;
;==================================================================================================
; UTILITY FUNCTIONS
;==================================================================================================
;
;
CHR_CR		.EQU	0DH
CHR_LF		.EQU	0AH
CHR_BS		.EQU	08H
CHR_ESC		.EQU	1BH
;
;__________________________________________________________________________________________________
;
; UTILITY PROCS TO PRINT SINGLE CHARACTERS WITHOUT TRASHING ANY REGISTERS
;
PC_SPACE:
	PUSH	AF
	LD	A,' '
	JR	PC_PRTCHR

PC_PERIOD:
	PUSH	AF
	LD	A,'.'
	JR	PC_PRTCHR

PC_COLON:
	PUSH	AF
	LD	A,':'
	JR	PC_PRTCHR

PC_COMMA:
	PUSH	AF
	LD	A,','
	JR	PC_PRTCHR

PC_LBKT:
	PUSH	AF
	LD	A,'['
	JR	PC_PRTCHR

PC_RBKT:
	PUSH	AF
	LD	A,']'
	JR	PC_PRTCHR

PC_LT:
	PUSH	AF
	LD	A,'<'
	JR	PC_PRTCHR

PC_GT:
	PUSH	AF
	LD	A,'>'
	JR	PC_PRTCHR

PC_LPAREN:
	PUSH	AF
	LD	A,'('
	JR	PC_PRTCHR

PC_RPAREN:
	PUSH	AF
	LD	A,')'
	JR	PC_PRTCHR

PC_ASTERISK:
	PUSH	AF
	LD	A,'*'
	JR	PC_PRTCHR

PC_CR:
	PUSH	AF
	LD	A,CHR_CR
	JR	PC_PRTCHR

PC_LF:
	PUSH	AF
	LD	A,CHR_LF
	JR	PC_PRTCHR

PC_PRTCHR:
	CALL	COUT
	POP	AF
	RET

NEWLINE:
	CALL	PC_CR
	CALL	PC_LF
	RET
;
; PRINT THE HEX BYTE VALUE IN A
;
PRTHEXBYTE:
	PUSH	AF
	PUSH	DE
	LD	DE,HEXSTRBUF
	CALL	HEXSTRBYTE
	LD	A,'$'
	LD	(DE),A
	LD	DE,HEXSTRBUF
	CALL	WRITESTR
	POP	DE
	POP	AF
	RET
;
; PRINT THE HEX WORD VALUE IN BC
;
PRTHEXWORD:
	PUSH	AF
	LD	A,B
	CALL	PRTHEXBYTE
	LD	A,C
	CALL	PRTHEXBYTE
	POP	AF
	RET
;
; CONVERT VALUE IN A TO A 2 CHARACTER HEX STRING AT DE
;
HEXCHR	.TEXT	"0123456789ABCDEF"
;
HEXSTRBYTE:
	PUSH	BC
	PUSH	HL
	PUSH	AF
	LD	BC,0
	RRA
	RRA
	RRA
	RRA
	AND	0FH
	LD	C,A
	LD	HL,HEXCHR
	ADD	HL,BC
	LD	A,(HL)
	LD	(DE),A
	INC	DE
	POP	AF
	PUSH	AF
	LD	BC,0
	AND	0FH
	LD	C,A
	LD	HL,HEXCHR
	ADD	HL,BC
	LD	A,(HL)
	LD	(DE),A
	INC	DE
	POP	AF
	POP	HL
	POP	BC
	RET
;
; CONVERT VALUE IN BC TO A 4 CHARACTER HEX STRING AT DE
;
HEXSTRWORD:
	LD	A,B
	CALL	HEXSTRBYTE
	LD	A,C
	CALL	HEXSTRBYTE
	RET

;
; PRINT A BYTE BUFFER IN HEX POINTED TO BY DE
; REGISTER A HAS SIZE OF BUFFER
;
PRTHEXBUF:
	CP	0		; EMPTY BUFFER?
	JP	Z,PRTHEXBUF2
	
