inthndlr.c

GNU FreeDOS兼容MS DOS很好的东东.

  }
  goto exit_dispatch;
long_check:
  if (lrc >= SUCCESS)
  {
    lr.AX = (UWORD)lrc;
    goto exit_dispatch;
  }
  rc = (int)lrc;
short_check:
  if (rc < SUCCESS)
    goto error_exit;
  goto exit_dispatch;
error_invalid:
  rc = DE_INVLDFUNC;
error_exit:
  lr.AX = -rc;
  if (CritErrCode == SUCCESS)
    CritErrCode = lr.AX;      /* Maybe set */
error_carry:
  SET_CARRY_FLAG();
exit_dispatch:
  fmemcpy(r, &lr, sizeof(lregs) - 4);
  r->DS = lr.DS;
  r->ES = lr.ES;
real_exit:;

#ifdef DEBUG
  if (bDumpRegs)
  {
    fmemcpy(&error_regs, user_r, sizeof(iregs));
    dump_regs = TRUE;
    dump();
  }
#endif
}

#if 0
        /* No kernel INT-23 handler required no longer -- 1999/04/15 ska */
/* ctrl-Break handler */
#pragma argsused
VOID INRPT FAR int23_handler(int es, int ds, int di, int si, int bp,
                             int sp, int bx, int dx, int cx, int ax,
                             int ip, int cs, int flags)
{
  tsr = FALSE;
  return_mode = 1;
  return_code = -1;
  mod_sto(CTL_C);
  DosMemCheck();
#ifdef TSC
  StartTrace();
#endif
  return_user();
}
#endif

struct int25regs {
  UWORD es, ds;
  UWORD di, si, bp, sp;
  UWORD bx, dx, cx, ax;
  UWORD flags, ip, cs;
};

/* 
    this function is called from an assembler wrapper function 
*/
VOID ASMCFUNC int2526_handler(WORD mode, struct int25regs FAR * r)
{
  ULONG blkno;
  UWORD nblks;
  BYTE FAR *buf;
  UBYTE drv;

  if (mode == 0x26)
    mode = DSKWRITEINT26;
  else
    mode = DSKREADINT25;

  drv = r->ax;

  if (drv >= lastdrive)
  {
    r->ax = 0x201;
    SET_CARRY_FLAG();
    return;
  }

#ifdef WITHFAT32
  {
    struct dpb FAR *dpbp = get_dpb(drv);
    if (dpbp != NULL && ISFAT32(dpbp))
    {
      r->ax = 0x207;
      SET_CARRY_FLAG();
      return;
    }
  }
#endif

  nblks = r->cx;
  blkno = r->dx;

  buf = MK_FP(r->ds, r->bx);

  if (nblks == 0xFFFF)
  {
    /*struct HugeSectorBlock FAR *lb = MK_FP(r->ds, r->bx); */
    blkno = ((struct HugeSectorBlock FAR *)buf)->blkno;
    nblks = ((struct HugeSectorBlock FAR *)buf)->nblks;
    buf = ((struct HugeSectorBlock FAR *)buf)->buf;
  }

  InDOS++;

  r->ax = dskxfer(drv, blkno, buf, nblks, mode);

  CLEAR_CARRY_FLAG();
  if (r->ax != 0)
  {
    SET_CARRY_FLAG();
    if (mode == DSKWRITEINT26)
      setinvld(drv);
  }
  --InDOS;
}

/*
VOID int25_handler(struct int25regs FAR * r) { int2526_handler(DSKREAD,r); }
VOID int26_handler(struct int25regs FAR * r) { int2526_handler(DSKWRITE,r); }
*/

#ifdef TSC
STATIC VOID StartTrace(VOID)
{
  if (bTraceNext)
  {
#ifdef DEBUG
    bDumpRegs = TRUE;
#endif
    bTraceNext = FALSE;
  }
#ifdef DEBUG
  else
    bDumpRegs = FALSE;
#endif
}
#endif

/* this function is called from an assembler wrapper function
   and serves the internal dos calls - int2f/12xx and int2f/4a01,4a02.
*/
struct int2f12regs {
#ifdef I386
#ifdef __WATCOMC__
  /* UWORD gs, fs;  ** GS/FS are protected through SI/DI */
#else
  UWORD high_edx,
#ifdef _MSC_VER
        high_ecx,
#else /* __BORLANDC__ */
        high_ebx,
#endif
        high_eax;
#endif
#endif
  UWORD es, ds;
  UWORD di, si, bp;
  xreg b, d, c, a;
  UWORD ip, cs, flags;
  UWORD callerARG1;             /* used if called from INT2F/12 */
};

