Add AMD64 implementations (SSE2/AVX2) of copyMacroblock

Author: gen2brain

video_amd64.go

@@ -0,0 +1,25 @@
+//go:build amd64 && !noasm
+
+package mpeg
+
+var isAVX2 bool
+
+func init() {
+	isAVX2 = hasAVX2()
+}
+
+func hasAVX2() bool
+
+//go:noescape
+func copyMacroblockSSE2(motionH, motionV, mbRow, mbCol, lumaWidth, chromaWidth int, s, d *Frame)
+
+//go:noescape
+func copyMacroblockAVX2(motionH, motionV, mbRow, mbCol, lumaWidth, chromaWidth int, s, d *Frame)
+
+func copyMacroblock(motionH, motionV, mbRow, mbCol, lumaWidth, chromaWidth int, s, d *Frame) {
+	if isAVX2 {
+		copyMacroblockAVX2(motionH, motionV, mbRow, mbCol, lumaWidth, chromaWidth, s, d)
+	} else {
+		copyMacroblockSSE2(motionH, motionV, mbRow, mbCol, lumaWidth, chromaWidth, s, d)
+	}
+}