	LD	B,A
PRTHEXBUF1:
	CALL	PC_SPACE
	LD	A,(DE)
	CALL	PRTHEXBYTE
	INC	DE
	DJNZ	PRTHEXBUF1
	JP	PRTHEXBUFX
	
PRTHEXBUF2:
	CALL	PC_SPACE
	LD	DE,STR_EMPTY
	CALL	WRITESTR

PRTHEXBUFX:
	RET
;
; OUTPUT A '$' TERMINATED STRING
;
WRITESTR:
	PUSH	AF
WRITESTR1:
	LD	A,(DE)
	CP	'$'			; TEST FOR STRING TERMINATOR
	JP	Z,WRITESTR2
	CALL	COUT
	INC	DE
	JP	WRITESTR1
WRITESTR2:
	POP	AF
	RET
;
; PANIC: TRY TO DUMP MACHINE STATE AND HALT
;
PANIC:
	PUSH	HL
	PUSH	DE
	PUSH	BC
	PUSH	AF
	LD	DE,STR_PANIC
	CALL	WRITESTR
	LD	DE,STR_AF
	CALL	WRITESTR
	POP	BC
	CALL	PRTHEXWORD
	LD	DE,STR_BC
	CALL	WRITESTR
	POP	BC
	CALL	PRTHEXWORD
	LD	DE,STR_DE
	CALL	WRITESTR
	POP	BC
	CALL	PRTHEXWORD
	LD	DE,STR_HL
	CALL	WRITESTR
	POP	BC
	CALL	PRTHEXWORD
	LD	DE,STR_PC
	CALL	WRITESTR
	POP	BC
	CALL	PRTHEXWORD
	LD	DE,STR_SP
	CALL	WRITESTR
	LD	(PANIC_SP),SP
	LD	BC,(PANIC_SP)
	CALL	PRTHEXWORD
	JP	0
;
;==================================================================================================
; CONSOLE CHARACTER I/O HELPER ROUTINES (REGISTERS PRESERVED)
;==================================================================================================
;
; OUTPUT CHARACTER FROM A
COUT:
	PUSH	AF
	PUSH	BC
	PUSH	DE
	PUSH	HL
#IFDEF CIOMODE_CONSOLE
  #DEFINE CIOMODE_NONDOS
	LD	E,A
	LD	A,(CONDEV)
	LD	C,A
	LD	B,BF_CIOOUT
	CALL	BIOS_DISPATCH
#ENDIF
#IFDEF CIOMODE_CBIOS
  #DEFINE CIOMODE_NONDOS
	LD	C,A
	CALL	CBIOS_CONOUT
#ENDIF
#IFNDEF CIOMODE_NONDOS
	LD	E,A
	LD	C,03H
	CALL	0005H
#ENDIF
	POP	HL
	POP	DE
	POP	BC
	POP	AF
	RET
;
; INPUT CHARACTER TO A
;
CIN:
	PUSH	BC
	PUSH	DE
	PUSH	HL
#IFDEF CIOMODE_CONSOLE
  #DEFINE CIOMODE_NONDOS
	LD	A,(CONDEV)
	LD	C,A
	LD	B,BF_CIOIN
	CALL	BIOS_DISPATCH
	LD	A,E
#ENDIF
#IFDEF CIOMODE_CBIOS
  #DEFINE CIOMODE_NONDOS
	CALL	CBIOS_CONIN
#ENDIF
#IFNDEF CIOMODE_NONDOS
	LD	C,01H
	CALL	0005H
#ENDIF
	POP	HL
	POP	DE
	POP	BC
	RET
;
; RETURN INPUT STATUS IN A (0 = NO CHAR, !=0 CHAR WAITING)
;
CST:
	PUSH	BC
	PUSH	DE
	PUSH	HL
#IFDEF CIOMODE_CONSOLE
  #DEFINE CIOMODE_NONDOS
	LD	B,BF_CIOIST
	LD	A,(CONDEV)
	LD	C,A
	CALL	BIOS_DISPATCH
#ENDIF
#IFDEF CIOMODE_CBIOS
  #DEFINE CIOMODE_NONDOS
	CALL	CBIOS_CONST
#ENDIF
#IFNDEF CIOMODE_NONDOS
	LD	C,0BH
	CALL	0005H
#ENDIF
	POP	HL
	POP	DE
	POP	BC
	RET
;
STR_PANIC	.DB	"\r\n\r\n>>> FATAL ERROR:$"
STR_AF		.DB	" AF=$"
STR_BC		.DB	" BC=$"
STR_DE		.DB	" DE=$"
STR_HL		.DB	" HL=$"
STR_PC		.DB	" PC=$"
STR_SP		.DB	" SP=$"
;
; INDIRECT JUMP TO ADDRESS IN HL
;
;   MOSTLY USEFUL TO PERFORM AN INDIRECT CALL LIKE:
;     LD	HL,xxxx
;     CALL	JPHL
;
JPHL:	JP	(HL)
;
; DELAY ABOUT 25us (100 TSTATES INCLUDING CALL AND RET)
;
;	TOTAL T STATES = ((B*13) + 51)
;	4MHZ CPU, B=4, 103 T STATES = 25.75us
;	8MHZ CPU, B=12, 207 TSTATES = 25.875us
;	B = ((2 * FREQ) - 4)
;
DELAY:					; 17 T STATES (FOR CALL)
	PUSH	BC			; 11 T STATES
	LD	B,((CPUFREQ * 2)  - 4)	; 8 T STATES
	DJNZ	$			; (B*13) - 5 T STATES
	POP	BC			; 10 T STATES
	RET				; 10 T STATES
;
; DELAY 25us * VALUE IN DE (VARIABLE DELAY)
;
VDELAY:
	CALL	DELAY
	DEC	DE
	LD	A,D
	OR	E
	JP	NZ,VDELAY
	RET
;
; DELAY ABOUT 0.5 SECONDS = 25us * 20,000
;
LDELAY:
	PUSH	DE
	LD	DE,20000
	CALL	VDELAY
	POP	DE
	RET
;
; MULTIPLY 8-BIT VALUES
; IN:  MULTIPLY H WITH E
; OUT: HL = RESULT
;
MULT8:
	LD D,0
	LD L,D
	LD B,8
MULT8_LOOP:
	ADD HL,HL
