1*412f47f9SXin Li/* 2*412f47f9SXin Li * strcpy/stpcpy - copy a string returning pointer to start/end. 3*412f47f9SXin Li * 4*412f47f9SXin Li * Copyright (c) 2018-2022, Arm Limited. 5*412f47f9SXin Li * SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception 6*412f47f9SXin Li */ 7*412f47f9SXin Li 8*412f47f9SXin Li#include "asmdefs.h" 9*412f47f9SXin Li 10*412f47f9SXin Li#if __ARM_FEATURE_SVE 11*412f47f9SXin Li/* Assumptions: 12*412f47f9SXin Li * 13*412f47f9SXin Li * ARMv8-a, AArch64 14*412f47f9SXin Li * SVE Available. 15*412f47f9SXin Li */ 16*412f47f9SXin Li 17*412f47f9SXin Li/* To build as stpcpy, define BUILD_STPCPY before compiling this file. */ 18*412f47f9SXin Li#ifdef BUILD_STPCPY 19*412f47f9SXin Li#define FUNC __stpcpy_aarch64_sve 20*412f47f9SXin Li#else 21*412f47f9SXin Li#define FUNC __strcpy_aarch64_sve 22*412f47f9SXin Li#endif 23*412f47f9SXin Li 24*412f47f9SXin LiENTRY (FUNC) 25*412f47f9SXin Li PTR_ARG (0) 26*412f47f9SXin Li PTR_ARG (1) 27*412f47f9SXin Li setffr /* initialize FFR */ 28*412f47f9SXin Li ptrue p2.b, all /* all ones; loop invariant */ 29*412f47f9SXin Li mov x2, 0 /* initialize offset */ 30*412f47f9SXin Li 31*412f47f9SXin Li .p2align 4 32*412f47f9SXin Li /* Read a vector's worth of bytes, stopping on first fault. */ 33*412f47f9SXin Li0: ldff1b z0.b, p2/z, [x1, x2] 34*412f47f9SXin Li rdffrs p0.b, p2/z 35*412f47f9SXin Li b.nlast 1f 36*412f47f9SXin Li 37*412f47f9SXin Li /* First fault did not fail: the whole vector is valid. 38*412f47f9SXin Li Avoid depending on the contexts of FFR beyond the branch. */ 39*412f47f9SXin Li cmpeq p1.b, p2/z, z0.b, 0 /* search for zeros */ 40*412f47f9SXin Li b.any 2f 41*412f47f9SXin Li 42*412f47f9SXin Li /* No zero found. Store the whole vector and loop. */ 43*412f47f9SXin Li st1b z0.b, p2, [x0, x2] 44*412f47f9SXin Li incb x2, all 45*412f47f9SXin Li b 0b 46*412f47f9SXin Li 47*412f47f9SXin Li /* First fault failed: only some of the vector is valid. 48*412f47f9SXin Li Perform the comparison only on the valid bytes. */ 49*412f47f9SXin Li1: cmpeq p1.b, p0/z, z0.b, 0 /* search for zeros */ 50*412f47f9SXin Li b.any 2f 51*412f47f9SXin Li 52*412f47f9SXin Li /* No zero found. Store the valid portion of the vector and loop. */ 53*412f47f9SXin Li setffr /* re-init FFR */ 54*412f47f9SXin Li st1b z0.b, p0, [x0, x2] 55*412f47f9SXin Li incp x2, p0.b 56*412f47f9SXin Li b 0b 57*412f47f9SXin Li 58*412f47f9SXin Li /* Zero found. Crop the vector to the found zero and finish. */ 59*412f47f9SXin Li2: brka p0.b, p2/z, p1.b 60*412f47f9SXin Li st1b z0.b, p0, [x0, x2] 61*412f47f9SXin Li#ifdef BUILD_STPCPY 62*412f47f9SXin Li add x0, x0, x2 63*412f47f9SXin Li sub x0, x0, 1 64*412f47f9SXin Li incp x0, p0.b 65*412f47f9SXin Li#endif 66*412f47f9SXin Li ret 67*412f47f9SXin Li 68*412f47f9SXin LiEND (FUNC) 69*412f47f9SXin Li 70*412f47f9SXin Li#endif 71*412f47f9SXin Li 72