Re: Erroneous code generation from GNAT or GCC?

["Yannick Duchêne (Hibou57)" <yannick_duchene@yahoo.fr>]

Le Tue, 30 Apr 2013 21:06:09 +0200, Simon Wright <simon@pushface.org> a  
écrit:
> I was wondering what you meant by using constraints "a", "b", "c", "d"
> .. I now see [3] that these are i386 constraints for the a..d registers
> respectively, no wonder they gave wierd results on x86_64 where they
> mean something quite different!

They do exists with 64 bits instructions too. a is eax; b is ebx, etc, for  
32 bits mode, and a is rax, b is rbx, etc, for 64 bits mode. There is also  
ax/ah/al, ax/bh/bl, etc, as sub‑parts of the above, except ax, bx, etc, is  
for 16 bits only, but ah, al, bh, bl are still a accessible in 32 bits  
mode — I don't know if it's still the case in 64 bits mode.

-- 
“Syntactic sugar causes cancer of the semi-colons.” [1]
“Structured Programming supports the law of the excluded muddle.” [1]
[1]: Epigrams on Programming — Alan J. — P. Yale University