/* * Copyright © 2024 Rémi Denis-Courmont. * * 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. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 THE COPYRIGHT OWNER OR CONTRIBUTORS 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. */ #include "libavutil/riscv/asm.S"         .macro  lx rd, addr#if (__riscv_xlen == 32)        lw      \rd, \addr#elif (__riscv_xlen == 64)        ld      \rd, \addr#else        lq      \rd, \addr#endif        .endm func ff_startcode_find_candidate_rvb, zbb        lpad    0        add     a1, a0, a1         // Potentially unaligned head        andi    t0, a0, -(__riscv_xlen / 8)        beq     a0, a1, 2f         andi    t1, a0, (__riscv_xlen / 8) - 1        lx      t2, (t0)        li      t3, __riscv_xlen        orc.b   t2, t2        slli    t1, t1, 3        not     t2, t2        sub     t3, t3, t1        srl     t2, t2, t1        addi    t0, t0, __riscv_xlen / 8        sll     t2, t2, t1        bnez    t2, 4f         // Main loop (including potentially short tail)        bge     t0, a1, 2f        li      t3, -11:        lx      t2, (t0)        addi    t0, t0, __riscv_xlen / 8        orc.b   t2, t2        bne     t2, t3, 3f // t2 != -1 iff (at least one) zero byte        blt     t0, a1, 1b 2:      // No zero byte found        sub     a0, a1, a0        ret 3:      // Zero byte found in main loop        not     t2, t24:      // Zero byte found in head        ctz     t2, t2        addi    t0, t0, -(__riscv_xlen / 8) // back-track        srl     t2, t2, 3        add     t0, t0, t2        // Uncomment the following line for exact POSIX C strnlen() semantics.        //minu    t0, t0, a1 // ignore zero byte in tail        sub     a0, t0, a0        retendfunc