projects
/
musl
/ blobdiff
commit
grep
author
committer
pickaxe
?
search:
re
summary
|
shortlog
|
log
|
commit
|
commitdiff
|
tree
raw
|
inline
| side by side
add qsort_r and make qsort a wrapper around it
[musl]
/
src
/
math
/
scalbn.c
diff --git
a/src/math/scalbn.c
b/src/math/scalbn.c
index
1fec432
..
182f561
100644
(file)
--- a/
src/math/scalbn.c
+++ b/
src/math/scalbn.c
@@
-1,29
+1,33
@@
-#include "libm.h"
+#include <math.h>
+#include <stdint.h>
double scalbn(double x, int n)
{
double scalbn(double x, int n)
{
- double scale;
+ union {double f; uint64_t i;} u;
+ double_t y = x;
if (n > 1023) {
if (n > 1023) {
-
x
*= 0x1p1023;
+
y
*= 0x1p1023;
n -= 1023;
if (n > 1023) {
n -= 1023;
if (n > 1023) {
-
x
*= 0x1p1023;
+
y
*= 0x1p1023;
n -= 1023;
if (n > 1023)
n = 1023;
}
} else if (n < -1022) {
n -= 1023;
if (n > 1023)
n = 1023;
}
} else if (n < -1022) {
- x *= 0x1p-1022;
- n += 1022;
+ /* make sure final n < -53 to avoid double
+ rounding in the subnormal range */
+ y *= 0x1p-1022 * 0x1p53;
+ n += 1022 - 53;
if (n < -1022) {
if (n < -1022) {
-
x *= 0x1p-1022
;
- n += 1022;
+
y *= 0x1p-1022 * 0x1p53
;
+ n += 1022
- 53
;
if (n < -1022)
n = -1022;
}
}
if (n < -1022)
n = -1022;
}
}
-
INSERT_WORDS(scale, (uint32_t)(0x3ff+n)<<20, 0)
;
-
STRICT_ASSIGN(double, x, x * scale)
;
+
u.i = (uint64_t)(0x3ff+n)<<52
;
+
x = y * u.f
;
return x;
}
return x;
}