Re: mipsisa32-unknown-elf-as: Error: too large constant specified

["Maciej W. Rozycki" <macro at ds2 dot pg dot gda dot pl>]

On Wed, 15 Oct 2003, Nigel Stephens wrote:

> Indeed. My argument is that it is "surprising" for the assembler to ever 
> generate zero-extended 64-bit immediate values for any instruction that 
> is not explicitly 64-bit. I agree that the logical operations, which 
> don't have 64-bit variants, are a problem - but surely portability of 
> existing 32-bit code is crucial. If I'm recompiling a 32-bit C program 
> for the n32 ABI, then I don't expect to have to change anything - unless 
> I explicitly use long long.

 Well, I suppose we can add "dand", "dor" and "dxor" support to gas
(following the "dli" precedent), but a sane C compiler should be aware it
is generating n32 code and sign-extend immediates as appropriate itself in
the first place.  And you shouldn't expect hand-written assembly to be
portable across ABIs, IMO. 

> Now that seems perverse! It would be easy enough for an assembler 
> programmer writing 64-bit code from scratch, and wanting a zero-extended 
> operand for  'or', 'and', etc, to write their new code thusly:
> 
> 	dli	$3, 0x80000000
> 	or	$2, $2, $3
> 
> 
> That's unambiguous, and puts the onus on the author of the 64-bit 
> assembler source code.

 It is, but one might want to write that as:

	.set	push
	.set	noat
	dli	$1, 0x80000000
	or	$2, $2, $1
	.set	pop

to avoid wasting a register and the resulting code starts becoming
obscure, sigh...

-- 
+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+--------------------------------------------------------------+
+        e-mail: macro@ds2.pg.gda.pl, PGP key available        +