Selectively disable optimization on macro?

May I suggest this simpler, faster C code.

void main()
{
//some code ..
{
bit ie = IE; IE = 0;
//critical code ..
IE = ie;
}
//some more code ..
}

May I suggest this simpler, faster C code.

void main()
{
//some code ..
{
bit ie = IE; IE = 0;
//critical code ..
IE = ie;
}
//some more code ..
}

Opps, I forgot the &ltpre&gt and &lt/pre&gt tags. ( Sure would be nice if the following message was before the message box: "Use &ltpre&gt and &lt/pre&gt tags surrounding any code posted." )

May I suggest this simpler, faster C code.

void main()
{
  //some code ..
  {
    bit ie = IE; IE = 0;
    //critical code ..
    IE = ie;
  }
  //some more code ..
} 

Opps, I forgot the &ltpre&gt and &lt/pre&gt tags. ( Sure would be nice if the following message was before the message box: "Use &ltpre&gt and &lt/pre&gt tags surrounding any code posted." )<br>
<br>
May I suggest this simpler, faster C code.<br>
<br>

void main()
{
  //some code ..
  {
    bit ie = IE; IE = 0;
    //critical code ..
    IE = ie;
  }
  //some more code ..
} 

(I think the Forum messed up my last post -- it seems to have copied Jon's instead of what I wrote (I previewed it first, and saw after posting it was all wrong ... anyway -- here's what _I_ wrote:)

Hi Jon.

That's very elegant. But can I do a bit declaration anywhere in the code (i.e. wherever I insert this macro?). I seem to recall that I can, as long as it's inside a {...} block.

Typically (but not always) my code looks something like what you've presented. But the problem is that in some instances, the Enter/ExitCritical() macros may be called more than once in a function and the number of each may not be equal (different "exit paths").

Will your method still work? I have to ponder that a bit. It's a whole lot faster than pushing things on the stack, though ...

Why not use the @pragma disable before a function definition. For example:

#pragma disable
void function (void)
{
// Do non-interruptable stuff in here.
}

             ; FUNCTION function (BEGIN)
0000 D3                SETB    C
0001 10AF01            JBC     EA,?C0002
0004 C3                CLR     C
0005         ?C0002:
0005 C0D0              PUSH    PSW

; // Do non-interruptable stuff in here.

0007 D0D0              POP     PSW
0009 92AF              MOV     EA,C
000B 22                RET     
             ; FUNCTION function (END)

For personal preference I prefer the structured approach where I can clearly see the acquistion & release of this resource. Jon Ward's idea of using "#pragma disable" is even cleaner (but uses 1 byte vs 1 bit of ram and is slightly bigger in code). Of course if you need the speed, just save the IE bit when you acquire the interrupt lock and restore IE when you release the lock.

Hi Jon.

That's an interesting idea.

I have to see how that fits into the code, and how elegantly I can incorporate it into the preprocessor.

Off the top of my head, I know of one place where my code requires attention when using this method. Look at this (inside a pragma-disabled function):

...
  for (many iterations) {
    do_something_looooooooong;
    enable interrupts;
    disable interrupts;
  }
...

I agree, your method gives finer-grain control.

Andrew

Maybe you'll want to change that to...

#pragma disable
void do_something (void)
{
.
.
.
}

void do_something_loop (void)
{
.
.
.
//enable interrupts
.
.
.
for (i = 0; i < ???; i++)
  do_something ();
.
.
.
}

Yes, that would work.

Andrew