initial BIOS disk int 13h wrapper, only passively detects and notes floppy disk change

git-svn-id: https://svn.code.sf.net/p/freedos/svn/kernel/branches/UNSTABLE@1154 6ac86273-5f31-0410-b378-82cca8765d1b

kernel/int2f.asm

@@ -56,6 +56,8 @@ FarTabRetn:
 Int2f3:
                 cmp     ah,12h
                 je      IntDosCal               ; Dos Internal calls
+                cmp     ah,13h
+                je      IntDosCal               ; Install Int13h Hook
                 cmp     ah,16h
                 je      IntDosCal               ; Win (Multitasking) Hook
                 cmp     ah,46h

kernel/inthndlr.c

@@ -41,7 +41,7 @@ BYTE *RcsId =
 
 #ifdef TSC
 STATIC VOID StartTrace(VOID);
-static bTraceNext = FALSE;
+STATIC bTraceNext = FALSE;
 #endif
 
 #if 0                           /* Very suspicious, passing structure by value??
@@ -1703,6 +1703,9 @@ struct int2f12regs {
   xreg callerARG1;		/* used if called from INT2F/12	*/
 };
 
+extern intvec BIOSInt13, UserInt13, BIOSInt19;
+
+
 /* WARNING: modifications in `r' are used outside of int2F_12_handler()
  * On input r.AX==0x12xx, 0x4A01 or 0x4A02
  * also handle Windows' DOS notification hooks, r.AH==0x16
@@ -1733,6 +1736,17 @@ VOID ASMCFUNC int2F_12_handler(struct int2f12regs r)
     r.BX = size;
     return;
   }
+  else if (r.AH == 0x13) /* set disk interrupt (13h) handler */
+  {
+    /* set new values for int13h calls, and must return old values */
+    register intvec tmp = UserInt13;
+    UserInt13 = MK_FP(r.ds, r.DX);            /* int13h handler to use */
+    r.ds = FP_SEG(tmp);  r.DX = FP_OFF(tmp);
+    tmp = BIOSInt13;
+    BIOSInt13 = MK_FP(r.es, r.BX);            /* int13h handler to restore on reboot */
+    r.es = FP_SEG(tmp);  r.BX = FP_OFF(tmp);
+    return;
+  }
   else if (r.AH == 0x16) /* Window/Multitasking hooks */
   {
 #ifdef WIN31SUPPORT  /* See "DOS Internals" or RBIL under DOSMGR for details */
@@ -1915,9 +1929,8 @@ VOID ASMCFUNC int2F_12_handler(struct int2f12regs r)
       case 0x80:          /* Win Release Time-slice */
       {
         /* This function is generally only called in idle loops */
-        enable;          /* enable interrupts */
+        __emit__(0xfb);  /* sti; enable interrupts */
-        // __emit__(0xf4);  /* halt              */
+        __emit__(0xf4);  /* hlt; halt until interrupt */
-        asm hlt;
         r.AX = 0;
         /* DebugPrintf(("Release Time Slice\n")); */
         break;
@@ -2259,6 +2272,91 @@ error_exit:
   r.FLAGS |= FLG_CARRY;
 }
 
