A compiler in a week-end: afterword

This project was (and still is!) a tremendous fun for me. I have learned quite a few things during the journey that ought to take just one week-end. It took much, much longer. I mean, the core compiler was made in one week-end (from Friday Jan 12 to Sunday Jan 14, 2024), you can check the commit history. But it went sideways:

• I accidentally learned C preprocessor black magic.
• I programmed my own lexer and my own parser even if it was not initially planned.
• I dived into the bottomless pit of optimizing compilers, and I am not sure to make it to the surface ever again.
• I met new people.
• And I have spent weeks if not months on test programs.

Have you ever wondered how to compute trigonometric functions when you do not have access to any math library and you have only integer variables?

int sin24(int x)

// sin(x) = x * (1 + x^2 * (0.00761 * x^2 - 0.16605))
// this formula works pretty well in the range [-pi/2, +pi/2]
int sin24(int x) {
    int sign;
    if x>0 { sign = 1; } else { sign = -1; x = -x; }    //
    while x>+79060768 { x = x - 105414357; }            // reduce the argument to the acceptable range
    if x>26353589 { return sign*sin24(52707179 - x); }  //
    return sign*(x/4096)*((16777216 + (((x/4096)*(x/4096))/4096)*((((x/4096)*(x/4096))/131 - 2785856)/4096))/4096);
}

Have you tried to emulate bitwise operations (not/and/or/xor) using only integer arithmetics?

int and(int a, int b)

int and(int a, int b) {
    int result;
    int pow;

    result = 0;
    if (a<0 && b<0) {
        result = -2147483648;
    }
    if (a<0) {
        a = a + 2147483648;
    }
    if (b<0) {
        b = b + 2147483648;
    }
    pow = 1;
    while a>0 || b>0 {
        if a % 2 == 1 && b % 2 == 1 {
            result = result + pow;
        }
        a = a / 2;
        b = b / 2;
        pow = pow * 2;
    }
    return result;
}

Have you tried to program a zero-player breakout game without having arrays?

Stay tuned, have fun!