SVFIG presentations by Dr. Ting and Wil Baden

[Jeff Fox <fox@xxxxxxxxxxxxxxxxxxx>]

Dear MISC readers:

Yesterday at the Silicon Valley Forth Interest Group meeting
Dr. C.H. Ting gave a presentation about the development that
he is doing in Taiwan with a new startup.  They have been 
looking at ways to extend his P16 and P24 designs.  With
five bit opcodes they have 32 instructions and Chuck had
been using 27 in his designs so they had five instructions
to play with. And the 24 bit design can support 4 slots of
6 bit instructions or 64 instructions to play with.

They have looked at variations in the architecture and
considered several architectural extensions.  The P16
offered the A register as an A register stack with no
change to the instruction set.  A! pushes the previous
value in the A register into the Astack and the A (A@)
instruction pops an old value when it transfers A to T.

This means P16 is really a 3 stack machine and they
have looked at 4 stack variations as well.  This involves
looking at the way it would be represented in schematic
or VHDL format as well as considering what changes it
implies in the instruction set.

With many new instructions to choose from they had
considered a variety and Dr. Ting explained the reasoning.
He covered things like short literals, branching, and math.

He also described a machine with 3 stacks in which the
third stack was 3 registers wide X Y Z and which was
synchonized to the movement of the Return stack when
CALL and RET instructions are executed.  This local stack
would not be moved by >R and R> instructions.  Dr. Ting
described variations in the way the local registers could
be initialized and used.  He had coded an eForth for
each of the designs and talked about some of the more
complex words in eForth and how the Local registers
were used and how one of these could contain the count
for the TIMES opcode to count down.  He showed how this
was used in the multiply step instruction which
combined the +* and 2/ operations in the MISC instruction
set.

In the afternoon session Wil Baden gave a presentation
where he reviewed the contents of Neil Bawd's "ugly web page" 
and explained some of the details of his development style,
how some of the tools work, and how these are related.  We
will be treated to another presentation at the Forth Day
meeting in November in two weeks.

I was able to get videos of Dr. Ting's and Wil Baden's
presentations and will make them available.  I have also
converted some videos to mpg format and will distribute
them on CD-ROM.  I placed a greatly compressed streaming
video version of Chuck's interview from tape 1 at my
web site.  It is in a format for dsl speed access and
28MB so I don't think you want to try to play it over
a slow dial-up modem.  I can place some small videos
at the web site.  

Best wishes,
Jeff Fox