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changeset 232:2d2653b5b609

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oscode for Dragon added
author boisy
date Wed, 17 Jul 2002 00:43:49 +0000
parents 3303186f9898
children 51bf3a85f457
files level1/modules/oscode_d64.asm
diffstat 1 files changed, 59 insertions(+), 0 deletions(-) [+]
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/level1/modules/oscode_d64.asm	Wed Jul 17 00:43:49 2002 +0000
@@ -0,0 +1,59 @@
+*        org 2600
+         nam Bootstrap
+         ttl   Dragon Bootstrap code
+
+os9start equ $EF00
+os9size  equ $0F80
+
+Start    fcc "OS"
+
+         clr   >$FF03
+         clr   >$FF01
+         sta   >$FFDF
+         ldb   #6
+         ldx   #$FFC6
+L0010    sta   ,x++
+         decb  
+         bne   L0010
+         sta   $01,x
+         ldx   #$8000
+         ldy   #$0200
+         lda   #$60
+L0020    sta   ,x+
+         leay  -$01,y
+         bne   L0020
+
+* Write "OS9 BOOT" to the screen
+         ldx   #$810C
+         leay  <L0056,pcr
+         ldb   #$08
+L002E    lda   ,y+
+         sta   ,x+
+         decb  
+         bne   L002E
+         tst   <$72
+         beq   L004C
+
+* Move the kernel to $F000
+         leau  >Start,pcr
+         ldx   #os9size
+         ldy   #os9start
+L0044    lda   ,u+
+         sta   ,y+
+         leax  -$01,x
+         bne   L0044
+
+* Jump to OS9
+L004C    jmp   >os9start+$4F     After the move, this is like jumping to L004F
+L004F    leax  <end,pcr
+         ldd   $09,x
+         jmp   d,x
+
+L0056    fcc  "OS"
+         fcb  $79
+         fcb  $60
+         fcb  'B
+         fcb  'O
+         fcb  'O
+         fcb  'T
+end      equ *