Merge 'svn/trunk' r4475-r4477kc/merge-r4477

r4475:

 - Specified path can be invalid if filename is a device. Fixes
   installer for World Series of Poker.

r4476:

 - Fix "Invalid Access Code" error when opening files. Preserve
   last error code when no error occurs.

r4477:

 - Support BIOS access with multiple images. Fixes some
   mutli-floppy installers: Dark Seed, Master of Magic, et al.

 - Implement INT 25h and INT 26h. Fixes some installers: Dark
   Seed, Gods, et al.

 - Allow low-level hacks for local drive HDD when floppy
   image(s) mounted. Fixes installing Amberstar from floppy
   images.

 - Use real pointer when writing faked sector contents.

 - Prevent problematic condition: booting floppy image files
   when floppy image(s) mounted.

 - FAT drive improvements regarding zero-length truncation of
   files.

 - Update Drive Parameter Table only when necessary.

9 files changed, 121 insertions, 33 deletions

diff --git a/include/drives.h b/include/drives.h
index aee341c47..51f5ff543 100644
--- a/include/drives.h
+++ b/include/drives.h
@@ -190,6 +190,7 @@ public:
 	uint8_t readSector(uint32_t sectnum, void * data);
 	uint8_t writeSector(uint32_t sectnum, void * data);
 	uint32_t getAbsoluteSectFromBytePos(uint32_t startClustNum, uint32_t bytePos);
+	uint32_t getSectorCount();
 	uint32_t getSectorSize(void);
 	uint32_t getClusterSize(void);
 	uint32_t getAbsoluteSectFromChain(uint32_t startClustNum, uint32_t logicalSector);
@@ -201,6 +202,8 @@ public:
 	bool directoryChange(uint32_t dirClustNumber, direntry *useEntry, int32_t entNum);
 	std::shared_ptr<imageDisk> loadedDisk;
 	bool created_successfully;
+	uint32_t partSectOff;
+
 private:
 	uint32_t getClusterValue(uint32_t clustNum);
 	void setClusterValue(uint32_t clustNum, uint32_t clustValue);
@@ -217,7 +220,6 @@ private:
 	bool readonly;
 	uint8_t fattype;
 	uint32_t CountOfClusters;
-	uint32_t partSectOff;
 	uint32_t firstDataSector;
 	uint32_t firstRootDirSect;
 
diff --git a/src/dos/dos.cpp b/src/dos/dos.cpp
index 977b9e266..0f297d32c 100644
--- a/src/dos/dos.cpp
+++ b/src/dos/dos.cpp
@@ -26,6 +26,7 @@
 
 #include "bios.h"
 #include "callback.h"
+#include "drives.h"
 #include "mem.h"
 #include "regs.h"
 #include "serialport.h"
@@ -1377,16 +1378,55 @@ static Bitu DOS_27Handler(void) {
 	return CBRET_NONE;
 }
 
