The 6809 was my fav 8 bitter to program. Relocatable code, many addressing
modes, the index registers, stack pointers, consistent instruction set..
There was a decent C compiler, Introl.  It's a shame that it never really
caught on. 

I've often wondered whether the RCA 1802 could've been considered "RISC".
Lots of registers (for the time). Simple instructions executing in 1 or
1.5 cycles if I recall. LoL, it even had a "SEX" instruction..

Cheers!

On Sun, Apr 21, 2024 at 10:16:32AM -0700, Chuck Guzis via cctalk wrote:
> On 4/21/24 09:37, Mike Katz wrote:
> > Even the 6809 could push up to 8 registers (up to 10 bytes) at once on
> > one of two stacks in a single two byte instruction.
> 
> The 6809 was introduced the same year as the 8086.  The 80186,
> introduced in 1982, did have the "PUSHA POPA" instructions and was
> considerably faster and more complex than the 8086.  As far as I could
> tell, the 6809 was an evolutionary dead-end, meant to fill the gap
> between the very slow 6800 and the very advanced 68000; that made the
> OEMs a bit uneasy, hence its limited adoption.  It was also very
> expensive for an 8 bit MPU--a key criterion for adoption.
> 
> --Chuck
> 
> 

-- 
Bill Duncan,         | http://billduncan.org/
bdun...@beachnet.org | - linux/unix/network/cloud
+1 416 697-9315      | - performance engineering, SRE

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