*************************************************************************
*                                                                       *
*       OSBYTE 122  KEYBOARD SCAN FROM &10 (16)                         *
*                                                                       *
*************************************************************************

    	            ;
F0CC	CLC         ;clear carry
F0CD	LDX #&10    ;set X to 10
    	            ;


*************************************************************************
*                                                                       *
*       OSBYTE 121  KEYBOARD SCAN FROM VALUE IN X                       *
*                                                                       *
*************************************************************************

F0CF	BCS &F068   ;if carry set (by osbyte 121) F068
    	            ;Jmps via KEYV and hence back to;


*************************************************************************
*        Scan Keyboard C=1, V=0 entry via KEYV                          *
*************************************************************************

F0D1	TXA         ;if X is +ve goto F0D9
F0D2	BPL &F0D9   ;
F0D4	JSR &F02A   ;else interrogate keyboard
F0D7	BCS &F12E   ;if carry set F12E to set Auto scan else
F0D9	PHP         ;push flags
F0DA	BCC &F0DE   ;if carry clear goto FODE else
F0DC	LDY #&EE    ;set Y so next operation saves to 2cd
F0DE	STA &01DF,Y ;can be 2cb,2cc or 2cd
F0E1	LDX #&09    ;set X to 9
F0E3	JSR &F129   ;select auto scan
F0E6	LDA #&7F    ;set port A for input on bit 7 others outputs
F0E8	STA &FE43   ;
F0EB	LDA #&03    ;stop auto scan
F0ED	STA &FE40   ;
F0F0	LDA #&0F    ;select non-existent keyboard column F (0-9 only!)
F0F2	STA &FE4F   ;
F0F5	LDA #&01    ;cancel keyboard interrupt
F0F7	STA &FE4D   ;
F0FA	STX &FE4F   ;select column X (9 max)
F0FD	BIT &FE4D   ;if bit 1 =0 there is no keyboard interrupt so
F100	BEQ &F123   ;goto F123
F102	TXA         ;else put column address in A

F103	CMP &01DF,Y ;compare with 1DF+Y
F106	BCC &F11E   ;if less then F11E
F108	STA &FE4F   ;else select column again
F10B	BIT &FE4F   ;and if bit 7 is 0
F10E	BPL &F11E   ;then F11E
F110	PLP         ;else push and pull flags
F111	PHP         ;
F112	BCS &F127   ;and if carry set goto F127
F114	PHA         ;else Push A
F115	EOR &0000,Y ;EOR with EC,ED, or EE depending on Y value
F118	ASL         ;shift left  
F119	CMP #&01    ;set carry if = or greater than number holds EC,ED,EE
F11B	PLA         ;get back A
F11C	BCS &F127   ;if carry set F127
F11E	CLC         ;else clear carry
F11F	ADC #&10    ;add 16
F121	BPL &F103   ;and do it again if 0=<result<128
F123	DEX         ;decrement X
F124	BPL &F0E3   ;scan again if greater than 0
F126	TXA         ;
F127	TAX         ;
F128	PLP         ;pull flags

F129	JSR &F12E   ;call autoscan
F12C	CLI         ;allow interrupts 
F12D	SEI         ;disable interrupts



*************Enable counter scan of keyboard columns *******************
    	            ;called from &EEFD, &F129

F12E	LDA #&0B    ;select auto scan of keyboard
F130	STA &FE40   ;tell VIA
F133	TXA         ;Get A into X
F134	RTS         ;and return