1 files changed, 105 insertions, 0 deletions
diff --git a/src/math/fmodf.c b/src/math/fmodf.c
new file mode 100644
index 00000000..4b50a3d3
--- /dev/null
+++ b/src/math/fmodf.c
@@ -0,0 +1,105 @@
+/* origin: FreeBSD /usr/src/lib/msun/src/e_fmodf.c */
+/*
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+/*
+ * fmodf(x,y)
+ * Return x mod y in exact arithmetic
+ * Method: shift and subtract
+ */
+
+#include "libm.h"
+
+static const float one = 1.0, Zero[] = {0.0, -0.0,};
+
+float fmodf(float x, float y)
+{
+	int32_t n,hx,hy,hz,ix,iy,sx,i;
+
+	GET_FLOAT_WORD(hx, x);
+	GET_FLOAT_WORD(hy, y);
+	sx = hx & 0x80000000;  /* sign of x */
+	hx ^= sx;              /* |x| */
+	hy &= 0x7fffffff;      /* |y| */
+
+	/* purge off exception values */
+	if (hy == 0 || hx >= 0x7f800000 ||  /* y=0,or x not finite */
+	    hy > 0x7f800000)                /* or y is NaN */
+		return (x*y)/(x*y);
+	if (hx < hy)                        /* |x| < |y| */
+		return x;
+	if (hx == hy)                       /* |x| = |y|, return x*0 */
+		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 -= 1;
+	} 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 -= 1;
+	} 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 = hx<<n;
+	}
+	if (iy >= -126)
+		hy = 0x00800000|(0x007fffff&hy);
+	else {          /* subnormal y, shift y to normal */
+		n = -126-iy;
+		hy = hy<<n;
+	}
+
+	/* fix point fmod */
+	n = ix - iy;
+	while (n--) {
+		hz = hx-hy;
+		if (hz<0)
+			hx = hx+hx;
+		else {
+			if(hz == 0)   /* return sign(x)*0 */
+				return Zero[(uint32_t)sx>>31];
+			hx = hz+hz;
+		}
+	}
+	hz = hx-hy;
+	if (hz >= 0)
+		hx = hz;
+
+	/* convert back to floating value and restore the sign */
+	if (hx == 0)               /* return sign(x)*0 */
+		return Zero[(uint32_t)sx>>31];
+	while (hx < 0x00800000) {  /* normalize x */
+		hx = hx+hx;
+		iy -= 1;
+	}
+	if (iy >= -126) {          /* normalize output */
+		hx = ((hx-0x00800000)|((iy+127)<<23));
+		SET_FLOAT_WORD(x, hx|sx);
+	} else {                   /* subnormal output */
+		n = -126 - iy;
+		hx >>= n;
+		SET_FLOAT_WORD(x, hx|sx);
+		x *= one;          /* create necessary signal */
+	}
+	return x;  /* exact output */
+}