--- nono/vm/bt45x.cpp	2026/04/29 17:05:20	1.1.1.2
+++ nono/vm/bt45x.cpp	2026/04/29 17:05:24	1.1.1.3
@@ -134,7 +134,7 @@ BT45xDevice::rgbstr[3] = { 'R', 'G', 'B'
 
 // LUNA のビデオボードは Bt454 か Bt458 かでバイト配置が異なるようだ。
 
-uint64
+busdata
 BT45xDevice::Read8(uint32 addr)
 {
 	if (bt454) {
@@ -152,7 +152,7 @@ BT45xDevice::Read8(uint32 addr)
 	}
 }
 
-uint64
+busdata
 BT45xDevice::Write8(uint32 addr, uint32 data)
 {
 	if (bt454) {
@@ -170,7 +170,7 @@ BT45xDevice::Write8(uint32 addr, uint32
 	}
 }
 
-uint64
+busdata
 BT45xDevice::Peek8(uint32 addr)
 {
 	if (bt454) {