+
+/* how registers pushed on stack prior to calling int wrapper function,
+   when returns these are then popped off, so any changes to these
+   will effectively set the returned value in these registers
+ */
+struct intXXregs {
+#ifdef I386
+  /* preserved 386+ only registers, compiler specific */
+#endif
+  UWORD es, ds;
+  UWORD di, si, bp;
+  xreg b, d, c, a;
+  UWORD intreq;  /* which interrupt filter request for */
+  UWORD flags;   /* flags duplicated, one pushed by int call ignored */
+  xreg  param;
+  UWORD ip, cs , oflags;
+  /* top item of int caller's stack, possibly additional params */
+};
+
+
+/* additional processing for various wrapped/filtered interrupts
+   WARNING: this function also called during kernel init phase
+   -- int 13h
+   filter for BIOS int13h support, only called on int13h error
+   for ms-dos compatibility this should at minimal 
+   watch for disk-change notification and set internal status
+   (may be called multiple times in row when BIOS reports same
+   change multiple times, ie delays clearing disk change status)
+   TODO: move DMA bounday check from int25/26 to here
+   Note: use stored user (usually BIOS) hooked int13 handler
+   -- int 19h
+   clean up prior to a warm reboot 
+   for ms compatibility this should at a minimal
+   restore original (or indicated as original) BIOS int13h handler
+   and any others that may be hooked (including this one)
+   if himem loaded clear high memory area (clear vdisk signature so himem loads)
+ */
+VOID ASMCFUNC intXX_filter(struct intXXregs r)
+{
+  DebugPrintf(("int %02xh filter\n", r.intreq));
+  switch(r.intreq)
+  {
+    case 0x19:  /* reboot via bootstrap */
+    {
+      setvec(0x13, BIOSInt13);
+      setvec(0x19, BIOSInt19);
+
+      /* clear vdisk signature if kernel loaded in hma */
+      if (version_flags & 0x10)
+        fmemset(MK_FP(0xffff, 0x0010),0,512);
+      break;
+    }
+    case 0x13:  /* error with disk handler */
+    {
+      DebugPrintf(("disk error %i [ah=%x] (drive %x)\n", r.a.b.h, r.param.b.h, r.param.b.l));
+      DebugPrintf(("bx==(%x) cx==(%x) dx==(%x)\n", r.BX, r.CX, r.DX));
+      /* currently just marks floppy as changed on disk change error */
+      if ((r.a.b.h == 0x06) && (r.param.b.l < 0x80))  /* diskchange and is it a floppy? */
+      {
+        register int i;
+
+        /* mark floppy as changed */
+        for(i=0; i < blk_dev.dh_name[0]; i++)
+        {
+          ddt *pddt = getddt(i);
+          if (pddt->ddt_driveno == r.param.b.l)
+          {
+            DebugPrintf(("ddt[%i] match, flags=%04x\n", i, pddt->ddt_descflags));
+            if ((pddt->ddt_descflags & DF_CHANGELINE) && /* drive must have changeline support */
+                (pddt->ddt_descflags & DF_CURBPBLOCK)) /* and BPB not currently locked (in-use) */
+              pddt->ddt_descflags |= DF_DISKCHANGE;
+            /* or get dpb pointer from ddt and set dpbp->dpb_flags = M_CHANGED; */
+          }
+        }
+      }
+      break;
+    }
+    default:
+      DebugPrintf(("INT_ERROR!\n"));
+      break;
+  }
+}
+
+
+
 /*
  * 2000/09/04  Brian Reifsnyder
  * Modified interrupts 0x25 & 0x26 to return more accurate error codes.

kernel/kernel.asm

@@ -652,6 +652,22 @@ _ext_open_action dw 0                   ;2DD - extended open action
 _ext_open_attrib dw 0                   ;2DF - extended open attrib
 _ext_open_mode   dw 0                   ;2E1 - extended open mode
 
+
+
+; these 3 placed here so init code and int wrapper can easily access
+; holds pointers to actual disk handler routines and interrupt
+; vectors that we try to restore before a warm reboot
+                global _SAVEDIVLST
+_SAVEDIVLST:
+                ; used by int13 handler and get/set via int 2f/13h
+                global  _BIOSInt13
+                global  _UserInt13
+_BIOSInt13 dd 0 ; used to restore int13 on reboot (see int19 wrapper)
+_UserInt13 dd 0 ; actual disk handler used by kernel
+                global  _BIOSInt19
+_BIOSInt19 dd 0 ; original int19
+
+
                 ; Pad to 0620h
                 times (300h - ($ - _internal_data)) db 0
                 global _szNames
@@ -846,6 +862,18 @@ initforceEnableA20:
     global __HMARelocationTableStart
 __HMARelocationTableStart:   
 
