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Re: RFA: Do solib address arithmetic with appropriate truncation
> There must be something around that this code can use. On something
>> like a mips, this would be wrong - remember the sign extension problem.
> I've never really understood the MIPS sign extension problem. Does it
> occur when TARGET_PTR_BIT is smaller than the size of one or more of
> the registers used to hold addresses?
The MIPS ISA when running 32 bit code, sign extends pointers. GDB
mimics this behavour. If it encounters a 32 bit pointer it will convert
it to/from a cannonical form (sign extended CORE_ADDR for MIPS). Such
pointers occure everywhere - debug info, registers, memory, ... By
always sign extending, GDB avoids any potential inconsistency and latent
bugs. POINTER_TO_ADDRESS and ADDRESS_TO_POINTER handle this.
When debugging MIPS, the first thing to check is that CORE_ADDRs are
sign exteded. A value like ``0x80001234'' as the patch would generate,
indicate a bug.
Interestingly, the SPARC is showing signs of the same, or similar, problems.