Merge branch 'joncampbell123:master' into vs2022

CHANGELOG

@@ -1,4 +1,10 @@
 NEXT
+  - Add "-o int13" option to IMGMOUNT to direct the FAT driver to do
+    all disk I/O through INT 13h instead of directly. This is intended
+    for certain demoscene productions that apparently like to make
+    files appear out of thin air by intercepting INT 13h floppy disk
+    I/O and then asking MS-DOS to run something from it. Hack for
+    "DS_BLISS" demo. (joncampbell123).
   - add option "[dos] automount drive directories" for Windows builds,
     this will mount existing drive directories from C to Y drive (aybe).
   - fix off-center and off-screen window after entering the

include/bios_disk.h

@@ -52,7 +52,8 @@ class imageDisk {
 			ID_VHD,
 			ID_D88,
 			ID_NFD,
-			ID_EMPTY_DRIVE
+			ID_EMPTY_DRIVE,
+			ID_INT13
 		};
 
 		virtual uint8_t Read_Sector(uint32_t head,uint32_t cylinder,uint32_t sector,void * data,unsigned int req_sector_size=0);
@@ -85,6 +86,10 @@ class imageDisk {
 		bool hardDrive = false;
 		uint64_t diskSizeK = 0;
 		FILE* diskimg = NULL;
+		bool diskChangeFlag = false;
+
+		/* this is intended only for when the disk can change out from under us while mounted */
+		virtual bool detectDiskChange(void) { const bool r = diskChangeFlag; diskChangeFlag = false; return r; }
 
 	protected:
 		imageDisk(IMAGE_TYPE class_id);
@@ -569,4 +574,29 @@ extern unsigned char INT13_ElTorito_NoEmuDriveNumber;
 extern signed char INT13_ElTorito_IDEInterface;
 extern char INT13_ElTorito_NoEmuCDROMDrive;
 
+class imageDiskINT13Drive : public imageDisk {
+public:
+	uint8_t Read_Sector(uint32_t head,uint32_t cylinder,uint32_t sector,void * data,unsigned int req_sector_size=0) override;
+	uint8_t Write_Sector(uint32_t head,uint32_t cylinder,uint32_t sector,const void * data,unsigned int req_sector_size=0) override;
+	uint8_t Read_AbsoluteSector(uint32_t sectnum, void * data) override;
+	uint8_t Write_AbsoluteSector(uint32_t sectnum, const void * data) override;
+
+	void UpdateFloppyType(void) override;
+	void Set_Reserved_Cylinders(Bitu resCyl) override;
+	uint32_t Get_Reserved_Cylinders() override;
+	void Set_Geometry(uint32_t setHeads, uint32_t setCyl, uint32_t setSect, uint32_t setSectSize) override;
+	void Get_Geometry(uint32_t * getHeads, uint32_t *getCyl, uint32_t *getSect, uint32_t *getSectSize) override;
+	uint8_t GetBiosType(void) override;
+	uint32_t getSectSize(void) override;
+	bool detectDiskChange(void) override;
+
+	imageDiskINT13Drive(imageDisk *sdisk);
+	virtual ~imageDiskINT13Drive();
+
+	uint8_t bios_disk = 0;
+	bool enable_int13 = false;
+	imageDisk* subdisk = NULL;
+	bool busy = false;
+};
+
 #endif

src/cpu/callback.cpp

@@ -691,6 +691,11 @@ Bitu CALLBACK_SetupExtra(Bitu callback, Bitu type, PhysPt physAddress, bool use_
 		phys_writeb(physAddress+0x01,(uint8_t)0xCF);		//An IRET Instruction
 		phys_writew(physAddress+0x02,(uint16_t)0x0ECD);		// int 0e
 		phys_writeb(physAddress+0x04,(uint8_t)0xCF);		//An IRET Instruction
+		// for the image disk support to call
+		phys_writew(physAddress+0x05,(uint16_t)0x13CD);		// int 13
+		phys_writeb(physAddress+0x07,0xFE);
+		phys_writeb(physAddress+0x08,0x38);
+		phys_writew(physAddress+0x09,(uint16_t)call_idle);
 		return (use_cb?9:5);
 	case CB_VESA_WAIT:
 		if (use_cb) E_Exit("VESA wait must not implement a callback handler!");

src/dos/dos_programs.cpp

@@ -6110,6 +6110,19 @@ class IMGMOUNT : public Program {
 				return false;
 			}
 
+			for (auto i=options.begin();i!=options.end();i++) {
+				if ((*i) == "int13") {
+					char buf[32];
+
+					if (drive >= 'C')
+						sprintf(buf,"=%u",drive+0x80-'C');
+					else
+						sprintf(buf,"=%u",drive-'A');
+
+					(*i) += buf;
+				}
+			}
+
 			bool imgsizedetect = isHardDrive && sizes[0] == 0;
 			int mediaid = -1;
 
@@ -6331,6 +6344,13 @@ class IMGMOUNT : public Program {
 						}
 					}
 				}
+
+				/* now that the image is attached to INT 13h the INT 13 image can use it now */
+				if (image->class_id == imageDisk::ID_INT13) {
+					imageDiskINT13Drive *x = (imageDiskINT13Drive*)image;
+					x->enable_int13 = true;
+					LOG_MSG("INT 13 image enabling calling");
+				}
 			}
 			return true;
 		}