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Altera_Forum's avatar
Altera_Forum
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13 years ago

New IP development

Hello, I am interested in developing some instructions which can do the bignum operations (like adding two operands of 1024 bit) and hence by plan to implement a simple Full Adder like this: ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
13 years ago

My problem with the performance counter block is that it is a 16bit slave - so it takes a lot of accesses to do anything.

A 32bit version would be much more friendly.

The lack of 'add with carry' could well be a problem, but one of the cmp instructions would do the job.

So code like: 

        sum = a + b + carry;
        carry = sum < a;

is amost right (needs an extra check for b[i] + carry == 0).

So 5 instructions (+ memory access) including 1 branch that can be staticly predicted 'not taken'.

With care and a combinatorial custom instruction (or 2) could be 3 instruction (I think).