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Old 09-01-2007, 02:54 AM
joewing joewing is offline
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Join Date: Sep 2007
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Hello!
I've implemented an Altair 680 on a Spartan-3E FPGA, unfortunately
getting BASIC to load is giving me difficulties. I've found two versions
of BASIC online and tried both with little success. I think my problem is
the setting of the flag registers.
Anyway, I guess my question is, do the TBA and TAB instructions affect
the flag registers? Also, what is the proper behavior for CPX, ROR, ASR,
and LSR?

For a little background, I'm using a Spartan-3E starter kit attached
to a VT-320. I'm using 16k of RAM (which is loaded on reset with BASIC)
all implemented in the FPGA. If anyone's interested in the source (all
Verilog), I'd be more than happy to provide it.

Thanks!
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