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Altera_Forum
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13 years ago

Q (number format) Multiply

I'm working on a project that uses a 32-bit accumulator, which it's input is a 32-bit step size (unsigned Q30.2) value. The accumulator can rollover when preforming a large number of iterations or w...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
13 years ago

Thanks for your help.

I'll consider using the package, but I'll need to convert all the code over.

If I continue down the same path using std_logic_vector, I understand that the product will be a Q62.2 value. How would I scale that value to be 32 bits? Would I use the upper 32-bits?

temp = CONV_STD_LOGIC_VECTOR(CONV_INTEGER(CONV_INTEGER(in tra_clk_offset) * CONV_INTEGER(step_size)), 64);

amplitude = temp(64 downto 32);

I know "CONV_STD_LOGIC_VECTOR" will not work with a 64 bit value, just using this as an example.