[Coco] Modifying Level1/coco1 for 6309 native mode

[Luis Antoniosi (CoCoDemus)]

Robert,

In my first tests the system hangs at the firs I$Write on sysgo to
display NitrOS system name.

put a 'TST $FF78' before it and you will trace it using 'wp ff78,1,rw'
on debug window.

On Sun, Jan 5, 2014 at 9:04 PM, Robert Gault <robert.gault at att.net> wrote:
> Since there have been requests for this and the challenge is interesting,
> I've been looking at this problem. Here are initial results.
>
> 1) LWTools port of NitrOS-9 used for testing.
> 2) All level1/coco1 pertinent makefiles modified, for example
>
> AFLAGS          += -I$(LEVEL1)/modules
>
> changed to
>
> AFLAGS          += -I$(LEVEL1)/modules -DH6309=1
>
> or
>
> AFLAGS          += -DH6309=1
>
> added. This will be necessary for defs, cmds, modules, and kernel.
> The main coco1 makefile was modified:
> CPU=6309
> AFLAGS += -DH6309=1
>
> Make sure that $(AFLAGS) gets added as needed to the makefiles or the H6309
> will be ignored.
>
> 3) It was necessary to modify level1/modules/rel.asm as native mode was not
> initiated soon enough in level1, even though this source code is used for
> Level2 6309 and already contains one LDMD #$03.
>
> start1   orcc  #IntMasks  turn off IRQ's
>          clr   >PIA0Base+3 turn off SAM IRQ's
>          clra             make A=0 for later
>          IFNE  H6309
>          tfr   0,dp       set direct page to $0000
>          ldmd  #3         native mode       !!!!!!!!!!!!!! new line
>
> Start    clr   PIA0Base+3
>
>          IFNE  (tano+d64+dalpha)
>          clr   PIA0Base+1               added for Dragon, works on CoCo
>          ENDC
>          IFNE  H6309         !!!!!!!!!!!!!!! 3 new lines
>          ldmd  #3                  native mode
>          ENDC
>
> With the above changes, the boot process proceeds much father than without
> the changes. The boot process without rel changes crashed at the first
> F$Link call.
>
> The best way to test progress is with the MESS debugger. Use a version of
> MESS that correctly handles coco emulation. Start coco3h (6309) emulation,
> as that gives you the 6309 cpu and will run normal Level1 coco1 Nitros-9.
> Turn on the MESS debugger and set a breakpoint at $2602. Enter the DOS
> command with your test disk and the debugger will start as soon as rel
> starts running.
> You should then tell MESS to start a trace, ex. trace 6309.log, and then
> leave the debugger. The text file 6309.log will be generated which will make
> it easy to spot where the boot process is crashing.
> You can do the same thing with a normal coco1 6809 disk and compare a
> 6809.log vs your 6309.log.
>
> It would make things much easier if there are other programmers interested
> enough to try this. We can compare notes and ideas. That could make Level1
> 6309 native mode a reality.
>
> Robert
>
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