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Altera_Forum
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16 years ago

Double precision floating point math problem with NiosII/e

I'm planning to use budget NiosII/e, provided by SOPC with Cyclone III. I wrote a simple program, to check if its double floating point math works correctly: #include <stdio.h> #includ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

Hello,

You can find some answers in the tutorial "Using Nios II Floating-Point Custom Instructions" (http://www.altera.com/literature/tt/tt_floating_point_custom_instructions.pdf (http://www.altera.com/literature/tt/tt_floating_point_custom_instructions.pdf%29)).

"The floating-point custom instructions, implement single precision floating-point arithmetic operations." So you cannot use floating point hardware for double precision calculation, whatever the type of processor (e/s/f).

For your case 3, I agree that if you disable it with pragma directives it should use software implementation as in case 1, but I don't know the second pragma directives you use (which finished with a 'd'), where do you find them. On the tutorial they put only the first ones (which finished with a 's').

Jérôme