18c2ecf20Sopenharmony_ci// SPDX-License-Identifier: GPL-2.0 28c2ecf20Sopenharmony_ci// Copyright (C) 2005-2017 Andes Technology Corporation 38c2ecf20Sopenharmony_ci 48c2ecf20Sopenharmony_ci#include <linux/linkage.h> 58c2ecf20Sopenharmony_ci 68c2ecf20Sopenharmony_ci/* 78c2ecf20Sopenharmony_ci void *memmove(void *dst, const void *src, int n); 88c2ecf20Sopenharmony_ci 98c2ecf20Sopenharmony_ci dst: $r0 108c2ecf20Sopenharmony_ci src: $r1 118c2ecf20Sopenharmony_ci n : $r2 128c2ecf20Sopenharmony_ci ret: $r0 - pointer to the memory area dst. 138c2ecf20Sopenharmony_ci*/ 148c2ecf20Sopenharmony_ci .text 158c2ecf20Sopenharmony_ci 168c2ecf20Sopenharmony_ciENTRY(memmove) 178c2ecf20Sopenharmony_ci move $r5, $r0 ! Set return value = det 188c2ecf20Sopenharmony_ci beq $r0, $r1, exit_memcpy ! Exit when det = src 198c2ecf20Sopenharmony_ci beqz $r2, exit_memcpy ! Exit when n = 0 208c2ecf20Sopenharmony_ci pushm $t0, $t1 ! Save reg 218c2ecf20Sopenharmony_ci srli $p1, $r2, #2 ! $p1 is how many words to copy 228c2ecf20Sopenharmony_ci 238c2ecf20Sopenharmony_ci ! Avoid data lost when memory overlap 248c2ecf20Sopenharmony_ci ! Copy data reversely when src < dst 258c2ecf20Sopenharmony_ci slt $p0, $r0, $r1 ! check if $r0 < $r1 268c2ecf20Sopenharmony_ci beqz $p0, do_reverse ! branch if dst > src 278c2ecf20Sopenharmony_ci 288c2ecf20Sopenharmony_ci ! No reverse, dst < src 298c2ecf20Sopenharmony_ci andi $r2, $r2, #3 ! How many bytes are less than a word 308c2ecf20Sopenharmony_ci li $t0, #1 ! Determining copy direction in byte_cpy 318c2ecf20Sopenharmony_ci beqz $p1, byte_cpy ! When n is less than a word 328c2ecf20Sopenharmony_ci 338c2ecf20Sopenharmony_ciword_cpy: 348c2ecf20Sopenharmony_ci lmw.bim $p0, [$r1], $p0 ! Read a word from src 358c2ecf20Sopenharmony_ci addi $p1, $p1, #-1 ! How many words left to copy 368c2ecf20Sopenharmony_ci smw.bim $p0, [$r0], $p0 ! Copy the word to det 378c2ecf20Sopenharmony_ci bnez $p1, word_cpy ! If remained words > 0 388c2ecf20Sopenharmony_ci beqz $r2, end_memcpy ! No left bytes to copy 398c2ecf20Sopenharmony_ci b byte_cpy 408c2ecf20Sopenharmony_ci 418c2ecf20Sopenharmony_cido_reverse: 428c2ecf20Sopenharmony_ci add $r0, $r0, $r2 ! Start with the end of $r0 438c2ecf20Sopenharmony_ci add $r1, $r1, $r2 ! Start with the end of $r1 448c2ecf20Sopenharmony_ci andi $r2, $r2, #3 ! How many bytes are less than a word 458c2ecf20Sopenharmony_ci li $t0, #-1 ! Determining copy direction in byte_cpy 468c2ecf20Sopenharmony_ci beqz $p1, reverse_byte_cpy ! When n is less than a word 478c2ecf20Sopenharmony_ci 488c2ecf20Sopenharmony_cireverse_word_cpy: 498c2ecf20Sopenharmony_ci lmw.adm $p0, [$r1], $p0 ! Read a word from src 508c2ecf20Sopenharmony_ci addi $p1, $p1, #-1 ! How many words left to copy 518c2ecf20Sopenharmony_ci smw.adm $p0, [$r0], $p0 ! Copy the word to det 528c2ecf20Sopenharmony_ci bnez $p1, reverse_word_cpy ! If remained words > 0 538c2ecf20Sopenharmony_ci beqz $r2, end_memcpy ! No left bytes to copy 548c2ecf20Sopenharmony_ci 558c2ecf20Sopenharmony_cireverse_byte_cpy: 568c2ecf20Sopenharmony_ci addi $r0, $r0, #-1 578c2ecf20Sopenharmony_ci addi $r1, $r1, #-1 588c2ecf20Sopenharmony_cibyte_cpy: ! Less than 4 bytes to copy now 598c2ecf20Sopenharmony_ci lb.bi $p0, [$r1], $t0 ! Read a byte from src 608c2ecf20Sopenharmony_ci addi $r2, $r2, #-1 ! How many bytes left to copy 618c2ecf20Sopenharmony_ci sb.bi $p0, [$r0], $t0 ! copy the byte to det 628c2ecf20Sopenharmony_ci bnez $r2, byte_cpy ! If remained bytes > 0 638c2ecf20Sopenharmony_ci 648c2ecf20Sopenharmony_ciend_memcpy: 658c2ecf20Sopenharmony_ci popm $t0, $t1 668c2ecf20Sopenharmony_ciexit_memcpy: 678c2ecf20Sopenharmony_ci move $r0, $r5 688c2ecf20Sopenharmony_ci ret 698c2ecf20Sopenharmony_ci 708c2ecf20Sopenharmony_ciENDPROC(memmove) 71