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Altera_Forum
Honored Contributor
Honored ContributorAre only MSBs outputted if bits are restricted?
Hi,
Suppose I have a complex multiplier from the MegaWizard with inputs having 16 bits each and the outputs also having 16 bits. Because 16*16 equals 32 bits, would restricting the output to 16 bits output the Most Significant Bits (MSBs), i.e. would it output [31 downto 16] bits of the total 32 bits? Also, would the above reasoning be the same for the altmult_add MegaWizard block too? Is it common for all the Quartus arithmetic in general (to output the MSBs)? If not, how can I force only the MSBs to be outputted? Thank you.11 Replies
Altera_ForumThe arithmetic functions should discard LSBs if it allows you less than maximum width. If in doubt, you may keep it maximum width then choose by hand the bits you want to keep and discard other bits.
