ref: 02dce7a2e4fd74d918cf7cd1f23fc99279365eb9
dir: /sys/src/ape/lib/ap/math/fmod.c/
/* floating-point mod function without infinity or NaN checking */ #include <math.h> double fmod (double x, double y) { int sign = 0, yexp; double r, yfr; if (y == 0) return 0; if (y < 0) y = -y; yfr = frexp (y, &yexp); if (x < 0) { sign = 1; r = -x; } else r = x; while (r >= y) { int rexp; double rfr = frexp (r, &rexp); r -= ldexp (y, rexp - yexp - (rfr < yfr)); } if (sign) r = -r; return r; }