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Altera_Forum
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20 years ago

dcache questions, bug in alt_dcache_flush

The alt_dcache_flush function from the hal may not correctly flush all dirty data in the cache. Consider the case where I want to flush the contents of a video buffer that is larger than the data cac...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
20 years ago

Hi all,

In my system, I have gotten 6 buffers for splash screens, video and OSD.

pOSDFrameBufferLA = (unsigned short*)alt_uncached_malloc(DUAL_VIEW_FRAME_SIZE*2 + 128);

The expression above will allocate a OSD buffer which will never be cached.

Nios have 4GB address space, but we can use only 2G. Because the higher 2GB is mapped to the lower 2GB. The only difference between higher 2GB and lower 2GB is that the higher 2GB will always bypass the cache.

FYI http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/biggrin.gif

David