vhdl code for division of two fixed point numbers

[ammassk]

dear all,

I need to do the division of two fixed point numbers.Can anybody help me to do coding for this.

eg: 1.75 /1.5

1.75 is 0000000111000000(16 bit representation)
1.5 is 0000000110000000(16 bit representation).

1.75 /1.5=1.166667. =0000000100101011.

 

[TrickyDicky]

yes, the simplest VHDL is:

output <= input1 / input2;

using the numeric_std or fixed point library.

But this will only produce a maximum pipeline length of 1. To get better pipelining, you need to use a divider IP core, which is provided by both altera and xilinx.

 

[Er.abdulrehman]

You must have heard about library named fixed_pkg.In terms of complexity this library can be placed some where between integer math and floating point maths.
e.g.

library ieee_proposed;
use ieee_proposed.fixed_pkg.all;

Restoring Algorithm, Successive division method can also be used

 

[ammassk]

I tried this. But not getting the correct answer. I used the library numeric_std also.

- - - Updated - - -

I tried restoring algorithm and got correct answer.But I got quotient and reminder separately. But my problem is I need to get this together as answer.
Eg: for 4/3 , getting quotient as 1 and reminder as 1. But I need to get the answer as 1.3. How it is possible?

 

[TrickyDicky]

you need to change the number of fraction bits you use.

 

[ablam]

yes, the simplest VHDL is:

output <= input1 / input2;

using the numeric_std or fixed point library.

But this will only produce a maximum pipeline length of 1. To get better pipelining, you need to use a divider IP core, which is provided by both altera and xilinx.

hi,
I am not able to use / operator for division.I am getting error like this" Operator <INVALID OPERATOR> must have constant operands or first operand must be power of 2"Can anyone tel me wat to do?Thanks in advance
-->

 

[TrickyDicky]

Yes, the division operator works fine in simulation, but some synthesisors put restrictions on it's use, mainly because a single clock cycle divide is very slow, so they think anyone doing it is silly (divide by 2^n is just a bit shift and therefore free to implement). You should use the divider cores provided by your chip vendor.

 

[FvM]

For clarity, you should tell about the synthesis tool and imported libraries.

 

[ABO_ATHAB]

hi ammassk
you can use fixed ponit library provided by bishop
search it on google and will get many result
regards

 

[TrickyDicky]

hi ammassk
you can use fixed ponit library provided by bishop
search it on google and will get many result
regards

You would have exactly the same problems I highlighted above.

 

[k621219]

You can find some VHDL code from "Circuit Design with VHDL Volnei A. Pedroni".

 

[ABO_ATHAB]

LOOK TO THIS WEB
AMAZING

https://vhdlguru.blogspot.com/2010/03/fixed-point-operations-in-vhdl-tutorial.html

 

[K-J]

hi,
I am not able to use / operator for division.I am getting error like this" Operator <INVALID OPERATOR> must have constant operands or first operand must be power of 2"Can anyone tel me wat to do?Thanks in advance
-->

Google for the source code for 'lpm_divide'. This is a pipelined, fast divider that can produce a new output on every clock cycle. If you really need the result of the division completed on the same clock cycle, then you will get a large, slow implementation...once you find a tool that allows you to synthesize '/'.

Kevin