more control codes supported for MEGA65 native screen

src/kernal/screen/chrout_screen_shift_onoff.s

@@ -11,11 +11,13 @@
 chrout_screen_SHIFT_ON:
 
 	lda #$00 // enable SHIFT+VENDOR combination
-!:
-	sta MODE
-	jmp chrout_screen_done
+	skip_2_bytes_trash_nvz
+
+	// FALLTROUGH
 
 chrout_screen_SHIFT_OFF:
 
 	lda #$80 // disable SHIFT+VENDOR combination
-	bne !-   // branch always
+
+	sta MODE
+	jmp chrout_screen_done

src/kernal/screen_m65/mega65_chrout_screen_control.s

@@ -73,81 +73,6 @@ m65_chrout_try_color_loop:
 
 
 
-
-// XXX: consider moving to separate files
-
-m65_chrout_screen_RETURN:
-
-	// RETURN clears quote and insert modes, it also clears reverse flag
-	
-	lda #$00
-	sta QTSW
-	sta INSRT
-	sta RVS
-
-	// XXX should we clear special colour attributes too?
-
-	// Move cursor to the beginning of the next line
-
-	sta M65__TXTCOL
-	inc M65__TXTROW
-
-	// Correct the column/row values
-
-	jmp m65_chrout_fix_column_row
-
-
-
-
-m65_chrout_screen_RVS_ON:
-
-	lda #$80
-	skip_2_bytes_trash_nvz
-
-	// FALLTROUGH
-
-m65_chrout_screen_RVS_OFF:
-
-	lda #$00
-
-	sta RVS
-	jmp m65_chrout_screen_done
-
-
-
-m65_chrout_screen_CRSR_RIGHT:
-
-	inc M65__TXTCOL
-	skip_2_bytes_trash_nvz
-
-	// FALLTROUGH
-
-m65_chrout_screen_CRSR_LEFT:
-	
-	dec M65__TXTCOL
-	skip_2_bytes_trash_nvz
-
-	// FALLTROUGH
-
-m65_chrout_screen_CRSR_DOWN:
-
-	inc M65__TXTROW
-	skip_2_bytes_trash_nvz
-
-	// FALLTROUGH
-
-m65_chrout_screen_CRSR_UP:
-
-	dec M65__TXTROW
-
-	// Correct the column/row values
-
-	jmp m65_chrout_fix_column_row
-
-
-
-
-
 // XXX: implement screen routines below:
 
 m65_chrout_screen_quote:
@@ -156,14 +81,6 @@ m65_chrout_screen_CLR:
 	nop
 m65_chrout_screen_HOME:
 	nop
-m65_chrout_screen_SHIFT_OFF:
-	nop
-m65_chrout_screen_SHIFT_ON:
-	nop
-m65_chrout_screen_TXT:
-	nop
-m65_chrout_screen_GFX:
-	nop
 m65_chrout_screen_INS:
 	nop
 m65_chrout_screen_TAB:

src/kernal/screen_m65/mega65_chrout_screen_control_1.s

@@ -0,0 +1,58 @@
+// #LAYOUT# M65 KERNAL_1 #TAKE
+// #LAYOUT# *   *        #IGNORE
+
+
+// Cursor movement
+
+m65_chrout_screen_CRSR_RIGHT:
+
+	inc M65__TXTCOL
+	skip_2_bytes_trash_nvz
+
+	// FALLTROUGH
+
+m65_chrout_screen_CRSR_LEFT:
+	
+	dec M65__TXTCOL
+	skip_2_bytes_trash_nvz
+
+	// FALLTROUGH
+
+m65_chrout_screen_CRSR_DOWN:
+
+	inc M65__TXTROW
+	skip_2_bytes_trash_nvz
+
+	// FALLTROUGH
+
+m65_chrout_screen_CRSR_UP:
+
+	dec M65__TXTROW
+	jmp_8 m65_chrout_screen_ctrl1_end
+
+
+// 'RETURN' key
+
+m65_chrout_screen_RETURN:
+
+	// RETURN clears quote and insert modes, it also clears reverse flag
+	
+	lda #$00
+	sta QTSW
+	sta INSRT
+	sta RVS
+
+	// XXX should we clear special colour attributes too?
+
+	// Move cursor to the beginning of the next line
+
+	sta M65__TXTCOL
+	inc M65__TXTROW
+
+	// FALLTROUGH
+
+m65_chrout_screen_ctrl1_end:
+
+	// Correct the column/row values
+
+	jmp m65_chrout_fix_column_row

src/kernal/screen_m65/mega65_chrout_screen_control_2.s

@@ -0,0 +1,58 @@
+// #LAYOUT# M65 KERNAL_1 #TAKE
+// #LAYOUT# *   *        #IGNORE
+
+
+// 'REVERSE' mode support
+
+m65_chrout_screen_RVS_ON:
+
+	lda #$80
+	skip_2_bytes_trash_nvz
+
+	// FALLTROUGH
+
+m65_chrout_screen_RVS_OFF:
+
+	lda #$00
+
+	sta RVS
+
+	// FALLTROUGH
+
+m65_chrout_screen_ctrl2_end:
+
+	jmp m65_chrout_screen_done
+
+
+// 'SHIFT ON/OFF' support
+
+m65_chrout_screen_SHIFT_ON:
+
+	lda #$00 // enable SHIFT+VENDOR combination
+	skip_2_bytes_trash_nvz
+
+	// FALLTROUGH
+
+m65_chrout_screen_SHIFT_OFF:
+
+	lda #$80 // disable SHIFT+VENDOR combination
+
+	sta MODE
+	jmp_8 m65_chrout_screen_ctrl2_end
+
+
+// GFX/TXT switching support
+
+m65_chrout_screen_GFX:
+
+	lda VIC_YMCSB
+	and #$02 // to upper case
+!:
+	sta VIC_YMCSB
+	jmp_8 m65_chrout_screen_ctrl2_end
+
+m65_chrout_screen_TXT:
+
+	lda VIC_YMCSB
+	ora #$02    // to lower case
+	bne !-      // branch always