From eed2b4fc6ce2768451bd0a68c0aabf232f8b8a96 Mon Sep 17 00:00:00 2001
From: Charles Mangin <option8@option8.com>
Date: Sun, 13 Jan 2019 09:47:25 -0500
Subject: [PATCH] Boot LOADER.SYSTEM

---
 LOADER.s | 126 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 126 insertions(+)
 create mode 100644 LOADER.s

diff --git a/LOADER.s b/LOADER.s
new file mode 100644
index 0000000..c78a975
--- /dev/null
+++ b/LOADER.s
@@ -0,0 +1,126 @@
+	DSK LOADER
+
+**************************************************
+* boot stub at $2000 to BLOAD real program at $0C00, JMP $0C00
+**************************************************
+* Variables
+**************************************************
+
+
+**************************************************
+* Apple Standard Memory Locations
+**************************************************
+CLRLORES  	EQU	$F832
+LORES     	EQU	$C050
+TXTSET    	EQU	$C051
+MIXCLR    	EQU	$C052
+MIXSET    	EQU	$C053
+TXTPAGE1  	EQU	$C054
+TXTPAGE2  	EQU	$C055
+KEY       	EQU	$C000
+C80STOREOF	EQU	$C000
+C80STOREON	EQU	$C001
+STROBE    	EQU	$C010
+SPEAKER   	EQU	$C030
+VBL       	EQU	$C02E
+RDVBLBAR  	EQU	$C019       ;not VBL (VBL signal low
+WAIT		EQU	$FCA8 
+RAMWRTAUX 	EQU	$C005
+RAMWRTMAIN	EQU	$C004
+SETAN3    	EQU	$C05E       ;Set annunciator-3 output to 0
+SET80VID  	EQU	$C00D       ;enable 80-column display mode (WR-only)
+CLR80VID	EQU	$C00C
+HOME 		EQU	$FC58		; clear the text screen
+CH        	EQU	$24			; cursor Horiz
+CV        	EQU	$25			; cursor Vert
+VTAB      	EQU	$FC22       ; Sets the cursor vertical position (from CV)
+COUT      	EQU	$FDED       ; Calls the output routine whose address is stored in CSW,
+          	   	            ;  normally COUTI
+STROUT		EQU	$DB3A 		;Y=String ptr high, A=String ptr low
+		
+ALTTEXT		EQU	$C055
+ALTTEXTOFF	EQU	$C054
+	
+ROMINIT   	EQU $FB2F
+ROMSETKBD 	EQU $FE89
+ROMSETVID 	EQU $FE93
+	
+ALTCHAR		EQU	$C00F		; enables alternative character set - mousetext
+	
+BLINK		EQU	$F3
+SPEED		EQU	$F1
+
+BELL   		EQU	$FF3A     				; Monitor BELL routine
+CROUT  		EQU	$FD8E     				; Monitor CROUT routine
+PRBYTE 		EQU	$FDDA     				; Monitor PRBYTE routine
+MLI    		EQU	$BF00     				; ProDOS system call
+OPENCMD		EQU	$C8						; OPEN command index
+READCMD		EQU	$CA						; READ command index
+CLOSECMD	EQU	$CC						; CLOSE command index
+
+
+**************************************************
+* START - sets up various fiddly zero page bits
+**************************************************
+
+				ORG $2000						; PROGRAM DATA STARTS AT $2000
+
+				JSR BLOAD						; BLOAD DATA
+					
+				JMP $0800						; jump to the new location
+	
+**************************************************
+*	Load "GREENSCALE" into memory at $0800
+**************************************************
+
+
+BLOAD   		JSR	OPEN    				;open "DATA"
+       			JSR READ
+       			JSR ERROR					
+				JSR CLOSE
+       			JSR ERROR					
+       			RTS            				;Otherwise done
+				
+OPEN 			JSR	MLI       				;Perform call
+       			DB	OPENCMD    				;CREATE command number
+       			DW	OPENLIST   				;Pointer to parameter list
+       			JSR	ERROR     				;If error, display it
+       			LDA REFERENCE
+       			STA READLIST+1
+       			STA CLOSELIST+1
+       			RTS				
+
+READ			JSR MLI
+				DB	READCMD
+				DW	READLIST
+				RTS
+
+CLOSE			JSR MLI
+				DB	CLOSECMD
+				DW	CLOSELIST
+				RTS
+				
+ERROR  			JSR	PRBYTE    				;Print error code
+       			JSR	BELL      				;Ring the bell
+       			JSR	CROUT     				;Print a carriage return
+       			RTS				
+
+OPENLIST		DB	$03						; parameter list for OPEN command
+				DW	FILENAME
+				DA	MLI-$400				; buffer snuggled up tight with PRODOS
+REFERENCE		DB	$00						; reference to opened file
+			
+READLIST		DB	$04
+				DB	$00						; REFERENCE written here after OPEN
+				DB	$00,$08					; write to $0C00
+				DB	$FF,$FF					; read as much as $FFFF - should error out with EOF before that.
+TRANSFERRED		DB	$00,$00				
+
+CLOSELIST		DB	$01
+				DB	$00
+				
+FILENAME		DB	ENDNAME-NAME 			;Length of name
+NAME    		ASC	'/GREENSCALE/GREENSCALE' ;followed by the name
+ENDNAME 		EQU	*
+
+