; From Ipso Facto issue #29 May 1982
; "Forth implementation notes, ACE" by Tony Hill, Ontario Canada
;
;******************************************************* 
;* FORTH I/O CODE -FOR INTERFACE TO A RESIDENT MONITOR * 
;* THIS CODE IS INTENDED TO PROVIDE AN EXAMPLE OF HOW  *
;* TO INTERFACE THE I/O ROUTINES IN YOUR RESIDENT      * 
;* MONITOR TO FIG-FORTH. CAREFUL STUDY OF THE REGISTER * 
;* USAGE OF YOUR MONITOR IS NECESSARY TO INSURE THAT   * 
;* ANY OF THE RESERVED FORTH REGISTERS IT USES ARE     *
;* SAVED BEFORE THE MONITOR ROUTINES ARE CALLED.       *
,* MODIFY THIS CODE ACCORDINGLY.                       * 
;******************************************************* 

;******************************
;* SAMPLE INITIALIZATION CODE * 
;******************************

0000 F8 07	INIT:	LDI START ; SET R(3) AS THE PC 
0002 A3 	PLO R3 ;
0003 F8 00 LDI #00 
0005 B3 	PHI R3 
0006 D3 	SEP R3 ; 
0007 F8 XY START: LDI CALL/256 ; SET UP SCRT REGISTERS 
0009 B4 	PHI R4 ; R(4) AND R(5)
OOOA F8 XY LDI RETURN/256 
OOOC D5 	PHI R5 ; ( ANY OTHER INITIALIZE 
OOOD F8 XZ LDI CALL ; CODE WOULD GO HERE 
OOOF A4 	PLO R4 ; TOO ) 
0010 F8 YZ LDI RETURN ; 
0012 A5 	PLO R5 ; 
0013 30 5E	BR #5E ; JUMP TO START OF FORTH 

;*********************************
;* EMIT -CHARACTER OUTPUT ROUTINE 
;*********************************

		.ORG #153D 
153D 19 EMIT: INC R9 SETUP R(9) 
153E E2 	SEX R2 ; 
153F 9A 	GHI RA ; EXAMPLE OF HOW TO SAVE A 
1540 73 	STXD ; RESERVED REGISTER IF USED 
1541 8A 	GLO RA ; BY THE MONITOR OUTPUT ROUTINE 
1542 73 	STXD ; 
1543 09 	LDN R9 ; GET OUTPUT BYTE 
1544 D4 WX ZY +CALL OUTPUT ; CALL MONITOR OUTPUT ROUTINE 
1547 60 	IRX ; EXAMPLE OF HOW TO RESTORE THE 
1548 72 	LDXA ; REGISTER SAVED AT THE START 
1549 AA 	PLO RA ; OF THIS ROUTINE 
154A F0 	LDX ;
l54B BA 	PHI RA ; 
154C 29 	DEC R9 ; 
154D 29 	DEC R9 ; CLEAN UP R(9) FOR FORTH
154E 29 	DEC R9 ; 
154F DC 	SEP RC ; RETURN TO FORTH INTERPRETER 

;***************************************
;* CR-CARRIAGE RETURN OUTPUT ROUTINE . * 
;***************************************

1550 E2 CR: SEX R2 ;
1551 9A 	GHI RA ; EXAMPLE OF HOW TO SAVE A
1552 73 	STXD ; RESERVED REGISTER IF USED
1553 8A 	GLO RA ; BY THE MONITOR OUTPUT ROUTINE
1554 73 	STXD ; 
1555 F8 0D LDI #0D ; LOAD A CARRIAGE RETURN
1557 D4 WX ZY +CALL OUTPUT ; PASS IT TO MONITOR OUTPUT
155A F8 0A LDI #0A ; LOAD A LINE FEED
155C D4 WX ZY +CALL OUTPUT ; PASS IT TO MONITOR OUTPUT 
155F 60 	IRX ; EXAMPLE OF HOW TO RESTORE THE
1560 72 	LDXA ; REGISTER SAVED AT THE START
1561 AA 	PLO RA ; OF THIS ROUTINE 
1562 F0	LDX
1563 BA 	PHI RA 
1564 DC 	SEP RC ;RETURN TO FORTH INTERPRETER 

;*********************************
;* KEY -CHARACTER INPUT ROUTINE * 
;*******************************

1565 19 KEY: INC R9 ; SET UP STORAGE AREA 
1566 19	INC R9 
1567 19	INC R9 
1568 E2	SEX R2 ; 
1569 9A	GHI RA ; EXAMPLE OF HOW TO SAVE A
156A 73	STDX ;RESERVED REGISTER IF USED 
156B 8A 	GLO RA ; BY THE MONITOR OUTPUT ROUTINE
156C 73	STXD 
156D D4 ZX WY +CALL INPUT	;GET INPUT FROM MONITOR ROUTINE
1570 60 	IRX	; EXAMPLE OF HOW TO roi:ESTORE THE 
1571 72 	LDXA	; REGISTER SAVED AT THE START 
1572 AA 	PLO RA	; Of THIS ROUTINE 
1573 F0 	LDX
1574 BA 	PHI RA
1575 9F 	GHI RF ; GET BYTE PASSED BACK FROM INPUT
1576 59 	STR R9 ; SAVE IT 
1577 29 	DEC R9 ; Cl.EAN UP STORAGE AREA
1578 F8 00 LDI #00
157A 59 	STR R9 
157B DC 	SEP RC 


;***************************************
;* QTERM -BREAK CONDITION TEST ROUTINE * 
;***************************************

157C 19 QTERM: INC R9 , SAMPLE DUMMY BREAK ROUTINE
157D 19 	INC R9 ;
157E 19 	INC R9 ;
157F F8 00 LDI #00 ;
1581 59 	STR R9 ;
1582 29 	DEC R9 ,
1583 59 	STR R9 ;
1584 DC 	SEP RC ;