Pandora Pandora Bios

[ldesnogu]

I think he means that it takes longer if its uncompressed, normally the cycles spent on decompression more than make up for the cycles wasted waiting for the data from storage.

That's it. However the flash is probably fast, so perhaps that compensates.
But usually very slow decompression is the sign of something wrongly set, such as L1 and/or L2 caches not yet enabled, that's the reason why I asked

 

[Squidge]

That's it. However the flash is probably fast, so perhaps that compensates.
But usually very slow decompression is the sign of something wrongly set, such as L1 and/or L2 caches not yet enabled, that's the reason why I asked

UBoot doesn't enable the MMU, so all memory areas are uncached. It does enable the L2 cache however (I've no idea if that actually makes any different with the MMU disabled).

My BIOS enables the MMU as part of it's init, but if it's left enabled, Linux crashes shortly after bootup, so it has to be disabled once everything is ready.

 

[cb88]

heh and i definitely don't do low level code... just trying to learn SDL openGL and POV-ray simultaneously X.x... which reminds me could the pandora logo be ray traced? apparently that is how many demos get the code so small and some can even do it fast

 

[methril]

UBoot doesn't enable the MMU, so all memory areas are uncached. It does enable the L2 cache however (I've no idea if that actually makes any different with the MMU disabled).

My BIOS enables the MMU as part of it's init, but if it's left enabled, Linux crashes shortly after bootup, so it has to be disabled once everything is ready.

Linux Init makes the MMU initialization to porting capabilities.

U-boot has some log boot-up patches that could be interesting to see some booting up and then change to Linux bootscreens.

For the users, i thought that could be interesting doesn't see the u-boot menu (easy) but if they have to see something, it could be a Pandora's logo.

 

[ldesnogu]

UBoot doesn't enable the MMU, so all memory areas are uncached. It does enable the L2 cache however (I've no idea if that actually makes any different with the MMU disabled).

My BIOS enables the MMU as part of it's init, but if it's left enabled, Linux crashes shortly after bootup, so it has to be disabled once everything is ready.

Well you indeed have to disable MMU before jumping into the kernel: http://www.arm.linux.org.uk/developer/booting.php