/* WARNING: modifications in `r' are used outside of int2F_12_handler()
 * On input r.AX==0x12xx, 0x4A01 or 0x4A02
 */
VOID ASMCFUNC int2F_12_handler(struct int2f12regs r)
{
  COUNT rc;
  long lrc;

  if (r.AH == 0x4a)
  {
    size_t size = 0, offs = 0xffff;

    r.ES = offs;
    if (FP_SEG(firstAvailableBuf) == offs) /* HMA present? */
    {
      offs = FP_OFF(firstAvailableBuf);
      size = ~offs;                        /* BX for query HMA   */
      if (r.AL == 0x02)                    /* allocate HMA space */
      {
        if (r.BX < size)
          size = r.BX;
        AllocateHMASpace(offs, offs+size);
        firstAvailableBuf += size;
      }
    }
    r.DI = offs;
    r.BX = size;
    return;
  }

  switch (r.AL)
  {
    case 0x00:                 /* installation check */
      r.AL = 0xff;
      break;

    case 0x03:                 /* get DOS data segment */
      r.DS = FP_SEG(&nul_dev);
      break;

    case 0x06:                 /* invoke critical error */

      /* code, drive number, error, device header */
      r.AL = CriticalError(r.callerARG1 >> 8,
                           (r.callerARG1 & (EFLG_CHAR << 8)) ? 0 :
                           r.callerARG1 & 0xff, r.DI, MK_FP(r.BP, r.SI));
      break;

    case 0x08:                 /* decrease SFT reference count */
      {
        sft FAR *p = MK_FP(r.ES, r.DI);

        r.AX = p->sft_count;

        if (--p->sft_count == 0)
          --p->sft_count;
      }
      break;

    case 0x0c:                 /* perform "device open" for device, set owner for FCB */

      if (lpCurSft->sft_flags & SFT_FDEVICE)
      {
        request rq;

        rq.r_unit = 0;
        rq.r_status = 0;
        rq.r_command = C_OPEN;
        rq.r_length = sizeof(request);
        execrh((request FAR *) & rq, lpCurSft->sft_dev);
      }

      /* just do it always, not just for FCBs */
      lpCurSft->sft_psp = cu_psp;
      break;

    case 0x0d:                 /* get dos date/time */

      r.AX = dos_getdate();
      r.DX = dos_gettime();
      break;

    case 0x11:                 /* normalise ASCIIZ filename */
    {
      char c;
      char FAR *s = MK_FP(r.DS, r.SI);
      char FAR *t = MK_FP(r.ES, r.DI);

      do
      {
        c = *s++;
        /* uppercase character */
        /* for now, ASCII only because nls.c cannot handle DS!=SS */
        if (c >= 'a' && c <= 'z')
          c -= 'a' - 'A';
        else if (c == '/')
          c = '\\';
        *t++ = c;
      }
      while (c);
      break;
    }

    case 0x12:                 /* get length of asciiz string */

      r.CX = fstrlen(MK_FP(r.ES, r.DI)) + 1;

      break;

    case 0x13:
      /* uppercase character */  
      /* for now, ASCII only because nls.c cannot handle DS!=SS */
      r.AL = (unsigned char)r.callerARG1;
      if (r.AL >= 'a' && r.AL <= 'z')
        r.AL -= 'a' - 'A';
      break;

    case 0x16:
      /* get address of system file table entry - used by NET.EXE
         BX system file table entry number ( such as returned from 2F/1220)
         returns
         ES:DI pointer to SFT entry
         BX relative entry number within SFT */
      {
        int rel_idx = idx_to_sft_(r.BX);

        if (rel_idx == -1)
        {
          r.FLAGS |= FLG_CARRY;
          break;
        }
        r.FLAGS &= ~FLG_CARRY;
        r.BX = rel_idx;
        r.ES = FP_SEG(lpCurSft);
        r.DI = FP_OFF(lpCurSft);
        break;
      }

    case 0x17:                 /* get current directory structure for drive - used by NET.EXE
                                   STACK: drive (0=A:,1=B,...)
                                   ; returns
                                   ;   CF set if error
                                   ;   DS:SI pointer to CDS for drive
                                   ; 
                                   ; called like
                                   ;   push 2 (c-drive)
                                   ;   mov ax,1217
                                   ;   int 2f
                                   ;
                                   ; probable use: get sizeof(CDSentry)
                                 */
      {
        struct cds FAR *cdsp = get_cds(r.callerARG1 & 0xff);

        if (cdsp == NULL)
        {
          r.FLAGS |= FLG_CARRY;
          break;
        }
        r.DS = FP_SEG(cdsp);
        r.SI = FP_OFF(cdsp);
        r.FLAGS &= ~FLG_CARRY;
        break;
      }

    case 0x18:                 /* get caller's registers */

      r.DS = FP_SEG(user_r);
      r.SI = FP_OFF(user_r);
      break;