+                global  _int13_handler
+                extern  reloc_call_int13_handler
+_int13_handler: jmp 0:reloc_call_int13_handler
+                call near forceEnableA20
+
+#if 0
+                global  _int19_handler
+                extern  reloc_call_int19_handler
+_int19_handler: jmp 0:reloc_call_int19_handler
+                call near forceEnableA20
+#endif
+
                 global  _int2f_handler
                 extern  reloc_call_int2f_handler
 _int2f_handler: jmp 0:reloc_call_int2f_handler

kernel/main.c

@@ -30,6 +30,7 @@
 #include "portab.h"
 #include "init-mod.h"
 #include "dyndata.h"
+#include "debug.h"
 
 #ifdef VERSION_STRINGS
 static BYTE *mainRcsId =
@@ -48,6 +49,7 @@ STATIC VOID init_internal_devices(void);
 
 STATIC VOID update_dcb(struct dhdr FAR *);
 STATIC VOID init_kernel(VOID);
+STATIC VOID do_fixup(VOID);
 STATIC VOID signon(VOID);
 STATIC VOID init_shell(VOID);
 STATIC VOID FsConfig(VOID);
@@ -55,6 +57,11 @@ STATIC VOID InitPrinters(VOID);
 STATIC VOID InitSerialPorts(VOID);
 STATIC void CheckContinueBootFromHarddisk(void);
 STATIC void setup_int_vectors(void);
+#define setup_fastprint_hook() setvec(0x29, int29_handler)  /* required for printf! */
+
+
+void setvec(unsigned char intno, intvec vector);
+
 
 #ifdef _MSC_VER
 BYTE _acrtused = 0;
@@ -67,6 +74,7 @@ __segment DosTextSeg = 0;
 #endif
 
 struct lol FAR * const LoL = &DATASTART;
+intvec FAR * const savedIVs = &SAVEDIVLST;
 
 void ASMCFUNC FreeDOSmain(void)
 {
@@ -120,14 +128,25 @@ void ASMCFUNC FreeDOSmain(void)
     fmemcpy(&InitKernelConfig, p, sizeof InitKernelConfig);
   }
 
-  setup_int_vectors();
+  /* printfs won't work until int29, fast console output hook is installed */
+  setup_fastprint_hook();
 
+  /* check if booting from CD before we hook too many interrupts */
   CheckContinueBootFromHarddisk();
 
+  /* display copyright info and kernel emulation status */
   signon();
-  init_kernel();
-  init_shell();
 
+  /* finish initial HMA segment relocation (move up until DOS=HIGH known) */
+  do_fixup();
+
+  /* install DOS API and other interrupt service routines, basic kernel functionality works */
+  setup_int_vectors();
+
+  /* initialize all internal variables, process CONFIG.SYS, load drivers, etc */
+  init_kernel();
+
+  init_shell();
   init_call_p_0(&Config); /* execute process 0 (the shell) */
 }
 
