18 Aug
2002
18 Aug
'02
8:18 a.m.
Of course if you have a 12 bit or 24 bit word, then
either octal or hex
are natural (3 hex digits = 4 octal digits). Again I guess which one you
use depends on the format of the instruction word.
The fun then comes with something like the ICT/ICL 1900 series* where the
24-bit word and the 7-bit opcode were "always" expressed in octal but the
instruction
F X N(M) was physically laid out as
X(3 bits)F(7 bits)M(2 bits)N(12 bits) [branches being slightly different]
which did not appear naturally in the octal expression.
* originally the FP6000 originating in Canada
Andy