perf(timer): improve tick() performance

urish · urish · commit 22f6bd46d2f3 · 2020-05-25T16:23:07.000+03:00
reduce the number of calls to TIFR/TIMSK getters
diff --git a/src/peripherals/timer.ts b/src/peripherals/timer.ts
@@ -363,15 +363,16 @@ export class AVRTimer {
     }
     this.tcntUpdated = false;
     if (this.cpu.interruptsEnabled) {
-      if (this.TIFR & TOV && this.TIMSK & TOIE) {
+      const { TIFR, TIMSK } = this;
+      if (TIFR & TOV && TIMSK & TOIE) {
         avrInterrupt(this.cpu, this.config.ovfInterrupt);
         this.TIFR &= ~TOV;
       }
-      if (this.TIFR & OCFA && this.TIMSK & OCIEA) {
+      if (TIFR & OCFA && TIMSK & OCIEA) {
         avrInterrupt(this.cpu, this.config.compAInterrupt);
         this.TIFR &= ~OCFA;
       }
-      if (this.TIFR & OCFB && this.TIMSK & OCIEB) {
+      if (TIFR & OCFB && TIMSK & OCIEB) {
         avrInterrupt(this.cpu, this.config.compBInterrupt);
         this.TIFR &= ~OCFB;
       }

Original file line number	Diff line number	Diff line change
`@@ -363,15 +363,16 @@ export class AVRTimer {`
`363`	`363`	`}`
`364`	`364`	`this.tcntUpdated = false;`
`365`	`365`	`if (this.cpu.interruptsEnabled) {`
`366`		`- if (this.TIFR & TOV && this.TIMSK & TOIE) {`
	`366`	`+ const { TIFR, TIMSK } = this;`
	`367`	`+ if (TIFR & TOV && TIMSK & TOIE) {`
`367`	`368`	`avrInterrupt(this.cpu, this.config.ovfInterrupt);`
`368`	`369`	`this.TIFR &= ~TOV;`
`369`	`370`	`}`
`370`		`- if (this.TIFR & OCFA && this.TIMSK & OCIEA) {`
	`371`	`+ if (TIFR & OCFA && TIMSK & OCIEA) {`
`371`	`372`	`avrInterrupt(this.cpu, this.config.compAInterrupt);`
`372`	`373`	`this.TIFR &= ~OCFA;`
`373`	`374`	`}`
`374`		`- if (this.TIFR & OCFB && this.TIMSK & OCIEB) {`
	`375`	`+ if (TIFR & OCFB && TIMSK & OCIEB) {`
`375`	`376`	`avrInterrupt(this.cpu, this.config.compBInterrupt);`
`376`	`377`	`this.TIFR &= ~OCFB;`
`377`	`378`	`}`