3 ms·
Yes, around 8 spare opcodes, and they were the ones Zilog used to escape into a large set of extensions for the (backwardly compatible to 8080) Z80.
by billforsternz 5y ago
Yes, around 8 spare opcodes, and they were the ones Zilog used to escape into a large set of extensions for the (backwardly compatible to 8080) Z80.
- phkahler 5y agoCan a Z80 be dropped into an 8080A socket? I'm thinking there were hardware differences.
- billforsternz 5y agoNo absolutely not. 8080 was a 3 chip solution from memory. The 8085 was, like a Z80, a 40 pin DIP, but even here the compatibility was strictly software not hardware. And in fact the software compatibility was a little less than 100% because Zilog decided to add an overflow flag by changing the 8080/8085 parity flag to actually reflect overflow instead of parity on arithmetic instructions.