	JR NC,MULT8_NOADD
	ADD HL,DE
MULT8_NOADD:
	DJNZ MULT8_LOOP
	RET
;
;==================================================================================================
; DSKY KEYBOARD ROUTINES
;==================================================================================================
;
#IF (DSKYENABLE)
;
;    _____C0______C1______C2______C3__
;B5 |	$20 D	$60 E	$A0 F	$E0 BO
;B4 |	$10 A	$50 B	$90 C	$D0 GO
;B3 |	$08 7	$48 8	$88 9	$C8 EX
;B2 |	$04 4	$44 5	$84 6	$C4 DE
;B1 |	$02 1	$42 2	$82 3	$C2 EN
;B0 |	$01 FW	$41 0	$81 BK	$C1 CL
;
KY_0	.EQU	000H
KY_1	.EQU	001H
KY_2	.EQU	002H
KY_3	.EQU	003H
KY_4	.EQU	004H
KY_5	.EQU	005H
KY_6	.EQU	006H
KY_7	.EQU	007H
KY_8	.EQU	008H
KY_9	.EQU	009H
KY_A	.EQU	00AH
KY_B	.EQU	00BH
KY_C	.EQU	00CH
KY_D	.EQU	00DH
KY_E	.EQU	00EH
KY_F	.EQU	00FH
KY_FW	.EQU	010H	; FORWARD
KY_BK	.EQU	011H	; BACKWARD
KY_CL	.EQU	012H	; CLEAR
KY_EN	.EQU	013H	; ENTER
KY_DE	.EQU	014H	; DEPOSIT
KY_EX	.EQU	015H	; EXAMINE
KY_GO	.EQU	016H	; GO
KY_BO	.EQU	017H	; BOOT
;
;__DSKY_INIT_________________________________________________________________________________________
;
;  CHECK FOR KEY PRESS, SAVE RAW VALUE, RETURN STATUS
;____________________________________________________________________________________________________
;
DSKY_INIT:
	LD	A,82H
	OUT 	(PPIX),A
	LD	A,30H			;disable /CS on PPISD card(s)
	OUT	(PPIC),A
	XOR	A
	LD	(KY_BUF),A
	RET
#IFDEF DSKY_KBD
;
;__KY_STAT___________________________________________________________________________________________
;
;  CHECK FOR KEY PRESS, SAVE RAW VALUE, RETURN STATUS
;____________________________________________________________________________________________________
;
KY_STAT:
	; IF WE ALREADY HAVE A KEY, RETURN WITH NZ
	LD	A,(KY_BUF)
	OR	A
	RET	NZ
	; SCAN FOR A KEYPRESS, A=0 NO DATA OR A=RAW BYTE
	CALL	KY_SCAN			; SCAN KB ONCE
	OR	A			; SET FLAGS
	RET	Z			; NOTHING FOUND, GET OUT
	LD	(KY_BUF),A		; SAVE RAW KEYCODE
	RET				; RETURN
;
;__KY_GET____________________________________________________________________________________________
;
;  GET A SINGLE KEY (WAIT FOR ONE IF NECESSARY)
;____________________________________________________________________________________________________
;
KY_GET:
	; SEE IF WE ALREADY HAVE A KEY SAVED, GO TO DECODE IF SO
	LD	A,(KY_BUF)
	OR	A
	JR	NZ,KY_DECODE
	; NO KEY SAVED, WAIT FOR ONE
KY_STATLOOP:
	CALL	KY_STAT
	OR	A
	JR	Z,KY_STATLOOP
	; DECODE THE RAW VALUE
KY_DECODE:
	LD	D,00H
	LD	HL,KY_KEYMAP		; POINT TO BEGINNING OF TABLE	
KY_GET_LOOP:
	CP	(HL)			; MATCH?
	JR	Z,KY_GET_DONE		; FOUND, DONE
	INC	HL
	INC	D			; D + 1
	JR	NZ,KY_GET_LOOP		; NOT FOUND, LOOP UNTIL EOT			
KY_GET_DONE:
	; CLEAR OUT KEY_BUF
	XOR	A
	LD	(KY_BUF),A
	; RETURN THE INDEX POSITION WHERE THE RAW VALUE WAS FOUND
	LD	A,D
	RET
;	
;__KY_SCAN____________________________________________________________________________________________
;
;  SCAN KEYBOARD MATRIX FOR AN INPUT
;____________________________________________________________________________________________________
;
KY_SCAN:
	LD	C,0000H
	LD	A,41H | 30H		;  SCAN COL ONE
	OUT 	(PPIC),A		;  SEND TO COLUMN LINES
	CALL	DELAY			;  DEBOUNCE
	IN	A,(PPIB)		;  GET ROWS
	AND	7FH			;ignore PB7 for PPISD
	CP	00H 			;  ANYTHING PRESSED?
	JR	NZ,KY_SCAN_FOUND	;  YES, EXIT 

	LD	C,0040H
	LD	A,42H | 30H		;  SCAN COL TWO
	OUT 	(PPIC),A		;  SEND TO COLUMN LINES
	CALL	DELAY			;  DEBOUNCE
	IN	A,(PPIB)		;  GET ROWS
	AND	7FH			;ignore PB7 for PPISD
	CP	00H 			;  ANYTHING PRESSED?
	JR	NZ,KY_SCAN_FOUND	;  YES, EXIT 

	LD	C,0080H
	LD	A,44H | 30H		;  SCAN COL THREE
	OUT	(PPIC),A		;  SEND TO COLUMN LINES
	CALL	DELAY			;  DEBOUNCE
	IN	A,(PPIB)		;  GET ROWS
	AND	7FH			;ignore PB7 for PPISD
	CP	00H 			;  ANYTHING PRESSED?
	JR	NZ,KY_SCAN_FOUND	;  YES, EXIT 

	LD	C,00C0H			;
	LD	A,48H | 30H		;  SCAN COL FOUR
	OUT	(PPIC),A		;  SEND TO COLUMN LINES
	CALL	DELAY			;  DEBOUNCE
	IN	A,(PPIB)		;  GET ROWS
	AND	7FH			;ignore PB7 for PPISD
	CP	00H 			;  ANYTHING PRESSED?
	JR	NZ,KY_SCAN_FOUND	;  YES, EXIT 

