strchr.s

一个操作系统,用C语言实现开发的,我在一个浙江大学的操作系统实验网站找到.大家学习以下

# Kernel Library
# strchr

.include "f_asm.inc"

.equ STR,	DES
.equ CHR,	SRC

.text

.global _strchr

_strchr:
	ENTER
		movl %esi, %edx
		
		movl STR(%ebp), %esi
		movl CHR(%ebp), %ecx
				
		xorl %eax, %eax
		cld
next:				
		lodsb
		cmpb %cl, %al
		jz find
		cmpb $0, %al
		jnz next
		jmp done

find:
		movl %esi, %eax
		decl %eax
done:
		movl %edx, %esi
		
	LEAVE
		ret