[Coco] 6309 microprocessor project - 10-24-2003

[john donaldson]

John,
   I thought there was a MAX size that a program could be
under OS9. Are you saying that now we can have a multi 
100K
program running at the same time. I always was told that
64K was the max size a program could be.

John Donaldson

On Fri, 24 Oct 2003 09:55:02 -0400
  "John Collyer" <johncollyer at zoominternet.net> wrote:
>The extra memory can be used for whatever you'd like,
>as far as I know there aren't any current applications
>using this memory except for VIDEOTEST  and
>MEMTEST by Robert Gault.
>
>----- Original Message ----- 
>From: "john donaldson" <jadonaldson at charter.net>
>To: <coco at maltedmedia.com>; "John Collyer" 
><johncollyer at zoominternet.net>
>Sent: Friday, October 24, 2003 9:34 AM
>Subject: Re: [Coco] 6309 microprocessor project - 
>10-24-2003
>
>
>>    John,
>>      This may sound like a silly question, but what will 
>> one
>> be able to do with the extra memory. Can it be used for
>> large programs, or is it only useful for graphics 
>>screens
>> and mabey a RAM Disk?/
>> 
>> John Donaldson
>> 
>> 
>> 
>> On Fri, 24 Oct 2003 08:48:53 -0400
>> "John  Collyer" <johncollyer at zoominternet.net> wrote:
>> >6309 microprocessor project.

>> >
>> >Hello,
>> >
>> >The special opcode $11FD (win32 functions) let you 
>> >manipulate files
>> >on the host system directly from your emulated coco 
>> >programs.  The
>> >data areas that you defined and initialize according 
>> to 
>> >the win32 api
>> >documentation will be converted from Big Endian to 
>>Little 
>> >Endian byte
>> >order for you automatically, naturally.  This allows 
>>you 
>> >to manipulate
>> >the win32 data structures in a natural way.
>> >
>> >The special opcode $11FF will let you run win32 code, 
>>but 
>> >I suspect this
>> >opcode will generally not be used heavily by anyone, 
>> >mostly because it's
>> >hard to use and awkward.
>> >
>> >I am starting on the memory portion of the emulator 
>> >today. The emulator's
>> >memory will be designated as read/write/execute, this 
>>is 
>> >to support the
>> >special opcode $11FF. Below see my vision of coco's 
>> >emulated memory.
>> >
>> >; FF9B  Reserved. | 2^11 = 1000000h = 16777216 = 2048 
>>MMU 
>> >blocks
>> >;                 | for a total memory of 2024 * 8192 = 
>> >16,580,608 (16Meg).
>> >;
>> >;       1MB and 2MB bits, Write only.
>> >;       Bit 7 - 16MB Video Bit           NoCan3 bits 
>>for 
>> >16MB.
>> >;       Bit 6 - 16MB Memory Bit          NoCan3 bits 
>>for 
>> >16MB.
>> >;       Bit 5 -  8MB Memory Bit          NoCan3 bits 
>>for 
>> >8MB.
>> >;       Bit 4 -  4MB Memory Bit          NoCan3 bits 
>>for 
>> >8MB.
>> >;       Bit 3 -  8MB Video Bit           NoCan3 bits 
>>for 
>> >8MB.
>> >;       Bit 2 -  4MB Video Bit           NoCan3 bits 
>>for 
>> >8MB.
>> >;       Bit 1 -  2MB Video Bit   Disto & NoCan2/3 bits 
>> >for 2MB.
>> >;       Bit 0 -  1MB Video Bit   Disto & NoCan2/3 bits 
>> >for 1MB.
>> >
>> >The memory bits (vmmmvvvv) at $FF9B have no effect 
>>until 
>> >a value is sent
>> >to an MMU register, $FFA0-$FFAF. When a value is sent 
>>to 
>> >an MMU register,
>> >the memory bits at $FF9B combine with the MMU register 
>>to 
>> >create a pseudo
>> >11 bit register. This enables access to 2048 (2^11) MMU 
>> >blocks for a total
>> >memory of 2024 * 8192 = 16,580,608 (16Meg).
>> >
>> >I've decided to use the Nocan3 memory model, which 
>>gives 
>> >us access to
>> >16 Megs of ram plus the 32K internal rom. With this 
>>model 
>> >there is no
>> >need for the jv coco3 emulator's use of the MMU 
>>extension 
>> >registers at
>> >$FF70 - $FF7F. That will leave these memory locations 
>> >free as they should
>> >be. If anyone would like to comment on my vision of 
>> >memory for the jc emulator,
>> >please do! The topic is open and I'd like to read all 
>> >your responses.
>> >
>> >
>> >More later
>> >
>> >John Collyer.
>> 
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>> 
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