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Altera_Forum's avatar
Altera_Forum
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10 years ago

Signed addition in Nios II

Hi all,

I need to add two numbers in Nios II.

For that i simply add two numbers in Nios II C program.

I have assigned the maximum possible 32 bit positive value .i.e. 0x7FFFFFFF in both.

What i expect is the result should saturate to 0x7FFFFFFF as in the case of micro controllers.

But the Nios II does not do like that.What can be the reason for that?

1 Reply

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

    The result doesn't saturate but Nios overflows and set the overflow status.

    AFAIK this is the normal behaviour on other microprocessors, too. I have worked with a few uP which could saturate the result instead of generating an overflow, but this was always an option you had to explicitly enable.