diff options
Diffstat (limited to 'newlib/libc/machine/arm/strcmp-armv7m.S')
| -rw-r--r-- | newlib/libc/machine/arm/strcmp-armv7m.S | 377 |
1 files changed, 0 insertions, 377 deletions
diff --git a/newlib/libc/machine/arm/strcmp-armv7m.S b/newlib/libc/machine/arm/strcmp-armv7m.S deleted file mode 100644 index d66d393fb..000000000 --- a/newlib/libc/machine/arm/strcmp-armv7m.S +++ /dev/null @@ -1,377 +0,0 @@ -/* - * Copyright (c) 2012-2014 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. - */ - -/* Very similar to the generic code, but uses Thumb2 as implemented - in ARMv7-M. */ - -/* Parameters and result. */ -#define src1 r0 -#define src2 r1 -#define result r0 /* Overlaps src1. */ - -/* Internal variables. */ -#define data1 r2 -#define data2 r3 -#define tmp2 r5 -#define tmp1 r12 -#define syndrome r12 /* Overlaps tmp1 */ - - .thumb - .syntax unified -def_fn strcmp - .cfi_startproc - eor tmp1, src1, src2 - tst tmp1, #3 - /* Strings not at same byte offset from a word boundary. */ - bne .Lstrcmp_unaligned - ands tmp1, src1, #3 - bic src1, src1, #3 - bic src2, src2, #3 - ldr data1, [src1], #4 - it eq - ldreq data2, [src2], #4 - beq 4f - /* 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 tmp1, tmp1, #3 - mvn data2, #MSB - lsl tmp1, tmp1, #3 - S2LO tmp1, data2, tmp1 - ldr data2, [src2], #4 - orr data1, data1, tmp1 - orr data2, data2, tmp1 - .p2align 2 - /* Critical loop. */ -4: - sub syndrome, data1, #0x01010101 - cmp data1, data2 - /* check for any zero bytes in first word */ - itttt eq - biceq syndrome, syndrome, data1 - tsteq syndrome, #0x80808080 - ldreq data1, [src1], #4 - ldreq data2, [src2], #4 - beq 4b -2: - /* There's a zero or a different byte in the word */ - S2HI result, data1, #24 - S2LO data1, data1, #8 - cmp result, #1 - it cs - cmpcs result, data2, S2HI #24 - it eq - S2LOEQ data2, data2, #8 - beq 2b - /* On a big-endian machine, RESULT 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 RESULT are all zero. For DATA2 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 __ARM_BIG_ENDIAN - sub result, result, data2, lsr #24 -#else - and data2, data2, #255 - lsrs result, result, #24 - subs result, result, data2 -#endif - RETURN - - -#if 0 - /* The assembly code below is based on the following alogrithm. */ -#ifdef __ARM_BIG_ENDIAN -#define RSHIFT << -#define LSHIFT >> -#else -#define RSHIFT >> -#define LSHIFT << -#endif - -#define body(shift) \ - mask = 0xffffffffU RSHIFT shift; \ - data1 = *src1++; \ - data2 = *src2++; \ - do \ - { \ - tmp2 = data1 & mask; \ - if (__builtin_expect(tmp2 != data2 RSHIFT shift, 0)) \ - { \ - data2 RSHIFT= shift; \ - break; \ - } \ - if (__builtin_expect(((data1 - b1) & ~data1) & (b1 << 7), 0)) \ - { \ - /* See comment in assembler below re syndrome on big-endian */\ - if ((((data1 - b1) & ~data1) & (b1 << 7)) & mask) \ - data2 RSHIFT= shift; \ - else \ - { \ - data2 = *src2; \ - tmp2 = data1 RSHIFT (32 - shift); \ - data2 = (data2 LSHIFT (32 - shift)) RSHIFT (32 - shift); \ - } \ - break; \ - } \ - data2 = *src2++; \ - tmp2 ^= data1; \ - if (__builtin_expect(tmp2 != data2 LSHIFT (32 - shift), 0)) \ - { \ - tmp2 = data1 >> (32 - shift); \ - data2 = (data2 << (32 - shift)) RSHIFT (32 - shift); \ - break; \ - } \ - data1 = *src1++; \ - } while (1) - - const unsigned* src1; - const unsigned* src2; - unsigned data1, data2; - unsigned mask; - unsigned shift; - unsigned b1 = 0x01010101; - char c1, c2; - unsigned tmp2; - - while (((unsigned) s1) & 3) - { - c1 = *s1++; - c2 = *s2++; - if (c1 == 0 || c1 != c2) - return c1 - (int)c2; - } - src1 = (unsigned*) (((unsigned)s1) & ~3); - src2 = (unsigned*) (((unsigned)s2) & ~3); - tmp2 = ((unsigned) s2) & 3; - if (tmp2 == 1) - { - body(8); - } - else if (tmp2 == 2) - { - body(16); - } - else - { - body (24); - } - - do - { -#ifdef __ARM_BIG_ENDIAN - c1 = (char) tmp2 >> 24; - c2 = (char) data2 >> 24; -#else /* not __ARM_BIG_ENDIAN */ - c1 = (char) tmp2; - c2 = (char) data2; -#endif /* not __ARM_BIG_ENDIAN */ - tmp2 RSHIFT= 8; - data2 RSHIFT= 8; - } while (c1 != 0 && c1 == c2); - return c1 - c2; -#endif /* 0 */ - - - /* First of all, compare bytes until src1(sp1) is word-aligned. */ -.Lstrcmp_unaligned: - tst src1, #3 - beq 2f - ldrb data1, [src1], #1 - ldrb data2, [src2], #1 - cmp data1, #1 - it cs - cmpcs data1, data2 - beq .Lstrcmp_unaligned - sub result, data1, data2 - bx lr - -2: - stmfd sp!, {r5} - .cfi_def_cfa_offset 4 - .cfi_offset 5, -4 - - ldr data1, [src1], #4 - and tmp2, src2, #3 - bic src2, src2, #3 - ldr data2, [src2], #4 - cmp tmp2, #2 - beq .Loverlap2 - bhi .Loverlap1 - - /* Critical inner Loop: Block with 3 bytes initial overlap */ - .p2align 2 -.Loverlap3: - bic tmp2, data1, #MSB - cmp tmp2, data2, S2LO #8 - sub syndrome, data1, #0x01010101 - bic syndrome, syndrome, data1 - bne 4f - ands syndrome, syndrome, #0x80808080 - it eq - ldreq data2, [src2], #4 - bne 5f - eor tmp2, tmp2, data1 - cmp tmp2, data2, S2HI #24 - bne 6f - ldr data1, [src1], #4 - b .Loverlap3 -4: - S2LO data2, data2, #8 - b .Lstrcmp_tail - -5: -#ifdef __ARM_BIG_ENDIAN - /* The syndrome value may contain false ones if the string ends - with the bytes 0x01 0x00. */ - tst data1, #0xff000000 - itt ne - tstne data1, #0x00ff0000 - tstne data1, #0x0000ff00 - beq .Lstrcmp_done_equal -#else - bics syndrome, syndrome, #0xff000000 - bne .Lstrcmp_done_equal -#endif - ldrb data2, [src2] - S2LO tmp2, data1, #24 -#ifdef __ARM_BIG_ENDIAN - lsl data2, data2, #24 -#endif - b .Lstrcmp_tail - -6: - S2LO tmp2, data1, #24 - and data2, data2, #LSB - b .Lstrcmp_tail - - /* Critical inner Loop: Block with 2 bytes initial overlap. */ - .p2align 2 -.Loverlap2: - S2HI tmp2, data1, #16 - sub syndrome, data1, #0x01010101 - S2LO tmp2, tmp2, #16 - bic syndrome, syndrome, data1 - cmp tmp2, data2, S2LO #16 - bne 4f - ands syndrome, syndrome, #0x80808080 - it eq - ldreq data2, [src2], #4 - bne 5f - eor tmp2, tmp2, data1 - cmp tmp2, data2, S2HI #16 - bne 6f - ldr data1, [src1], #4 - b .Loverlap2 - -5: -#ifdef __ARM_BIG_ENDIAN - /* The syndrome value may contain false ones if the string ends - with the bytes 0x01 0x00 */ - tst data1, #0xff000000 - it ne - tstne data1, #0x00ff0000 - beq .Lstrcmp_done_equal -#else - lsls syndrome, syndrome, #16 - bne .Lstrcmp_done_equal -#endif - ldrh data2, [src2] - S2LO tmp2, data1, #16 -#ifdef __ARM_BIG_ENDIAN - lsl data2, data2, #16 -#endif - b .Lstrcmp_tail - -6: - S2HI data2, data2, #16 - S2LO tmp2, data1, #16 -4: - S2LO data2, data2, #16 - b .Lstrcmp_tail - - /* Critical inner Loop: Block with 1 byte initial overlap. */ - .p2align 2 -.Loverlap1: - and tmp2, data1, #LSB - cmp tmp2, data2, S2LO #24 - sub syndrome, data1, #0x01010101 - bic syndrome, syndrome, data1 - bne 4f - ands syndrome, syndrome, #0x80808080 - it eq - ldreq data2, [src2], #4 - bne 5f - eor tmp2, tmp2, data1 - cmp tmp2, data2, S2HI #8 - bne 6f - ldr data1, [src1], #4 - b .Loverlap1 -4: - S2LO data2, data2, #24 - b .Lstrcmp_tail -5: - /* The syndrome value may contain false ones if the string ends - with the bytes 0x01 0x00. */ - tst data1, #LSB - beq .Lstrcmp_done_equal - ldr data2, [src2], #4 -6: - S2LO tmp2, data1, #8 - bic data2, data2, #MSB - b .Lstrcmp_tail -.Lstrcmp_done_equal: - mov result, #0 - .cfi_remember_state - ldmfd sp!, {r5} - .cfi_restore 5 - .cfi_def_cfa_offset 0 - RETURN - -.Lstrcmp_tail: - .cfi_restore_state - and r2, tmp2, #LSB - and result, data2, #LSB - cmp result, #1 - it cs - cmpcs result, r2 - itt eq - S2LOEQ tmp2, tmp2, #8 - S2LOEQ data2, data2, #8 - beq .Lstrcmp_tail - sub result, r2, result - ldmfd sp!, {r5} - .cfi_restore 5 - .cfi_def_cfa_offset 0 - RETURN - .cfi_endproc - .size strcmp, . - strcmp |