-static Bitu DOS_25Handler(void) {
+static uint16_t DOS_SectorAccess(const bool read)
+{
+	auto drive = static_cast<fatDrive *>(Drives[reg_al]);
+	auto bufferSeg = SegValue(ds);
+	auto bufferOff = reg_bx;
+	auto sectorCnt = reg_cx;
+	auto sectorNum = static_cast<uint32_t>(reg_dx) + drive->partSectOff;
+	auto sectorEnd = drive->getSectorCount() + drive->partSectOff;
+
+	if (sectorCnt == 0xffff) { // large partition form
+		bufferSeg = real_readw(SegValue(ds), reg_bx + 8);
+		bufferOff = real_readw(SegValue(ds), reg_bx + 6);
+		sectorCnt = real_readw(SegValue(ds), reg_bx + 4);
+		sectorNum = real_readd(SegValue(ds), reg_bx + 0) + drive->partSectOff;
+	} else if (sectorEnd > 0xffff)
+		return 0x0207; // must use large partition form
+
+	uint8_t sectorBuf[512];
+	while (sectorCnt--) {
+		if (sectorNum >= sectorEnd)
+			return 0x0408; // sector not found
+		if (read) {
+			if (drive->readSector(sectorNum++, &sectorBuf))
+				return 0x0408;
+			for (auto &sector_byte : sectorBuf)
+				real_writeb(bufferSeg, bufferOff++, sector_byte);
+		} else {
+			for (auto &sector_byte : sectorBuf)
+				sector_byte = real_readb(bufferSeg, bufferOff++);
+			if (drive->writeSector(sectorNum++, &sectorBuf))
+				return 0x0408;
+		}
+	}
+	return 0;
+}
+
+static Bitu DOS_25Handler(void)
+{
 	if (reg_al >= DOS_DRIVES || !Drives[reg_al] || Drives[reg_al]->isRemovable()) {
 		reg_ax = 0x8002;
 		SETFLAGBIT(CF,true);
+	} else if (strncmp(Drives[reg_al]->GetInfo(), "fatDrive", 8) == 0) {
+		reg_ax = DOS_SectorAccess(true);
+		SETFLAGBIT(CF, reg_ax != 0);
 	} else {
 		if (reg_cx == 1 && reg_dx == 0) {
 			if (reg_al >= 2) {
-				PhysPt ptr = PhysMake(SegValue(ds),reg_bx);
 				// write some BPB data into buffer for MicroProse installers
-				mem_writew(ptr+0x1c,0x3f); // hidden sectors
+				real_writew(SegValue(ds), reg_bx + 0x1c, 0x3f); // hidden sectors
 			}
 		} else {
 			LOG(LOG_DOSMISC,LOG_NORMAL)("int 25 called but not as disk detection drive %u",reg_al);
@@ -1401,6 +1441,9 @@ static Bitu DOS_26Handler(void) {
 	if (reg_al >= DOS_DRIVES || !Drives[reg_al] || Drives[reg_al]->isRemovable()) {	
 		reg_ax = 0x8002;
 		SETFLAGBIT(CF,true);
+	} else if (strncmp(Drives[reg_al]->GetInfo(), "fatDrive", 8) == 0) {
+		reg_ax = DOS_SectorAccess(false);
+		SETFLAGBIT(CF, reg_ax != 0);
 	} else {
 		SETFLAGBIT(CF,false);
 		reg_ax = 0;
diff --git a/src/dos/dos_devices.cpp b/src/dos/dos_devices.cpp
index 8c279d5fe..aae2a2b2b 100644
--- a/src/dos/dos_devices.cpp
+++ b/src/dos/dos_devices.cpp
@@ -346,10 +346,12 @@ uint8_t DOS_FindDevice(char const * name) {
 	char* name_part = strrchr(fullname,'\\');
 	if(name_part) {
 		*name_part++ = 0;
-		//Check validity of leading directory.
-		if(!Drives[drive]->TestDir(fullname)) return DOS_DEVICES;
-	} else name_part = fullname;
-   
+		// Check validity of leading directory.
+		//		if(!Drives[drive]->TestDir(fullname)) return
+		// DOS_DEVICES; //can be invalid
+	} else
+		name_part = fullname;
+
 	char* dot = strrchr(name_part,'.');
 	if(dot) *dot = 0; //no ext checking
 
diff --git a/src/dos/dos_files.cpp b/src/dos/dos_files.cpp
index 7356b42a4..656f0bf33 100644
--- a/src/dos/dos_files.cpp
+++ b/src/dos/dos_files.cpp
@@ -573,11 +573,14 @@ bool DOS_OpenFile(char const * name,uint8_t flags,uint16_t * entry,bool fcb) {
 	if (device) {
 		Files[handle]=new DOS_Device(*Devices[devnum]);
 	} else {
-		exists=Drives[drive]->FileOpen(&Files[handle],fullname,flags);
+		const auto old_errorcode = dos.errorcode;
+		dos.errorcode = 0;
+		exists = Drives[drive]->FileOpen(&Files[handle], fullname, flags);
 		if (exists)
 			Files[handle]->SetDrive(drive);
-		else if (dos.errorcode == DOSERR_ACCESS_CODE_INVALID)
+		if (dos.errorcode)
 			return false;
+		dos.errorcode = old_errorcode;
 	}
 	if (exists || device ) { 
 		Files[handle]->AddRef();
@@ -798,7 +801,8 @@ bool DOS_CreateTempFile(char * const name,uint16_t * entry) {
 			tempname++;
 		}
 	}
-	dos.errorcode=0;
+	const auto old_errorcode = dos.errorcode;
+	dos.errorcode = 0;
 
 	static const auto randomize_letter = CreateRandomizer<char>('A', 'Z');
 	do {
@@ -808,8 +812,12 @@ bool DOS_CreateTempFile(char * const name,uint16_t * entry) {
 		}
 		tempname[8]=0;
 	} while (DOS_FileExists(name));
+
 	DOS_CreateFile(name,0,entry);
-	if (dos.errorcode) return false;
+	if (dos.errorcode)
+		return false;
+
+	dos.errorcode = old_errorcode;
 	return true;
 }
 
diff --git a/src/dos/drive_fat.cpp b/src/dos/drive_fat.cpp
index c69eb6de3..c306a0304 100644
--- a/src/dos/drive_fat.cpp
+++ b/src/dos/drive_fat.cpp
@@ -171,7 +171,10 @@ bool fatFile::Write(uint8_t * data, uint16_t *size) {
 
