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
