Very less resource fixed point 32x32 bit multiplier and 32/3

[Pratap]

Hi all,
I need to build an ASIC synthesizable fixed point 32x32 multiplier and
fixed point 32/32 divider with very less hardware resource for my
design.Speed is not at all a matter for me.
I can space 100s of cycles for my computaions.
Can anybody help me with the code (preferably in VHDL) or suitable
references?
Thanks,
Pratap

 

[whygee]

Pratap wrote:

Hi all,
I need to build an ASIC synthesizable fixed point 32x32 multiplier and
fixed point 32/32 divider with very less hardware resource for my
design.Speed is not at all a matter for me.
I can space 100s of cycles for my computaions.
Can anybody help me with the code (preferably in VHDL) or suitable
references?
Thanks,
Pratap

The first multi-cycle multiply/divide circuit was designed
long ago, look at this report from 1946 :
http://www.cs.unc.edu/~adyilie/comp265/vonNeumann.html
You only need enough bits storage for the operands, 32+32 FF,
as they are progressively replaced by computation results
in 32+32 cycles. It's a tricky but clever technique.

However, today, people use these techniques :
http://www.andraka.com/multipli.htm

Oh, and Wikipedia has some hints too :
http://en.wikipedia.org/wiki/Multiplication_ALU

yg

 

[Kevin Neilson]

Pratap wrote:

Hi all,
I need to build an ASIC synthesizable fixed point 32x32 multiplier and
fixed point 32/32 divider with very less hardware resource for my
design.Speed is not at all a matter for me.
I can space 100s of cycles for my computaions.
Can anybody help me with the code (preferably in VHDL) or suitable
references?
Thanks,
Pratap

If speed isn't an issue, you could put in a small 8- or 16-bit

microprocessor and small instruction ROM and let the C compiler take
care of the floating point operations.
-Kevin

 

[Kevin Neilson]

Kevin Neilson wrote:

Pratap wrote:
Hi all,
I need to build an ASIC synthesizable fixed point 32x32 multiplier and
fixed point 32/32 divider with very less hardware resource for my
design.Speed is not at all a matter for me.
I can space 100s of cycles for my computaions.
Can anybody help me with the code (preferably in VHDL) or suitable
references?
Thanks,
Pratap

If speed isn't an issue, you could put in a small 8- or 16-bit
microprocessor and small instruction ROM and let the C compiler take
care of the floating point operations.
-Kevin
Sorry; I just noticed you said "fixed point" and not "floating point".

If you've got lots of time, you can make a multiplier from a single
adder and a divider from a single subtractor. Or if you wanted to be
smaller, you could go down to a single two-bit full adder, or use
bit-serial techniques. I would think, though, that in an ASIC, you have
plenty of gates, and simple "*" will be nicely synthesized into a small
core from the ASIC library.
-Kevin