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-rw-r--r--sysdeps/libm-ieee754/e_exp.c48
1 files changed, 15 insertions, 33 deletions
diff --git a/sysdeps/libm-ieee754/e_exp.c b/sysdeps/libm-ieee754/e_exp.c
index 660c5bc88d..5eae12a19c 100644
--- a/sysdeps/libm-ieee754/e_exp.c
+++ b/sysdeps/libm-ieee754/e_exp.c
@@ -76,8 +76,8 @@ __ieee754_exp (double x)
/* Check for usual case. */
if (isless (x, himark) && isgreater (x, lomark))
{
- static const double TWO43 = 8796093022208.0;
- static const double TWO52 = 4503599627370496.0;
+ static const double THREEp42 = 13194139533312.0;
+ static const double THREEp51 = 6755399441055744.0;
/* 1/ln(2). */
static const double M_1_LN2 = 1.442695040888963387;
/* ln(2), part 1 */
@@ -94,40 +94,22 @@ __ieee754_exp (double x)
fesetround (FE_TONEAREST);
/* Calculate n. */
- if (x >= 0)
- {
- n = x * M_1_LN2 + TWO52;
- n -= TWO52;
- }
- else
- {
- n = x * M_1_LN2 - TWO52;
- n += TWO52;
- }
+ n = x * M_1_LN2 + THREEp51;
+ n -= THREEp51;
x = x - n*M_LN2_0;
- if (x >= 0)
- {
- /* Calculate t/512. */
- t = x + TWO43;
- t -= TWO43;
- x -= t;
-
- /* Compute tval = t. */
- tval = (int) (t * 512.0);
-
- x -= __exp_deltatable[tval];
- }
- else
- {
- /* As above, but x is negative. */
- t = x - TWO43;
- t += TWO43;
- x -= t;
- tval = (int) (t * 512.0);
+ /* Calculate t/512. */
+ t = x + THREEp42;
+ t -= THREEp42;
+ x -= t;
- x += __exp_deltatable[-tval];
- }
+ /* Compute tval = t. */
+ tval = (int) (t * 512.0);
+
+ if (t >= 0)
+ x -= __exp_deltatable[tval];
+ else
+ x += __exp_deltatable[-tval];
/* Now, the variable x contains x + n*ln(2)_1. */
dely = n*M_LN2_1;