preparation for using DMAgic in the screen editor

STATUS.md

@@ -70,7 +70,7 @@ The following ROM features are currently missing:
 | :----------------: | :------: | :------------------------------------------------: |
 | VIC-II             | DONE     |                                                    |
 | 80 columns, VDC    | NOT DONE |                                                    |
-| 80 columns, Mega65 | PARTIAL  | work-in-progreess, not useable yet                 |
+| 80 columns, Mega65 | PARTIAL  | work-in-progress                                   |
 
 <br />
 

src/aliases/,aliases_ram_lowmem_m65.s

@@ -52,6 +52,24 @@
 	.label M65_TXTWIN_X1    = $590 //            text window - bottom-right X coordinate + 1
 	.label M65_TXTWIN_Y1    = $591 //            text window - bottom-right Y coordinate + 1
 	.label M65_TXTROW_OFF   = $592 // $592-$593  offset to the current text row
-	                               // $594-$5FF  -- UNUSED --
+	                               // $594-$5EB  -- UNUSED --
+	.label M65_DMAGIC_LIST  = $5EF // $5EF-$5FF  reserved for DMAgic list, 17 bytes
 	.label M65_RS232_INBUF  = $600 // $600-$6FF  -- reserved for RS-232 input buffer --
 	.label M65_RS232_OUTBUF = $700 // $700-$7FF  -- reserved for RS-232 output buffer --
+
+	//
+	// Addresses for configuring the DMA job
+	//
+
+	.label M65_DMAJOB_SIZE_0    = M65_DMAGIC_LIST + 7
+	.label M65_DMAJOB_SIZE_1    = M65_DMAGIC_LIST + 8
+
+	.label M65_DMAJOB_SRC_0     = M65_DMAGIC_LIST + 10
+	.label M65_DMAJOB_SRC_1     = M65_DMAGIC_LIST + 11
+	.label M65_DMAJOB_SRC_2     = M65_DMAGIC_LIST + 9
+	.label M65_DMAJOB_SRC_3     = M65_DMAGIC_LIST + 2
+
+	.label M65_DMAJOB_DST_0     = M65_DMAGIC_LIST + 13
+	.label M65_DMAJOB_DST_1     = M65_DMAGIC_LIST + 14
+	.label M65_DMAJOB_DST_2     = M65_DMAGIC_LIST + 12
+	.label M65_DMAJOB_DST_3     = M65_DMAGIC_LIST + 4

src/kernal/board_m65/mega65_dmagic.s

@@ -0,0 +1,63 @@
+// #LAYOUT# M65 KERNAL_0 #TAKE
+// #LAYOUT# *   *        #IGNORE
+
+// Helper routines for DMAgic usage
+
+// See:
+// - https://c65gs.blogspot.com/2019/03/auto-detecting-required-revision-of.html
+// - https://c65gs.blogspot.com/2018/01/improving-dmagic-controller-interface.html
+
+
+// XXX: finish the implementation, use in screen editor
+
+
+m65_dmagic_oper_copy:
+
+	// To configure parameters, use:
+	// - M65_DMAJOB_SIZE_*
+	// - M65_DMAJOB_SRC_*
+	// - M65_DMAJOB_DST_*	
+
+	lda #$00
+	sta M65_DMAGIC_LIST+6              // operation: copy
+
+	jmp_8 m65_dmagic_common
+
+m65_dmagic_oper_fill:
+
+	// XXX provide implementation
+
+	// FALLTROUGH
+
+m65_dmagic_common:
+
+	lda #$0A
+	sta M65_DMAGIC_LIST+0              // <- $0A = use F018A list format (it is shorter by 1 byte)
+	lda #$80
+	sta M65_DMAGIC_LIST+1              // <- $80 = next byte is highest 8 bits of source address
+	inc_a
+	sta M65_DMAGIC_LIST+3              // <- $80 = next byte is highest 8 bits of destination address
+
+	lda #$00
+	sta M65_DMAGIC_LIST+5              // <- end of options
+
+	sta M65_DMAGIC_LIST+15             // <- set modulo to 0
+	sta M65_DMAGIC_LIST+16
+
+	// FALLTROUGH
+
+m65_dmagic_launch:
+
+	// Launch the DMA list
+
+	lda #$00
+	sta DMA_ADDRBANK                   // $D702
+	sta DMA_ADDRMB                     // $D704
+
+	lda #>M65_DMAGIC_LIST
+	sta DMA_ADDRMSB                    // $D701
+
+	lda #<M65_DMAGIC_LIST
+	sta DMA_ETRIG                      // $D705
+
+	rts

src/kernal/board_m65/mega65_imports.s

@@ -38,6 +38,8 @@
 .label viciv_unhide                    = KERNAL_0.viciv_unhide
 .label viciv_init                      = KERNAL_0.viciv_init
 .label viciv_shutdown                  = KERNAL_0.viciv_shutdown
+.label m65_dmagic_oper_copy            = KERNAL_0.m65_dmagic_oper_copy
+.label m65_dmagic_oper_fill            = KERNAL_0.m65_dmagic_oper_fill
 
 .label m65_scrtab_txtwidth             = KERNAL_0.m65_scrtab_txtwidth
 .label m65_scrtab_txtheight            = KERNAL_0.m65_scrtab_txtheight

src/kernal/screen_m65/mega65_chrout_screen_control_1.s

@@ -42,8 +42,6 @@ m65_chrout_screen_RETURN:
 	sta INSRT
 	sta RVS
 
-	// XXX should we clear special colour attributes too?
-
 	// Move cursor to the beginning of the next line
 
 	bit M65_SCRWINMODE

src/kernal/screen_m65/mega65_clrscr.s

@@ -31,6 +31,7 @@ m65_clrscr_takeover: // .A has to be 0
 	sta M65_TXTROW_OFF+1
 
 	// Clear the whole screen+color memory
+	// XXX consider using DMAgic for this - FILL command
 
 	phz
 

src/kernal/screen_m65/mega65_clrwin.s

@@ -3,6 +3,7 @@
 
 
 // XXX deduplicate pointer manipulation, see M65_CLRSCR
+// XXX consider using DMAgic for this - FILL command
 
 M65_CLRWIN: