From c6bfe5c4d756913297db03f55e42016d1c48918c Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Sat, 8 Feb 2014 01:49:39 +0000 Subject: 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. --- sysdeps/arm/armv6/rawmemchr.S | 109 ++++++++++++++++++++ sysdeps/arm/armv6/stpcpy.S | 1 + sysdeps/arm/armv6/strchr.S | 147 +++++++++++++++++++++++++++ sysdeps/arm/armv6/strcpy.S | 231 ++++++++++++++++++++++++++++++++++++++++++ sysdeps/arm/armv6/strlen.S | 103 +++++++++++++++++++ sysdeps/arm/armv6/strrchr.S | 131 ++++++++++++++++++++++++ 6 files changed, 722 insertions(+) create mode 100644 sysdeps/arm/armv6/rawmemchr.S create mode 100644 sysdeps/arm/armv6/stpcpy.S create mode 100644 sysdeps/arm/armv6/strchr.S create mode 100644 sysdeps/arm/armv6/strcpy.S create mode 100644 sysdeps/arm/armv6/strlen.S create mode 100644 sysdeps/arm/armv6/strrchr.S (limited to 'sysdeps/arm/armv6') diff --git a/sysdeps/arm/armv6/rawmemchr.S b/sysdeps/arm/armv6/rawmemchr.S new file mode 100644 index 0000000000..c34fdc6988 --- /dev/null +++ b/sysdeps/arm/armv6/rawmemchr.S @@ -0,0 +1,109 @@ +/* rawmemchr -- find a byte within an unsized memory block. + 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 + . */ + +#include + + .syntax unified + .text + +ENTRY (__rawmemchr) + @ r0 = start of string + @ r1 = character to match + @ returns a pointer to the match, which must be present. + sfi_breg r0, \ + ldrb r2, [\B] @ load first byte asap + + @ To cater to long strings, we want to search through a few + @ characters until we reach an aligned pointer. To cater to + @ small strings, we don't want to start doing word operations + @ immediately. The compromise is a maximum of 16 bytes less + @ whatever is required to end with an aligned pointer. + @ r3 = number of characters to search in alignment loop + and r3, r0, #7 + uxtb r1, r1 + rsb r3, r3, #15 @ 16 - 1 peeled loop iteration + cmp r2, r1 + it eq + bxeq lr + + @ Loop until we find ... +1: sfi_breg r0, \ + ldrb r2, [\B, #1]! + subs r3, r3, #1 @ ... the alignment point + it ne + cmpne r2, r1 @ ... or C + bne 1b + + @ Disambiguate the exit possibilites above + cmp r2, r1 @ Found C + it eq + bxeq lr + add r0, r0, #1 + + @ So now we're aligned. + sfi_breg r0, \ + ldrd r2, r3, [\B], #8 + orr r1, r1, r1, lsl #8 @ Replicate C to all bytes +#ifdef ARCH_HAS_T2 + movw ip, #0x0101 + sfi_pld r0, #64 + movt ip, #0x0101 +#else + ldr ip, =0x01010101 + sfi_pld r0, #64 +#endif + orr r1, r1, r1, lsl #16 + + @ Loop searching for C, 8 bytes at a time. + @ 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. +2: eor r2, r2, r1 @ Convert C bytes to 0 + eor r3, r3, r1 + uqsub8 r2, ip, r2 @ Find C + uqsub8 r3, ip, r3 + sfi_pld r0, #128 + orrs r3, r3, r2 @ Test both words for found + it eq + sfi_breg r0, \ + ldrdeq r2, r3, [\B], #8 + beq 2b + + @ Found something. Disambiguate between first and second words. + @ Adjust r0 to point to the word containing the match. + @ Adjust r2 to the found bits for the word containing the match. + cmp r2, #0 + sub r0, r0, #4 + ite eq + moveq r2, r3 + subne r0, r0, #4 + + @ Find the bit-offset of the match within the word. Note that the + @ bit result from clz will be 7 higher than "true", but we'll + @ immediately discard those bits converting to a byte offset. +#ifdef __ARMEL__ + rev r2, r2 @ For LE, count from the little end +#endif + clz r2, r2 + add r0, r0, r2, lsr #3 @ Adjust the pointer to the found byte + bx lr + +END (__rawmemchr) + +weak_alias (__rawmemchr, rawmemchr) +libc_hidden_def (__rawmemchr) diff --git a/sysdeps/arm/armv6/stpcpy.S b/sysdeps/arm/armv6/stpcpy.S new file mode 100644 index 0000000000..21a4f385be --- /dev/null +++ b/sysdeps/arm/armv6/stpcpy.S @@ -0,0 +1 @@ +/* Defined in strcpy.S. */ diff --git