从另一个文件中的nasm调用子例程 [英] nasm calling subroutine from another file

问题描述

我正在做一个项目，该项目将我编写的子例程附加到老师包含的主文件中.他给了我们有关使子程序全局化的说明，但显然我是个白痴.这两个asm文件位于同一文件夹中，我使用的是nasm -f elf -g prt_dec.asm和ld prt_dec，然后对main.asm执行相同的操作.这是main.asm中的相关代码:

I'm doing a project that attaches a subroutine that I wrote to a main file included by the teacher. He gave us the instructions for making our subroutine global but apparently I'm an idiot. The two asm files are in the same folder, I'm using nasm -f elf -g prt_dec.asm and ld prt_dec and then doing the same for main.asm. Here's the relevant code in the main.asm:

    SECTION .text                   ; Code section.
global  _start                  ; let loader see entry point
extern  prt_dec

_start:
mov     ebx, 17
mov     edx, 214123
mov     edi, 2223187809
mov     ebp, 1555544444


mov     eax, dword 0x0
call    prt_dec
call    prt_lf

当我使用ld main.o

这是我prt_dec.asm中的代码段:

Here's the a code segment from my prt_dec.asm:

    Section .text
    global prt_dec
    global _start

start:
prt_dec:
      (pushing some stuff)
L1_top:
(code continues)

推荐答案

您要在另一个asm文件或目标文件中调用例程吗? 如果您正在组装prt_dec.asm并链接了要在主程序中使用的多个asm文件，则这里是一个示例，其中2个asm文件已组装并链接在一起... *注意* hello.asm *没有* 带有开始标签！

You want to call a routine in another asm file or object file? if you are Assembling prt_dec.asm and are linking multiple asm files to use in your main program, here is a sample, 2 asm files Assembled and linked together... * NOTE * hello.asm *DOES NOT * have a start label!

主要asm文件:hellothere.asm

Main asm file: hellothere.asm

sys_exit    equ 1

extern Hello 
global _start 

section .text
_start:
    call    Hello

    mov     eax, sys_exit
    xor     ebx, ebx
    int     80H

第二个asm文件:hello.asm

Second asm file: hello.asm

sys_write   equ 4
stdout      equ 1

global Hello

section .data
szHello     db  "Hello", 10
Hello_Len   equ ($ - szHello)

section .text
Hello:
        mov     edx, Hello_Len
        mov     ecx, szHello
        mov     eax, sys_write
        mov     ebx, stdout
        int     80H   
    ret

makefile:

APP = hellothere

$(APP): $(APP).o hello.o
    ld -o $(APP) $(APP).o hello.o

$(APP).o: $(APP).asm 
    nasm -f elf $(APP).asm 

hello.o: hello.asm
    nasm -f elf hello.asm

现在，如果您只想将代码分成多个asm文件，则可以将它们包含在您的主要源代码中:在主要源文件的开头加上%include "asmfile.asm"，只需汇编和链接您的主要文件即可.

Now, if you just want to separate your code into multiple asm files, you can include them into your main source: with %include "asmfile.asm" at the beginning of your main source file and just assemble and link your main file.

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