FPU Context

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>

//#define RUIN_STACK 1

int main()
{
    //__asm__("xchg %bx, %bx");
    float a = 5.7, b = 1.2;

    union ud
    {
        float c;
        int cc;
    };

    union ud u;

    __asm__ __volatile__(
        "flds %1;"
        "flds %0;"
        "fdivrp %%st,%%st(1);"
        :
        : "m" (b), "m" (a)
    );

#ifdef RUIN_STACK
    pid_t pid;
    if ( (pid = fork()) == 0 )
    {
        float t;

        __asm__ __volatile__(
            "fstps %0;"
            "fldz;"
            "fldz;"
            "fldz;"
            "fldz;"
            "fldz;"
            "fldz;"
            "fldz;"
            "fldz;"
            : "=m" (t)
            :
        );
        exit(0);
    }
    wait(NULL);
#endif

    __asm__ __volatile__(
        "fstps %0;"
        : "=m" (u.c)
        :
        );

    fprintf(stderr,"rrrFather: %x\n",u.cc);
}