use DMAgic for MEGA65 screen clearing

src/kernal/screen_m65/mega65_clrscr.s

@@ -1,8 +1,6 @@
 // #LAYOUT# M65 KERNAL_1 #TAKE
 // #LAYOUT# *   *        #IGNORE
 
-// #define DMAGIC_CLRSCR
-
 
 M65_CLRSCR:
 
@@ -17,23 +15,7 @@ M65_CLRSCR:
 
 	// FALLTROUGH
 
-m65_clrscr_takeover: // .A has to be 0
-
-	// Set the viewport to the beginning of screen memory - variable:
-	// - M65_COLVIEW
-	// It will serve as line counter
-
-	sta M65_COLVIEW+0
-	sta M65_COLVIEW+1
-
-	// Clear the row offset, so that it won't interfere
-
-	sta M65_TXTROW_OFF+0
-	sta M65_TXTROW_OFF+1
-
-#if DMAGIC_CLRSCR
-
-	// XXX for some reason this does not work correctly - find out, why
+m65_clrscr_takeover:
 
 	// Clear the whole screen + colour memory
 
@@ -43,104 +25,28 @@ m65_clrscr_takeover: // .A has to be 0
 	lda M65_COLGUARD+1
 	sta M65_DMAJOB_SIZE_1
 
-	// Screen start address
-	lda M65_SCRBASE+0
-	sta M65_DMAJOB_DST_0
-	lda M65_SCRBASE+1
-	sta M65_DMAJOB_DST_1
-	lda M65_SCRSEG+0
-	sta M65_DMAJOB_DST_2
-	lda M65_SCRSEG+1
-	sta M65_DMAJOB_DST_3
 
-	// Fill with spaces
+	// Fill screen memory with spaces
+	jsr m65_screen_dmasrcdst_screen
 	lda #$20
 	jsr m65_dmagic_oper_fill
 
-	// Colour RAM start address
-	lda #$00
-	sta M65_DMAJOB_DST_0
-	sta M65_DMAJOB_DST_1
-	lda #$F8
-	sta M65_DMAJOB_DST_2
-	lda #$0F
-	sta M65_DMAJOB_DST_3
-
-	// Fill with colour, without attributes
+	// Fill color memory with the current color
+	jsr m65_screen_dmasrcdst_color
 	lda COLOR
 	and #$0F
 	jsr m65_dmagic_oper_fill
 
-#else
+	// Set the viewport to the beginning of virtual screen
+	// XXX deduplicate with mode setting routine
 
-	// Clear the whole screen+color memory
-	// XXX consider using DMAgic for this - FILL command
-
-	phz
-
-	// FALLTROUGH
-
-m65_clrscr_loop:
-
-	// Prepare M65_LPNT_SCR, let it point to color memory
-
-	jsr m65_helper_scrlpnt_color
-
-	// Clear color for the whole line
-
-	ldz #$4F                                     // 80 bytes
-	lda COLOR
-!:
-	sta_lp (M65_LPNT_SCR),z
-
-	dez
-	bpl !-
-
-	// Let M65_LPNT_SCR point to scren memory
-
-	jsr m65_helper_scrlpnt_to_screen
-
-	// Clear characters in the whole line
-
-	ldz #$4F                                     // 80 bytes
-	lda #$20
-!:
-	sta_lp (M65_LPNT_SCR),z
-
-	dez
-	bpl !-
-
-	// Advance by one line, do next iteration
-
-	// XXX this can probably be deduplicated
-	clc
-	lda M65_COLVIEW+0
-	adc #$50
+	lda #$00
 	sta M65_COLVIEW+0
-	bcc !+
-	inc M65_COLVIEW+1
-!:
-	// Check if we are allowed to progress further
-
-	lda M65_COLVIEW+1
-	cmp M65_COLGUARD+1
-	bne m65_clrscr_loop
-	lda M65_COLVIEW+0
-	cmp M65_COLGUARD+0
-	bne m65_clrscr_loop
-
-m65_clrscr_loop_done:
-
-	// Nothing more to clear - restore .Z register
-
-	plz
-
-#endif // no DMAGIC_CLRSCR
+	sta M65_COLVIEW+1
 
 	// Set screen+color base address in VIC IV
 	// XXX deduplicate with mode setting routine
 
-	lda #$00
 	sta VIC_COLPTR+0
 	sta VIC_COLPTR+1
 	sta M65_COLVIEW+0
@@ -151,12 +57,10 @@ m65_clrscr_loop_done:
 	lda M65_SCRBASE+1
 	sta VIC_SCRNPTR+1
 
-    // Set screen variables
+    // Set logical row length
 
     jsr m65_screen_set_indx
 
-	// XXX provide proper implementation
-
     // FALLTROUGH
 
 M65_HOME: