/**************************************************************************** * libs/libc/machine/xtensa/arch_strncpy.S * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance with the * License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include "xtensa_asm.h" #include #include /**************************************************************************** * Public Functions ****************************************************************************/ .section .text .begin schedule .align 4 .literal_position __strncpy_aux: .Lsrc1mod2: # src address is odd l8ui a8, a3, 0 # get byte 0 addi a3, a3, 1 # advance src pointer s8i a8, a10, 0 # store byte 0 addi a4, a4, -1 # decrement n beqz a4, .Lret # if n is zero addi a10, a10, 1 # advance dst pointer beqz a8, .Lfill # if byte 0 is zero bbci.l a3, 1, .Lsrcaligned # if src is now word-aligned .Lsrc2mod4: # src address is 2 mod 4 l8ui a8, a3, 0 # get byte 0 addi a4, a4, -1 # decrement n s8i a8, a10, 0 # store byte 0 beqz a4, .Lret # if n is zero addi a10, a10, 1 # advance dst pointer beqz a8, .Lfill # if byte 0 is zero l8ui a8, a3, 1 # get byte 0 addi a3, a3, 2 # advance src pointer s8i a8, a10, 0 # store byte 0 addi a4, a4, -1 # decrement n beqz a4, .Lret # if n is zero addi a10, a10, 1 # advance dst pointer bnez a8, .Lsrcaligned j .Lfill .Lret: RET(16) .align 4 .global strncpy .type strncpy, @function strncpy: ENTRY(16) /* a2 = dst, a3 = src */ mov a10, a2 # leave dst in return value register beqz a4, .Lret # if n is zero movi a11, MASK0 movi a5, MASK1 movi a6, MASK2 movi a7, MASK3 bbsi.l a3, 0, .Lsrc1mod2 bbsi.l a3, 1, .Lsrc2mod4 .Lsrcaligned: /* Check if the destination is aligned. */ movi a8, 3 bnone a10, a8, .Laligned j .Ldstunaligned /* Fill the dst with zeros -- n is at least 1. */ .Lfill: movi a9, 0 bbsi.l a10, 0, .Lfill1mod2 bbsi.l a10, 1, .Lfill2mod4 .Lfillaligned: blti a4, 4, .Lfillcleanup /* Loop filling complete words with zero. */ #if XCHAL_HAVE_LOOPS srai a8, a4, 2 loop a8, 1f s32i a9, a10, 0 addi a10, a10, 4 1: slli a8, a8, 2 sub a4, a4, a8 #else /* !XCHAL_HAVE_LOOPS */ 1: s32i a9, a10, 0 addi a10, a10, 4 addi a4, a4, -4 bgei a4, 4, 1b #endif /* !XCHAL_HAVE_LOOPS */ beqz a4, 2f .Lfillcleanup: /* Fill leftover (1 to 3) bytes with zero. */ s8i a9, a10, 0 # store byte 0 addi a4, a4, -1 # decrement n addi a10, a10, 1 bnez a4, .Lfillcleanup 2: RET(16) .Lfill1mod2: # dst address is odd s8i a9, a10, 0 # store byte 0 addi a4, a4, -1 # decrement n beqz a4, 2b # if n is zero addi a10, a10, 1 # advance dst pointer bbci.l a10, 1, .Lfillaligned # if dst is now word-aligned .Lfill2mod4: # dst address is 2 mod 4 s8i a9, a10, 0 # store byte 0 addi a4, a4, -1 # decrement n beqz a4, 2b # if n is zero s8i a9, a10, 1 # store byte 1 addi a4, a4, -1 # decrement n beqz a4, 2b # if n is zero addi a10, a10, 2 # advance dst pointer j .Lfillaligned /* dst is word-aligned; src is word-aligned; n is at least 1. */ .align 4 #if XCHAL_HAVE_LOOPS #if XCHAL_HAVE_DENSITY /* (2 mod 4) alignment for loop instruction */ #else /* (1 mod 4) alignment for loop instruction */ .byte 0 .byte 0 #endif #endif .Laligned: #if XCHAL_HAVE_LOOPS #if XCHAL_HAVE_DENSITY _movi.n a8, 0 # set up for the maximum loop count #else _movi a8, 0 # set up for the maximum loop count #endif loop a8, 1f # loop forever (almost anyway) blti a4, 5, .Ldstunaligned # n is near limit; do one at a time l32i a8, a3, 0 # get word from src addi a3, a3, 4 # advance src pointer bnone a8, a11, .Lz0 # if byte 0 is zero bnone a8, a5, .Lz1 # if byte 1 is zero bnone a8, a6, .Lz2 # if byte 2 is zero s32i a8, a10, 0 # store word to dst addi a4, a4, -4 # decrement n addi a10, a10, 4 # advance dst pointer bnone a8, a7, .Lfill # if byte 3 is zero 1: #else /* !XCHAL_HAVE_LOOPS */ 1: blti a4, 5, .Ldstunaligned # n is near limit; do one at a time l32i a8, a3, 0 # get word from src addi a3, a3, 4 # advance src pointer bnone a8, a11, .Lz0 # if byte 0 is zero bnone a8, a5, .Lz1 # if byte 1 is zero bnone a8, a6, .Lz2 # if byte 2 is zero s32i a8, a10, 0 # store word to dst addi a4, a4, -4 # decrement n addi a10, a10, 4 # advance dst pointer bany a8, a7, 1b # no zeroes #endif /* !XCHAL_HAVE_LOOPS */ j .Lfill .Lz0: /* Byte 0 is zero. */ #if XCHAL_HAVE_BE movi a8, 0 #endif s8i a8, a10, 0 addi a4, a4, -1 # decrement n addi a10, a10, 1 # advance dst pointer j .Lfill .Lz1: /* Byte 1 is zero. */ #if XCHAL_HAVE_BE extui a8, a8, 16, 16 #endif s16i a8, a10, 0 addi a4, a4, -2 # decrement n addi a10, a10, 2 # advance dst pointer j .Lfill .Lz2: /* Byte 2 is zero. */ #if XCHAL_HAVE_BE extui a8, a8, 16, 16 #endif s16i a8, a10, 0 movi a8, 0 s8i a8, a10, 2 addi a4, a4, -3 # decrement n addi a10, a10, 3 # advance dst pointer j .Lfill .align 4 #if XCHAL_HAVE_LOOPS #if XCHAL_HAVE_DENSITY /* (2 mod 4) alignment for loop instruction */ #else /* (1 mod 4) alignment for loop instruction */ .byte 0 .byte 0 #endif #endif .Ldstunaligned: #if XCHAL_HAVE_LOOPS #if XCHAL_HAVE_DENSITY _movi.n a8, 0 # set up for the maximum loop count #else _movi a8, 0 # set up for the maximum loop count #endif loop a8, 2f # loop forever (almost anyway) #endif 1: l8ui a8, a3, 0 addi a3, a3, 1 s8i a8, a10, 0 addi a4, a4, -1 beqz a4, 3f addi a10, a10, 1 #if XCHAL_HAVE_LOOPS beqz a8, 2f #else bnez a8, 1b #endif 2: j .Lfill 3: RET(16) .end schedule .size strncpy, . - strncpy