[OpenBIOS] Tokenizer (fcode-utils 1.0.2) support for 64-bit constants.

Segher Boessenkool segher at kernel.crashing.org
Sat Apr 18 12:51:40 CEST 2009

> I think 64bit constants won't work on architectures with a 32bit  
> cell size, so FCode using them will not be platform independent.

An FCode driver can check for 64-bit support at runtime and skip over
some code if it's not there.

> Can you give a usage example of 64bit constants? I would assume  
> it's not BARs as those can be read from PCI config space?

Some devices have 64-bit MMIO registers that should not be accessed as
(pairs of) 32-bit registers.

> What's the expected output of the tokenizer? put two 32bit  
> constants on the stack, shift one by 32bit and OR them?

32-bit-const-1 32-bit-const-2 lxjoin

Note that 32-bit consts are sign-extended on 64-bit systems.

> To be sure, we could add a command line option for enabling 64bit  
> constants support and print a warning or an error in case it is not  
> set. Does that sound reasonable?

Sure.  Error please.


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