1 files changed, 125 insertions, 0 deletions
diff --git a/src/math/remquof.c b/src/math/remquof.c
new file mode 100644
index 00000000..11569ce8
--- /dev/null
+++ b/src/math/remquof.c
@@ -0,0 +1,125 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/s_remquof.c */
+/*-
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunSoft, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+/*
+ * Return the IEEE remainder and set *quo to the last n bits of the
+ * quotient, rounded to the nearest integer.  We choose n=31 because
+ * we wind up computing all the integer bits of the quotient anyway as
+ * a side-effect of computing the remainder by the shift and subtract
+ * method.  In practice, this is far more bits than are needed to use
+ * remquo in reduction algorithms.
+ */
+
+#include "libm.h"
+
+static const float Zero[] = {0.0, -0.0,};
+
+float remquof(float x, float y, int *quo)
+{
+	int32_t n,hx,hy,hz,ix,iy,sx,i;
+	uint32_t q,sxy;
+
+	GET_FLOAT_WORD(hx, x);
+	GET_FLOAT_WORD(hy, y);
+	sxy = (hx ^ hy) & 0x80000000;
+	sx = hx & 0x80000000;   /* sign of x */
+	hx ^= sx;               /* |x| */
+	hy &= 0x7fffffff;       /* |y| */
+
+	/* purge off exception values */
+	if (hy == 0 || hx >= 0x7f800000 || hy > 0x7f800000) /* y=0,NaN;or x not finite */
+		return (x*y)/(x*y);
+	if (hx < hy) {       /* |x| < |y| return x or x-y */
+		q = 0;
+		goto fixup;
+	} else if(hx==hy) {  /* |x| = |y| return x*0*/
+		*quo = 1;
+		return Zero[(uint32_t)sx>>31];
+	}
+
+	/* determine ix = ilogb(x) */
+	if (hx < 0x00800000) {  /* subnormal x */
+		for (ix = -126, i=hx<<8; i>0; i<<=1) ix--;
+	} else
+		ix = (hx>>23) - 127;
+
+	/* determine iy = ilogb(y) */
+	if (hy < 0x00800000) {  /* subnormal y */
+		for (iy = -126, i=hy<<8; i>0; i<<=1) iy--;
+	} else
+		iy = (hy>>23) - 127;
+
+	/* set up {hx,lx}, {hy,ly} and align y to x */
+	if (ix >= -126)
+		hx = 0x00800000|(0x007fffff&hx);
+	else {  /* subnormal x, shift x to normal */
+		n = -126 - ix;
+		hx <<= n;
+	}
+	if (iy >= -126)
+		hy = 0x00800000|(0x007fffff&hy);
+	else {  /* subnormal y, shift y to normal */
+		n = -126 - iy;
+		hy <<= n;
+	}
+
+	/* fix point fmod */
+	n = ix - iy;
+	q = 0;
+	while (n--) {
+		hz = hx - hy;
+		if (hz < 0)
+			hx = hx << 1;
+		else {
+			hx = hz << 1;
+			q++;
+		}
+		q <<= 1;
+	}
+	hz = hx - hy;
+	if (hz >= 0) {
+		hx = hz;
+		q++;
+	}
+
+	/* convert back to floating value and restore the sign */
+	if (hx == 0) {                             /* return sign(x)*0 */
+		*quo = sxy ? -q : q;
+		return Zero[(uint32_t)sx>>31];
+	}
+	while (hx < 0x00800000) {  /* normalize x */
+		hx <<= 1;
+		iy--;
+	}
+	if (iy >= -126) {          /* normalize output */
+		hx = (hx-0x00800000)|((iy+127)<<23);
+	} else {                   /* subnormal output */
+		n = -126 - iy;
+		hx >>= n;
+	}
+fixup:
+	SET_FLOAT_WORD(x,hx);
+	y = fabsf(y);
+	if (y < 0x1p-125f) {
+		if (x + x > y || (x + x == y && (q & 1))) {
+			q++;
+			x -= y;
+		}
+	} else if (x > 0.5f*y || (x == 0.5f*y && (q & 1))) {
+		q++;
+		x -= y;
+	}
+	GET_FLOAT_WORD(hx, x);
+	SET_FLOAT_WORD(x, hx ^ sx);
+	q &= 0x7fffffff;
+	*quo = sxy ? -q : q;
+	return x;
+}