Re: Compilers

[David Given <dg@cowlark.com>]

Mark Junker wrote:
[...]
>> A -fno-frame-pointer option would be nice, too. I guess that most people
>> wouldn't want them on ELKS, and it will make code smaller and use less
>> stack space.
> 
> This can (sometimes) produce smaller code.

The main advantage is that you free up a register that can be used for 
other things. On the register-starved x86 family this is a huge benefit.

I really don't know why people use a frame pointer anyway. Given that 
the i86 can do arbitrary relative stack addressing there's no real need 
for it. It makes debugging marginally easier, but then the debug 
information should provide all the necessary data to find the stack 
frame from any point in the code...

(I work for a company that produces embedded operating systems, with our 
own cross-platform compiler architecture. The PowerPC has 32 
general-purpose registers. Guess how many the 386 has? *Five*. That 
leads to interesting scalability issues in our register allocation code...)

-- 
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