* libc/include/machine/ieeefp.h: Comment about new configuration

	macros _FLT_LARGEST_EXPONENT_IS_NORMAL and _FLT_NO_DENORMALS.
	* libm/common/fdlib.h: Define new macros for testing floats.
	* libm/common/sf_*: Use them.
	* libm/math/ef_*: Likewise.
	* libm/math/sf_*: Likewise.

1 files changed, 104 insertions, 2 deletions

diff --git a/newlib/libm/common/fdlibm.h b/newlib/libm/common/fdlibm.h
index 752d24246..5ca1a917b 100644
--- a/newlib/libm/common/fdlibm.h
+++ b/newlib/libm/common/fdlibm.h
@@ -18,14 +18,116 @@
 /* CYGNUS LOCAL: Default to XOPEN_MODE.  */
 #define _XOPEN_MODE
 
+/* Most routines need to check whether a float is finite, infinite, or not a
+   number, and many need to know whether the result of an operation will
+   overflow.  These conditions depend on whether the largest exponent is
+   used for NaNs & infinities, or whether it's used for finite numbers.  The
+   macros below wrap up that kind of information:
+
+   FLT_UWORD_IS_FINITE(X)
+	True if a positive float with bitmask X is finite.
+
+   FLT_UWORD_IS_NAN(X)
+	True if a positive float with bitmask X is not a number.
+
+   FLT_UWORD_IS_INFINITE(X)
+	True if a positive float with bitmask X is +infinity.
+
+   FLT_UWORD_MAX
+	The bitmask of FLT_MAX.
+
+   FLT_UWORD_HALF_MAX
+	The bitmask of FLT_MAX/2.
+
+   FLT_UWORD_EXP_MAX
+	The bitmask of the largest finite exponent (129 if the largest
+	exponent is used for finite numbers, 128 otherwise).
+
+   FLT_UWORD_LOG_MAX
+	The bitmask of log(FLT_MAX), rounded down.  This value is the largest
+	input that can be passed to exp() without producing overflow.
+
+   FLT_UWORD_LOG_2MAX
+	The bitmask of log(2*FLT_MAX), rounded down.  This value is the
+	largest input than can be passed to cosh() without producing
+	overflow.
+
+   FLT_LARGEST_EXP
+	The largest biased exponent that can be used for finite numbers
+	(255 if the largest exponent is used for finite numbers, 254
+	otherwise) */
+
+#ifdef _FLT_LARGEST_EXPONENT_IS_NORMAL
+#define FLT_UWORD_IS_FINITE(x) 1
+#define FLT_UWORD_IS_NAN(x) 0
+#define FLT_UWORD_IS_INFINITE(x) 0
+#define FLT_UWORD_MAX 0x7fffffff
+#define FLT_UWORD_EXP_MAX 0x43010000
+#define FLT_UWORD_LOG_MAX 0x42b2d4fc
+#define FLT_UWORD_LOG_2MAX 0x42b437e0
+#define HUGE ((float)0X1.FFFFFEP128)
+#else
+#define FLT_UWORD_IS_FINITE(x) ((x)<0x7f800000L)
+#define FLT_UWORD_IS_NAN(x) ((x)>0x7f800000L)
+#define FLT_UWORD_IS_INFINITE(x) ((x)==0x7f800000L)
+#define FLT_UWORD_MAX 0x7f7fffff
+#define FLT_UWORD_EXP_MAX 0x43000000
+#define FLT_UWORD_LOG_MAX 0x42b17217
+#define FLT_UWORD_LOG_2MAX 0x42b2d4fc
+#define HUGE ((float)3.40282346638528860e+38)
+#endif
+#define FLT_UWORD_HALF_MAX (FLT_UWORD_MAX-(1<<23))
+#define FLT_LARGEST_EXP (FLT_UWORD_MAX>>23)
+
+/* Many routines check for zero and subnormal numbers.  Such things depend
+   on whether the target supports denormals or not:
+
+   FLT_UWORD_IS_ZERO(X)
+	True if a positive float with bitmask X is +0.	Without denormals,
+	any float with a zero exponent is a +0 representation.	With
+	denormals, the only +0 representation is a 0 bitmask.
+
+   FLT_UWORD_IS_SUBNORMAL(X)
+	True if a non-zero positive float with bitmask X is subnormal.
+	(Routines should check for zeros first.)
+
+   FLT_UWORD_MIN
+	The bitmask of the smallest float above +0.  Call this number
+	REAL_FLT_MIN...
+
+   FLT_UWORD_EXP_MIN
+	The bitmask of the float representation of REAL_FLT_MIN's exponent.
+
+   FLT_UWORD_LOG_MIN
+	The bitmask of |log(REAL_FLT_MIN)|, rounding down.
+
+   FLT_SMALLEST_EXP
+	REAL_FLT_MIN's exponent - EXP_BIAS (1 if denormals are not supported,
+	-22 if they are).
+*/
+
+#ifdef _FLT_NO_DENORMALS
+#define FLT_UWORD_IS_ZERO(x) ((x)<0x00800000L)
+#define FLT_UWORD_IS_SUBNORMAL(x) 0
+#define FLT_UWORD_MIN 0x00800000
+#define FLT_UWORD_EXP_MIN 0x42fc0000
+#define FLT_UWORD_LOG_MIN 0x42aeac50
+#define FLT_SMALLEST_EXP 1
+#else
+#define FLT_UWORD_IS_ZERO(x) ((x)==0)
+#define FLT_UWORD_IS_SUBNORMAL(x) ((x)<0x00800000L)
+#define FLT_UWORD_MIN 0x00000001
+#define FLT_UWORD_EXP_MIN 0x43160000
+#define FLT_UWORD_LOG_MIN 0x42cff1b5
+#define FLT_SMALLEST_EXP -22
+#endif
+
 #ifdef __STDC__
 #define	__P(p)	p
 #else
 #define	__P(p)	()
 #endif
 
-#define	HUGE	((float)3.40282346638528860e+38)
-
 /* 
  * set X_TLOSS = pi*2**52, which is possibly defined in <values.h>
  * (one may replace the following line by "#include <values.h>")