; FKEY for TurboDOS
; By ESKAY 4/85 No Lefts Reversed
;
	LOC	Data#
;
LEADIN:: BYTE	0X01		; LEAD-IN CHARACTER
LASTC:	BYTE	0		; PREVIOUS CHAR
INFK:	BYTE	0		; FF=IN SEQUENCE
FKPTR:	WORD	0		; POINTS TO CURRENT FKEY
FKEYS::	BYTE	0
	RES	4095
;
	LOC	Code#
;
FKEY::	MOV	BX,&LEADIN
	CMP	AL,[BX]
	JZ	ISLI		; JUMP IF IT IS LEADIN
	INC	BX
	MOV	[BX],AL
	RET
;
; COME HERE IF WE JUST RECEIVED A LEADIN CHARACTER
;
ISLI:	CMP	FKEYS,=0
	JNZ	DOFK		; FKEYS ARE ENABLED
	RET
;
DOFK:	INC	BX
	MOV	[BX],AL		; SET PREVIOUS CHAR
	PUSH	DX
	MOV	DL,=1		; GET CHAR
	CALL	SERIAL#
;
; THIS CHAR IS THE FKEY
;
	PUSH	CX
	MOV	BX,&FKEYS-1	; HL POINTS TO FKEYS
	MOV	CX,=4095	; 4095 CHARS TO CHECK
	MOV	AH,AL		; SAVE CHAR
BEGOFK:	INC	BX
	CMP	[BX],AH
	JZ	FNDFK
	CMP	BYTE [BX],=0XFF	;EOF?
	JZ	PDEX
	INC	BX
	DEC	CX
NXTFK:	CMP	BYTE [BX],=0
	JZ	BEGOFK
	CMP	BYTE [BX],=0XFF
	JZ	PDEX
	INC	BX
	LOOP	NXTFK
PDEX:	POP	CX
	POP	DX
	RET			; FKEY NOT IN TABLE
;
FNDFK:	INC	BX
	MOV	BYTE INFK,=0XFF
	MOV	AL,[BX]
	INC	BX
	MOV	FKPTR,BX
	JMPS	PDEX
;
GETFK::	CMP	BYTE INFK,=0
	JNZ	__X
	RET			; NO FKEY SEQUENCE
;
__X:	MOV	BX,FKPTR
	MOV	AL,[BX]
	INC	FKPTR
	OR	AL,AL
	JNZ	RETFK
	MOV	BYTE INFK,=0	; RESET IN-FK FLAG
	RET			; RETURN (CONTINUE NORMALLY)
;
RETFK:	POP	BX		; KILL RET ADDR
	RET			; RETURN TO PREVIOUS CALLER
	END