Lpc2000

--- In lpc2000@yahoogroups.com, "Paul Curtis" <plc@...> wrote:

> You're acting like a spoilt child.

I will ignore this comment knowing you for what you are :)

> Something concrete:
> 
> void do_something_nasty(void)
> {
>   // I need to do something fast without a call, I need a register,
>   // so I'll pick r5 as the/ code generator seems it's not using that
>   // one when I run it under the debugger.
>   asm("ldr r5, =0x12345678");
> 
>   // Now do soemthing with r5 because I did something above.
> }

Excellent example of INCORRECT use of inline assembly.

You want to use "r5" for your own purpose but have chosen not to tell
the compiler.  You appear not to know, or to have forgotten, that the
compiler is responsible for allocation of registers.

Although I question the validity your particular requirement (as I can
gather from your comments), the compiler nonetheless will accodomate
your requirement (subject to reasonable limits) if you were to include
the following declaraction in your function:

> register int r5 asm ("r5");

If you do not tell the compiler you are using a register that it also
uses, you should not be surprised at what happens as a result.

While the reference to "r5" in the ASM statement may be obvious to you
as a human, the compiler does not parse this string at all.


Jaya