1/* 2 * strcpy/stpcpy - copy a string returning pointer to start/end. 3 * 4 * Copyright (c) 2018-2021, Arm Limited. 5 * SPDX-License-Identifier: MIT 6 */ 7 8#include "../asmdefs.h" 9 10#if __ARM_FEATURE_SVE 11/* Assumptions: 12 * 13 * ARMv8-a, AArch64 14 * SVE Available. 15 */ 16 17/* To build as stpcpy, define BUILD_STPCPY before compiling this file. */ 18#ifdef BUILD_STPCPY 19#define FUNC __stpcpy_aarch64_sve 20#else 21#define FUNC __strcpy_aarch64_sve 22#endif 23 24ENTRY (FUNC) 25 PTR_ARG (0) 26 PTR_ARG (1) 27 setffr /* initialize FFR */ 28 ptrue p2.b, all /* all ones; loop invariant */ 29 mov x2, 0 /* initialize offset */ 30 31 .p2align 4 32 /* Read a vector's worth of bytes, stopping on first fault. */ 330: ldff1b z0.b, p2/z, [x1, x2] 34 rdffrs p0.b, p2/z 35 b.nlast 1f 36 37 /* First fault did not fail: the whole vector is valid. 38 Avoid depending on the contexts of FFR beyond the branch. */ 39 cmpeq p1.b, p2/z, z0.b, 0 /* search for zeros */ 40 b.any 2f 41 42 /* No zero found. Store the whole vector and loop. */ 43 st1b z0.b, p2, [x0, x2] 44 incb x2, all 45 b 0b 46 47 /* First fault failed: only some of the vector is valid. 48 Perform the comparison only on the valid bytes. */ 491: cmpeq p1.b, p0/z, z0.b, 0 /* search for zeros */ 50 b.any 2f 51 52 /* No zero found. Store the valid portion of the vector and loop. */ 53 setffr /* re-init FFR */ 54 st1b z0.b, p0, [x0, x2] 55 incp x2, p0.b 56 b 0b 57 58 /* Zero found. Crop the vector to the found zero and finish. */ 592: brka p0.b, p2/z, p1.b 60 st1b z0.b, p0, [x0, x2] 61#ifdef BUILD_STPCPY 62 add x0, x0, x2 63 sub x0, x0, 1 64 incp x0, p0.b 65#endif 66 ret 67 68END (FUNC) 69 70#endif 71 72