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Date: Fri, 2 Feb 2001 14:13:02 -0600
From: JT Williams <jeffw AT darwin DOT sfbr DOT org>
To: djgpp-workers AT delorie DOT com
Cc: Bill Currie <bill AT taniwha DOT org>
Subject: djasm.txi patch
Message-ID: <20010202141302.A7211@kendall.sfbr.org>
Mail-Followup-To: djgpp-workers AT delorie DOT com, Bill Currie <bill AT taniwha DOT org>
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Reply-To: djgpp-workers AT delorie DOT com

Here's a partial patch for djasm.txi (the part that adds discussion
of enumeration type).  Could a few extra eyes read this over before
I commit it?  I'm not sure about some of the markup.  Thanks.
(And thanks, Bill, for making it so easy ;-)
-- 
jtw


--- djasm.txi	Sun Jan 14 16:45:43 2001
+++ ./my-djasm-docs/djasm.txi	Fri Feb  2 14:00:07 2001
@@ -743,6 +783,76 @@
 system tables).
 
 @comment node-name, next, previous, up
+@node Enumerations
+@subsubsection Enumerations
+
+@pindex enumeration
+@cindex type AT r{, enumeration}
+
+The enumeration type allows arbitrary mnemonic identifiers (the
+`enumeration constants') to be mapped to a set of integer values.
+A textbook example is that of defining a boolean variable.
+The following construct defines @samp{boolean} as an enumeration
+type that can take the values 0 (false) or 1 (true).
+
+@example
+.enum boolean
+        false
+        true
+.ends
+@end example
+
+@noindent
+In this example, @samp{pets} is defined to be an enumeration type
+having integral values 0 (bird), 1 (cat), 2 (dog), or 3 (rock).
+
+@example
+.enum pets
+        bird
+        cat
+        dog
+        rock
+.ends
+@end example
+
+@noindent
+The above enumeration types could then be referenced as follows:
+
+@example
+.start
+        nop
+        mov     ax,true                 ; ax <- 1
+        mov     bx,pets.dog             ; bx <- 2
+        mov     cx,pets.rock            ; cx <- 3
+        mov     dx,pets.bird            ; dx <- 0
+        int     0x20
+@end example
+
+If the enumeration constants are not explicitly initialized, then they
+are assigned consecutive integer values starting with zero.
+Explicitly and implicitly initialized enumeration constants can be
+used within the same enumeration type, in which case an enumeration
+constant without an initializer will be assigned either the predecessor
+or successor of the adjacent enumeration constant.
+
+In this example, the enumeration constants @samp{foo}, @samp{bar},
+and @samp{e} are implicitly initialized.
+The enumeration @samp{snafu} therefore takes one of the following integer
+values: foo (-1), bar (0), a (1), b (2), c (4), d (8), or e (9).
+
+@example
+.enum snafu
+        foo
+        bar
+        a=1
+        b=2
+        c=4
+        d=8
+        e
+.ends
+@end example
+
+@comment node-name, next, previous, up
 @node Prefixes
 @subsection Segment Override Prefixes