On Thursday 21 August 2003 18:58, Ralf Guetlein wrote:
> Hi,
> I'm looking for the least time and memory consuming
> solution of an interrupt routine. I realized that there
> are useless register saves/restores when using bit
> manipulation. I broke it down to the examples below.
>
> By the way...
> In lack of a real-world application I used nonsensical
> interrupt vectors ("-1" and "-2", see below). The compiler
> answered with a really funny warning:
>
> "warning: Interrupt vector 0xffdf assigned
> to ISR 'testint1' does make sense"
>
> ;-)
>
> Cheers,
> Ralf
>
>
>
> here the examples:
>
>
> the source lines:
> =================
>
> volatile int Counter;
>
> char fAdjust;
>
> interrupt (-2) testint2(void)
> {
> if (fAdjust)
> Counter++;
> }
>
> compile to:
> ===========
>
> interrupt (-2) testint2(void)
> {
> if (fAdjust)
> 0: c2 93 00 00 cmp.b #0, &0x0000 ;r3 As==00
> 4: 02 24 jz $+6 ;abs 0xa
> Counter++;
> 6: 92 53 00 00 inc &0x0000 ;
> }
> a: 00 13 reti
>
> whereas the source lines:
> =========================
>
> struct {
> int Adjust: 1;
> } Flags;
>
> interrupt (-1) testint1(void)
> {
> if (Flags.Adjust)
> Counter++;
> }
>
> compile to:
> ===========
>
> interrupt (-1) testint1(void)
> {
> c: 0f 12 push r15 ;
> if (Flags.Adjust)
> e: d2 b3 00 00 bit.b #1, &0x0000 ;r3 As==01
> 12: 02 24 jz $+6 ;abs 0x18
> Counter++;
> 14: 92 53 00 00 inc &0x0000 ;
> }
> 18: 3f 41 pop r15 ;
> 1a: 00 13 reti
>
>
>
>
>
>
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