AMD 64 Problem with assembling

AMD 64 Problem with assembling

[Florian Michel]

Hello,

I have a question concerning successfully assembling and linking the following assembly program on a linux AMD 64 machine:

#cpuid2.s View the CPUID Vendor ID string using C library calls
.section .datatext
output:
.asciz "The processor Vendor ID is '%s'\n"
.section .bss
.lcomm buffer, 12
.section .text
.globl main
main:
movl $0, %eax
cpuid
movl $buffer, %edi
movl %ebx, (%edi)
movl %edx, 4(%edi)
movl %ecx, 8(%edi)
push $buffer
push $output
call printf
addl $8, %esp
push $0
call exit

This part of a book on assembly programming I am reading.

Compile and Link: gcc -o cpuid2 cpuid2.s
When running cpuid2 it crashes with a segmentation fault.
Which switches do I have to add to call gcc?

Thanks a lot!

Greetings,
Florian

Re: AMD 64 Problem with assembling

[Ian Lance Taylor]

Florian Michel <florian__michel@web.de> writes:

> I have a question concerning successfully assembling and linking the
> following assembly program on a linux AMD 64 machine:

The gcc-help mailing list is for questions about using gcc.  It is not
for general questions about how to write correct programs, or correct
assembly code.  Thanks.

That said, the easiest way to write correct assembly code is to copy
at gcc output, as generated by -S or --save-temps.

And the bug here is in this line:

> .section .datatext

You want something like:

.section .datatext,"a"

Ian