(Radix Modes): Clarify two's complement notation.

2 files changed, 22 insertions, 16 deletions

diff --git a/doc/misc/ChangeLog b/doc/misc/ChangeLog
index 0e467c22d61..b71b6ccd0c6 100644
--- a/doc/misc/ChangeLog
+++ b/doc/misc/ChangeLog
@@ -1,3 +1,7 @@
+2009-12-15  Jay Belanger  <jay.p.belanger@gmail.com>
+
+        * calc/calc.texi (Radix Modes): Clarify two's complement notation.
+
 2009-12-14  Chong Yidong  <cyd@stupidchicken.com>
 
         * sem-user.texi (Semantic mode, Idle Scheduler, Smart Completion)
diff --git a/doc/misc/calc.texi b/doc/misc/calc.texi
index cb29d8bcbfb..748268b2ed2 100644
--- a/doc/misc/calc.texi
+++ b/doc/misc/calc.texi
@@ -13173,34 +13173,36 @@ are displayed with at least enough digits to represent
 in the current radix.  (Larger integers will still be displayed in their
 entirety.) 
 
-
-Calc can display @expr{w}-bit integers using two's complement notation
-and binary, octal or hexadecimal display radix with the commands
-@kbd{C-u d 2}, @kbd{C-u d 8} or @kbd{C-u d 6}, respectively.  In this
-case a negative word size might be appropriate (@pxref{Binary Functions}).
-The integers in the symmetric interval from
+@cindex Two's complements
+With the binary, octal and hexadecimal display modes, Calc can
+display @expr{w}-bit integers using two's complement notation.  These
+versions of the display radices are selected with the key sequences
+@kbd{C-u d 2}, @kbd{C-u d 8} and @kbd{C-u d 6}, respectively.
+In these cases a negative word size might be appropriate
+(@pxref{Binary Functions}). In two's complement notation, the integers 
+in the (nearly) symmetric interval from
 @texline @math{-2^{w-1}}
 @infoline @expr{-2^(w-1)}
 to
 @texline @math{2^{w-1}-1}
 @infoline @expr{2^(w-1)-1}
-will be represented by using the integers from @expr{0} to @expr{2^w};
+are represented by the integers from @expr{0} to @expr{2^w-1}:
 the integers from @expr{0} to
 @texline @math{2^{w-1}-1}
 @infoline @expr{2^(w-1)-1}
-will be represented by themselves and the integers
-from
+are represented by themselves and the integers from
 @texline @math{-2^{w-1}}
 @infoline @expr{-2^(w-1)}
-to @expr{-1} will have @expr{2^w} added to them, so they will be
-represented by the integers from
+to @expr{-1} are represented by the integers from 
 @texline @math{2^{w-1}}
 @infoline @expr{2^(w-1)}
-to @expr{2^w}.  Calc will represent a twos-complement integer
-by the radix (either @expr{2}, @expr{8} or @expr{16}), two @kbd{#}
-symbols, and then the digits (including any necessary leading zeros to
-include all @expr{w} bits).  Numbers that are not displayed in 
-twos-complement notation (i.e., that aren't integers from
+to @expr{2^w-1} (the integer @expr{k} is represented by @expr{k+2^w}).
+Calc will display a two's complement integer by the radix (either
+@expr{2}, @expr{8} or @expr{16}), two @kbd{#} symbols, and then its
+representation (including any leading zeros necessary to include all
+@expr{w} bits).  In a two's complement display mode, numbers that
+are not displayed in two's complement notation (i.e., that aren't
+integers from  
 @texline @math{-2^{w-1}}
 @infoline @expr{-2^(w-1)}
 to