more work towards windowed mode support

src/kernal/screen_m65/mega65_chrout_screen.s

@@ -100,7 +100,26 @@ m65_chrout_screen_literal: // entry point for m65_chrout_screen_quote
 
 m65_chrout_fix_column_row:
 
-	// XXX continue the implementation - fix the cursor position
+	ldy M65_SCRMODE
+
+	bit M64_SCRWINMODE
+	bmi m65_chrout_fix_column_row_win
+
+	// Non-windowed mode
+
+	// XXX
+	// XXX provide implementation
+	// XXX
+
+	jmp_8 m65_chrout_screen_done
+
+m65_chrout_fix_column_row_win:
+
+	// Windowed mode
+
+	// XXX
+	// XXX provide implementation
+	// XXX
 
 	nop
 

src/kernal/screen_m65/mega65_chrout_screen_control_1.s

@@ -46,6 +46,12 @@ m65_chrout_screen_RETURN:
 
 	// Move cursor to the beginning of the next line
 
+	bit M64_SCRWINMODE
+	bpl !+
+	lda M65_TXTWIN_X0
+	skip_2_bytes_trash_nvz
+!:
+	lda #$00
 	sta M65__TXTCOL
 	inc M65__TXTROW
 

src/kernal/screen_m65/mega65_setwin.s

@@ -0,0 +1,56 @@
+// #LAYOUT# M65 KERNAL_0 #TAKE
+// #LAYOUT# *   *        #IGNORE
+
+
+M65_SETWIN_XY:
+
+	stx M65_TXTWIN_X0
+	sty M65_TXTWIN_Y0
+
+	rts
+
+
+M65_SETWIN_WH:
+
+	pha
+
+	clc
+	txa
+	adc M65_TXTWIN_X0
+	sta M65_TXTWIN_X1
+
+	clc
+	tya
+	adc M65_TXTWIN_Y0
+	sta M65_TXTWIN_Y1
+
+	pla
+	rts
+
+
+M65_SETWIN_N:
+
+	pha
+
+	lda #$00
+	sta M64_SCRWINMODE
+
+	pla
+	rts
+
+
+M65_SETWIN_Y:
+
+	pha
+
+	lda #$FF
+	sta M64_SCRWINMODE
+
+	lda M65_TXTWIN_X0
+	sta M65__TXTCOL
+
+	lda M65_TXTWIN_Y0	
+	sta M65__TXTROW
+
+	pla
+	rts