Design change: Do keyboard polling internally without calling the kernal

in the system bank. For one this performs better (several %), second it
allows to handle the function keys in conformance with other platforms.
Without the custom keyboard routine, we would have to apply some more
magic to the function keys to make them work as with other cc65 targets.


git-svn-id: svn://svn.cc65.org/cc65/trunk@2811 b7a2c559-68d2-44c3-8de9-860c34a00d81

libsrc/cbm610/cgetc.s

@@ -5,69 +5,46 @@
 ;
 
 	.export	   	_cgetc
-	.import	   	plot, write_crtc, sys_bank, restore_bank
+	.import	   	plot, write_crtc
 	.import	   	cursor
-        .import         sysp0: zp, sysp3: zp
 
-	.include   	"cbm610.inc"
+        .import         keyidx: zp, keybuf: zp, config: zp
 
 
-_cgetc:	lda     IndReg
-        pha
-        lda     #$0F
-        sta     IndReg          ; Switch to the system bank
 
-        ldy     #$D1
-        lda     (sysp0),y       ; Get number of keys in keyboard buffer
-	bne	L2 	  	; Jump if there are already chars waiting
+_cgetc:	lda    	keyidx 	        ; Get number of characters
+	bne	L2    	  	; Jump if there are already chars waiting
 
 ; Switch on the cursor if needed
 
        	lda	cursor
-       	beq    	L0 	    	; Jump if no cursor
+       	beq	L1    	    	; Jump if no cursor
 
-       	jsr	plot		; Set the current cursor position
-        ldy     #$D4
-        lda     (sysp0),y       ; Get the cursor format
+       	jsr	plot  		; Set the current cursor position
        	ldy	#10
-       	jsr	write_crtc	; Set the cursor format
+       	lda	config 	       	; Cursor format
+       	jsr	write_crtc	; Set the cursor formar
 
-L0:     ldy     #$D1
-L1:     lda     (sysp0),y       ; Get the number of keys in the buffer
-       	beq	L1              ; Wait until we have some keys
+L1:    	lda	keyidx
+       	beq	L1
 
        	ldy	#10
-       	lda	#$20		; Cursor off
+       	lda	#$20  		; Cursor off
        	jsr	write_crtc
 
-L2:     ldy     #$D1
-        lda     (sysp0),y       ; Get number of chars in buffer
-        tax
-        ldy     #$AB
-        lda     (sysp3),y       ; Get first char from keyboard buffer
-        sta     c               ; Save for return
-        dex
-        txa
-        ldy     #$D1
-        sta     (sysp0),y
-        sei
-        jmp     L4
-L3:     iny
-        lda     (sysp3),y
-        dey
-        sta     (sysp3),y
-        iny
-L4:     dex
-        bpl     L3       
-        cli
+L2:    	ldx    	#$00  		; Get index
+       	ldy	keybuf		; Get first character in the buffer
+       	sei
+L3:    	lda	keybuf+1,x	; Move up the remaining chars
+       	sta	keybuf,x
+       	inx
+       	cpx	keyidx
+       	bne	L3
+       	dec	keyidx
+       	cli
 
-        pla
-        sta     IndReg          ; Restore old segment
-
-       	ldx	#$00		; High byte
-       	lda     c               ; First char from buffer
+       	ldx	#$00  		; High byte
+       	tya	      		; First char from buffer
        	rts
 
-.bss
 
-c:      .byte   0