Remove INT 16h when entering PC-98 mode. DOS CONIO emulation calls INT

16h handler directly (well... somewhat indirectly due to how INT16h
expects to implement idle). INT 10h-17h are now zeroed out in PC-98
mode.

include/callback.h

@@ -65,6 +65,7 @@ void CALLBACK_Idle(void);
 
 void CALLBACK_RunRealInt(Bit8u intnum);
 void CALLBACK_RunRealFar(Bit16u seg,Bit16u off);
+void CALLBACK_RunRealFarInt(Bit16u seg,Bit16u off);
 
 bool CALLBACK_Setup(Bitu callback,CallBack_Handler handler,Bitu type,const char* descr);
 Bitu CALLBACK_Setup(Bitu callback,CallBack_Handler handler,Bitu type,PhysPt addr,const char* descr);

src/cpu/callback.cpp

@@ -114,7 +114,23 @@ static Bitu stop_handler(void) {
 	return CBRET_STOP;
 }
 
+Bitu FillFlags(void);
 
+void CALLBACK_RunRealFarInt(Bit16u seg,Bit16u off) {
+	FillFlags();
+
+	reg_sp-=6;
+	mem_writew(SegPhys(ss)+reg_sp,RealOff(CALLBACK_RealPointer(call_stop)));
+	mem_writew(SegPhys(ss)+reg_sp+2,RealSeg(CALLBACK_RealPointer(call_stop)));
+	mem_writew(SegPhys(ss)+reg_sp+4,reg_flags);
+	Bit32u oldeip=reg_eip;
+	Bit16u oldcs=SegValue(cs);
+	reg_eip=off;
+	SegSet16(cs,seg);
+	DOSBOX_RunMachine();
+	reg_eip=oldeip;
+	SegSet16(cs,oldcs);
+}
 
 void CALLBACK_RunRealFar(Bit16u seg,Bit16u off) {
 	reg_sp-=4;

src/dos/dev_con.h

@@ -28,6 +28,7 @@
 extern bool DOS_BreakFlag;
 
 Bitu INT10_Handler(void);
+Bitu INT16_Handler_Wrap(void);
 
 class device_CON : public DOS_Device {
 public:
@@ -223,7 +224,16 @@ bool device_CON::Read(Bit8u * data,Bit16u * size) {
 	}
 	while (*size>count) {
 		reg_ah=(IS_EGAVGA_ARCH)?0x10:0x0;
-		CALLBACK_RunRealInt(0x16);
+
+        /* FIXME: PC-98 emulation should eventually use CONIO emulation that
+         *        better emulates the actual platform. The purpose of this
+         *        hack is to allow our code to call into INT 16h without
+         *        setting up an INT 16h vector */
+        if (IS_PC98_ARCH)
+            INT16_Handler_Wrap();
+        else
+            CALLBACK_RunRealInt(0x16);
+
 		switch(reg_al) {
 		case 13:
 			data[count++]=0x0D;
@@ -570,7 +580,16 @@ Bit16u device_CON::GetInformation(void) {
 		Bitu saved_ax = reg_ax;
 
 		reg_ah = (IS_EGAVGA_ARCH)?0x11:0x1; // check for keystroke
-		CALLBACK_RunRealInt(0x16);
+
+        /* FIXME: PC-98 emulation should eventually use CONIO emulation that
+         *        better emulates the actual platform. The purpose of this
+         *        hack is to allow our code to call into INT 16h without
+         *        setting up an INT 16h vector */
+        if (IS_PC98_ARCH)
+            INT16_Handler_Wrap();
+        else
+            CALLBACK_RunRealInt(0x16);
+
 		if (!GETFLAG(ZF)) { /* key is present, waiting to be returned on AH=0x10 or AH=0x00 */
 			ret = 0x8093; /* Key Available */
 		}

src/ints/bios_keyboard.cpp

@@ -532,7 +532,7 @@ static bool IsEnhancedKey(Bit16u &key) {
 bool int16_unmask_irq1_on_read = true;
 bool int16_ah_01_cf_undoc = true;
 
-static Bitu INT16_Handler(void) {
+Bitu INT16_Handler(void) {
 	Bit16u temp=0;
 	switch (reg_ah) {
 	case 0x00: /* GET KEYSTROKE */
@@ -643,6 +643,18 @@ static Bitu INT16_Handler(void) {
 	return CBRET_NONE;
 }
 
+/* The INT16h handler manipulates reg_ip and expects it to work
+ * based on the layout of the callback. So to allow calling
+ * directly we have to save/restore CS:IP and run the DOS
+ * machine. */
+Bitu INT16_Handler_Wrap(void) {
+    Bitu proc;
+
+    proc = CALLBACK_RealPointer(call_int16);
+    CALLBACK_RunRealFarInt(proc >> 16/*seg*/,proc & 0xFFFFU/*off*/);
+    return 0;
+}
+
 //Keyboard initialisation. src/gui/sdlmain.cpp
 extern bool startup_state_numlock;
 extern bool startup_state_capslock;
@@ -675,6 +687,7 @@ void CALLBACK_DeAllocate(Bitu in);
 void BIOS_UnsetupKeyboard(void) {
     if (call_int16 != 0) {
         CALLBACK_DeAllocate(call_int16);
+        RealSetVec(0x16,0);
         call_int16 = 0;
     }
     if (call_irq1 != 0) {
@@ -695,10 +708,19 @@ void BIOS_SetupKeyboard(void) {
 	/* Init the variables */
 	InitBiosSegment();
 
-	/* Allocate/setup a callback for int 0x16 and for standard IRQ 1 handler */
+    if (IS_PC98_ARCH) {
-	call_int16=CALLBACK_Allocate();	
+        /* HACK */
-	CALLBACK_Setup(call_int16,&INT16_Handler,CB_INT16,"Keyboard");
+        /* Allocate/setup a callback for int 0x16 and for standard IRQ 1 handler */
-	RealSetVec(0x16,CALLBACK_RealPointer(call_int16));
+        call_int16=CALLBACK_Allocate();	
+        CALLBACK_Setup(call_int16,&INT16_Handler,CB_INT16,"Keyboard");
+        /* DO NOT set up an INT 16h vector. This exists only for the DOS CONIO emulation. */
+    }
+    else {
+        /* Allocate/setup a callback for int 0x16 and for standard IRQ 1 handler */
+        call_int16=CALLBACK_Allocate();	
+        CALLBACK_Setup(call_int16,&INT16_Handler,CB_INT16,"Keyboard");
+        RealSetVec(0x16,CALLBACK_RealPointer(call_int16));
+    }
 
 	call_irq1=CALLBACK_Allocate();
 	if (machine == MCH_PCJR) { /* PCjr keyboard interrupt connected to NMI */