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 e2ca4ed..b5d9211 100644 (file)
--- 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