From: Alan Cox <alan@etchedpixels.co.uk>
Date: Thu, 27 Nov 2014 23:36:30 +0000 (+0000)
Subject: dragon: move the display to 0x6000
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=f2619bf5888b4e36b0632649eaa32c5160f29bdf;p=FUZIX.git

dragon: move the display to 0x6000

This gives us clear space below 0x6000 to possibly allow for bigger binaries
(but there are some nasties about changing how the vectors must work that
 won't be doable on a "real" Dragon ROM)

It's also the needed basis for 32K COCO and Dragon32 support given a banked
cartridge unit and banked call support.
---

diff --git a/Kernel/platform-dragon/setup.s b/Kernel/platform-dragon/setup.s
index e2ca4eda..b5d9211d 100644
--- a/Kernel/platform-dragon/setup.s
+++ b/Kernel/platform-dragon/setup.s
@@ -34,9 +34,12 @@ samwipe:
 	deca
 	bne samwipe
 
-	sta 0xffc7	; Display at 0x200
+	sta 0xffcf	;
+	sta 0xffd1	; Display at 0x6000
+	sta 0xffd3	; In the upper bank
 	;FIXME - DD or DB needed to get it right
 	sta 0xffdd	; 64K dynamic RAM
+	sta 0xffd5	; Use RAM bank 1 at 0x0000 (providing ffde is clear)
 
 	; PIA0 A is all input
 	; PIA0 B is all output
@@ -72,14 +75,14 @@ samwipe:
 	;
 	; Say hello
 	;
-	ldx #0x200
+	ldx #0x6000
 cls:	lda #' '
 	sta ,x+
-	cmpx #0x800
+	cmpx #0x6200
 	bne cls
 
-	ldu #0x0200	; U is our screen pointer
-	lds #0x7ffe
+	ldu #0x6000	; U is our screen pointer
+	lds #0x0400	; Somewhere safe out of the way
 	ldx #hello
 	bsr strout
 
@@ -87,7 +90,7 @@ cls:	lda #' '
 	;	Clear memory (we ought to tidily clear bits listed in
 	;	a tweaked DECB but what the heck..
 
-	ldx #0x800
+	ldx #0x6200
 wiper:
 	clr ,x+
 	cmpx #0x8000