The logb() functions are not just ieee754 "test" functions, but are

standard in C99 and POSIX.1-2001+.  They are also not deprecated, since
apart from being standard they can handle special args slightly better
than the ilogb() functions.

Move their documentation to ilogb.3.  Try to use consistent and improved
wording for both sets of functions.  All of ieee854, C99 and POSIX
have better wording and more details for special args.

Add history for the logb() functions and ilogbl().  Fix history for
ilogb().

lib/msun/Makefile

@@ -129,10 +129,10 @@ MLINKS+=fmax.3 fmaxf.3 fmax.3 fmaxl.3 \
 	fmax.3 fmin.3 fmax.3 fminf.3 fmax.3 fminl.3
 MLINKS+=fmod.3 fmodf.3
 MLINKS+=hypot.3 cabs.3 hypot.3 cabsf.3 hypot.3 hypotf.3
-MLINKS+=ieee_test.3 logb.3 ieee_test.3 logbf.3
 MLINKS+=ieee_test.3 scalb.3 ieee_test.3 scalbf.3
 MLINKS+=ieee_test.3 significand.3 ieee_test.3 significandf.3
-MLINKS+=ilogb.3 ilogbf.3 ilogb.3 ilogbl.3
+MLINKS+=ilogb.3 ilogbf.3 ilogb.3 ilogbl.3 \
+	ilogb.3 logb.3 ilogb.3 logbf.3
 MLINKS+=j0.3 j1.3 j0.3 jn.3 j0.3 y0.3 j0.3 y1.3 j0.3 y1f.3 j0.3 yn.3
 MLINKS+=j0.3 j0f.3 j0.3 j1f.3 j0.3 jnf.3 j0.3 y0f.3 j0.3 ynf.3
 MLINKS+=lgamma.3 gamma.3 lgamma.3 gammaf.3 lgamma.3 lgammaf.3 lgamma.3 tgamma.3

lib/msun/man/ieee_test.3

@@ -32,12 +32,10 @@
 .\"     from: @(#)ieee.3	6.4 (Berkeley) 5/6/91
 .\" $FreeBSD$
 .\"
-.Dd March 10, 1994
+.Dd Nov 6, 2005
 .Dt IEEE_TEST 3
 .Os
 .Sh NAME
-.Nm logb ,
-.Nm logbf ,
 .Nm scalb ,
 .Nm scalbf ,
 .Nm significand ,
@@ -48,10 +46,6 @@
 .Sh SYNOPSIS
 .In math.h
 .Ft double
-.Fn logb "double x"
-.Ft float
-.Fn logbf "float x"
-.Ft double
 .Fn scalb "double x" "double n"
 .Ft float
 .Fn scalbf "float x" "float n"
@@ -64,18 +58,6 @@ These functions allow users to test conformance to
 .St -ieee754 .
 Their use is not otherwise recommended.
 .Pp
-.Fn logb x
-and
-.Fn logbf x
-return
-.Fa x Ns 's exponent
-.Fa n ,
-a signed integer converted to double\-precision floating\-point.
-.Fn logb \*(Pm\*(If
-= +\*(If;
-.Fn logb 0
-= -\*(If with a division by zero exception.
-.Pp
 .Fn scalb x n
 and
 .Fn scalbf x n

lib/msun/man/ilogb.3

@@ -32,13 +32,15 @@
 .\"     from: @(#)ieee.3	6.4 (Berkeley) 5/6/91
 .\" $FreeBSD$
 .\"
-.Dd January 26, 2005
+.Dd Nov 6, 2005
 .Dt ILOGB 3
 .Os
 .Sh NAME
 .Nm ilogb ,
 .Nm ilogbf ,
-.Nm ilogbl
+.Nm ilogbl ,
+.Nm logb ,
+.Nm logbf
 .Nd extract exponent
 .Sh LIBRARY
 .Lb libm
@@ -50,24 +52,40 @@
 .Fn ilogbf "float x"
 .Ft int
 .Fn ilogbl "long double x"
+.Ft double
+.Fn logb "double x"
+.Ft float
+.Fn logbf "float x"
 .Sh DESCRIPTION
 .Fn ilogb ,
 .Fn ilogbf
 and
 .Fn ilogbl
 return
-.Fa x Ns 's exponent,
+.Fa x Ns 's exponent
 in integer format.
 .Fn ilogb \*(Pm\*(If
 returns
 .Dv INT_MAX ,
 .Fn ilogb \*(Pm\*(Na
 returns
-.Dv FP_ILOGBNAN
+.Dv FP_ILOGBNAN ,
 and
 .Fn ilogb 0
 returns
 .Dv FP_ILOGB0 .
+.Pp
+.Fn logb x
+and
+.Fn logbf x
+return
+.Fa x Ns 's exponent
+in floating\-point format with the same precision as
+.Fa x .
+.Fn logb \*(Pm\*(If
+returns +\*(If, and
+.Fn logb 0
+returns -\*(If with a division by zero exception.
 .Sh SEE ALSO
 .Xr frexp 3 ,
 .Xr ieee 3 ,
@@ -77,19 +95,33 @@ returns
 The
 .Fn ilogb ,
 .Fn ilogbf ,
+.Fn ilogbl ,
+.Fn logb
 and
-.Fn ilogbl
+.Fn logbf
 routines conform to
 .St -isoC-99 .
-They provide functionality similar to the Logb function recommended by
+.Fn logb
+and
+.Fn logbf
+implement the logb function recommended by
 .St -ieee754 .
 .Sh HISTORY
 The
+.Fn logb
+function appeared in
+.Bx 4.3 .
+The
 .Fn ilogb
-and
+function appeared in
+.Fx 1.1.5 .
+The
 .Fn ilogbf
-functions appeared in
-.Bx 4.3
 and
-.Fx 2.0 ,
-respectively.
+.Fn logbf
+functions appeared in
+.Fx 2.0 .
+The
+.Fn ilogbl
+function appeared in
+.Fx 5.4 .

lib/msun/man/math.3

@@ -32,7 +32,7 @@
 .\"	from: @(#)math.3	6.10 (Berkeley) 5/6/91
 .\" $FreeBSD$
 .\"
-.Dd April 5, 2005
+.Dd Nov 6, 2005
 .Dt MATH 3
 .Os
 .if n \{\
@@ -97,6 +97,7 @@ isnormal	determine whether a value is normalized
 frexp	extract exponent and mantissa
 ilogb	extract exponent
 ldexp	multiply by power of 2
+logb	extract exponent
 scalbln	adjust exponent
 scalbn	adjust exponent
 .El