Here's a neat usage of macros for table/label generation.
Sometimes I need to have a table of vectors to code, so I can load a code
address via an entry number/index and then branch to the code. I usually
have a table of hand-maintained equates giving the 'NAME' of an entry and
its ordinal number, and I use that name (*2) to access the table entry. And
the table entries have to be in the same order as the numeric order of the
tokens.
TOKEN_JUMP equ 0
TOKEN_LOCK equ 1
TOKEN_MOVE equ 2
TOKEN_UNLOCK equ 3
TOKEN_DONE equ 4
TOKEN_FLIP equ 5
AnimVec
.word AnimateJUMP
.word AnimateLOCK
.word AnimateMOVE
.word AnimateUNLOCK
.word AnimateDONE
.word AnimateFLIP
AnimateJUMP
; code here
rts
AnimateLOCK
; code here
rts
;etc...
Here's a much better way...
;---------------------------------------------------------------------------
---
; Automatically define tokens and a vector table to token-processing
code
; This is fairly neat, as the ordering of the entries in the table
auto-generates
; the appropriate equates to access the table correctly!
TOK SET 0
MAC TOKEN
TOKEN_{1} equ TOK
TOK SET TOK + 1
.word Animate{1}
ENDM
AnimVec
TOKEN JUMP
TOKEN LOCK
TOKEN MOVE
TOKEN UNLOCK
TOKEN DONE
TOKEN FLIP
The big *advantage* of doing it with the macro like this is that you never
need worry about the values of tokens, or adding/removing or reordering
entries in the vector table. If you add a new entry to the AnimVec, a new
token is generated, with a new value, and all will continue working
properly.
There are a couple of gotchas - the entries in the table must be unique.
The labels of the code vectored TO should be of consistent format. That is
easy to get around, if you want to have two parameters for the macro - one
the label, one the token name.
Anyway, thought I'd pass this on. I find it quite elegant.
Cheers
A
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