[Coco] CCASM procedures

[Roger Taylor]

I hope this scheme is okay for accessing symbols outside of a namespace or 
procedure.  By prefixing any identifier with ':', it prevents the 
expression evaluator from preprending whatever namespace or procedure name 
is in effect.

I defined "outside" in the main code, then accessed it from within the 
procedure (which otherwise follows namespace rules).

I want to get to a stopping point because there's so many ideas that can be 
put to use to make the assembler behave sort of like a compiler when it 
comes to lex levels, scoping, etc.  If I can just simulate that to some 
small degree, I'll be happy and can start writing some libraries.


	org	3584

res	rmb	2
outside	rmb	2

* pass-by-reference example

shl	proc	bits:byte,value:word,result:word
count	var	1
	begin	shl		procedure entry
	ldb	bits,u
	stb	count,u
	ldd	value,u		access pass-by-value parameter
a@	lslb
	rola
	dec	count,u
	bne	a@
	std	[result,u]	change pass-by-ref parameter
	lda	:outside		access a symbol outside of the procedure
*	lda	outside		<--- generates UNDEFINED SYMBOL error
	endproc

start	call	shl,2,4,res
	ldd	res
	std	1024
	rts

	end	start

	

-- 
Roger Taylor