X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Fmath%2Fceil.c;h=b13e6f2d63689818ff349f1327fb5d1bb25eb49d;hb=2f2348c9588d61680123bbe438db38acf5dfea4c;hp=c2ab4a54866f15b0d067243d23feb8c4204ce489;hpb=b69f695acedd4ce2798ef9ea28d834ceccc789bd;p=musl

diff --git a/src/math/ceil.c b/src/math/ceil.c
index c2ab4a54..b13e6f2d 100644
--- a/src/math/ceil.c
+++ b/src/math/ceil.c
@@ -1,83 +1,31 @@
-/* origin: FreeBSD /usr/src/lib/msun/src/s_ceil.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.
- * ====================================================
- */
-/*
- * ceil(x)
- * Return x rounded toward -inf to integral value
- * Method:
- *      Bit twiddling.
- * Exception:
- *      Inexact flag raised if x not equal to ceil(x).
- */
-
 #include "libm.h"
 
-static const double huge = 1.0e300;
+#if FLT_EVAL_METHOD==0 || FLT_EVAL_METHOD==1
+#define EPS DBL_EPSILON
+#elif FLT_EVAL_METHOD==2
+#define EPS LDBL_EPSILON
+#endif
+static const double_t toint = 1/EPS;
 
 double ceil(double x)
 {
-	int32_t i0,i1,j0;
-	uint32_t i,j;
+	union {double f; uint64_t i;} u = {x};
+	int e = u.i >> 52 & 0x7ff;
+	double_t y;
 
-	EXTRACT_WORDS(i0, i1, x);
-	// FIXME signed shift
-	j0 = ((i0>>20)&0x7ff) - 0x3ff;
-	if (j0 < 20) {
-		if (j0 < 0) {
-			 /* raise inexact if x != 0 */
-			if (huge+x > 0.0) {
-				/* return 0*sign(x) if |x|<1 */
-				if (i0 < 0) {
-					i0 = 0x80000000;
-					i1=0;
-				} else if ((i0|i1) != 0) {
-					i0=0x3ff00000;
-					i1=0;
-				}
-			}
-		} else {
-			i = (0x000fffff)>>j0;
-			if (((i0&i)|i1) == 0) /* x is integral */
-				return x;
-			/* raise inexact flag */
-			if (huge+x > 0.0) {
-				if (i0 > 0)
-					i0 += 0x00100000>>j0;
-				i0 &= ~i;
-				i1 = 0;
-			}
-		}
-	} else if (j0 > 51) {
-		if (j0 == 0x400)  /* inf or NaN */
-			return x+x;
-		return x;         /* x is integral */
-	} else {
-		i = (uint32_t)0xffffffff>>(j0-20);
-		if ((i1&i) == 0)
-			return x; /* x is integral */
-		/* raise inexact flag */
-		if (huge+x > 0.0) {
-			if (i0 > 0) {
-				if (j0 == 20)
-					i0 += 1;
-				else {
-					j = i1 + (1<<(52-j0));
-					if (j < i1)  /* got a carry */
-						i0 += 1;
-					i1 = j;
-				}
-			}
-			i1 &= ~i;
-		}
+	if (e >= 0x3ff+52 || x == 0)
+		return x;
+	/* y = int(x) - x, where int(x) is an integer neighbor of x */
+	if (u.i >> 63)
+		y = x - toint + toint - x;
+	else
+		y = x + toint - toint - x;
+	/* special case because of non-nearest rounding modes */
+	if (e <= 0x3ff-1) {
+		FORCE_EVAL(y);
+		return u.i >> 63 ? -0.0 : 1;
 	}
-	INSERT_WORDS(x, i0, i1);
-	return x;
+	if (y < 0)
+		return x + y + 1;
+	return x + y;
 }