GAS compiling error

[Abel Romero Pérez]

Hello binutil's staff,

I was writing a simple code and compiling it with gas. The code is what follows:

.globl _start

.globl setuid

.section .text

_start:

    call write

    call setuid

    jmp exit

write:

    movq $4, %rax

    movq $1, %rbx

    push $0x4142430a

    mov %rsp, %rcx    // here seems to be the error

    movq $4, %rdx

    int $0x80

    retq

setuid:

    movq $23, %rax

    xor %rbx, %rbx

    int $0x80

    retq

exit:

    movq $1, %rax

    movq $0, %rbx

    int $0x80

.section .rodata

text:

    .ascii "writed.\n";

text_l = . - text

--

When assembled and linked with gas and ld I obtain a binary. So everything goes fine.

When I execute that binary I obtain a segvfault.

I have the occurence of use gdb for viewing the code (which is okay) but when runned it (the binary) I obtained the next segvfault:

Program received signal SIGSEGV, Segmentation fault.

0x000000004142430a in ?? ()

It seems to be moving the content of %rsp to %rcx instead of the address contained by %rsp. Like doing: mov (%rsp), %rcx. But disassembling its okay... and it diferenciates between one form and the another form.

Abel.

Regards.