@@ -195,6 +214,30 @@ void setvec(unsigned char intno, intvec vector)
 }
 #endif
 
+
+/* ensures int vectors we may need to restore are saved */
+STATIC VOID save_int_vectors(VOID)
+{
+  /* we create far pointers otherwise compiler sets value
+     in initial data segment (IDATA) which does us no good.
+   */
+  extern intvec BIOSInt13, UserInt13, BIOSInt19;  /* in kernel.asm */
+  intvec FAR *pBIOSInt13, FAR *pUserInt13, FAR *pBIOSInt19;
+
+  pBIOSInt13 = MK_FP(FP_SEG(savedIVs), FP_OFF(savedIVs));
+  pUserInt13 = pBIOSInt13 + 1;
+  pBIOSInt19 = pBIOSInt13 + 2;
+
+  /* store for later use by our replacement int13handler */
+  *pBIOSInt13 = getvec(0x13);  /* save original BIOS int 0x13 handler */
+  *pUserInt13 = *pBIOSInt13;   /* default to it for user int 0x13 handler */
+  *pBIOSInt19 = getvec(0x19);  /* save reboot handler so we can clean up a little */
+
+  DDebugPrintf(("\n"));  /* force anything printed to start on next line after BS */
+  DDebugPrintf(("BIOSInt13(at %p) is %p\n", pBIOSInt13, *pBIOSInt13));
+  DDebugPrintf(("BIOSInt19(at %p) is %p\n", pBIOSInt19, *pBIOSInt19));
+}
+
 STATIC void setup_int_vectors(void)
 {
   static struct vec
@@ -208,20 +251,27 @@ STATIC void setup_int_vectors(void)
       { 0x1, FP_OFF(empty_handler) },  /* single step */
       { 0x3, FP_OFF(empty_handler) },  /* debug breakpoint */
       { 0x6, FP_OFF(int6_handler) },   /* invalid opcode */
+      { 0x13, FP_OFF(int13_handler) }, /* BIOS disk filter */
+#if 0
+      { 0x19, FP_OFF(int19_handler) }, /* BIOS bootstrap loader, vdisk */
+#endif
       { 0x20, FP_OFF(int20_handler) },
-      { 0x21, FP_OFF(int21_handler) },
+      { 0x21, FP_OFF(int21_handler) }, /* primary DOS API */
       { 0x22, FP_OFF(int22_handler) },
       { 0x24, FP_OFF(int24_handler) },
-      { 0x25, FP_OFF(low_int25_handler) },
+      { 0x25, FP_OFF(low_int25_handler) }, /* DOS abs read/write calls */
       { 0x26, FP_OFF(low_int26_handler) },
       { 0x27, FP_OFF(int27_handler) },
       { 0x28, FP_OFF(int28_handler) },
       { 0x2a, FP_OFF(int2a_handler) },
-      { 0x2f, FP_OFF(int2f_handler) }
+      { 0x2f, FP_OFF(int2f_handler) }  /* multiplex int */
     };
   struct vec *pvec;
   int i;
 
+  save_int_vectors();
+
+  /* install default handlers */
   for (i = 0x23; i <= 0x3f; i++)
     setvec(i, empty_handler);
   for (pvec = vectors; pvec < ENDOF(vectors); pvec++)
@@ -229,7 +279,7 @@ STATIC void setup_int_vectors(void)
   pokeb(0, 0x30 * 4, 0xea);
   pokel(0, 0x30 * 4 + 1, (ULONG)cpm_entry);
 
-  /* these two are in the device driver area LOWTEXT (0x70) */
+  /* handlers for int 0x1b and 0x29 are in the device driver area LOWTEXT (0x70) */
   setvec(0x1b, got_cbreak);
   setvec(0x29, int29_handler);  /* required for printf! */
 }
@@ -251,14 +301,8 @@ STATIC void printIRQvectors(void)
 }
 #endif
 
-STATIC void init_kernel(void)
+STATIC void do_fixup(void)
 {
-  COUNT i;
-
-  LoL->os_setver_major = LoL->os_major = MAJOR_RELEASE;
-  LoL->os_setver_minor = LoL->os_minor = MINOR_RELEASE;
-  LoL->rev_number = REVISION_SEQ;
-
   /* move kernel to high conventional RAM, just below the init code */
   /* Note: kernel.asm actually moves and jumps here, but MoveKernel
            must still be called to do the necessary segment fixups */
@@ -275,6 +319,15 @@ STATIC void init_kernel(void)
      chunk allocated, lpTop. I.e. lpTop is top of free conv memory
    */
   lpTop = MK_FP(FP_SEG(lpTop) - 0xfff, 0xfff0);
+}
+
+STATIC void init_kernel(void)
+{
+  COUNT i;
+
+  LoL->os_setver_major = LoL->os_major = MAJOR_RELEASE;
+  LoL->os_setver_minor = LoL->os_minor = MINOR_RELEASE;
+  LoL->rev_number = REVISION_SEQ;
 
   /* Initialize IO subsystem                                      */
   init_internal_devices();