23 Nov
2023
23 Nov
'23
3:08 a.m.
On 2023-11-22 6:53 p.m., Chuck Guzis via cctalk wrote:
On 11/22/23 16:47, Fred Cisin via cctalk wrote:
Yup. I have vivid memories of the Intel rep telling
us that not only
was the 8086 compatible with the 8085, conversion could be automated
through their ISIS-II based conversion program--and it would result in a
smaller (memory footprint) program.
To be fair to Intel,I think they did good job of encoding the
instruction set
for the most common sequences being shorter. 8 bit bytes only give space
for byte or word instructions, not both. Prefix bytes are good
compromise with the segmented 64K memory space. Data and code space are
optimized for 16 bits. You want 32 bits, buy a 432. Still only 64Kb
segments.
Ben.