init: 自 zomaintain/backend/rdplib 平移独立成库; module path 从上游 github.com/nakagami/grdp 改为 git.zeroonesoft.cn/golib/rdplib

2026-09-19 18:55:43 +08:00
commit 1096fbce9d
94 changed files with 36790 additions and 0 deletions
@@ -0,0 +1,37 @@
+//go:build arm64
+
+package rdpgfx
+
+import "unsafe"
+
+// ictToBGRANEON processes n pixels (n must be a multiple of 8) converting
+// int16 YCbCr planes to packed BGRA using the ICT formula.  Implemented as
+// ARMv8-A NEON assembly for throughput.
+//
+//go:noescape
+func ictToBGRANEON(y, cb, cr, dst unsafe.Pointer, n int)
+
+// ictToBGRA dispatches to the NEON path for full 8-pixel batches and falls
+// back to scalar arithmetic for any remaining pixels.
+func ictToBGRA(yRow, cbRow, crRow []int16, dst []byte, n int) {
+	full := (n / 8) * 8
+	if full > 0 {
+		ictToBGRANEON(
+			unsafe.Pointer(&yRow[0]),
+			unsafe.Pointer(&cbRow[0]),
+			unsafe.Pointer(&crRow[0]),
+			unsafe.Pointer(&dst[0]),
+			full,
+		)
+	}
+	for col := full; col < n; col++ {
+		yv := int32(yRow[col])
+		cb := int32(cbRow[col])
+		cr := int32(crRow[col])
+		ys := (yv + 4096) << 16
+		bv := uint32(max(0, min((cb*115992+ys)>>21, 255)))
+		gv := uint32(max(0, min((ys-cb*22527-cr*46819)>>21, 255)))
+		rv := uint32(max(0, min((cr*91916+ys)>>21, 255)))
+		*(*uint32)(unsafe.Pointer(&dst[col*4])) = bv | gv<<8 | rv<<16 | 0xFF000000
+	}
+}