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ARM > uses a non-zero frametable_base_pdx to offset into the frame table (PPC also > defines it). > > Fix the generic macros to subtract/add frametable_base_pdx, defaulting > to 0 when the arch does not define it. This makes the generic macros > correct for all architectures, even though they are only used on x86 > today. Hm, I assume this offset was added because the original mask PDX compression won't (usually) compress the gap between 0 and the start of RAM. However the newish offset PDX compression should be able to compress from 0 to start of RAM, and hence you don't need to apply an extra PDX offset there? If that's indeed the case it might be better to integrate frametable_base_pdx into the mask compression algorithm itself, so that on some arches it's a mask plus a decrease. Thanks, Roger.