libm/e_scalb.c: remove unused #ifdef _SCALB_INT branches

libm/s_ldexp.c: add TODO

1 files changed, 19 insertions, 3 deletions

diff --git a/libm/s_ldexp.c b/libm/s_ldexp.c
index 1b681cb81..b2809afc8 100644
--- a/libm/s_ldexp.c
+++ b/libm/s_ldexp.c
@@ -13,11 +13,27 @@
 #include "math_private.h"
 #include <errno.h>
 
+/* TODO: POSIX says:
+ *
+ * "If the integer expression (math_errhandling & MATH_ERRNO) is non-zero,
+ * then errno shall be set to [ERANGE]. If the integer expression
+ * (math_errhandling & MATH_ERREXCEPT) is non-zero, then the underflow
+ * floating-point exception shall be raised."
+ *
+ * *And it says the same about scalbn*! Thus these two functions
+ * are the same and can be just aliased.
+ *
+ * Currently, ldexp tries to be vaguely POSIX compliant while scalbn
+ * does not (it does not set ERRNO).
+ */
+
 double ldexp(double value, int exp)
 {
-	if(!isfinite(value)||value==0.0) return value;
-	value = scalbn(value,exp);
-	if(!isfinite(value)||value==0.0) errno = ERANGE;
+	if (!isfinite(value) || value == 0.0)
+		return value;
+	value = scalbn(value, exp);
+	if (!isfinite(value) || value == 0.0)
+		errno = ERANGE;
 	return value;
 }
 libm_hidden_def(ldexp)