On 9/23/2018 9:59 PM, Kyle Owen wrote:
I've been informed that "set cpu noeae" will disable the EAE.
I just tried that:
Simulation stopped, PC: 01210 (JMP 1207)
sim> show cpu
CPU, idle enabled, stability wait = 20s, 32KW, no EAE
sim> c
R F4
*FLOAT/G$
1.000002 1.000002 0.000000
2.000002 1.414215 0.693147
3.000002 1.732053 1.098614
4.000002 2.000002 1.386296
5.000002 2.236070 1.609439
6.000002 2.449491 1.791761
7.000002 2.645753 1.945912
8.000001 2.828429 2.079443
9.000002 3.000002 2.197226
(Deleted)
Just tried it with that...and there's the problem. No FPP or EAE seems
like a bad combination for running FORTRAN IV code that does any bit
of math operations.
From SIMH (with EAE and FPP disabled):
.R F4
*FLOAT/G$
1.000002 1.000002 0.000000
2.000002 1.000031 0.693147
3.000002 1.224747 1.098614
4.000002 2.000002 1.386296
5.000002 5.798176 1.609439
6.000002 4.015202 1.791761
7.000002 3.522211 1.837092
8.000001 2.000061 -1.920560
9.000002 2.121345 -1.802777
...
So, in summary, either EAE or FPP (or both) works fine. Without at
least one, don't count on any floating point math to be right (based
on my limited assessment).
Surely this must've been known about 40+ years ago...right?
Since it's (apparently) working for me, it seems like your FRTS.SV is
probably a version with a bug in the EAE-disabled FP emulator. Note that
getting the parts of the compiler right is hard, which is why the PiDP-8
project has put a lot of work into building their OS/8 distro from known
good parts, mostly starting from source.
-Rick
