fix integer overflow in WIFSTOPPED macro

[musl] / src / math / trunc.c

diff --git a/src/math/trunc.c b/src/math/trunc.c
index 44b04ec..d13711b 100644 (file)
--- a/src/math/trunc.c
+++ b/src/math/trunc.c
@@ -1,63 +1,19 @@
-/* origin: FreeBSD /usr/src/lib/msun/src/s_trunc.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.
- * ====================================================
- */
-/*
- * trunc(x)
- * Return x rounded toward 0 to integral value
- * Method:
- *      Bit twiddling.
- * Exception:
- *      Inexact flag raised if x not equal to trunc(x).
- */
-
 #include "libm.h"
 
-static const double huge = 1.0e300;
-
 double trunc(double x)
 {
-       int32_t i0,i1,j0;
-       uint32_t i;
+       union {double f; uint64_t i;} u = {x};
+       int e = (int)(u.i >> 52 & 0x7ff) - 0x3ff + 12;
+       uint64_t m;
 
-       EXTRACT_WORDS(i0, i1, x);
-       j0 = ((i0>>20)&0x7ff) - 0x3ff;
-       if (j0 < 20) {
-               if (j0 < 0) { /* |x|<1, return 0*sign(x) */
-                       /* raise inexact if x != 0 */
-                       if (huge+x > 0.0) {
-                               i0 &= 0x80000000U;
-                               i1 = 0;
-                       }
-               } else {
-                       i = 0x000fffff>>j0;
-                       if (((i0&i)|i1) == 0)
-                               return x; /* x is integral */
-                       /* raise inexact */
-                       if (huge+x > 0.0) {
-                               i0 &= ~i;
-                               i1 = 0;
-                       }
-               }
-       } else if (j0 > 51) {
-               if (j0 == 0x400)
-                       return x + x;  /* inf or NaN */
-               return x;              /* x is integral */
-       } else {
-               i = (uint32_t)0xffffffff>>(j0-20);
-               if ((i1&i) == 0)
-                       return x;      /* x is integral */
-               /* raise inexact */
-               if (huge+x > 0.0)
-                       i1 &= ~i;
-       }
-       INSERT_WORDS(x, i0, i1);
-       return x;
+       if (e >= 52 + 12)
+               return x;
+       if (e < 12)
+               e = 1;
+       m = -1ULL >> e;
+       if ((u.i & m) == 0)
+               return x;
+       FORCE_EVAL(x + 0x1p120f);
+       u.i &= ~m;
+       return u.f;
 }