    case 0x1b:                 /* #days in February - valid until 2099. */

      r.AL = (r.CL & 3) ? 28 : 29;
      break;

    case 0x20:                 /* get job file table entry */
      {
        psp FAR *p = MK_FP(cu_psp, 0);
        unsigned char FAR *idx;

        if (r.BX >= p->ps_maxfiles)
        {
          r.AL = -DE_INVLDHNDL;
          r.FLAGS |= FLG_CARRY;
          break;
        }
        idx = &p->ps_filetab[r.BX];
        r.FLAGS &= ~FLG_CARRY;
        r.ES = FP_SEG(idx);
        r.DI = FP_OFF(idx);
      }
      break;

    case 0x21:                 /* truename */

      DosTruename(MK_FP(r.DS, r.SI), MK_FP(r.ES, r.DI));

      break;

    case 0x23:                 /* check if character device */
      {
        struct dhdr FAR *dhp;

        dhp = IsDevice((BYTE FAR *) DirEntBuffer.dir_name);

        if (dhp == NULL)
        {
          r.FLAGS |= FLG_CARRY;
          break;
        }
        r.BH = dhp->dh_attr;
        r.FLAGS &= ~FLG_CARRY;
      }
      break;

    case 0x25:                 /* get length of asciiz string */

      r.CX = fstrlen(MK_FP(r.DS, r.SI)) + 1;
      break;

    case 0x26:                 /* open file */
      r.FLAGS &= ~FLG_CARRY;
      CritErrCode = SUCCESS;
      lrc = DosOpen(MK_FP(r.DS, r.DX), O_LEGACY | O_OPEN | r.CL, 0);
      goto long_check;

    case 0x27:                 /* close file */
      r.FLAGS &= ~FLG_CARRY;
      CritErrCode = SUCCESS;
      rc = DosClose(r.BX);
      goto short_check;

    case 0x28:                 /* move file pointer */
      /*
       * RBIL says: "sets user stack frame pointer to dummy buffer,
       * moves BP to AX, performs LSEEK, and restores frame pointer"
       * We obviously don't do it like that. Does this do any harm?! --L.G.
       */
      r.FLAGS &= ~FLG_CARRY;
      CritErrCode = SUCCESS;
      if (r.BP < 0x4200 || r.BP > 0x4202)
        goto error_invalid;
#if 0
      {
        sft FAR *s = get_sft(r.BX);
        if ((rc = _SftSeek(s, MK_ULONG(r.CX, r.DX), r.BP & 0xff)) >= SUCCESS)
        {
          r.DX = hiword (s->sft_posit);
          r.AX = loword (s->sft_posit);
        }
      }
      goto short_check;
#else
        goto error_invalid;
#endif

    case 0x29:                 /* read from file */
      r.FLAGS &= ~FLG_CARRY;
      CritErrCode = SUCCESS;
      lrc = DosRead(r.BX, r.CX, MK_FP(r.DS, r.DX));
      goto long_check;

    case 0x2a:                 /* Set FastOpen but does nothing. */

      r.FLAGS &= ~FLG_CARRY;
      break;

    case 0x2c:                 /* added by James Tabor For Zip Drives
                                   Return Null Device Pointer          */
      /* by UDOS+RBIL: get header of SECOND device driver in device chain, 
         omitting the NUL device TE */
      r.BX = FP_SEG(nul_dev.dh_next);
      r.AX = FP_OFF(nul_dev.dh_next);

      break;

    case 0x2e:                 /* GET or SET error table addresse - ignored
                                   called by MS debug with  DS != DOSDS, printf
                                   doesn't work!! */
      break;

    case 0x2f:
      if (r.DX)
      {
        os_setver_major = r.DL;
        os_setver_minor = r.DH;
      }
      else
      {
        os_setver_major = os_major;
        os_setver_minor = os_minor;
      }
      break;

    default:
      if (r.AL <= 0x31)
      {
        put_string("unimplemented internal dos function INT2F/12");
        put_unsigned(r.AL, 16, 2);
        put_string("\n");
        r.FLAGS |= FLG_CARRY;
      }
  }
  return;
long_check:
  if (lrc >= SUCCESS)
  {
    r.AX = (UWORD)lrc;
    return;
  }
  rc = (int)lrc;
short_check:
  if (rc < SUCCESS)
    goto error_exit;
  return;
error_invalid:
  rc = DE_INVLDFUNC;
error_exit:
  r.AX = -rc;
  if (CritErrCode == SUCCESS)
    CritErrCode = r.AX;      /* Maybe set */
  r.FLAGS |= FLG_CARRY;
}

/*
 * 2000/09/04  Brian Reifsnyder
 * Modified interrupts 0x25 & 0x26 to return more accurate error codes.
 */