8 Feb
2022
8 Feb
'22
12:01 a.m.
An excellent point and I had been thinking about that as I wrote this.
And then I said, "When was the last time I actually used a JFCL and
JOV". Well, yeah if you are doing big math, but that just doesn't
happen in day to day systems programming. There wasn't any in all of
Galaxy, even when I fixed to to calculate dates properly.
Makes a great no-op, though.
On 2/7/22 5:51 PM, Robert Armstrong wrote:
The PDP-10 is
interesting (or strange) in that it uses skips to convey
the result of various tests and comparisons.� You don't use tests to set
PC flags and do conditional jumps on them (like nearly every other
architecture that comes to mind immediately).
It's worth pointing out that
the PDP-10 _does_ have PC flags and instructions to test them (just check my domain name!)
but they're not used for things like zero/negative tests. There is a carry flag of
sorts (the APR overflow bit) but it was almost never used. With 36 bits you didn't
worry much about overflows :)
Bob
_______________________________________________
HECnet mailing list -- hecnet(a)lists.dfupdate.se
To unsubscribe send an email to hecnet-leave(a)lists.dfupdate.se