a/sysdeps/arm/armv6/strchr.S b/sysdeps/arm/armv6/strchr.S new file mode 100644 index 0000000000..e4de0f3323 --- /dev/null +++ b/sysdeps/arm/armv6/strchr.S @@ -0,0 +1,147 @@ +/* strchr -- find the first instance 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 + . */ + +#include + + .syntax unified + .text + +ENTRY (strchr) + @ r0 = start of string + @ r1 = character to match + @ returns NULL for no match, or a pointer to the match + sfi_breg r0, \ + ldrb r2, [\B] @ load the first byte asap + uxtb r1, r1 + + @ To cater to long strings, we want to search through a few + @ characters until we reach an aligned pointer. To cater to + @ small strings, we don't want to start doing word operations + @ immediately. The compromise is a maximum of 16 bytes less + @ whatever is required to end with an aligned pointer. + @ r3 = number of characters to search in alignment loop + and r3, r0, #7 + rsb r3, r3, #15 @ 16 - 1 peeled loop iteration + cmp r2, r1 @ Found C? + it ne + cmpne r2, #0 @ Found EOS? + beq 99f + + @ Loop until we find ... +1: sfi_breg r0, \ + ldrb r2, [\B, #1]! + subs r3, r3, #1 @ ... the aligment point + it ne + cmpne r2, r1 @ ... or the character + it ne + cmpne r2, #0 @ ... or EOS + bne 1b + + @ Disambiguate the exit possibilites above + cmp r2, r1 @ Found the character + it ne + cmpne r2, #0 @ Found EOS + beq 99f + add r0, r0, #1 + + @ So now we're aligned. Now we actually need a stack frame. + 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) + + sfi_breg r0, \ + ldrd r2, r3, [\B], #8 + orr r1, r1, r1, lsl #8 @ Replicate C to all bytes +#ifdef ARCH_HAS_T2 + movw ip, #0x0101 + sfi_pld r0, #64 + movt ip, #0x0101 +#else + ldr ip, =0x01010101 + sfi_pld r0, #64 +#endif + orr r1, r1, r1, lsl #16 + + @ Loop searching for EOS or C, 8 bytes at a time. +2: + @ 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 r4, ip, r2 @ Find EOS + eor r6, r2, r1 @ Convert C bytes to 0 + uqsub8 r5, ip, r3 + eor r7, r3, r1 + uqsub8 r6, ip, r6 @ Find C + sfi_pld r0, #128 @ Prefetch 2 lines ahead + uqsub8 r7, ip, r7 + orr r4, r4, r6 @ Combine found for EOS and C + orr r5, r5, r7 + orrs r6, r4, r5 @ Combine the two words + it eq + sfi_breg r0, \ + ldrdeq r2, r3, [\B], #8 + beq 2b + + @ Found something. Disambiguate between first and second words. + @ Adjust r0 to point to the word containing the match. + @ Adjust r2 to the contents of the word containing the match. + @ Adjust r4 to the found bits for the word containing the match. + cmp r4, #0 + sub r0, r0, #4 + itte eq + moveq r4, r5 + moveq r2, r3 + subne r0, r0, #4 + + @ Find the bit-offset of the match within the word. +#if defined(__ARMEL__) + @ For LE, swap the found word so clz searches from the little end. + rev r4, r4 +#else + @ For BE, byte swap the word to make it easier to extract the byte. + rev r2, r2 +#endif + @ We're counting 0x01 (not 0x80), so the bit offset is 7 too high. + clz r3, r4 + sub r3, r3, #7 + lsr r2, r2, r3 @ Shift down found byte + uxtb r1, r1 @ Undo replication of C + uxtb r2, r2 @ Extract found byte + add r0, r0, r3, lsr #3 @ Adjust the pointer to the found byte + + pop { r4, r5, r6, r7 } + cfi_adjust_cfa_offset (-16) + cfi_restore (r4) + cfi_restore (r5) + cfi_restore (r6) + cfi_restore (r7) + + @ Disambiguate between EOS and C. +99: + cmp r2, r1 + it ne + movne r0, #0 @ Found EOS, return NULL + bx lr + +END (strchr) + +weak_alias (strchr, index) +libc_hidden_builtin_def (strchr) diff --git a/sysdeps/arm/armv6/strcpy.S b/sysdeps/arm/armv6/strcpy.S new file mode 100644 index 0000000000..833a83c28f --- /dev/null +++ b/sysdeps/arm/armv6/strcpy.S @@ -0,0 +1,231 @@ +/* strcpy -- copy 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 + . */ + +#include + +/* Endian independent macros for shifting bytes within registers. */ +#ifdef __ARMEB__ +#define lsh_gt lsr +#define lsh_ls lsl +#else +#define lsh_gt lsl +#define lsh_ls lsr +#endif + + .syntax unified + .text + +ENTRY (__stpcpy) + @ Signal stpcpy with NULL in IP. + mov ip, #0 + b 0f +END (__stpcpy) + +weak_alias (__stpcpy, stpcpy) +libc_hidden_def (__stpcpy) +libc_hidden_builtin_def (stpcpy) + +ENTRY (strcpy) + @ Signal strcpy with DEST in IP. + mov ip, r0 +0: + sfi_pld r0 + sfi_pld r1 + + @ To cater to long strings, we want 8 byte alignment in the source. + @ To cater to small strings, we don't want to start that right away. + @ Loop up to 16 times, less whatever it takes to reach alignment. + and r3, r1, #7 + rsb r3, r3, #16 + + @ Loop until we find ... +1: sfi_breg r1, \ + ldrb r2, [\B], #1 + subs r3, r3, #1 @ ... the alignment point + sfi_breg r0, \ + strb r2, [\B], #1 + it ne + cmpne r2, #0 @ ... or EOS + bne 1b + + @ Disambiguate the exit possibilites above + cmp r2, #0 @ Found EOS + beq .Lreturn + + @ Load the next two words asap + sfi_breg r1, \ + ldrd r2, r3, [\B], #8 + sfi_pld r0, #64 + sfi_pld r1, #64 + + @ For longer strings, we actaully need a stack frame. + 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) + + @ Subtracting (unsigned saturating) from 1 for any byte 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. +#ifdef ARCH_HAS_T2 + movw r7, #0x0101 + tst r0, #3 @ Test alignment of DEST + movt r7, #0x0101 +#else + ldr r7, =0x01010101 + tst r0, #3 +#endif + bne .Lunaligned + + @ So now source (r1) is aligned to 8, and dest (r0) is aligned to 4. + @ Loop, reading 8 bytes at a time, searching for EOS. + .balign 16 +2: uqsub8 r4, r7, r2 @ Find EOS + uqsub8 r5, r7, r3 + sfi_pld r1, #128 + cmp r4, #0 @ EOS in first word? + sfi_pld r0, #128 + bne 3f + sfi_breg r0, \ + str r2, [\B], #4 + cmp r5, #0 @ EOS in second word? + bne 4f + sfi_breg r0, \ + str r3, [\B], #4 + sfi_breg r1, \ + ldrd r2, r3, [\B], #8 + b 2b + +3: sub r1, r1, #4 @ backup to first word +4: sub r1, r1, #4 @ backup to second word + + @ ... then finish up any tail a byte at a time. + @ Note that we generally back up and re-read source bytes, + @ but we'll not re-write dest bytes. +.Lbyte_loop: + sfi_breg r1, \ + ldrb r2, [\B], #1 + cmp r2, #0 + sfi_breg r0, \ + strb r2, [\B], #1 + bne .Lbyte_loop + + pop { r4, r5, r6, r7 } + cfi_remember_state + cfi_adjust_cfa_offset (-16) + cfi_restore (r4) + cfi_restore (r5) + cfi_restore (r6) + cfi_restore (r7) + +.Lreturn: + cmp ip, #0 @ Was this strcpy or stpcpy? + ite eq + subeq r0, r0, #1 @ stpcpy: undo post-inc from store + movne r0, ip @ strcpy: return original dest + bx lr + +.Lunaligned: + cfi_restore_state + @ Here, source is aligned to 8, but the destination is not word + @ aligned. Therefore we have to shift the data in order to be + @ able to perform aligned word stores. + + @ Find out which misalignment we're dealing with. + tst r0, #1 + beq .Lunaligned2 + tst r0, #2 + bne .Lunaligned3 + @ Fallthru to .Lunaligned1. + +.macro unaligned_copy unalign + @ Prologue to unaligned loop. Seed shifted non-zero bytes. + uqsub8 r4, r7, r2 @ Find EOS + uqsub8 r5, r7, r3 + mvns r4, r4 @ EOS in first word? + it ne + subne r1, r1, #8 + bne .Lbyte_loop +#ifdef __ARMEB__ + rev r2, r2 @ Byte stores below need LE data +#endif + @ Store a few bytes from the first word. + @ At the same time we align r0 and shift out bytes from r2. +.rept 4-\unalign + sfi_breg r0, \ + strb r2, [\B], #1 + lsr r2, r2, #8 +.endr +#ifdef __ARMEB__ + rev r2, r2 @ Undo previous rev +#endif + @ Rotated unaligned copy loop. The tail of the prologue is + @ shared with the loop itself. + .balign 8 +1: mvns r5, r5 @ EOS in second word? + bne 4f + @ Combine first and second words + orr r2, r2, r3, lsh_gt #(\unalign*8) + @ Save leftover bytes from the two words + lsh_ls r6, r3, #((4-\unalign)*8) + sfi_breg r0, \ + str r2, [\B], #4 + @ The "real" start of the unaligned copy loop. + sfi_breg r1, \ + ldrd r2, r3, [\B], #8 @ Load 8 more bytes + uqsub8 r4, r7, r2 @ Find EOS + sfi_pld r1, #128 + uqsub8 r5, r7, r3 + sfi_pld r0, #128 + mvns r4, r4 @ EOS in first word? + bne 3f + @ Combine the leftover and the first word + orr r6, r6, r2, lsh_gt #(\unalign*8) + @ Discard used bytes from the first word. + lsh_ls r2, r2, #((4-\unalign)*8) + sfi_breg r0, \ + str r6, [\B], #4 + b 1b + @ Found EOS in one of the words; adjust backward +3: sub r1, r1, #4 + mov r2, r6 +4: sub r1, r1, #4 + @ And store the remaining bytes from the leftover +#ifdef __ARMEB__ + rev r2, r2 +#endif +.rept \unalign + sfi_breg r0, \ + strb r2, [\B], #1 + lsr r2, r2, #8 +.endr + b .Lbyte_loop +.endm + +.Lunaligned1: + unaligned_copy 1 +.Lunaligned2: + unaligned_copy 2 +.Lunaligned3: + unaligned_copy 3 + +END (strcpy) + +libc_hidden_builtin_def (strcpy) diff --git a/sysdeps/arm/armv6/strlen.S b/sysdeps/arm/armv6/strlen.S new file mode 100644 index 0000000000..290d7bc86d --- /dev/null +++ b/sysdeps/arm/armv6/strlen.S @@ -0,0 +1,103 @@ +/* strlen -- find the length of 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 + . */ + +#include + + .syntax unified + .text + +ENTRY (strlen) + @ r0 = start of string + sfi_breg r0, \ + ldrb r2, [\B] @ load the first byte asap + + @ To cater to long strings, we want to search through a few + @ characters until we reach an aligned pointer. To cater to + @ small strings, we don't want to start doing word operations + @ immediately. The compromise is a maximum of 16 bytes less + @ whatever is required to end with an aligned pointer. + @ r3 = number of characters to search in alignment loop + and r3, r0, #7 + mov r1, r0 @ Save the input pointer + rsb r3, r3, #15 @ 16 - 1 peeled loop iteration + cmp r2, #0 + beq 99f + + @ Loop until we find ... +1: sfi_breg r0, \ + ldrb r2, [\B, #1]! + subs r3, r3, #1 @ ... the aligment point + it ne + cmpne r2, #0 @ ... or EOS + bne 1b + + @ Disambiguate the exit possibilites above + cmp r2, #0 @ Found EOS + beq 99f + add r0, r0, #1 + + @ So now we're aligned. + sfi_breg r0, \ + ldrd r2, r3, [\B], #8 +#ifdef ARCH_HAS_T2 + movw ip, #0x0101 + sfi_pld r0, #64 + movt ip, #0x0101 +#else + ldr ip, =0x01010101 + sfi_pld r0, #64 +#endif + + @ Loop searching for EOS, 8 bytes at a time. + @ Subtracting (unsigned saturating) from 1 for any byte means that + @ we get 1 for any byte that was originally zero and 0 otherwise. + @ Therefore we consider the lsb of each byte the "found" bit. + .balign 16 +2: uqsub8 r2, ip, r2 @ Find EOS + uqsub8 r3, ip, r3 + sfi_pld r0, #128 @ Prefetch 2 lines ahead + orrs r3, r3, r2 @ Combine the two words + it eq + sfi_breg r0, \ + ldrdeq r2, r3, [\B], #8 + beq 2b + + @ Found something. Disambiguate between first and second words. + @ Adjust r0 to point to the word containing the match. + @ Adjust r2 to the found bits for the word containing the match. + cmp r2, #0 + sub r0, r0, #4 + ite eq + moveq r2, r3 + subne r0, r0, #4 + + @ Find the bit-offset of the match within the word. Note that the + @ bit result from clz will be 7 higher than "true", but we'll + @ immediately discard those bits converting to a byte offset. +#ifdef __ARMEL__ + rev r2, r2 @ For LE, count from the little end +#endif + clz r2, r2 + add r0, r0, r2, lsr #3 @ Adjust the pointer to the found byte +99: + sub r0, r0, r1 @ Subtract input to compute length + bx lr + +END (strlen) + +libc_hidden_builtin_def (strlen) 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 + . */ + +#include + + .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) -- cgit 1.4.1