separated screen part of CHROUT

c64/kernal/chrout_screen.s

@@ -1,86 +1,9 @@
 
 //
-// Official Kernal routine, described in:
-//
-// - [RG64] C64 Programmer's Reference Guide   - page 278/279
-// - [CM64] Compute's Mapping the Commodore 64 - page 228
-//
-// CPU registers that has to be preserved (see [RG64]): .Y
+// CHROUT routine - screen support
 //
 
 
-chrout_real:
-
-	sta SCHAR
-
-	// Save X and Y values
-	// (Confirmed by writing a test program that X and Y
-	// don't get modified, in agreement with C64 PRG's
-	// description of CHROUT)
-	txa
-	pha
-	tya
-	pha
-	php
-
-	// Determine the device number
-	lda DFLTO
-
-	cmp #$03 // screen
-	beq chrout_screen
-
-	jsr iec_check_devnum
-	bcs chrout_done_unknown_device // not a supported device
-
-chrout_iec:
-
-	lda SCHAR
-	jsr JCIOUT
-	bcc chrout_done
-
-	// FALLTROUGH
-
-chrout_done_fail:
-	jsr show_cursor_if_enabled
-
-	plp
-
-	// Restore X and Y
-	pla
-	tay
-	pla
-	tax
-	sec // indicate failure
-	rts
-
-chrout_done_unknown_device:
-	jsr show_cursor_if_enabled
-
-	plp
-
-	// Restore X and Y
-	pla
-	tay
-	pla
-	tax
-
-	// End wioth error
-	jmp lvs_device_not_found_error
-
-chrout_done:
-	jsr show_cursor_if_enabled
-
-	plp
-
-	// Restore X and Y
-	pla
-	tay
-	pla
-	tax
-	lda SCHAR
-	clc // indicate success
-	rts
-
 chrout_screen:
 
 	// Crude implementation of character output	

c64/kernal/f1ca.chrout.jmp.s

@@ -1,6 +0,0 @@
-
-// Our implementation is longer than the original one,
-// placing it here would cause a collision with CHKIN
-
-CHROUT:
-    jmp chrout_real

c64/kernal/f1ca.chrout.s

@@ -0,0 +1,82 @@
+
+//
+// Official Kernal routine, described in:
+//
+// - [RG64] C64 Programmer's Reference Guide   - page 278/279
+// - [CM64] Compute's Mapping the Commodore 64 - page 228
+//
+// CPU registers that has to be preserved (see [RG64]): .Y
+//
+
+CHROUT:
+
+	sta SCHAR
+
+	// Save X and Y values
+	// (Confirmed by writing a test program that X and Y
+	// don't get modified, in agreement with C64 PRG's
+	// description of CHROUT)
+	txa
+	pha
+	tya
+	pha
+	php
+
+	// Determine the device number
+	lda DFLTO
+
+	cmp #$03 // screen
+	bne !+
+	jmp chrout_screen
+!:
+	jsr iec_check_devnum
+	bcs chrout_done_unknown_device // not a supported device
+
+chrout_iec:
+
+	lda SCHAR
+	jsr JCIOUT
+	bcc chrout_done
+
+	// FALLTROUGH
+
+chrout_done_fail:
+	jsr show_cursor_if_enabled
+
+	plp
+
+	// Restore X and Y
+	pla
+	tay
+	pla
+	tax
+	sec // indicate failure
+	rts
+
+chrout_done_unknown_device:
+	jsr show_cursor_if_enabled
+
+	plp
+
+	// Restore X and Y
+	pla
+	tay
+	pla
+	tax
+
+	// End wioth error
+	jmp lvs_device_not_found_error
+
+chrout_done:
+	jsr show_cursor_if_enabled
+
+	plp
+
+	// Restore X and Y
+	pla
+	tay
+	pla
+	tax
+	lda SCHAR
+	clc // indicate success
+	rts