Re: [RFA] mips 32/64 register/stack fix

[Andrew Cagney <cagney@gnu.org>]

> On Wed, Apr 28, 2004 at 05:45:22PM -0400, Andrew Cagney wrote:
> 
>>>> >Here's your tdep info:
>>>> >{elf_flags = 1610625025, mips_abi = MIPS_ABI_EABI32,
>>
>>> 
>>> I was looking to see if anything like that was present -> it is clearly 
>>> identified as a 32-bit ABI binary.
>>> 
>>> I think the bug is in mips_register_type, the tail end should probably 
>>> be changed to read something like:
>>> 
>>>   else if (regnum >= NUM_REGS
>>> 	   && gdbarch_tdep (gdbarch)->mips64_transfers_32bit_regs_p)
>>>     /* The target, while using a 64-bit raw register buffer, is only
>>>        transfering 32-bits of each integer register.  Reflect this in
>>>        the cooked/pseudo register value.  */
>>>     return builtin_type_int32;
>>>   else if (regnum > NUM_REGS

 >= NUM_REGS

>>> 	   && mips_saved_regsize (gdbarch) == 4)
>>>     /* A 32-bit ABI such as o32 possibly running on a 64-bit ISA.  */
>>>     return builtin_type_int32;
>>>   else if (mips_regsize (gdbarch) == 8)
>>>     /* 64-bit ISA.  */
>>>     return builtin_type_int64;
>>>   else
>>>     /* 32-bit ISA.  */
>>>     return builtin_type_int32;
> 
> 
> Would you mind clarifying the reason for having mips_regsize, which is
> used in a number of other places, return a regsize based on the ISA?

Hasn't this all come up before?

It's the register size of the underlying ISA, on top of which the ABI is 
implemented.  I think I'll rename mips_regsize and mips_saved_regsize to 
clarify this.

> This change to mips_register_type conveys the fact that we've only got
> 32 bits of data.  But we'll choose to print (in info registers) a
> 64-bit wide field for each GPR if the binary is tagged E_MIPS_ARCH_64 |
> E_MIPS_ABI_EABI32, and a 32-bit field if it's tagged E_MIPS_ARCH_2 |
> E_MIPS_ABI_EABI32.  Conceptually, I think we're interested in some
> combination of the available register size (-> a property of the target)
> and the size of registers known to the inferior program (-> unclear mix
> of its ABI and ISA).

It does?  With the above it should always print a 32-bit GPR reflecting 
the 32-bit ABI.  If you think it should display something else, look at 
user-regs which lets you implement registers using the frame register 
values (something psuedo registers can't handle).

Andrew