On Sunday 17 October 2004 12:26 pm, Wouter van Ooijen wrote:
> > if (foo == 3) {
> >
> > would collect "foo" and subtract the #3 to test for zero
> >
> > if (3 == foo) {
> >
> > would collect 3, place it on the stack, then collect foo,
> > then subtract foo from stack value "3"
>
> stack??

...just thinking-out-loud that C is supposed to be cross-platform.  ;-)

C is usually analyzed from left to right.
If you wish to speak PIC, you could say a fictional compiler creates this....
if (foo == 3) {
	movfw	foo
	xorlw	3
	skpz
	goto	endif
	;do "if" here

if (3 == foo) {
	movlw	3
	movwf	scratchpad_temp
	movfw	foo
	xorlw	scratchpad_temp
	skpz
	goto	endif
	;do "if" here


> Some compilers might do that, but most C compilers for PICs I know will
> evaluate 3 == foo and foo == 3 the same way. Jal certainly does.

Yes, there are optimizing compilers, but if you want your code to be 
transportable, you can't assume all compilers optimize to that degree.
I've had to optimize more than enough code, so "if (foo == 3) {" has become 
second nature to me...
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