--- nono/vm/extram.cpp	2026/04/29 17:05:17	1.1
+++ nono/vm/extram.cpp	2026/04/29 17:05:29	1.1.1.4
@@ -11,6 +11,7 @@
 // TS-6BE16 互換だと $0100'0000 〜 $01ff'ffff の 16MB。
 // 060turbo 互換だと $1000'0000 〜 $17ff'ffff の 128MB、
 //                   $1000'0000 〜 $1fff'ffff の 256MB。
+//                   $1000'0000 〜 $2fff'ffff の 512MB。(独自拡張)
 //
 
 // 拡張 RAM はロングワード単位でホストバイトオーダ配置なので、
@@ -40,7 +41,7 @@ ExtRAMDevice::Init()
 
 	const ConfigItem& item = gConfig->Find("extram-size");
 	uint32 extram_size_MB = item.AsInt();
-	if (extram_size_MB <= 0) {
+	if (extram_size_MB == 0) {
 		return true;
 	}
 	switch (extram_size_MB) {
@@ -49,15 +50,22 @@ ExtRAMDevice::Init()
 		break;
 	 case 128:
 	 case 256:
+	 case 384:
+	 case 512:
 		ram_addr = 0x10'000000;
 		break;
 	 default:
-		item.Err("Valid size is 16, 128, and 256 for now");
+		item.Err("Valid size are 16, 128, 256, 384 or 512 for now");
 		return false;
 	}
 
 	ram_size = extram_size_MB * 1024 * 1024;
-	ram.reset(new uint8[ram_size]);
+	ram.reset(new(std::nothrow) uint8[ram_size]);
+	if ((bool)ram == false) {
+		errno = ENOMEM;
+		warn("ExtRAM(%u bytes)", ram_size);
+		return false;
+	}
 
 	return true;
 }
@@ -78,73 +86,54 @@ ExtRAMDevice::Decoder(uint32 addr) const
 	return (addr - ram_addr);
 }
 
-uint64
-ExtRAMDevice::Read8(uint32 addr)
-{
-	uint32 offset = Decoder(addr);
-	uint32 data = ram[HLB(offset)];
-	putlog(4, "$%08x.B -> $%02x", addr, data);
-	return data;
-}
-
-uint64
-ExtRAMDevice::Read16(uint32 addr)
+busdata
+ExtRAMDevice::Read(busaddr addr)
 {
-	uint32 offset = Decoder(addr);
-	uint32 data = *(uint16 *)&ram[HLW(offset)];
-	putlog(4, "$%08x.W -> $%04x", addr, data);
-	return data;
-}
+	uint32 offset = Decoder(addr.Addr());
+	busdata data;
 
-uint64
-ExtRAMDevice::Read32(uint32 addr)
-{
-	uint32 offset = Decoder(addr);
-	uint32 data = *(uint32 *)&ram[offset];
-	putlog(4, "$%08x.L -> $%08x", addr, data);
+	data  = *(uint32 *)&ram[offset & ~3U];
+	putlog(4, "$%08x -> $%08x", addr.Addr(), data.Data());
+	data |= BusData::Size4;
 	return data;
 }
 
-uint64
-ExtRAMDevice::Write8(uint32 addr, uint32 data)
+busdata
+ExtRAMDevice::Write(busaddr addr, uint32 data)
 {
-	uint32 offset = Decoder(addr);
-	ram[HLB(offset)] = data;
-	putlog(3, "$%08x.B <- $%02x", addr, data);
-	return 0;
-}
-
-uint64
-ExtRAMDevice::Write16(uint32 addr, uint32 data)
-{
-	uint32 offset = Decoder(addr);
-	*(uint16 *)&ram[HLW(offset)] = data;
-	putlog(3, "$%08x.W <- $%04x", addr, data);
-	return 0;
-}
+	uint32 paddr = Decoder(addr.Addr());
+	uint32 reqsize = addr.GetSize();
+	uint32 datasize = std::min(4 - (paddr & 3U), reqsize);
+
+	if (datasize == 4) {
+		*(uint32 *)&ram[paddr] = data;
+		putlog(3, "$%08x <- $%08x", addr.Addr(), data);
+	} else {
+		data >>= (reqsize - datasize) * 8;
+		putlog(3, "$%08x <- $%0*x", addr.Addr(), datasize * 2, data);
+		for (int i = datasize - 1; i >= 0; i--) {
+			ram[HLB(paddr + i)] = data;
+			data >>= 8;
+		}
+	}
 
-uint64
-ExtRAMDevice::Write32(uint32 addr, uint32 data)
-{
-	uint32 offset = Decoder(addr);
-	*(uint32 *)&ram[offset] = data;
-	putlog(3, "$%08x.L <- $%08x", addr, data);
-	return 0;
+	busdata r = BusData::Size4;
+	return r;
 }
 
-uint64
-ExtRAMDevice::Peek8(uint32 addr)
+busdata
+ExtRAMDevice::Peek1(uint32 addr)
 {
 	uint32 offset = Decoder(addr);
 	return ram[HLB(offset)];
 }
 
-uint64
-ExtRAMDevice::Poke8(uint32 addr, uint32 data)
+bool
+ExtRAMDevice::Poke1(uint32 addr, uint32 data)
 {
 	if ((int32)data >= 0) {
 		uint32 offset = Decoder(addr);
 		ram[HLB(offset)] = data;
 	}
-	return 0;
+	return true;
 }