math: use the rounding idiom consistently

[musl] / src / math / round.c

diff --git a/src/math/round.c b/src/math/round.c
index 4b38d1f..130d58d 100644 (file)
--- a/src/math/round.c
+++ b/src/math/round.c
@@ -1,5 +1,12 @@
 #include "libm.h"
 
+#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 round(double x)
 {
        union {double f; uint64_t i;} u = {x};
@@ -12,10 +19,10 @@ double round(double x)
                x = -x;
        if (e < 0x3ff-1) {
                /* raise inexact if x!=0 */
-               FORCE_EVAL(x + 0x1p52);
+               FORCE_EVAL(x + toint);
                return 0*u.f;
        }
-       y = (double)(x + 0x1p52) - 0x1p52 - x;
+       y = x + toint - toint - x;
        if (y > 0.5)
                y = y + x - 1;
        else if (y <= -0.5)