[Coco] Color Forth Help Request

Stephen Pereira spereira1952 at comcast.net
Fri Feb 20 19:02:35 EST 2015


Hi Art,

I don’t know much of anything about the inner workings of the VCC emulator.  I just used it as a second platform to test my code and verify the things I am experiencing on my real physical system.

Of course, the ROMS didn’t change at all on the physical system, only the processor did.

Am I getting your question correct?

smp
--
Stephen M. Pereira
Bedford, NH  03110
KB1SXE


> On Feb 20, 2015, at 6:50 PM, Arthur Flexser <flexser at fiu.edu> wrote:
> 
> Are you sure the Disk ROM version is identical for the  6809 and 6309
> tests?  Those ROM calls will only work for one of the two versions.
> 
> Art
> 
> On Fri, Feb 20, 2015 at 6:20 PM, Stephen Pereira <spereira1952 at comcast.net>
> wrote:
> 
>> Hi Art,
>> 
>> Thanks a million for your replies!  Greatly appreciated.
>> 
>> Here is my code:
>> 
>> *
>> * BRUTE FORCE ROUTINE TO LOAD SCREENS 1 THRU 8
>> * USING THE DECB LOADM ROUTINE
>> * JAN 2015, SMP
>> * ERROR CHECK & ADVICE FROM BRETT GORDON
>> *
>>        FCB     $84,'L,'S,'C,'R+$80
>>        FDB     SSCR-7
>> LSCR    FDB     *+2
>>        PSHS    CC,A,B,DP,X,Y,U SAVE ALL JUST IN CASE
>>        LDX     #$094C  CLEAR FILE NAME LOCATION
>>        LDA     #32
>> L3      STA     ,X+
>>        CMPX    #$0954
>>        BNE     L3
>>        LDX     #$094C  FILE NAME LOCATION
>> L4      JSR     $A1B1   GET KEY IN A
>>        TFR     A,B     SAVE KEY IN B
>>        PSHS    B,X,Y
>>        JSR     [$A002] ECHO KEY
>>        PULS    Y,X,B
>>        TFR     B,A     GET KEY IN A
>>        CMPA    #13     CR?
>>        BEQ     NXT2    CR ENDS LOOP
>>        STA     ,X+     STORE KEY IN FILE NAME
>>        CMPX    #$0954  DONE IF 8 KEYS
>>        BNE     L4
>> NXT2    LDX     #$0954  FILE EXTENSION LOCATION
>>        LDA     #$42    B
>>        STA     ,X+
>>        LDA     #$49    I
>>        STA     ,X+
>>        LDA     #$4E    N
>>        STA     ,X
>>        LDD     #$0200  FILE TYPE = 2, ASCII FLAG = 0
>>        STD     $0957
>>        LDX     #$0000
>>        STX     #$00D3  OFFSET = 0
>>        JSR     $CA07   OPEN NEXT AVAIL FILE FOR INPUT
>>        LDD     #RET2   RETURN ADDR FOR LOADM RTS
>>        PSHS    D
>>        JMP     $CFE3   LOADM
>> RET2    PULS    U,Y,X,DP,B,A,CC RESTORE ALL
>>        JMP     NEXT    RETURN TO FORTH
>> 
>> This code works fine on a stock CoCo 3, as well as in VCC with a 6809
>> CPU.  It is not elegant, and I don’t think I tried any fancy stuff.  Don’t
>> worry about the first few lines of code - they are for linking into Color
>> Forth, and that seem to be fine.
>> 
>> As far as I can tell, this code does not initiate any disk activity when
>> the CPU is a 6309, the machine simply goes off into never-never-land.
>> 
>> Thanks, in advance, for whatever observations or advice you may have to
>> offer.
>> 
>> smp
>> --
>> Stephen M. Pereira
>> Bedford, NH  03110
>> KB1SXE
>> 
>> 
>>> On Feb 20, 2015, at 5:54 PM, Arthur Flexser <flexser at fiu.edu> wrote:
>>> 
>>> The only time that I'm aware of when the 6309 in emulation mode does not
>>> behave exactly like a 6809 is when it encounters an illegal opcode, where
>>> the 6309 vectors to an error location.  (The 6809 will just skip the
>>> illegal opcode, usually.)  So my guess would be that that's what's
>>> happening somewhere in Color Forth.  The 6309 error vector, not having
>> been
>>> initialized to anything in particular, looks like it winds up in a
>> section
>>> of the ROM CLOAD code.
>>> 
>>> If the 6309 pushes registers enroute to the error vector (I'm not sure if
>>> it does or not, but this would be documented), you could tell what
>> location
>>> the error is coming from by pointing the error vector to a routine that
>>> could look at the stack contents and tell you what the PC register
>>> contained at the time of the error.
>>> 
>>> Art
>>> 
>>> On Fri, Feb 20, 2015 at 5:20 PM, Stephen Pereira <
>> spereira1952 at comcast.net>
>>> wrote:
>>> 
>>>> Hello again, all,
>>>> 
>>>> I am happy to say that I am one of the lucky ones who was able to get
>> one
>>>> of the last CoCo 3 systems from Cloud-9 - I got a fully tricked out
>> CoCo 3
>>>> with a Pro-Tektor, a 6309 processor, and the Triad 512K RAM upgrade
>> (Thanks
>>>> a million for a great machine, Mark!).
>>>> 
>>>> I discovered a problem (for me):  My Color Forth code does not run
>>>> properly on this machine!  What I found is that I can LOADM”CC-FORTH”
>> and
>>>> EXEC just fine.  I can issue Color Forth commands (although I have not
>>>> attempted every command) and things seem OK.  I can issue my added DIR
>> or
>>>> BASIC commands, and those works well.  Then I try to load a file of
>> Forth
>>>> screens with my LSCR command.  Upon execution of that command, the CoCo
>>>> goes off into never-never-land.  Usually, the machine simply goes off
>> and
>>>> never returns.  It does not access the disk, it just disappears.
>> Sometimes
>>>> I get a beautiful screen of scrambled graphics, but not usually.
>>>> 
>>>> I had the bright idea to try all this on my VCC emulator.  The 512k RAM
>>>> does not make any difference.  Color Forth runs just fine.  However,
>> when I
>>>> change the CPU to be a 6309, VCC fails in exactly the same way as I
>>>> described above on my real system.  Actually, on VCC, when I execute the
>>>> LSCR command with a filename, I get a blank green screen with an S in
>> the
>>>> upper left hand corner, as if the machine is trying to load a cassette
>>>> file.  Since I removed all the cassette file code from the Color Forth
>>>> source code, I am puzzled why this screen appears.
>>>> 
>>>> I am puzzled by this altogether.  Why should the 6309 not work like the
>>>> 6809, if it is supposed to be code compatible?
>>>> 
>>>> I would like to hear from anyone who may be able to assist me in
>> figuring
>>>> out why my code that works fine on a CoCo with a 6809 does not work on a
>>>> CoCo with a 6309.  Am I doomed to purchasing a 6890 and installing that
>>>> instead?
>>>> 
>>>> Thanks very much for listening!
>>>> 
>>>> --
>>>> Stephen M. Pereira
>>>> Bedford, NH  03110
>>>> KB1SXE
>>>> 
>>>> 
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>>>> 
>>> 
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