HAS_T2 + movw ip, #0x0101 + movt ip, #0x0101 +#else + ldr ip, =0x01010101 +#endif + orr r1, r1, r1, lsl #16 + mov r2, #0 @ No found bits yet + + @ Loop searching for EOS and C, 8 bytes at a time. + @ Any time we find a match in a word, we copy the address of + @ the word to r0, and the found bits to r2. +3: sfi_breg r3, \ + ldrd r4, r5, [\B], #8 + @ Subtracting (unsigned saturating) from 1 means result of 1 for + @ any byte that was originally zero and 0 otherwise. Therefore + @ we consider the lsb of each byte the "found" bit. + uqsub8 r6, ip, r4 @ Find EOS + uqsub8 r7, ip, r5 + eor r4, r4, r1 @ Convert C bytes to 0 + eor r5, r5, r1 + uqsub8 r4, ip, r4 @ Find C + uqsub8 r5, ip, r5 + cmp r6, #0 @ Found EOS, first word + bne 4f + cmp r4, #0 @ Handle C, first word + itt ne + subne r0, r3, #8 + movne r2, r4 + cmp r7, #0 @ Found EOS, second word + bne 5f + cmp r5, #0 @ Handle C, second word + itt ne + subne r0, r3, #4 + movne r2, r5 + b 3b + + @ Found EOS in second word; fold to first word. +5: add r3, r3, #4 @ Dec pointer to 2nd word, with below + mov r4, r5 @ Overwrite first word C found + mov r6, r7 @ Overwrite first word EOS found + + @ Found EOS. Zap found C after EOS. +4: sub r3, r3, #8 @ Decrement pointer to first word +#ifdef __ARMEB__ + @ Byte swap to be congruent with LE, which is easier from here on. + rev r6, r6 @ Byte swap found EOS, + rev r4, r4 @ ... this found C + rev r2, r2 @ ... prev found C +#endif + sub r7, r6, #1 @ Toggle EOS lsb and below + eor r6, r6, r7 @ All bits below and including lsb + ands r4, r4, r6 @ Zap C above EOS + itt ne + movne r2, r4 @ Copy to result, if still non-zero + movne r0, r3 + + pop { r4, r5, r6, r7 } + cfi_adjust_cfa_offset (-16) + cfi_restore (r4) + cfi_restore (r5) + cfi_restore (r6) + cfi_restore (r7) + + @ Adjust the result pointer if we found a word containing C. + cmp r2, #0 + clz r2, r2 @ Find the bit offset of the last C + itt ne + rsbne r2, r2, #32 @ Convert to a count from the right + addne r0, r0, r2, lsr #3 @ Convert to byte offset and add. + bx lr + +END (strrchr) + +weak_alias (strrchr, rindex) +libc_hidden_builtin_def (strrchr) |