32-Bit Comparator on Xilinx FPGA

[kalyansumankv]

32-Bit Comparator

Hi All,

I am planning to implement a 32-bit comparator on Xilinx FPGA, but the Xilinx FPGA has only 16 bit comparators only, is there any method to implement the 32-bit comparision using 2 16-bit comparisions

I want to use a 32-bit comparision in my RTL, so that it operates at high frequency range(more than 300Mhz). Can any one let me know the procedure for doing tht.

Regards
KalyanSuman KV

 

[bapodradhairyab]

32-Bit Comparator

compare firs most significant 16 bit if they are equal than only you need to check the least significant 16 bit or you can use

mux that has select line is comparison result of most significant 16 bits (say 1 for equal and 0 for not equal)

for both most significant 16 bit and least significant 16 bit you will get 3 output (eq, gt and ls)

mux it if selectline (result of first comparison is 1) select result of MSB-16 only else LSB-16

are you clear or need block diagram... short of think...

dear think some what this is simple solution...

 

[bapodradhairyab]

32-Bit Comparision On Xilinx Virtex 5

i had replied you in your topic 32 bit comparison read it carefully you will get it...

and for virtex 5 it will sure work at 300 MHz as combinatorial you will use from primitive only, and just add one stage of 2-1 mux

 

[kalyansumankv]

Re: 32-Bit Comparator

Dear bapodradhairyab,

Thanks for the reply,
The procedure you have mentions holds good for the unsigned magnitude comparision, but i need the procedure for signed numbers., please let me know if you have any procedure for signed number comparision.

Regards
Kalyan Suman

 

[bapodradhairyab]

32-Bit Comparator

if signed comparison of 16 bit is there??

if so you need to compare MSB 16 with signed comparison...

else

you will lead to heavy combinational

with 1st sign bit will be used as mux if signs are not equal than the negative is smaller if equal than same procedure explained above just need to invert if sign bit indicate negative...

this procedure is not for 2' or 1' complement number

number with sign bit added as msb this method will work

got it???
or not...???

 

[kalyansumankv]

Re: 32-Bit Comparator

Dear bapodradhairyab.

Thanks a lot, i got it!!

Regards
KalyanSuman