Saturn Emulator

[CyberAngel]

(11-13-2019 06:09 AM)cyrille de brébisson Wrote:  hello,

That helps the read/write, BUT, it means that each nibble has to be handled individually instead of being able to be handled as packs.

For example, if you work with "packed" nibbles, you can describe 1 register as 1 64 bit integer (and use masks), so any saturn binary operation can be done in basically 1 PPL line as in: A:= (A and not mask) OR ((A and mask) + (B and mask));
regardless of the field...

Working nibble by nibbles means loops, which are much less efficient...

Cyrille

I C... masks are easy... thus:
It looks like every odd nibble read (ARM read is in bytes) has to be in a buffer
in order to combine it with "upper" 4 bits of the unaltered Saturn information
producing an even number of nibbles (= a byte).
Every odd nibble write needs first a read into a buffer before the write
to yet again combine the just read upper part of the byte with the 4 bits of that odd nibble
to get a full byte to be written.

Was that an explanation that others in this group can understand?

Is that how you did it with the HP 49/50 ARM version, Cyrille?