Reworked version by Oliver Schmidt

git-svn-id: svn://svn.cc65.org/cc65/trunk@2913 b7a2c559-68d2-44c3-8de9-860c34a00d81

libsrc/apple2/dosdetect.s

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+;
+; Oliver Schmidt, 08.03.2004
+;
+; Identify DOS version we're running on as one of these:
+;
+; AppleDOS 3.3	$00
+; ProDOS 1.0.1	$10
+; ProDOS 1.0.2	$10
+; ProDOS 1.1.1	$11
+; ProDOS 1.2	$12
+; ProDOS 1.3	$13
+; ProDOS 1.4	$14
+; ProDOS 1.5	$15
+; ProDOS 1.6	$16
+; ProDOS 1.7	$17
+; ProDOS 1.8	$18
+; ProDOS 1.9	$18
+; ProDOS 2.0.1  $21
+; ProDOS 2.0.2  $22
+; ProDOS 2.0.3  $23
+
+
+	.constructor	initdostype
+	.export		__dos_type
+
+	.include	"apple2.inc"
+
+; Identify DOS version according to:
+; - "Beneath Apple ProDOS", chapter 6-63
+; - "Apple II ProDOS 8 TechNote #023: ProDOS 8 Changes and Minutia"
+; - ProDOS TechRefMan, chapter 5.2.4
+
+initdostype:
+	lda	MLI
+	cmp	#$4C		; Is MLI present? (JMP opcode)
+	bne	done
+	lda	$BFFF		; ProDOS KVERSION
+	cmp	#$10
+	bpl	L1
+	ora	#$10		; Make high nibble match major version
+L1:	sta	__dos_type
+done:	rts
+
+	.bss
+
+__dos_type:	.res	1