Interrups

Categories

Contents

IFSHLP.SYS - GET ENTRY POINT

AH = 3Fh
BX = file handle for device "IFS$HLP$"
CX = 0008h (size of buffer in bytes)
DS:DX -> buffer for entry point record (see #01415)

Return:
CF clear if successful
AX = number of bytes actually read (0 if at EOF before call)
CF set on error
AX = error code (05h,06h) (see #01680 at AH=59h/BX=0000h)

Program: IFSHLP.SYS is a support driver for Microsoft Windows for Workgroups

See Also: AX=4402h"IFSHLP"

Format of IFSHLP.SYS entry point record:

Offset  Size    Description     (Table 01415)
00h  4 BYTEs   (call) required signature if called via IOCTL
70h E9h 34h 37h for Windows 3.11
70h E9h 35h 37h for Windows 3.11
(ret) signature 34h 37h 70h EFh (Windows 3.11)
(ret) signature 35h 37h 70h EFh (Windows95)
04h    DWORD   (ret) pointer to FAR call entry point (see #01416)


(Table 01416)
Call IFSHLP.SYS entry point with:.
STACK:
WORD    function number (00h-0Ch)
00h get ??? data
01h set interrupt intercepts (trap)
02h remove interrupt intercepts (untrap)
03h ??? LPT2
04h ??? LPT1
05h revector INT 2F to trap and remove trap for others
06h set ??? flag
07h clear ??? flag
08h get ??? flag word
---Windows 3.11 only---
09h ???
0Ah ???
0Bh ???
0Ch get ???
---if function 00h---

Return:
DX:AX -> ??? data (see #01417)
BX destroyed
---if function 01h---.
STACK:
DWORD   new intercept (trap) address

Return:
AX = status
0000h successful
0001h failed (already set)
DX = 0000h
BX destroyed

Note: The trap handler is called with a function number in BX, and the original BX on top of the stack; a null handler must perform a POP BX and an IRET ---if function 02h---

Return:
AX = status
0000h successful
0001h failed (not set)
DX = 0000h
BX destroyed
---if function 03h,04h---.
STACK:
WORD    ???

Return:
AX = 0000h
DX = 0000h
BX destroyed
---if function 05h---
???

Return:
BX destroyed
---if function 06h---

Return:
AX = 0001h and DX = 0000h if already set
AX,DX unchanged if successful
BX destroyed
---if function 07h---

Return:
AX = 0001h and DX = 0000h if not set
AX,DX unchanged if successful
BX destroyed
---if function 08h---

Return:
DX = 0000h
AX = flags
bit 0:
Set/cleared by functions 06h and 07h
bit 1:
Trap is currently set (refer to functions 01h/02h).
BX destroyed
---if function 09h---

Return:
AX = status
0000h successful
0001h failed (already called)
BX destroyed
---if function 0Ah---.
STACK:
WORD    ???.
???

Return:
BX destroyed
---if function 0Bh---

Return:
AX = status
0000h successful
0001h failed (not set)
BX destroyed
---if function 0Ch---

Return:
AX = 0000h
ES:BX -> ??? data
---if function > 0Ch---

Return:
AX = 0001h
DX = 0000h
BX destroyed

Format of IFSHLP ??? data:

Offset  Size    Description     (Table 01417)
00h    DWORD   -> DOS Swappable Data Area (see #01687,#01689)
02h    WORD    ??? offset in DOS data segment?
04h    WORD    offset in DOS data segment of current-PSP WORD
06h    WORD    ???
08h    WORD    ???
0Ah    WORD    ???
0Ch    DWORD   -> DOS List of Lists (see #01627)
10h    ???

See Also: #01416

Category: Uncatagorized - Int 21h - I

Interrups

Categories

Contents