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Altera_Forum's avatar
Altera_Forum
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22 years ago

Sign Extend operation

Hi, Now I am worry about performance of Sign Extend operation. for example, char sc(unsgined char uc) { return (signed char) uc; } Nios II GCC will generates following cod...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
22 years ago

Hi,

I know custom instruction (CI) is useful for this. But Nios II compiler does not support embeding CI as corresponding operation. To use CI, source modification is required. When Nios I, no need to modify. That's my frustration.

Also, shift performance of Nios II on Cyclone is worst, and operational clock is not fixed. In embedded system, sometimes it is critical issue.

Is there any idea of performance up shift (or sign extension) operation without source modification? Like Nios I could.

Regards,