写一个操作系统_09 C语言和汇编语言

int sub(int a , int b){ // 被调
    return a-b;
}
int s = sub(3,2);       // 调用

调用:
push 2
push 3
call sub

被调:
push ebp
mov ebp,esp
mov eax,[ebp+8]
sub eax,[ebp+12]
pop ebp         // 恢复 ebp

char* str = "C & ASM Code\n";
int count = 0;
int main()
{
    asm("pusha;\
            movl $4,%eax;\
            movl $1,%ebx;\
            movl str,%ecx;\
            movl $13,%edx;\
            int $0x80;\
            movl %eax,count;\
            popa;\
            ");
}
// gcc -m32 casm.c