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Diffstat (limited to 'sysdeps/arm/armv6/strlen.S')
| -rw-r--r-- | sysdeps/arm/armv6/strlen.S | 99 |
1 files changed, 0 insertions, 99 deletions
diff --git a/sysdeps/arm/armv6/strlen.S b/sysdeps/arm/armv6/strlen.S deleted file mode 100644 index 64a971f2de..0000000000 --- a/sysdeps/arm/armv6/strlen.S +++ /dev/null @@ -1,99 +0,0 @@ -/* strlen -- find the length of a nul-terminated string. - Copyright (C) 2013-2017 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> - - .syntax unified - .text - -ENTRY (strlen) - @ r0 = start of string - ldrb r2, [r0] @ 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: ldrb r2, [r0, #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. - ldrd r2, r3, [r0], #8 -#ifdef ARCH_HAS_T2 - movw ip, #0x0101 - pld [r0, #64] - movt ip, #0x0101 -#else - ldr ip, =0x01010101 - 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 - pld [r0, #128] @ Prefetch 2 lines ahead - orrs r3, r3, r2 @ Combine the two words - it eq - ldrdeq r2, r3, [r0], #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) |