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Altera_Forum's avatar
Altera_Forum
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20 years ago

Selective Cache Enable/Disable support

Hi, Does NIOSII processor support selective caching of the entire system-address space. For example in system address space we have the SDRAM, and all other addressable-peripherals. Whenever ...
Altera_Forum's avatar
Altera_Forum
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20 years ago

the linux provides the following facilities to read/write io regs:

inb/outb, inw/outw, inl/outl, ...

the following to read/write device memories (bypass caches):

readb/writeb, readw/writew, readl/writel.

these facilities are implemented using cache bypassing instructions.

If you want to read/write IO regions like normal ram access, you can use the 31 bit address line. Without an MMU, uClinux has no other way of bypassing cache for specific region.