diff options
Diffstat (limited to 'libc/arch-arm/bionic/strcmp.S')
| -rw-r--r-- | libc/arch-arm/bionic/strcmp.S | 317 |
1 files changed, 0 insertions, 317 deletions
diff --git a/libc/arch-arm/bionic/strcmp.S b/libc/arch-arm/bionic/strcmp.S deleted file mode 100644 index 6dba942..0000000 --- a/libc/arch-arm/bionic/strcmp.S +++ /dev/null @@ -1,317 +0,0 @@ -/* - * Copyright (c) 2011 The Android Open Source Project - * Copyright (c) 2008 ARM Ltd - * All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * 3. The name of the company may not be used to endorse or promote - * products derived from this software without specific prior written - * permission. - * - * THIS SOFTWARE IS PROVIDED BY ARM LTD ``AS IS'' AND ANY EXPRESS OR IMPLIED - * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF - * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. - * IN NO EVENT SHALL ARM LTD BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, - * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED - * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR - * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF - * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING - * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS - * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. - */ - -#include <machine/cpu-features.h> -#include <private/bionic_asm.h> - - .text - -#ifdef __ARMEB__ -#define SHFT2LSB lsl -#define SHFT2LSBEQ lsleq -#define SHFT2MSB lsr -#define SHFT2MSBEQ lsreq -#define MSB 0x000000ff -#define LSB 0xff000000 -#else -#define SHFT2LSB lsr -#define SHFT2LSBEQ lsreq -#define SHFT2MSB lsl -#define SHFT2MSBEQ lsleq -#define MSB 0xff000000 -#define LSB 0x000000ff -#endif - -#define magic1(REG) REG -#define magic2(REG) REG, lsl #7 - -ENTRY(strcmp) - pld [r0, #0] - pld [r1, #0] - eor r2, r0, r1 - tst r2, #3 - - /* Strings not at same byte offset from a word boundary. */ - bne .Lstrcmp_unaligned - ands r2, r0, #3 - bic r0, r0, #3 - bic r1, r1, #3 - ldr ip, [r0], #4 - it eq - ldreq r3, [r1], #4 - beq 1f - - /* Although s1 and s2 have identical initial alignment, they are - * not currently word aligned. Rather than comparing bytes, - * make sure that any bytes fetched from before the addressed - * bytes are forced to 0xff. Then they will always compare - * equal. - */ - eor r2, r2, #3 - lsl r2, r2, #3 - mvn r3, #MSB - SHFT2LSB r2, r3, r2 - ldr r3, [r1], #4 - orr ip, ip, r2 - orr r3, r3, r2 -1: - /* Load the 'magic' constant 0x01010101. */ - str r4, [sp, #-4]! - mov r4, #1 - orr r4, r4, r4, lsl #8 - orr r4, r4, r4, lsl #16 - .p2align 2 -4: - pld [r0, #8] - pld [r1, #8] - sub r2, ip, magic1(r4) - cmp ip, r3 - itttt eq - - /* check for any zero bytes in first word */ - biceq r2, r2, ip - tsteq r2, magic2(r4) - ldreq ip, [r0], #4 - ldreq r3, [r1], #4 - beq 4b -2: - /* There's a zero or a different byte in the word */ - SHFT2MSB r0, ip, #24 - SHFT2LSB ip, ip, #8 - cmp r0, #1 - it cs - cmpcs r0, r3, SHFT2MSB #24 - it eq - SHFT2LSBEQ r3, r3, #8 - beq 2b - /* On a big-endian machine, r0 contains the desired byte in bits - * 0-7; on a little-endian machine they are in bits 24-31. In - * both cases the other bits in r0 are all zero. For r3 the - * interesting byte is at the other end of the word, but the - * other bits are not necessarily zero. We