 	if(seekpos < filelength && *size == 0) {
 		/* Truncate file to current position */
-		myDrive->deleteClustChain(firstCluster, seekpos);
+		if (firstCluster != 0)
+			myDrive->deleteClustChain(firstCluster, seekpos);
+		if (seekpos == 0)
+			firstCluster = 0;
 		filelength = seekpos;
 		goto finalizeWrite;
 	}
@@ -554,7 +557,16 @@ uint8_t fatDrive::writeSector(uint32_t sectnum, void * data) {
 	return loadedDisk->Write_Sector(head, cylinder, sector, data);
 }
 
-uint32_t fatDrive::getSectorSize(void) {
+uint32_t fatDrive::getSectorCount()
+{
+	if (bootbuffer.totalsectorcount != 0)
+		return check_cast<uint32_t>(bootbuffer.totalsectorcount);
+	else
+		return bootbuffer.totalsecdword;
+}
+
+uint32_t fatDrive::getSectorSize(void)
+{
 	return bootbuffer.bytespersector;
 }
 
@@ -989,9 +1001,12 @@ bool fatDrive::FileCreate(DOS_File **file, char *name, uint16_t attributes) {
 	/* Check if file already exists */
 	if(getFileDirEntry(name, &fileEntry, &dirClust, &subEntry)) {
 		/* Truncate file */
-		fileEntry.entrysize=0;
+		if (fileEntry.loFirstClust != 0) {
+			deleteClustChain(fileEntry.loFirstClust, 0);
+			fileEntry.loFirstClust = 0;
+		}
+		fileEntry.entrysize = 0;
 		directoryChange(dirClust, &fileEntry, subEntry);
-		if(fileEntry.loFirstClust != 0) deleteClustChain(fileEntry.loFirstClust, 0);
 	} else {
 		/* Can we even get the name of the file itself? */
 		if(!getEntryName(name, &dirName[0])) return false;
diff --git a/src/dos/drives.cpp b/src/dos/drives.cpp
index 5120471fa..a526b4b9b 100644
--- a/src/dos/drives.cpp
+++ b/src/dos/drives.cpp
@@ -15,12 +15,13 @@
  *  with this program; if not, write to the Free Software Foundation, Inc.,
  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  */
-
 #include "drives.h"
 
+#include <string_view>
+
+#include "bios_disk.h"
 #include "ide.h"
 #include "string_utils.h"
-#include <string_view>
 
 extern char sfn[DOS_NAMELENGTH_ASCII];
 
@@ -264,7 +265,17 @@ void DriveManager::CycleDisks(int requested_drive, bool notify)
 		currentDisk = (currentDisk + 1) % numDisks;
 		DOS_Drive* newDisk = driveInfos[drive].disks[currentDisk];
 		driveInfos[drive].currentDisk = currentDisk;
-		
+		if (drive < MAX_DISK_IMAGES && imageDiskList[drive] != nullptr) {
+			if (strncmp(newDisk->GetInfo(), "fatDrive", 8) == 0) {
+				imageDiskList[drive] = reinterpret_cast<fatDrive *>(newDisk)->loadedDisk;
+			} else {
+				imageDiskList[drive].reset(reinterpret_cast<imageDisk *>(newDisk));
+			}
+			if ((drive == 2 || drive == 3) && imageDiskList[drive]->hardDrive) {
+				updateDPT();
+			}
+		}
+
 		// copy working directory, acquire system resources and finally switch to next drive		
 		strcpy(newDisk->curdir, oldDisk->curdir);
 		newDisk->Activate();
diff --git a/src/dos/program_boot.cpp b/src/dos/program_boot.cpp
index 4bd811c12..643359498 100644
--- a/src/dos/program_boot.cpp
+++ b/src/dos/program_boot.cpp
@@ -222,6 +222,11 @@ void BOOT::Run(void)
 				continue;
 			}
 
