parent
32bc64e632
commit
d67c4c6ab0
2 changed files with 29 additions and 15 deletions
@ -1,21 +1,31 @@ |
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%include "config.asm" |
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global main |
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extern puts |
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; hello.asm a first program for nasm for Linux, Intel, gcc |
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; |
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; assemble: nasm -f elf -l hello.lst hello.asm |
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; link: gcc -o hello hello.o |
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; run: hello |
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; output is: Hello World |
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section .data |
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hi db 'Hello, World', 0 |
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%include "config.asm" |
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%ifdef FOO |
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%define RETVAL HELLO |
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%endif |
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section .text |
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main: |
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push rbp |
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lea rdi, [rel hi] |
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call puts wrt ..plt |
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pop rbp |
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mov ebx,RETVAL |
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mov eax,1 |
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int 0x80 |
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SECTION .data ; data section |
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msg: db "Hello World",10 ; the string to print, 10=cr |
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len: equ $-msg ; "$" means "here" |
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; len is a value, not an address |
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SECTION .text ; code section |
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global main ; make label available to linker |
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main: ; standard gcc entry point |
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mov edx,len ; arg3, length of string to print |
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mov ecx,msg ; arg2, pointer to string |
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mov ebx,1 ; arg1, where to write, screen |
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mov eax,4 ; write sysout command to int 80 hex |
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int 0x80 ; interrupt 80 hex, call kernel |
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mov ebx,RETVAL ; exit code, 0=normal |
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mov eax,1 ; exit command to kernel |
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int 0x80 ; interrupt 80 hex, call kernel |
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