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Altera_Forum's avatar
Altera_Forum
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13 years ago

Floating point custom instruction in nios2

To perform the floating point multiplication in the Floating Point Custom Instruction which is inbuilt, how should I pass the values from the nios code?

Do I have to use a specific format for the numbers or use additional instructions in nios code for the floating point multiplication to be offloaded to the custom instruction hardware ?

1 Reply

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    13 years ago

    The custom instructions use the standard ieee format used by C for 'float' variables.

    If you want to use the custom instructions you need to ensure that you never use 'double' - so all constants need to be explictly marked (eg 1.5f).

    You may need to check carefully that none of the C library functions are unexpectedly called.