1/*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2024 Getz Mikalsen <getz@FreeBSD.org> 5*/ 6 7#include <machine/asm.h> 8 9 .weak strlen 10 .set strlen, __strlen 11 .text 12 13ENTRY(__strlen) 14 bic x10, x0, #0xf // aligned src 15 and x9, x0, #0xf 16 ldr q0, [x10] 17 cmeq v0.16b, v0.16b, #0 18 shrn v0.8b, v0.8h, #4 19 fmov x1, d0 20 cbz x9, .Laligned 21 lsl x2, x0, #2 // get the byte offset 22 lsr x1, x1, x2 // shift by offset index 23 cbz x1, .Lloop 24 rbit x1, x1 25 clz x0, x1 26 lsr x0, x0, #2 27 ret 28 29.Laligned: 30 cbnz x1, .Ldone 31 32.Lloop: 33 ldr q0, [x10, #16]! 34 cmeq v0.16b, v0.16b, #0 35 shrn v0.8b, v0.8h, #4 // reduce to fit mask in GPR 36 fmov x1, d0 37 cbz x1, .Lloop 38.Ldone: 39 sub x0, x10, x0 40 rbit x1, x1 // reverse bits as NEON has no ctz 41 clz x3, x1 42 lsr x3, x3, #2 43 add x0, x0, x3 44 ret 45END(__strlen) 46