[oc] Extract/Deposite

[Ali Mashtizadeh <ali@alikat.org>]

I am implementing an Extract/Deposite functions in my ALU and I am using
up to much resources it seems. It is because I need an array of masks
like:

MASK[0] = 64'b0..0;
MASK[1] = 64'b0..01;
MASK[2] = 64'b0..011;
MASK[3] = 64'b0..0111;
...
...
...
MASK[63] = 64'b1111....1111;

On my xilinx chip (Spartan II-200K Gate) the synthesizer converts this
to a rom and that uses way too much resources. The design won't fit
since this mask array takes up so many Look up tables for this rom. Is
there any way to implement this in a simpler way.

The Extract/Deposite functions are just like in the itainium
architecture or alpha. It shifts the data and &'s it to the correct
mask. The deposite similar. Can anyone suggest a way to simplify these
functions?

Ali

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