[Coco] Re: Someone here who knows Japanese?!?

[jdaggett at gate.net]

Torsten 

Not really. As much as a suspected the 6309 does not bring a lot of 
"new" instructions so much as it adds registers and opcodes to to 
the already existing instructions on current 6809 registers. The only 
"new instructions" are the logic in memory,  EIM, OIM, ...,  the 
MULD, DIVD, DIVQ, TFM and the bit manipulation instructions like 
BAND, BIAND, and so forth. The rest are just an expansion of the 
existing instrtuctions and ones to handle the new registers. 

I do think I get a better understanding where the term "prebyte" 
comes from on the two opcodes $10 and $11. There are not 
actually prebyte. Instead these two opcodes act more as a switch. 
These two opcodes then force another fetch cycle and set latches to 
affect the main programable state machine. 

If you study the opcode map, you will see that almost all 
instruction's addressing mode and function is derived from one 8 
byte instructions. Secondly it can clearly be seen that the page2 and 
page 3 opcodes alter the registers acted on and/or the fuctionality 
slightly. Hitachi kept this in mind when they assigned the new 
opcodes. 

It does seem that Hitachi did stay away from the $4E opcode. If I 
remember correctly this is the HCF (Halt and Catch Fire) opcode. 
On the 6801/3 this opcode turns the program counter into a general 
16 bit counter. Not very useful. Not sure if that is a carry over from 
the 6800 or not, but the $4E opcode is not valid in the 6800/2/8 
either and the 6803 does mention its function. 

I also wonder also if Hitachi kept the $3E opcode (restart)? I do see 
that the $14 is SEXW and the $15,$18, and $1B are not used. 
These may have activated the IRQ, FIRQ and NMI partially from 
software. I seem to rember something from about 20 yrs ago that 
you put fcb  $1(4/5/8/b) in the code and you entered the ISR. Also a 
FCB $3E would reset/restart the computer. 

james





On 7 Jan 2005 at 19:15, Torsten Dittel wrote:

To:             	coco at maltedmedia.com
From:           	Torsten Dittel <Torsten at Dittel.info>
Date sent:      	Fri, 07 Jan 2005 19:15:15 +0100
Subject:        	[Coco] Re: Someone here who knows 
Japanese?!?
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> Hi James,
> 
> > Thanks, the opcode  map. I had starrted creating one myself and this
> > save a bit of time. 
> 
> I'm not into 6309 programming, so: do you see any additional
> information in this map compared to what has already known from the
> usenet memo?
> 
> Torsten
> 
> 
> 
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