📄 memset.s
字号:
/* Copyright (C) 1998 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Philip Blundell <philb@gnu.org> The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */#include <sys/syscall.h> .text .global memset; .type memset,%function .align 4; \memset: mov a4, a1 cmp a3, $8 @ at least 8 bytes to do? blt 2f orr a2, a2, a2, lsl $8 orr a2, a2, a2, lsl $161: tst a4, $3 @ aligned yet? strneb a2, [a4], $1 subne a3, a3, $1 bne 1b mov ip, a21: cmp a3, $8 @ 8 bytes still to do? blt 2f stmia a4!, {a2, ip} sub a3, a3, $8 cmp a3, $8 @ 8 bytes still to do? blt 2f stmia a4!, {a2, ip} sub a3, a3, $8 cmp a3, $8 @ 8 bytes still to do? blt 2f stmia a4!, {a2, ip} sub a3, a3, $8 cmp a3, $8 @ 8 bytes still to do? stmgeia a4!, {a2, ip} subge a3, a3, $8 bge 1b2: movs a3, a3 @ anything left? moveq pc, lr @ nope rsb a3, a3, $7 add pc, pc, a3, lsl $2 mov r0, r0 strb a2, [a4], $1 strb a2, [a4], $1 strb a2, [a4], $1 strb a2, [a4], $1 strb a2, [a4], $1 strb a2, [a4], $1 strb a2, [a4], $1 mov pc, lr.size memset,.-memset;
⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -