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Hey, guys, I am trying to understand this piece of code any help would be great

CLyna
Beginner
424 Views

rotW <= w(3)(23 downto 0) & w(3)(31 downto 24);

subRotW(8*(i+1)-1 downto 8*i) <= subKey(conv_integer(rotW(8*(i+1)-1 downto 8*i)));

I know that rotW is being populated by the values from w backwards, but can someone tell me whats going on in the next line? is it converting the value from rotW to an integer then storing it in subKey?

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1 Reply
Vicky1
Employee
89 Views

Hi,

By looking at the second line, it should execute as you mentioned because the "conv_integer" function converts an argument of type integer,unsigned, signed or std_ulogic to an integer return value. This function also has limitation range corresponds to 31 bit unsigned value or signed value, it can`t convert an argument outside of this range.

 

Regards,

Vikas

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