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1/*2 * memchr - find a character in a memory zone3 *4 * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.5 * See https://llvm.org/LICENSE.txt for license information.6 * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception7 */8 9#if __ARM_FEATURE_SVE10/* Assumptions:11 *12 * ARMv8-a, AArch6413 * SVE Available.14 */15 16 .arch armv8-a+sve17 .text18 19 .globl __memchr_aarch64_sve20 .type __memchr_aarch64_sve, %function21 .p2align 422__memchr_aarch64_sve:23 dup z1.b, w1 /* duplicate c to a vector */24 setffr /* initialize FFR */25 mov x3, 0 /* initialize off */26 nop27 280: whilelo p1.b, x3, x2 /* make sure off < max */29 b.none 9f30 31 /* Read a vector's worth of bytes, bounded by max,32 stopping on first fault. */33 ldff1b z0.b, p1/z, [x0, x3]34 rdffrs p0.b, p1/z35 b.nlast 2f36 37 /* First fault did not fail: the vector bounded by max is valid.38 Avoid depending on the contents of FFR beyond the branch. */39 incb x3 /* speculate increment */40 cmpeq p2.b, p1/z, z0.b, z1.b /* search for c */41 b.none 0b42 decb x3 /* undo speculate */43 44 /* Found C. */451: brkb p2.b, p1/z, p2.b /* find the first c */46 add x0, x0, x3 /* form partial pointer */47 incp x0, p2.b /* form final pointer to c */48 ret49 50 /* First fault failed: only some of the vector is valid.51 Perform the comparison only on the valid bytes. */522: cmpeq p2.b, p0/z, z0.b, z1.b53 b.any 1b54 55 /* No C found. Re-init FFR, increment, and loop. */56 setffr57 incp x3, p0.b58 b 0b59 60 /* Found end of count. */619: mov x0, 0 /* return null */62 ret63 64 .size __memchr_aarch64_sve, . - __memchr_aarch64_sve65#endif66