Interested In VHDL Training? Click Here

0 votes
in VHDL by (200 points)

How do you do multiplication in VHDL?

2 Answers

0 votes
by (500 points)

There are 2 ways to do multiplication. The first one is the '*' operator. The second one is instantiation of a multiplier component that contains multiplication logic.

Example :

signal x : signed ( 5 downto 0 ) ;
signal y : signed ( 8 downto 0 ) ;
signal result : signed ( 14 downto 0 ) ;

result <= x * y ; -- First method.
instantiation_of_multiplier : multiplier -- Second method. port map
input_data_1 => x ,
input_data_2 => y ,

result => result
) ;
Note: Multiplication should always be regarded as an "expensive" operation and therefore should be avoided when possible. For example: multiplication by 2 can be done by simply shifting left - avoiding the need of actually using a multiplier.
0 votes
by (500 points)

This depends on the application. When I don't care how it will done by synthesis tools I just type a * b. In other situations, if I design the FPGA project I use DSP slices. If I design ASIC or this is FPGA prototyping I do it using device's fabric (logic).

In most of my experiences I need high performance. So in the last case, I use a pipelined parallel binary multiplier scheme.

Want to improve your VHDL skills?

Click Here - Sign Up For VHDL Training

© 2022 by Hardware Coder. User contributions are licensed under cc by-sa 4.0 with attribution required. Attribution means a link to the question, answer, user, etc on this site.

This site is owned and operated by Hardware Coder in McKinney, Texas.

Send Us A Message
About Us

By using this site, you agree to the following:

Privacy Policy
Terms and Conditions
DMCA Policy
Earnings Disclaimer
Legal Disclaimer