/* memset/bzero -- set memory area to CH/0 Highly optimized version for ix86, x>=6. Copyright (C) 1999-2022 Free Software Foundation, Inc. This file is part of the GNU C Library. 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, see . */ #include #include "asm-syntax.h" #define PARMS 4+4 /* space for 1 saved reg */ #define RTN PARMS #define DEST RTN #define CHR DEST+4 #define LEN CHR+4 .text #if defined SHARED && IS_IN (libc) ENTRY_CHK (__memset_chk) movl 12(%esp), %eax cmpl %eax, 16(%esp) jb HIDDEN_JUMPTARGET (__chk_fail) END_CHK (__memset_chk) #endif ENTRY (memset) cld pushl %edi cfi_adjust_cfa_offset (4) movl DEST(%esp), %edx movl LEN(%esp), %ecx movzbl CHR(%esp), %eax jecxz 1f movl %edx, %edi cfi_rel_offset (edi, 0) andl $3, %edx jz 2f /* aligned */ jp 3f /* misaligned at 3, store just one byte below */ stosb /* misaligned at 1 or 2, store two bytes */ decl %ecx jz 1f 3: stosb decl %ecx jz 1f xorl $1, %edx jnz 2f /* was misaligned at 2 or 3, now aligned */ stosb /* was misaligned at 1, store third byte */ decl %ecx 2: movl %ecx, %edx shrl $2, %ecx andl $3, %edx imul $0x01010101, %eax rep stosl movl %edx, %ecx rep stosb 1: movl DEST(%esp), %eax /* start address of destination is result */ popl %edi cfi_adjust_cfa_offset (-4) cfi_restore (edi) ret END (memset) libc_hidden_builtin_def (memset)