diff options
| author | Yuval Adam <_@yuv.al> | 2017-08-30 08:25:59 +0000 |
|---|---|---|
| committer | Yuval Adam <_@yuv.al> | 2017-08-30 08:25:59 +0000 |
| commit | 8e4bff4cab0ddac6060645b0715210484d02ff40 (patch) | |
| tree | 3a5c3024371a04692a3a6d9974d001cdff8ebf84 /arch/arm/lib/memcmpksm.S | |
Diffstat (limited to 'arch/arm/lib/memcmpksm.S')
| -rw-r--r-- | arch/arm/lib/memcmpksm.S | 394 |
1 files changed, 394 insertions, 0 deletions
diff --git a/arch/arm/lib/memcmpksm.S b/arch/arm/lib/memcmpksm.S new file mode 100644 index 00000000..576ef2bb --- /dev/null +++ b/arch/arm/lib/memcmpksm.S @@ -0,0 +1,394 @@ +/* + * Copyright (C) 2008 The Android Open Source Project + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * 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. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "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 THE + * COPYRIGHT OWNER OR CONTRIBUTORS 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 <linux/linkage.h> +#include <asm/assembler.h> + +#ifndef _ARM32_ASM_H_ +#define _ARM32_ASM_H_ + +#ifdef __ELF__ +# define _C_LABEL(x) x +#else +# ifdef __STDC__ +# define _C_LABEL(x) _ ## x +# else +# define _C_LABEL(x) _/**/x +# endif +#endif +#define _ASM_LABEL(x) x + +#ifndef _ALIGN_TEXT +# define _ALIGN_TEXT .align 0 +#endif + +/* + * gas/arm uses @ as a single comment character and thus cannot be used here + * Instead it recognised the # instead of an @ symbols in .type directives + * We define a couple of macros so that assembly code will not be dependant + * on one or the other. + */ +#define _ASM_TYPE_FUNCTION #function +#define _ASM_TYPE_OBJECT #object +#define _ENTRY(x) \ + .text; _ALIGN_TEXT; .globl x; .type x,_ASM_TYPE_FUNCTION; x: .fnstart + +#define _ASM_SIZE(x) .size x, .-x; + +#define _END(x) \ + .fnend; \ + _ASM_SIZE(x) + +#ifdef GPROF +# ifdef __ELF__ +# define _PROF_PROLOGUE \ + mov ip, lr; bl __mcount +# else +# define _PROF_PROLOGUE \ + mov ip,lr; bl mcount +# endif +#else +# define _PROF_PROLOGUE +#endif + +#define ENTRY(y) _ENTRY(_C_LABEL(y)); _PROF_PROLOGUE +#define END(y) _END(_C_LABEL(y)) + +#define ASMSTR .asciz + +#endif /* !_ARM_ASM_H_ */ + +#ifdef HAVE_32_BYTE_CACHE_LINE +#define CACHE_LINE_SIZE 32 +#else +#define CACHE_LINE_SIZE 64 +#endif + +/* + * Optimized memcmp() for Cortex-A9. + */ + +ENTRY(memcmpksm) + pld [r0, #(CACHE_LINE_SIZE * 0)] + pld [r0, #(CACHE_LINE_SIZE * 1)] + + /* take of the case where length is 0 or the buffers are the same */ + cmp r0, r1 + moveq r0, #0 + bxeq lr + + pld [r1, #(CACHE_LINE_SIZE * 0)] + pld [r1, #(CACHE_LINE_SIZE * 1)] + + /* make sure we have at least 8+4 bytes, this simplify things below + * and avoid some overhead for small blocks + */ + cmp r2, #(8+4) + bmi 10f +/* + * Neon optimization + * Comparing 32 bytes at a time + */ +#if defined(__ARM_NEON__) && defined(NEON_UNALIGNED_ACCESS) + subs r2, r2, #32 + blo 3f + + /* preload all the cache lines we need. */ + pld [r0, #(CACHE_LINE_SIZE * 2)] + pld [r1, #(CACHE_LINE_SIZE * 2)] + +1: /* The main loop compares 32 bytes at a time */ + vld1.8 {d0 - d3}, [r0]! + pld [r0, #(CACHE_LINE_SIZE * 2)] + vld1.8 {d4 - d7}, [r1]! + pld [r1, #(CACHE_LINE_SIZE * 2)] + + /* Start subtracting the values and merge results */ + vsub.i8 q0, q2 + vsub.i8 q1, q3 + vorr q2, q0, q1 + vorr d4, d5 + vmov r3, ip, d4 + /* Check if there are any differences among the 32 bytes */ + orrs r3, ip + bne 2f + subs r2, r2, #32 + bhs 1b + b 3f +2: + /* Check if the difference was in the first or last 16 bytes */ + sub r0, #32 + vorr d0, d1 + sub r1, #32 + vmov r3, ip, d0 + orrs r3, ip + /* if the first 16 bytes are equal, we only have to rewind 16 bytes */ + ittt eq + subeq r2, #16 + addeq r0, #16 + addeq r1, #16 + +3: /* fix-up the remaining count */ + add r2, r2, #32 + + cmp r2, #(8+4) + bmi 10f +#endif + + .save {r4, lr} + /* save registers */ + stmfd sp!, {r4, lr} + + /* since r0 hold the result, move the first source + * pointer somewhere else + */ + mov r4, r0 + + /* align first pointer to word boundary + * offset = -src & 3 + */ + rsb r3, r4, #0 + ands r3, r3, #3 + beq 0f + + /* align first pointer */ + sub r2, r2, r3 +1: ldrb r0, [r4], #1 + ldrb ip, [r1], #1 + subs r0, r0, ip + bne 9f + subs r3, r3, #1 + bne 1b + + +0: /* here the first pointer is aligned, and we have at least 4 bytes + * to process. + */ + + /* see if the pointers are congruent */ + eor r0, r4, r1 + ands r0, r0, #3 + bne 5f + + /* congruent case, 32 bytes per iteration + * We need to make sure there are at least 32+4 bytes left + * because we effectively read ahead one word, and we could + * read past the buffer (and segfault) if we're not careful. + */ + + ldr ip, [r1] + subs r2, r2, #(32 + 4) + bmi 1f + +0: pld [r4, #(CACHE_LINE_SIZE * 2)] + pld [r1, #(CACHE_LINE_SIZE * 2)] + ldr r0, [r4], #4 + ldr lr, [r1, #4]! + eors r0, r0, ip + ldreq r0, [r4], #4 + ldreq ip, [r1, #4]! + eoreqs r0, r0, lr + ldreq r0, [r4], #4 + ldreq lr, [r1, #4]! + eoreqs r0, r0, ip + ldreq r0, [r4], #4 + ldreq ip, [r1, #4]! + eoreqs r0, r0, lr + ldreq r0, [r4], #4 + ldreq lr, [r1, #4]! + eoreqs r0, r0, ip + ldreq r0, [r4], #4 + ldreq ip, [r1, #4]! + eoreqs r0, r0, lr + ldreq r0, [r4], #4 + ldreq lr, [r1, #4]! + eoreqs r0, r0, ip + ldreq r0, [r4], #4 + ldreq ip, [r1, #4]! + eoreqs r0, r0, lr + bne 2f + subs r2, r2, #32 + bhs 0b + + /* do we have at least 4 bytes left? */ +1: adds r2, r2, #(32 - 4 + 4) + bmi 4f + + /* finish off 4 bytes at a time */ +3: ldr r0, [r4], #4 + ldr ip, [r1], #4 + eors r0, r0, ip + bne 2f + subs r2, r2, #4 + bhs 3b + + /* are we done? */ +4: adds r2, r2, #4 + moveq r0, #0 + beq 9f + + /* finish off the remaining bytes */ + b 8f + +2: /* the last 4 bytes are different, restart them */ + sub r4, r4, #4 + sub r1, r1, #4 + mov r2, #4 + + /* process the last few bytes */ +8: ldrb r0, [r4], #1 + ldrb ip, [r1], #1 + // stall + subs r0, r0, ip + bne 9f + subs r2, r2, #1 + bne 8b + +9: /* restore registers and return */ + ldmfd sp!, {r4, lr} + bx lr + +10: /* process less than 12 bytes */ + cmp r2, #0 + moveq r0, #0 + bxeq lr + mov r3, r0 +11: + ldrb r0, [r3], #1 + ldrb ip, [r1], #1 + subs r0, ip + bxne lr + subs r2, r2, #1 + bne 11b + bx lr + +5: /*************** non-congruent case ***************/ + and r0, r1, #3 + cmp r0, #2 + bne 4f + + /* here, offset is 2 (16-bits aligned, special cased) */ + + /* make sure we have at least 16 bytes to process */ + subs r2, r2, #16 + addmi r2, r2, #16 + bmi 8b + + /* align the unaligned pointer */ + bic r1, r1, #3 + ldr lr, [r1], #4 + +6: pld [r1, #(CACHE_LINE_SIZE * 2)] + pld [r4, #(CACHE_LINE_SIZE * 2)] + mov ip, lr, lsr #16 + ldr lr, [r1], #4 + ldr r0, [r4], #4 + orr ip, ip, lr, lsl #16 + eors r0, r0, ip + moveq ip, lr, lsr #16 + ldreq lr, [r1], #4 + ldreq r0, [r4], #4 + orreq ip, ip, lr, lsl #16 + eoreqs r0, r0, ip + moveq ip, lr, lsr #16 + ldreq lr, [r1], #4 + ldreq r0, [r4], #4 + orreq ip, ip, lr, lsl #16 + eoreqs r0, r0, ip + moveq ip, lr, lsr #16 + ldreq lr, [r1], #4 + ldreq r0, [r4], #4 + orreq ip, ip, lr, lsl #16 + eoreqs r0, r0, ip + bne 7f + subs r2, r2, #16 + bhs 6b + sub r1, r1, #2 + /* are we done? */ + adds r2, r2, #16 + moveq r0, #0 + beq 9b + /* finish off the remaining bytes */ + b 8b + +7: /* fix up the 2 pointers and fallthrough... */ + sub r1, r1, #(4+2) + sub r4, r4, #4 + mov r2, #4 + b 8b + + +4: /*************** offset is 1 or 3 (less optimized) ***************/ + + stmfd sp!, {r5, r6, r7} + + // r5 = rhs + // r6 = lhs + // r7 = scratch + + mov r5, r0, lsl #3 /* r5 = right shift */ + rsb r6, r5, #32 /* r6 = left shift */ + + /* align the unaligned pointer */ + bic r1, r1, #3 + ldr r7, [r1], #4 + sub r2, r2, #8 + +6: mov ip, r7, lsr r5 + ldr r7, [r1], #4 + ldr r0, [r4], #4 + orr ip, ip, r7, lsl r6 + eors r0, r0, ip + moveq ip, r7, lsr r5 + ldreq r7, [r1], #4 + ldreq r0, [r4], #4 + orreq ip, ip, r7, lsl r6 + eoreqs r0, r0, ip + bne 7f + subs r2, r2, #8 + bhs 6b + + sub r1, r1, r6, lsr #3 + ldmfd sp!, {r5, r6, r7} + + /* are we done? */ + adds r2, r2, #8 + moveq r0, #0 + beq 9b + + /* finish off the remaining bytes */ + b 8b + +7: /* fix up the 2 pointers and fallthrough... */ + sub r1, r1, #4 + sub r1, r1, r6, lsr #3 + sub r4, r4, #4 + mov r2, #4 + ldmfd sp!, {r5, r6, r7} + b 8b +END(memcmpksm) |
