OpenEuler 中C與彙編的混合程式設計(選做)
阿新 • • 發佈:2021-12-05
2.5 OpenEuler 中C與彙編的混合程式設計(選做)
一、X86_64實踐內容
2.5.1
1.程式碼如下:
/************a.c*************/
#include<stdio.h>
extern int B();
int A(int x,int y)
{
int d,e,f;
d =4; e =5; f=6;
d=B(d,e);
}
經過彙編命令gcc -m32 -S a.c -o a.s
得到彙編檔案
/************a.s*************/ .file "a.c" .text .globl A .type A, @function A: .LFB0: .cfi_startproc endbr32 pushl %ebp .cfi_def_cfa_offset 8 .cfi_offset 5, -8 movl %esp, %ebp .cfi_def_cfa_register 5 pushl %ebx subl $20, %esp .cfi_offset 3, -12 call __x86.get_pc_thunk.ax addl $_GLOBAL_OFFSET_TABLE_, %eax movl $4, -20(%ebp) movl $5, -16(%ebp) movl $6, -12(%ebp) subl $8, %esp pushl -16(%ebp) pushl -20(%ebp) movl %eax, %ebx call B@PLT addl $16, %esp movl %eax, -20(%ebp) nop movl -4(%ebp), %ebx leave .cfi_restore 5 .cfi_restore 3 .cfi_def_cfa 4, 4 ret .cfi_endproc .LFE0: .size A, .-A .section .text.__x86.get_pc_thunk.ax,"axG",@progbits,__x86.get_pc_thunk.ax,comdat .globl __x86.get_pc_thunk.ax .hidden __x86.get_pc_thunk.ax .type __x86.get_pc_thunk.ax, @function __x86.get_pc_thunk.ax: .LFB1: .cfi_startproc movl (%esp), %eax ret .cfi_endproc .LFE1: .ident "GCC: (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0" .section .note.GNU-stack,"",@progbits .section .note.gnu.property,"a" .align 4 .long 1f - 0f .long 4f - 1f .long 5 0: .string "GNU" 1: .align 4 .long 0xc0000002 .long 3f - 2f 2: .long 0x3 3: .align 4 4:
2.5.2
1.程式碼如下:
/************s.c*************/
#include <stdio.h>
extern int get_ebp();
extern int get_esp();
int main()
{
int ebp, esp;
ebp = get_ebp();
esp = get_esp();
printf("ebp=%8x esp=%8x\n",ebp,esp);
}
/************s.s*************/ .global get_esp,get_ebp get_esp: movl %esp,%eax ret get_ebp: movl %ebp,%eax ret
經過彙編命令gcc -m32 s.s s.c -o s.out
得到彙編檔案
2.5.3
/************smysum.s*************/
.text
.global mysum,printf
mysum:
#(1)Entry:
pushl $ebp
movl %esp,%ebp
#(2)Function Body code
movl 8(%ebp),%eax
addl 12(%ebp),%eax
#(3)Exit Code
movl %ebp,%esp
pop %ebp
ret
/************smysum.c*************/ #include<stdio.h> int main() { int a,b,c; a = 123;b = 456; c = mysum(a,b); printf("c=%d\n",c); }
彙編指令:gcc -m32 -o mysum.out mysum.s mysum.c
2.5.4
/************prt.c*************/
int a,b;
int main()
{
a = 100;b = 200;
sub();
}
/************prt.s*************/
.text
.global sub,a,b,printf
sub:
pushl %ebp
movl %esp,%ebp
pushl b
pushl a
pushl $fmt
call printf
addl $12,%esp
movl %ebp,%esp
popl %ebp
ret
.data
fmt: .asciz "a=%d b=%d\n"
彙編命令:gcc -m32 prt.c prt.s -o prt.out