	LD	A,040H | 30H		;  TURN OFF ALL COLUMNS
	OUT	(PPIC),A		;  SEND TO COLUMN LINES
	LD	A,00H			;  RETURN NULL
	RET				;  EXIT

KY_SCAN_FOUND:
	AND	3FH			;  CLEAR TOP TWO BITS
	OR	C			;  ADD IN ROW BITS 
	LD	C,A			;  STORE VALUE

	; WAIT FOR KEY TO BE RELEASED
	LD	A,4FH | 30H		; SCAN ALL COL LINES
	OUT	(PPIC),A		; SEND TO COLUMN LINES
	CALL	DELAY			; DEBOUNCE
KY_CLEAR_LOOP:				; WAIT FOR KEY TO CLEAR
	IN	A,(PPIB)		; GET ROWS
	AND	7FH			;ignore PB7 for PPISD
	CP	00H 			; ANYTHING PRESSED?
	JR	NZ,KY_CLEAR_LOOP	; YES, LOOP UNTIL KEY RELEASED

	LD	A,040H | 30H		;  TURN OFF ALL COLUMNS
	OUT 	(PPIC),A		;  SEND TO COLUMN LINES

	LD	A,C			;  RESTORE VALUE
	RET
;
;_KEYMAP_TABLE_____________________________________________________________________________________________________________
; 
KY_KEYMAP:
;               0    1    2    3    4    5    6    7
	.DB	041H,002H,042H,082H,004H,044H,084H,008H
;               8    9    A    B    C    D    E    F
	.DB	048H,088H,010H,050H,090H,020H,060H,0A0H
;               FW   BK   CL   EN   DE   EX   GO   BO
	.DB	001H,081H,0C1H,0C2H,0C4H,0C8H,0D0H,0E0H
#ENDIF	; DSKY_KBD
;
;==================================================================================================
; DSKY HEX DISPLAY
;==================================================================================================
;
DSKY_HEXOUT:
	LD	B,DSKY_HEXBUFLEN
	LD	HL,DSKY_BUF
	LD	DE,DSKY_HEXBUF
DSKY_HEXOUT1:
	LD	A,(DE)		; FIRST NIBBLE
	SRL	A
	SRL	A
	SRL	A
	SRL	A
	LD	(HL),A
	INC	HL
	LD	A,(DE)		; SECOND NIBBLE
	AND	0FH
	LD	(HL),A
	INC	HL
	INC	DE		; NEXT BYTE
	DJNZ	DSKY_HEXOUT1

	LD	A,82H			; SETUP PPI
	OUT	(PPIX),A
	CALL	DSKY_COFF
	LD	A,0D0H			; 7218 -> (DATA COMING, HEXA DECODE)
	OUT	(PPIA),A
	CALL	DSKY_STROBEC

	LD	HL,DSKY_BUF		; POINT TO START OF BUF
	LD	B,DSKY_BUFLEN		; NUMBER OF DIGITS
	LD	C,PPIA
DSKY_HEXOUT2:
	OUTI
	JP	Z,DSKY_STROBE		; DO FINAL STROBE AND RETURN
	CALL	DSKY_STROBE
	JR	DSKY_HEXOUT2
	
DSKY_STROBEC:
	LD	A,80H | 30H
	JP	DSKY_STROBE0

DSKY_STROBE:
	LD	A,00H | 30H		; SET WRITE STROBE

DSKY_STROBE0:
	OUT	(PPIC),A		; OUT TO PORTC
	CALL	DELAY			; DELAY
DSKY_COFF
	LD	A,40H | 30H		; SET CONTROL PORT OFF
	OUT	(PPIC),A		; OUT TO PORTC
	CALL	DELAY			; WAIT
	RET
#ENDIF
;
;==================================================================================================
; DATA
;==================================================================================================
;
STR_EMPTY	.TEXT	"<EMPTY>$"
;
HEXSTRBUF	.TEXT	"XX$"
;	
KY_BUF		.DB	0
DSKY_BUF:	.FILL	8,0
DSKY_BUFLEN	.EQU	$ - DSKY_BUF
DSKY_HEXBUF	.FILL	4,0
DSKY_HEXBUFLEN	.EQU	$ - DSKY_HEXBUF
;
PANIC_SP	.DW	0