A86 Assembler - Need Hello World printf in 64 Bits

Author

Need Hello World printf in 64 Bits

Steven Green

2007-07-03, 6:58 pm

Hi all. I am an assembly noob.
I want to call C routines from an assembly program.

I am using YASM and would like a basic hello world type program using
printf and 64 bit assembly.

I have googled a couple days away looking for a basic place to start, but
have found little for 64 bit and C interfacing.

Could someone please take a few seconds and post a simple printf hello
world program.

I would be grateful.

Thanks,

Steve

Spoon

2007-07-03, 6:58 pm

Steven Green wrote:

> Hi all. I am an assembly noob.
> I want to call C routines from an assembly program.
>
> I am using YASM and would like a basic hello world type program using
> printf and 64 bit assembly.
>
> I have googled a couple days away looking for a basic place to start, but
> have found little for 64 bit and C interfacing.
>
> Could someone please take a few seconds and post a simple printf hello
> world program.

You could study gcc's output.

$ cat ex.c
#include <stdio.h>
int main(void)
{
printf("Hello world\n");
return 0;
}

$ gcc -S ex.c
$ vim ex.s

Or did you want to call the underlying system call? (i.e. write)

dave

2007-07-03, 6:58 pm

Spoon <spamtrap@crayne.org> wrote:
> Steven Green wrote:
>
>
> You could study gcc's output.
>
> $ cat ex.c
> #include <stdio.h>
> int main(void)
> {
> printf("Hello world\n");
> return 0;
> }
>
> $ gcc -S ex.c
> $ vim ex.s

Compiled on 64-bit OpenBSD running on Athlon 64 3500+

.file "ex.c"
.section .rodata
...LC0:
.string "Hello world\n"
.text
.globl main
.type main, @function
main:
...LFB19:
pushq %rbp
...LCFI0:
movq %rsp, %rbp
...LCFI1:
movl $.LC0, %edi
movl $0, %eax
call printf
movl $0, %eax
leave
ret
...LFE19:
.size main, .-main
.section .eh_frame,"a",@progbits
...Lframe1:
.long .LECIE1-.LSCIE1
...LSCIE1:
.long 0x0
.byte 0x1
.string ""
.uleb128 0x1
.sleb128 -8
.byte 0x10
.byte 0xc
.uleb128 0x7
.uleb128 0x8
.byte 0x90
.uleb128 0x1
.align 8
...LECIE1:
...LSFDE1:
.long .LEFDE1-.LASFDE1
...LASFDE1:
.long .LASFDE1-.Lframe1
.quad .LFB19
.quad .LFE19-.LFB19
.byte 0x4
.long .LCFI0-.LFB19
.byte 0xe
.uleb128 0x10
.byte 0x86
.uleb128 0x2
.byte 0x4
.long .LCFI1-.LCFI0
.byte 0xd
.uleb128 0x6
.align 8
...LEFDE1:

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