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Altera_Forum
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14 years ago

Adding and resizing in one step

Hi, Is there a way to add two unsigned numbers and extract only the x most significant bits from it in one step? I want something like this: sum <= resize(number1 + number2,4) In...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

If your tool understands and supports the following:

sum = (num1 + num2)/2**4;

Then it is equivalent to discarding 4 bits from result unless it goes silly and creates a division module.

alternatively if you can accept truncation errors then:

sum <= num1(6 downto 4) + num2(6 downto 4);

is almost equivalent but division is done on operands.