--- nono/vm/sram.cpp	2026/04/29 17:04:28	1.1
+++ nono/vm/sram.cpp	2026/04/29 17:04:32	1.1.1.3
@@ -3,10 +3,11 @@
 // Copyright (C) 2017 isaki@NetBSD.org
 //
 
-#include "configfile.h"
+#include "mainapp.h"
 #include "sram.h"
 #include <sys/fcntl.h>
 #include <sys/mman.h>
+#include <sys/stat.h>
 
 //
 // SRAM
@@ -15,7 +16,7 @@
 // 必要ならアクセス時に都度変換すること。
 //
 
-SRAMDevice *gSRAM;
+std::unique_ptr<SRAMDevice> gSRAM;
 
 SRAMDevice::SRAMDevice()
 {
@@ -43,19 +44,40 @@ SRAMDevice::~SRAMDevice()
 bool
 SRAMDevice::Init()
 {
-	filename = gConfig->GetConfigDir() + "SRAM030.DAT";
+	struct stat st;
+
+	filename = gMainApp.GetVMDir() + "SRAM030.DAT";
+	memlen = 16 * 1024;
 
 	fd = open(filename.c_str(), O_RDWR);
 	if (fd == -1) {
-		warn("%s: cannot open %s", devname, filename.c_str());
+		warn("SRAM \"%s\" open failed", filename.c_str());
 		return false;
 	}
 
-	memlen = 16 * 1024;
+	// ファイルサイズをチェック。
+	// ファイルが短くても mmap はしれっと成功してしまうようだ。
+	if (fstat(fd, &st) == -1) {
+		warn("SRAM \"%s\" fstat failed", filename.c_str());
+		close(fd);
+		return false;
+	}
+	if (st.st_size < memlen) {
+		warnx("SRAM \"%s\" is too short (filesize is expected %d but %d)",
+			filename.c_str(), memlen, (int)st.st_size);
+		close(fd);
+		return false;
+	}
+	if (st.st_size > memlen) {
+		// 大きすぎるほうはワーニングだけでいいか
+		warnx("SRAM \"%s\" is too large (ignore %d bytes)",
+			filename.c_str(), (int)st.st_size - memlen);
+	}
+
 	mem = (uint8 *)mmap(NULL, memlen, PROT_READ | PROT_WRITE,
 		MAP_SHARED, fd, 0);
 	if (mem == MAP_FAILED) {
-		warn("%s: cannot mmap %s", devname, filename.c_str());
+		warn("SRAM \"%s\" mmap failed", filename.c_str());
 		close(fd);
 		return false;
 	}
@@ -63,26 +85,37 @@ SRAMDevice::Init()
 	return true;
 }
 
+// アドレスデコーダ
+inline uint64
+SRAMDevice::Decoder(uint32 addr) const
+{
+	return addr - baseaddr;
+}
+
 uint64
 SRAMDevice::Read8(uint32 addr)
 {
-	return mem[addr - baseaddr];
+	uint32 offset = Decoder(addr);
+	return mem[offset];
 }
 
 uint64
 SRAMDevice::Read16(uint32 addr)
 {
-	return be16toh(*(uint16 *)&mem[addr - baseaddr]);
+	uint32 offset = Decoder(addr);
+	return be16toh(*(uint16 *)&mem[offset]);
 }
 
 uint64
 SRAMDevice::Write8(uint32 addr, uint32 data)
 {
+	uint32 offset = Decoder(addr);
+
 	if (writeable) {
-		if (addr - baseaddr < 0x100) {
+		if (offset < 0x100) {
 			putlog(1, "更新 $%06x <- $%02x", addr, data);
 		}
-		mem[addr - baseaddr] = data;
+		mem[offset] = data;
 	} else {
 		putlog(1, "書き込み禁止 $%06x <- $%02x", addr, data);
 	}
@@ -92,11 +125,13 @@ SRAMDevice::Write8(uint32 addr, uint32 d
 uint64
 SRAMDevice::Write16(uint32 addr, uint32 data)
 {
+	uint32 offset = Decoder(addr);
+
 	if (writeable) {
-		if (addr - baseaddr < 0x100) {
+		if (offset < 0x100) {
 			putlog(1, "更新 $%06x <- $%04x", addr, data);
 		}
-		*(uint16 *)&mem[addr - baseaddr] = htobe16(data);
+		*(uint16 *)&mem[offset] = htobe16(data);
 	} else {
 		putlog(1, "書き込み禁止 $%06x <- $%04x", addr, data);
 	}
@@ -106,7 +141,8 @@ SRAMDevice::Write16(uint32 addr, uint32
 uint64
 SRAMDevice::Peek8(uint32 addr)
 {
-	return mem[addr - baseaddr];
+	uint32 offset = Decoder(addr);
+	return mem[offset];
 }
 
 void