[Qemu-devel] How to add my implementation of the fmadds instruction to QEMU

[G 3]

I made my own experimental implementation of the fmadds instruction  
that I would like to add to QEMU. How would I do this?

My implementation would probably look like this:

void fmadds(float *frD, float frA, float frC, float frB)
{
        *frD = frA * frC + frB;
}


I then want to see if this implementation will make things faster.  
This code will test my implementation:

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

/*
    fmadds basically does this frD = frA * frC + frB
*/

int main (int argc, const char * argv[]) {
    const int iteration_count = 100000000;
    double iter, frD, frA, frB, frC;
    clock_t start_time, end_time;

    frA = 10;
    frB = 5;
    frC = 2;

    start_time = clock();
    for(iter = 0; iter < iteration_count; iter++)
    {
        asm volatile("fmadds %0, %1, %2, %3" : "=f" (frD) :  
"f" (frA), "f" (frC), "f" (frB));
    }
    end_time = clock();
    printf("frD:%f frA:%f frB:%f frC:%f\n", frD, frA, frB, frC);
    printf("Time elapsed: %0.2f seconds\n", (float)(end_time -  
start_time) / CLOCKS_PER_SEC);

    return 0;
}