feat(demo): show simulation speed

1 files changed, 33 insertions, 0 deletions

diff --git a/demo/src/cpu-performance.ts b/demo/src/cpu-performance.ts
new file mode 100644
index 0000000..f61d038
--- /dev/null
+++ b/demo/src/cpu-performance.ts
@@ -0,0 +1,33 @@
+import { ICPU } from 'avr8js';
+
+export class CPUPerformance {
+  private prevTime = 0;
+  private prevCycles = 0;
+  private samples = new Float32Array(64);
+  private sampleIndex = 0;
+
+  constructor(private cpu: ICPU, private MHZ: number) {}
+
+  reset() {
+    this.prevTime = 0;
+    this.prevCycles = 0;
+    this.sampleIndex = 0;
+  }
+
+  update() {
+    if (this.prevTime) {
+      const delta = performance.now() - this.prevTime;
+      const deltaCycles = this.cpu.cycles - this.prevCycles;
+      const deltaCpuMillis = 1000 * (deltaCycles / this.MHZ);
+      const factor = deltaCpuMillis / delta;
+      if (!this.sampleIndex) {
+        this.samples.fill(factor);
+      }
+      this.samples[this.sampleIndex++ % this.samples.length] = factor;
+    }
+    this.prevCycles = this.cpu.cycles;
+    this.prevTime = performance.now();
+    const avg = this.samples.reduce((x, y) => x + y) / this.samples.length;
+    return avg;
+  }
+}