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Altera_Forum
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13 years ago

Subtraction with numeric_Std doesn't work

Hello What am i doing in wrong in the code below. subtraction doesn't work! I am using numeric_std and the numbers are in twos complement format. // mattgust library ieee; use ieee....
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
11 years ago

If x is indeed an integer, then this code:

y1<=(unsigned(x)-y);
Will not compile. unsigned() can be used to convert a std_logic_vector to unsigned, but if you are converting from an integer, then you need to use the to_unsigned() function, and specify the number of bits for the result.

Besides
y1<=x-y;
should be enough