+			if (imageDiskList[0] != nullptr || imageDiskList[1] != NULL) {
+				WriteOut(MSG_Get("PROGRAM_BOOT_IMAGE_MOUNTED"));
+				return;
+			}
+
 			if (i >= MAX_SWAPPABLE_DISKS) {
 				return; // TODO give a warning.
 			}
@@ -520,6 +525,7 @@ void BOOT::AddMessages() {
 	        "\033[34;1mIMGMOUNT\033[0m command.\n\n"
 	        "Type \033[34;1mBOOT /?\033[0m for the syntax of this command.\033[0m\n");
 	MSG_Add("PROGRAM_BOOT_UNABLE","Unable to boot off of drive %c");
+	MSG_Add("PROGRAM_BOOT_IMAGE_MOUNTED", "Floppy image(s) already mounted.\n");
 	MSG_Add("PROGRAM_BOOT_IMAGE_OPEN","Opening image file: %s\n");
 	MSG_Add("PROGRAM_BOOT_IMAGE_NOT_OPEN","Cannot open %s");
 	MSG_Add("PROGRAM_BOOT_BOOT","Booting from drive %c...\n");
diff --git a/src/dos/program_imgmount.cpp b/src/dos/program_imgmount.cpp
index 20990c6b0..d449a8e72 100644
--- a/src/dos/program_imgmount.cpp
+++ b/src/dos/program_imgmount.cpp
@@ -383,14 +383,12 @@ void IMGMOUNT::Run(void) {
         }
         WriteOut(MSG_Get("PROGRAM_MOUNT_STATUS_2"), drive, tmp.c_str());
 
-        if (paths.size() == 1) {
-            auto *newdrive = static_cast<fatDrive*>(imgDisks[0]);
-            if (('A' <= drive && drive <= 'B' && !(newdrive->loadedDisk->hardDrive)) ||
-                ('C' <= drive && drive <= 'D' && newdrive->loadedDisk->hardDrive)) {
-                const size_t idx = drive_index(drive);
-                imageDiskList[idx] = newdrive->loadedDisk;
-                updateDPT();
-            }
+        auto *newdrive = static_cast<fatDrive*>(imgDisks[0]);
+        if (('A' <= drive && drive <= 'B' && !(newdrive->loadedDisk->hardDrive)) ||
+            ('C' <= drive && drive <= 'D' && newdrive->loadedDisk->hardDrive)) {
+            const size_t idx = drive_index(drive);
+            imageDiskList[idx] = newdrive->loadedDisk;
+            updateDPT();
         }
     } else if (fstype=="iso") {
         if (Drives[drive_index(drive)]) {
@@ -474,7 +472,7 @@ void IMGMOUNT::Run(void) {
 
         if (hdd) newImage->Set_Geometry(sizes[2],sizes[3],sizes[1],sizes[0]);
         imageDiskList[drive - '0'].reset(newImage);
-        updateDPT();
+        if ((drive == '2' || drive == '3') && hdd) updateDPT();
         WriteOut(MSG_Get("PROGRAM_IMGMOUNT_MOUNT_NUMBER"),drive - '0',temp_line.c_str());
     }
 
diff --git a/src/ints/bios_disk.cpp b/src/ints/bios_disk.cpp
index 0bc94d94e..538836b83 100644
--- a/src/ints/bios_disk.cpp
+++ b/src/ints/bios_disk.cpp
@@ -297,7 +297,7 @@ static uint8_t GetDosDriveNumber(uint8_t biosNum) {
 }
 
 static bool driveInactive(uint8_t driveNum) {
-	if(driveNum>=(2 + MAX_HDD_IMAGES)) {
+	if (driveNum >= MAX_DISK_IMAGES) {
 		LOG(LOG_BIOS,LOG_ERROR)("Disk %d non-existent", driveNum);
 		last_status = 0x01;
 		CALLBACK_SCF(true);
@@ -380,7 +380,7 @@ static Bitu INT13_DiskHandler(void) {
 			CALLBACK_SCF(true);
 			return CBRET_NONE;
 		}
-		if (!any_images) {
+		if (drivenum < MAX_DISK_IMAGES && imageDiskList[drivenum] == nullptr) {
 			if (drivenum >= DOS_DRIVES || !Drives[drivenum] || Drives[drivenum]->isRemovable()) {
 				reg_ah = 0x01;
 				CALLBACK_SCF(true);
@@ -389,10 +389,13 @@ static Bitu INT13_DiskHandler(void) {
 			// Inherit the Earth cdrom and Amberstar use it as a disk test
 			if (((reg_dl&0x80)==0x80) && (reg_dh==0) && ((reg_cl&0x3f)==1)) {
 				if (reg_ch==0) {
-					PhysPt ptr = PhysMake(SegValue(es),reg_bx);
 					// write some MBR data into buffer for Amberstar installer
-					mem_writeb(ptr+0x1be,0x80); // first partition is active
-					mem_writeb(ptr+0x1c2,0x06); // first partition is FAT16B
+					real_writeb(SegValue(es),
+					            reg_bx + 0x1be,
+					            0x80); // first partition is active
+					real_writeb(SegValue(es),
+					            reg_bx + 0x1c2,
+					            0x06); // first partition is FAT16B
 				}
 				reg_ah = 0;
 				CALLBACK_SCF(false);