Re: [f-cpu] Yet Another Upload

[Yann Guidon <whygee@f-cpu.org>]

hi !

Michael Riepe wrote:

> I'm going to upload fcpu-mr-20030418.tar.gz to
> http://f-cpu.seul.org/~f-cpu/new/ tonight.
>
> Highlights:
>
>    * EU_AFU is included.
>  
hmmm i better look at it :-)

>    * EU_ASU now supports twenty-four (24) operations, not counting
>      SIMD, chunk sizes or immediate instructions:
>
>        add     a + b                   modulo 2**n
>        addc    a + b                   with carry-out
>        avg     (a + b) / 2             unsigned
>        avgs    (a + b) / 2             signed
>        addus   saturate(a + b)         unsigned
>        addss   saturate(a + b)         signed
>
>        add1    a + b + 1               modulo 2**n
>        addc1   a + b + 1               with carry-out
>        avg1    (a + b + 1) / 2         unsigned
>        avgs1   (a + b + 1) / 2         signed
>        addus1  saturate(a + b + 1)     unsigned
>        addss1  saturate(a + b + 1)     signed
>
>        sub     a - b                   modulo 2**n
>        subb    a - b                   with borrow-out
>        diff    (a - b) / 2             unsigned
>        diffs   (a - b) / 2             signed
>        subus   saturate(a - b)         unsigned
>        subss   saturate(a - b)         signed
>
>        sub1    a - b - 1               modulo 2**n
>        subb1   a - b - 1               with borrow-out
>        diff1   (a - b - 1) / 2         unsigned
>        diffs1  (a - b - 1) / 2         signed
>        subus1  saturate(a - b - 1)     unsigned
>        subss1  saturate(a - b - 1)     signed
>  
it is getting really impressing !

> 	  Carry and borrow outputs use the numeric values 0 and 1.
> 	  I'm currently considering additional `widening' addw/subw
> 	  instructions that will provide a `correct' value in the
> 	  upper half, as if the operands had been sign-extended and
> 	  added/subtracted in a wider mode.
>
>    * EU_SHL will now scale up to 2048 bits, and I finally implemented
>      the widen instruction.  Shift, rotate, bitrev, byterev and widen
>      operate on individual chunks while other bytewise instructions
>      (mix, expand, permute, sdup and cshift) may transfer data from
>      one chunk to another.  Word width is limited to 2048 bits because
>      permute/sdup can only address up to 256 8-bit chunks internally.
>      Other operations will work with wider words, too.
>
>    * package Generic_Adder now includes the new carry-select adder
>      I'm using everywhere.  The carry-increment adder should not
>      be used any longer.
>
> As usual, packages and units have been tested with the included
> testbenches.
>  
cool.

i should however reinstall NCSIM but i am very very busy now and in the 
following months.

> Synthesis reports welcome.  BTW: You may also try to synthesize 128-bit
> or 256-bit versions of individual units (except IMul64 which doesn't
> auto-scale yet).
>  
I am more worried about the correct work of the general scripts and what 
they can do now.
Tests must also be redone regularly to check that all the sources work
correctly with all the known tools. If someone wants to do a regression 
server .....
I seem to remember that a lot of important things were missing in the 
main script.
But keeping it up to date made me forget what was missing ....

Hmmmm now that Michael has added yet more functions, the C version of 
the unit
must be rewritten : cool ! ....

YG (way behind)

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