Add a "fork" of musl as //fusl.

fusl/src/math/remquol.c

+#include "libm.h"
+
+#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+long double remquol(long double x, long double y, int *quo)
+{
+        return remquo(x, y, quo);
+}
+#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
+long double remquol(long double x, long double y, int *quo)
+{
+        union ldshape ux = {x}, uy = {y};
+        int ex = ux.i.se & 0x7fff;
+        int ey = uy.i.se & 0x7fff;
+        int sx = ux.i.se >> 15;
+        int sy = uy.i.se >> 15;
+        uint32_t q;
+
+        *quo = 0;
+        if (y == 0 || isnan(y) || ex == 0x7fff)
+                return (x*y)/(x*y);
+        if (x == 0)
+                return x;
+
+        /* normalize x and y */
+        if (!ex) {
+                ux.i.se = ex;
+                ux.f *= 0x1p120f;
+                ex = ux.i.se - 120;
+        }
+        if (!ey) {
+                uy.i.se = ey;
+                uy.f *= 0x1p120f;
+                ey = uy.i.se - 120;
+        }
+
+        q = 0;
+        if (ex >= ey) {
+                /* x mod y */
+#if LDBL_MANT_DIG == 64
+                uint64_t i, mx, my;
+                mx = ux.i.m;
+                my = uy.i.m;
+                for (; ex > ey; ex--) {
+                        i = mx - my;
+                        if (mx >= my) {
+                                mx = 2*i;
+                                q++;
+                                q <<= 1;
+                        } else if (2*mx < mx) {
+                                mx = 2*mx - my;
+                                q <<= 1;
+                                q++;
+                        } else {
+                                mx = 2*mx;
+                                q <<= 1;
+                        }
+                }
+                i = mx - my;
+                if (mx >= my) {
+                        mx = i;
+                        q++;
+                }
+                if (mx == 0)
+                        ex = -120;
+                else
+                        for (; mx >> 63 == 0; mx *= 2, ex--);
+                ux.i.m = mx;
+#elif LDBL_MANT_DIG == 113
+                uint64_t hi, lo, xhi, xlo, yhi, ylo;
+                xhi = (ux.i2.hi & -1ULL>>16) | 1ULL<<48;
+                yhi = (uy.i2.hi & -1ULL>>16) | 1ULL<<48;
+                xlo = ux.i2.lo;
+                ylo = ux.i2.lo;
+                for (; ex > ey; ex--) {
+                        hi = xhi - yhi;
+                        lo = xlo - ylo;
+                        if (xlo < ylo)
+                                hi -= 1;
+                        if (hi >> 63 == 0) {
+                                xhi = 2*hi + (lo>>63);
+                                xlo = 2*lo;
+                                q++;
+                        } else {
+                                xhi = 2*xhi + (xlo>>63);
+                                xlo = 2*xlo;
+                        }
+                        q <<= 1;
+                }
+                hi = xhi - yhi;
+                lo = xlo - ylo;
+                if (xlo < ylo)
+                        hi -= 1;
+                if (hi >> 63 == 0) {
+                        xhi = hi;
+                        xlo = lo;
+                        q++;
+                }
+                if ((xhi|xlo) == 0)
+                        ex = -120;
+                else
+                        for (; xhi >> 48 == 0; xhi = 2*xhi + (xlo>>63), xlo = 2*xlo, ex--);
+                ux.i2.hi = xhi;
+                ux.i2.lo = xlo;
+#endif
+        }
+
+        /* scale result and decide between |x| and |x|-|y| */
+        if (ex <= 0) {
+                ux.i.se = ex + 120;
+                ux.f *= 0x1p-120f;
+        } else
+                ux.i.se = ex;
+        x = ux.f;
+        if (sy)
+                y = -y;
+        if (ex == ey || (ex+1 == ey && (2*x > y || (2*x == y && q%2)))) {
+                x -= y;
+                q++;
+        }
+        q &= 0x7fffffff;
+        *quo = sx^sy ? -(int)q : (int)q;
+        return sx ? -x : x;
+}
+#endif