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
