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Yahoo!!!!!!! RSTS/E is fully running on Supnik's simulator on PC
I got BASIC-PLUS working on Win95 with Pentium processor. The bug is
apparently in the emulation of the Floating Point Processor. I built a
version of BASIC-PLUS and told it the processor had no FPP. This version
works fine! After some experimenting I came to the conclusion that the bug
was in the FPP instructions and not the integer instructions.
Here's what I did:
At this point the light bulb went off in my head. The lexical scanner in
BASIC-PLUS assumes all numeric constants are floating point until it sees
the percent sign, at which time it tries to convert it to either a one byte
or two byte integer constant. So I thought, if the FPP emulation was wrong,
then the conversion to an integer might be wrong. I then thought, I can
build a BASIC-PLUS with floating point emulation in the interpreter, and
sure enough it works fine.
I bet the reason it works on the Alpha is because the Alpha's native
floating point is probably closer to the PDP-11s floating point. The
Pentium's floating point is probably different.