sub.asm

一个小型的操作系统,采用gcc进行开发,几千行的代码,方便初学者学习

; sub.asm
; to make : nasm -f elf sub.asm -o sub.o
global subab
extern printf
fmstr db " in subab: a=%d b=%d",10,0
; int subab(int a,int b)
subab:
	push ebp
	mov ebp,esp
	push dword [ebp+12] ;arg b
	push dword [ebp+8]  ;arg a
	push dword fmstr
	call printf
	add esp,12
	mov eax,[ebp+8]
	sub eax,[ebp+12]

	leave
	ret