diff options
Diffstat (limited to 'sysdeps/arm/armv6')
| -rw-r--r-- | sysdeps/arm/armv6/rawmemchr.S | 109 | ||||
| -rw-r--r-- | sysdeps/arm/armv6/stpcpy.S | 1 | ||||
| -rw-r--r-- | sysdeps/arm/armv6/strchr.S | 147 | ||||
| -rw-r--r-- | sysdeps/arm/armv6/strcpy.S | 231 | ||||
| -rw-r--r-- | sysdeps/arm/armv6/strlen.S | 103 | ||||
| -rw-r--r-- | sysdeps/arm/armv6/strrchr.S | 131 |
6 files changed, 722 insertions, 0 deletions
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 + <http://www.gnu.org/licenses/>. */ + +#include <sysdep.h> + + .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 + <http://www.gnu.org/licenses/>. */ + +#include <sysdep.h> + + .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 + <http://www.gnu.org/licenses/>. */ + +#include <sysdep.h> + +/* 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 + <http://www.gnu.org/licenses/>. */ + +#include <sysdep.h> + + .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 + <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) |