daniel tian wrote: > Only do using R0. Like the following with loading 0x12345: > > MOVI 0x2345 -L //To load the lower 16bit data > MOVI 0x1 -H //Load the up 16bit data > OK. So it appears to me like R0 needs to be an intermediate secondary reload for register anytime you have a load of a large constant integer into any class other than R0_REGS (I'm assuming you've put R0 into its own class, which would normally be named R0_REGS).
> Now my approach is to define the Macro PREFERRED_RELOAD_CLASS(X, > CLASS), and make sure if the X is const int and larger than 512, it > will return the R0_REG register class. > That will certainly help, but won't be sufficient to handle all the cases. You still need to define your secondary reload class macros/functions. > PS: I think that if I don't define the macro LEGITIMIZE_RELOAD_ADDRESS > which will push reload the larger const int, the > PREFERRED_RELOAD_CLASS won't be called. is it right? > I don't know offhand. If I remember correctly, PREFERRED_RELOAD_CLASS is another method for optimizing the code -- which means your port should work with or without PREFERRED_RELOAD_CLASS defined. It also means there's no guarantee PREFERRED_RELOAD_CLASS will be honored in all cases. Jeff
