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How to write vectors in VHDL
von John S. (johnsmith)

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I would like to ask, how can I write vectors in VHDL.

Below I have written the VHDL code in Integers, But I am having 
difficulties in writing it as Vectors?

The equation I am working with to find the correct answer from Waveform 
is:

FX= A0 +A1x +A2^x2 +A3^x3
1
ENTITY Polynomial1 IS

2
PORT ( clk, res : IN BIT;

3
ai, x : IN INTEGER:=0; 

4
fx : OUT INTEGER:=0);

5
END Polynomial1;

6
ARCHITECTURE bhv OF Polynomial1 IS SIGNAL reg : INTEGER:=0;

7
BEGIN

8
PROCESS

9
BEGIN

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WAIT UNTIL (clk'EVENT AND clk = '1');

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IF res = '1' THEN reg <= 0; 

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ELSE reg <= x * (ai + reg);

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END IF;

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END PROCESS;

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fx <= reg + ai; 

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END bhv;




I have had a go at Vectors with assumable bits:


1
ENTITY Polynomial1 IS

2
PORT ( clk, reset : IN STD_LOGIC;

3
a0, a1, a2, a3 : IN  STD_LOGIC_VECTOR(2 DOWNTO 0);

4
x : IN  STD_LOGIC_VECTOR (1 DOWNTO 0);

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fx: OUT  STD_LOGIC_VECTOR(8 DOWNTO 0)) ;

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END Polynomial1;


I would like to apologies if i have made any format mistakes.

: Edited by Moderator
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Re: How to write vectors in VHDL
von Lothar M. (Company: Titel) (lkmiller) (Moderator)

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John Smith wrote:
> Below I have written the VHDL code in Integers, But I am having
> difficulties in writing it as Vectors?
Check out the numeric_std package and its conversions and casts. Try 
this (its German but you will get the point):
http://www.lothar-miller.de/s9y/archives/14-Numeric_Std.html

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