Re: [avr-gcc-list] testsuite saga continues

[David Brown]

Wouter van Gulik wrote:
> Well, the GCC library provides most (if not all) functions for 64-bit
> operations. Alas this is written in C and the compiler can't make this
> nearly as good as an handwritten assembler routine. Mostly due to the lack
> of carry support in gcc.

Is it feasible to introduce carry support in gcc?  There are many 
architectures that would benefit from direct access to the carry flag 
(and other flags commonly found in cpus, such as overflow flags, sign 
flags, the avr's "T" flag, or the "extended" flag on m68k cpus).  It 
would mean that long arithmetic functions could be written almost 
optimally in C, as well as benefiting other types of code (such as crc 
routines or anything else involving rotations).  It's certainly a 
feature that many commercial microcontroller compilers support - the 
ability to write things like "if (CARRY) ..." can be a big win for some 
code.

I guess it's just wishful thinking...

mvh.,

David