[Coco] Modifying Level1/coco1 for 6309 native mode

[L. Curtis Boyle]

This is exactly what Bill and I did to make NitrOS9 in the first place. :-)
(To be honest, this earliest stage was much more Bill than me).

L. Curtis Boyle
curtisboyle at sasktel.net



On Feb 14, 2014, at 10:47 AM, Robert Gault <robert.gault at att.net> wrote:

> Made some progress with a native 6309 code for the coco1. I can now get as far as a time entry request from setime. The screen waits for a key press and crashes on the first one.
> 
> To get this far, you need to edit rbf.asm looking for all the ,u entries. These will need to be compared to level2/rbf.asm and all pertinent entries changed to R$reg,u.
> 
> shortly after L02E9  change stx $06,u to stx R$X,u
> 
> Seek     ldb   $0A,y
>         bitb  #$02
>         beq   L037B
>         lda   R$X+1,u        $05,u
>         ldb   R$U,u          $08,u
>         subd  $0C,y
>         bne   L0376
>         lda   R$X,u          $04,u
>         sbca  $0B,y
>         beq   L037F
> L0376    lbsr  L0D72
>         bcs   L0383
> L037B    ldd   R$X,u         $04,u
>         std   $0B,y
> L037F    ldd   R$U,u         $08,u
>         std   $0D,y
> L0383    rts
> 
> L03BA    ldu   $06,y
>         ldd   R$Y,u         $06,u
>         subd  $02,s
>         std   R$Y,u         $06,u
>         bra   L040E
> L03C4    ldd   R$Y,u         $06,u
>         bsr   L03CD
>         bcs   L03F1
>         std   R$Y,u         $06,u
>         rts
> 
> L0414    ldd   R$X,u         $04,u
>         ldx   R$Y,u         $06,u
> 
> WriteLn  pshs  y
>         clrb
>         ldy   R$Y,u         $06,u
>         beq   L0498
>         ldx   R$X,u         $04,u
> L0484    leay  -$01,y
>         beq   L0498
>         lda   ,x+
>         cmpa  #$0D
>         bne   L0484
>         tfr   y,d
>         nega
>         negb
>         sbca  #$00
>         addd  R$Y,u        $06,u
>         std   R$Y,u        $06,u
> L0498    puls  y
> 
> Write    ldd   R$Y,u        $06,u
> 
> GetStat  ldb   R$B,u           $02,u
>         cmpb  #SS.Opt
>         beq   L0543
>         cmpb  #$06
>         bne   L052F
>         clr   R$B,u           $02,u
> L0529    clra
>         ldb   #$01
>         lbra  L03CD
> L052F    cmpb  #SS.Ready
>         bne   L0536
>         clr   R$B,u           $02,u
>         rts
> L0536    cmpb  #SS.Size
>         bne   L0544
>         ldd   $0F,y
>         std   R$X,u           $04,u
>         ldd   <$11,y
>         std   R$U,u           $08,u
> L0543    rts
> L0544    cmpb  #SS.Pos
>         bne   L0551
>         ldd   $0B,y
>         std   R$X,u          $04,u
>         ldd   $0D,y
>         std   R$U,u          $08,u
> Gst5FF   rts
> L0551    cmpb  #SS.FD
>         bne   SSFDInf
>         lbsr  L0CD4
>         bcs   L0543
>         ldu   $06,y
>         ldd   R$Y,u          was $06,u
>         tsta
>         beq   L0564
>         ldd   #$0100
> L0564    ldx   R$X,u          was $04,u
> 
> shortly after L05C6
>         ldx   R$X,u          was $04,u
> 
> shortly after L0604
>         lda   R$X+1,u        was $05,u
> 
> 
> It is safe to say that there will be more level1 code which was disassembled without conversion to the R$reg format. When going from 6809 to native 6309 code, the register stack changes and all $nm,u type code referring to registers can fail.
> 
> Robert
> 
> 
> 
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