9 Jul
2007
9 Jul
'07
12:07 a.m.
e.stiebler schrieb:
Jules Richardson wrote:
I have these. IMHO the series is incomplete, though, and has never been
followed up later.
The architecture is quite interesting, in that it has only a single type
of instruction, and several memory mapped functional units.
The instruction is basically: MOVE DATA FROM SOURCE ADDRESS TO TARGET
ADDRESS.
The ALU, as well as the PC, and I/O ports, and any number of register
were mapped to certain addresses in the available address range.
That is, a jump instruction is just: MOVE content of constant cell TO PC,
an addition is
MOVE value1 TO ALU-OPERAND1-ADDRESS
MOVE value2 TO ALU-ADD-ADDRESS
MOVE ALU-RESULT-ADDRESS TO result cell (this could be for instance
the PC itself, to form an indexed jump.
It was IIRC a 12 bit address space, and also 12 bit data (but I've to
look that up).
--
Holger
I've been thinking more and more this last week about designing a CPU
to be built from TTL logic ICs, purely as an interesting exercise.
Try to find somebody with a copy of the 1974 "elector" magazine (uk).
They had a series of articles about a "computer74" which was designed
in '74, and made of 74' series chips. Was a 16 bit thing.