need a signed result - * representing the differnece in the unsigned bytes, so for the - * little-endian case we can't just shift the interesting bits up. - */ -#ifdef __ARMEB__ - sub r0, r0, r3, lsr #24 -#else - and r3, r3, #255 - /* No RSB instruction in Thumb2 */ -#ifdef __thumb2__ - lsr r0, r0, #24 - sub r0, r0, r3 -#else - rsb r0, r3, r0, lsr #24 -#endif -#endif - ldr r4, [sp], #4 - bx lr - -.Lstrcmp_unaligned: - wp1 .req r0 - wp2 .req r1 - b1 .req r2 - w1 .req r4 - w2 .req r5 - t1 .req ip - @ r3 is scratch - - /* First of all, compare bytes until wp1(sp1) is word-aligned. */ -1: - tst wp1, #3 - beq 2f - ldrb r2, [wp1], #1 - ldrb r3, [wp2], #1 - cmp r2, #1 - it cs - cmpcs r2, r3 - beq 1b - sub r0, r2, r3 - bx lr - -2: - str r5, [sp, #-4]! - str r4, [sp, #-4]! - mov b1, #1 - orr b1, b1, b1, lsl #8 - orr b1, b1, b1, lsl #16 - - and t1, wp2, #3 - bic wp2, wp2, #3 - ldr w1, [wp1], #4 - ldr w2, [wp2], #4 - cmp t1, #2 - beq 2f - bhi 3f - - /* Critical inner Loop: Block with 3 bytes initial overlap */ - .p2align 2 -1: - bic t1, w1, #MSB - cmp t1, w2, SHFT2LSB #8 - sub r3, w1, b1 - bic r3, r3, w1 - bne 4f - ands r3, r3, b1, lsl #7 - it eq - ldreq w2, [wp2], #4 - bne 5f - eor t1, t1, w1 - cmp t1, w2, SHFT2MSB #24 - bne 6f - ldr w1, [wp1], #4 - b 1b -4: - SHFT2LSB w2, w2, #8 - b 8f - -5: -#ifdef __ARMEB__ - /* The syndrome value may contain false ones if the string ends - * with the bytes 0x01 0x00 - */ - tst w1, #0xff000000 - itt ne - tstne w1, #0x00ff0000 - tstne w1, #0x0000ff00 - beq 7f -#else - bics r3, r3, #0xff000000 - bne 7f -#endif - ldrb w2, [wp2] - SHFT2LSB t1, w1, #24 -#ifdef __ARMEB__ - lsl w2, w2, #24 -#endif - b 8f - -6: - SHFT2LSB t1, w1, #24 - and w2, w2, #LSB - b 8f - - /* Critical inner Loop: Block with 2 bytes initial overlap */ - .p2align 2 -2: - SHFT2MSB t1, w1, #16 - sub r3, w1, b1 - SHFT2LSB t1, t1, #16 - bic r3, r3, w1 - cmp t1, w2, SHFT2LSB #16 - bne 4f - ands r3, r3, b1, lsl #7 - it eq - ldreq w2, [wp2], #4 - bne 5f - eor t1, t1, w1 - cmp t1, w2, SHFT2MSB #16 - bne 6f - ldr w1, [wp1], #4 - b 2b - -5: -#ifdef __ARMEB__ - /* The syndrome value may contain false ones if the string ends - * with the bytes 0x01 0x00 - */ - tst w1, #0xff000000 - it ne - tstne w1, #0x00ff0000 - beq 7f -#else - lsls r3, r3, #16 - bne 7f -#endif - ldrh w2, [wp2] - SHFT2LSB t1, w1, #16 -#ifdef __ARMEB__ - lsl w2, w2, #16 -#endif - b 8f - -6: - SHFT2MSB w2, w2, #16 - SHFT2LSB t1, w1, #16 -4: - SHFT2LSB w2, w2, #16 - b 8f - - /* Critical inner Loop: Block with 1 byte initial overlap */ - .p2align 2 -3: - and t1, w1, #LSB - cmp t1, w2, SHFT2LSB #24 - sub r3, w1, b1 - bic r3, r3, w1 - bne 4f - ands r3, r3, b1, lsl #7 - it eq - ldreq w2, [wp2], #4 - bne 5f - eor t1, t1, w1 - cmp t1, w2, SHFT2MSB #8 - bne 6f - ldr w1, [wp1], #4 - b 3b -4: - SHFT2LSB w2, w2, #24 - b 8f -5: - /* The syndrome value may contain false ones if the string ends - * with the bytes 0x01 0x00 - */ - tst w1, #LSB - beq 7f - ldr w2, [wp2], #4 -6: - SHFT2LSB t1, w1, #8 - bic w2, w2, #MSB - b 8f -7: - mov r0, #0 - ldr r4, [sp], #4 - ldr r5, [sp], #4 - bx lr - -8: - and r2, t1, #LSB - and r0, w2, #LSB - cmp r0, #1 - it cs - cmpcs r0, r2 - itt eq - SHFT2LSBEQ t1, t1, #8 - SHFT2LSBEQ w2, w2, #8 - beq 8b - sub r0, r2, r0 - ldr r4, [sp], #4 - ldr r5, [sp], #4 - bx lr -END(strcmp) |