28 Jul
2023
28 Jul
'23
2:33 a.m.
On 7/27/23, Noel Chiappa <jnc(a)mercury.lcs.mit.edu> wrote:
Someone who's familiar with the 360 instruction set should be able to look
at e.g.:
and see how compatible it is.
Thanks for the pointer. I took a quick look. My knowledge of the
S/360 instruction set is very rusty at this point--it's been over 40
years since I programmed in it.
The program status word (PSW) format looks very familiar. Both
architectures seem to support 24-bit addressing.
Interdata has some data types and instructions for manipulating them
not present in S/360. Circular lists, for example, and instructions
for CRC calculation.
I didn't see anything about packed or zoned decimal support.
So perhaps an extended subset of S/360. I'd have to do a side-by-side
comparison between this document and S/360 Principles of Operation to
determine the level of binary program compatibility, if any. But it
looks like it might be better than the HitchHiker's Guide to the
Galaxy adage: "almost, but not quite, entirely unlike tea."
-Paul W