diff options
Diffstat (limited to '410user/libx86/bzero.S')
| -rw-r--r-- | 410user/libx86/bzero.S | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/410user/libx86/bzero.S b/410user/libx86/bzero.S new file mode 100644 index 0000000..6675745 --- /dev/null +++ b/410user/libx86/bzero.S @@ -0,0 +1,47 @@ +/* + * Written by J.T. Conklin <jtc@netbsd.org>. + * Public domain. + */ + +#include <asm_style.h> + +#if defined(LIBC_SCCS) + RCSID("$NetBSD: bzero.S,v 1.8 1995/04/28 22:57:58 jtc Exp $") +#endif + + +ENTRY(bzero) + pushl %edi + movl S_ARG1,%edi + movl S_ARG2,%edx + + cld /* set fill direction forward */ + xorl %eax,%eax /* set fill data to 0 */ + + /* + * if the string is too short, it's really not worth the overhead + * of aligning to word boundries, etc. So we jump to a plain + * unaligned set. + */ + cmpl $16,%edx + jb L1 + + movl %edi,%ecx /* compute misalignment */ + negl %ecx + andl $3,%ecx + subl %ecx,%edx + rep /* zero until word aligned */ + stosb + + movl %edx,%ecx /* zero by words */ + shrl $2,%ecx + andl $3,%edx + rep + stosl + +L1: movl %edx,%ecx /* zero remainder by bytes */ + rep + stosb + + popl %edi + ret |