; isdigit(c) -- decimal-p
	.globl	_isdigit
_isdigit:
	jsr	popax		; get the char
	cmp	#'0'		; < '0'?
	bcc	ret0		; less, return 0
	cmp	#'9'+1		; >= '8'?
	bcs	ret0		; yes, return 0
	lda	#1		; no, return a 1
	rts
ret0:
	txa
	rts