gistfile1.txt

#include <stdio.h>
#include <system.h>
#include <io.h>
#include <unistd.h>

#define WR_REG(reg, val) IOWR(SNES_##reg##_BASE, 0, val)
#define RD_REG(reg) IORD(SNES_##reg##_BASE, 0)

int main(void)
{
    for (;;)
    {
        WR_REG(CLK, 1);
        
        WR_REG(LATCH, 0);
        usleep(12);
        WR_REG(LATCH, 1);
        usleep(12);
        WR_REG(LATCH, 0);
        
        unsigned val = 0;
        unsigned i;
        for (i = 0; i < 12; i++)
        {
            usleep(6);
            val >>= 1;
            val |= (RD_REG(DATA) & 1) << 11;
            WR_REG(CLK, 0);
            usleep(6);
            WR_REG(CLK, 1);
        }
        
        val = (~val) & ((1 << 12) - 1);
        IOWR(LEDR_BASE, 0, val);
    }
}