/* test signal stack alignment (sigframe) */
/* Markus F.X.J. Oberhumer <markus@oberhumer.com> */

#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

volatile unsigned long signal_sp = 0;

#if defined(__x86_64__)
/* amd64: signal stack is properly aligned */
asm(
    ".text\n .align 16\n"
"my_sighandler:\n"
    "lea 8(%rsp),%rax\n"
    "movq %rax,(signal_sp)\n"
    "retq\n"
);
#elif defined(__i386__)
/* i386: signal stack is always mis-aligned to 4-bytes */
asm(
    ".text\n .align 16\n"
"my_sighandler:\n"
    "lea 4(%esp),%eax\n"
    "movl %eax,(signal_sp)\n"
    "ret\n"
);
#else
#error "arch not supported - please insert your code here"
#endif


#if defined(__cplusplus)
extern "C"
#endif
void my_sighandler(int);


int main()
{
    int signo = SIGUSR1;

#if 1
    /* randomize stack */
    void * volatile dummy = NULL;
    srand((unsigned)clock() % RAND_MAX);
    dummy = __builtin_alloca(rand() % 2048ul);
#endif

    signal_sp = 0;
    signal(signo, my_sighandler);
    raise(signo);
    printf("sp = 0x%lx  alignment = %lu\n", signal_sp, signal_sp & 15);
    if (signal_sp & 15)
        printf("  error: signal stack not aligned\n");

    return 0;
}


/* vim:set ts=4 et: */