1 files changed, 13 insertions, 46 deletions
diff --git a/src/math/truncf.c b/src/math/truncf.c
index 0afcdfbf..1a7d03c3 100644
--- a/src/math/truncf.c
+++ b/src/math/truncf.c
@@ -1,52 +1,19 @@
-/* origin: FreeBSD /usr/src/lib/msun/src/s_truncf.c */
-/*
- * ====================================================
- * 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.
- * ====================================================
- */
-/*
- * truncf(x)
- * Return x rounded toward 0 to integral value
- * Method:
- *      Bit twiddling.
- * Exception:
- *      Inexact flag raised if x not equal to truncf(x).
- */
-
 #include "libm.h"
 
-static const float huge = 1.0e30f;
-
 float truncf(float x)
 {
-	int32_t i0,j0;
-	uint32_t i;
+	union {float f; uint32_t i;} u = {x};
+	int e = (int)(u.i >> 23 & 0xff) - 0x7f + 9;
+	uint32_t m;
 
-	GET_FLOAT_WORD(i0, x);
-	j0 = ((i0>>23)&0xff) - 0x7f;
-	if (j0 < 23) {
-		if (j0 < 0) {  /* |x|<1, return 0*sign(x) */
-			/* raise inexact if x != 0 */
-			if (huge+x > 0.0f)
-				i0 &= 0x80000000;
-		} else {
-			i = 0x007fffff>>j0;
-			if ((i0&i) == 0)
-				return x; /* x is integral */
-			/* raise inexact */
-			if (huge+x > 0.0f)
-				i0 &= ~i;
-		}
-	} else {
-		if (j0 == 0x80)
-			return x + x;  /* inf or NaN */
-		return x;              /* x is integral */
-	}
-	SET_FLOAT_WORD(x, i0);
-	return x;
+	if (e >= 23 + 9)
+		return x;
+	if (e < 9)
+		e = 1;
+	m = -1U >> e;
+	if ((u.i & m) == 0)
+		return x;
+	FORCE_EVAL(x + 0x1p120f);
+	u.i &= ~m;
+	return u.f;
 }