question on register data type

[srblinux]

Hi all,
Where we use Register data type varible in Device drivers?
Before the .obj or .exe Generation where we use register data type
Declaration.

[Ian Collins]

sr******@gmail.com wrote:

Hi all,
Where we use Register data type varible in Device drivers?
Before the .obj or .exe Generation where we use register data type
Declaration.

In general, don't bother, let the compiler do the register assignment
for you.

--
Ian Collins.

[Nick Keighley]

On Jan 4, 10:52*am, "[e-mail]" <[e-mail]:

*Where we use Register data type varible

I don't think register (note all lower case) is a data type.
It's a modifier I think.

The usual answer on comp.lang.c is that register is a suggestion
to the compiler which it is at liberty to ignore. With modern
compilers register is unnecessary as the compiler does a better job
than a human. [this applies 99% occasionally judicious use of
register may beat the compiler. But you'd probably have to know
your compiler really well and you *must* measure your programs
performance with actual data]

in Device drivers?

ah. Well some embedded compilers may be less good. But the
same advice applies. Examine the assembler output with and
without register. Measure the performance with real data.

* *Before the .obj or .exe Generation where we use register data type
* *Declaration.

what? register to the best of my knowlege is a source level
thingy. I don't see what it has to do with obj and .exe files.
Anway obj and exe are compiler specific you need a compiler
specific or embedded group for these sort of details.
--
Nick Keighley

[Richard Bos]

"sr******@gmail.com" <sr******@gmail.comwrote:

Where we use Register data type varible in Device drivers?

- It's not Register, it's register. C is case-sensitive.
- It's not a data type, it's a storage class.
- These days, we don't use it anywhere. Your optimiser will know better
than you what is the most efficient use of registers.

Richard

[santosh]

sr******@gmail.com wrote:

Hi all,
Where we use Register data type varible in Device drivers?
Before the .obj or .exe Generation where we use register data type
Declaration.

Just forget about register and let your compiler's optimiser do it's
job.