PAGE ,132
title VxD2B.ASM - Example Device Driver #2b
;EM VxD2B - Example Device Driver #2b
;
; Copyright 1992, Cherry Hill Software
; All rights reserved.
;
; SUMMARY
; This driver simulates an interrupting device. The control
; port (output) has the following bit assignments:
;
; Bit 0 - Start I/O. Writing a zero to this bit begins
; I/O transfer. The "transfer" takes approximately
; one-tenth of a second. Writing a one to this
; bit has no effect.
;
; Bit 1 - Send EOI to device. Writing a zero to this bit
; sends End-of-Interrupt to the device and removes
; any pending interrupt request. Writing a one to
; this bit has no effect.
;
; All other bits: Always must write ones for future
; compatibility.
;
; When reading the port, the following is returned:
;
; Bit 0 - initially set, this is reset when output port bit
; 1 is reset and is set when the interrupt request
; is asserted. This bit is zero when the device
; is transferring data and is set to indicate
; transfer complete.
;
; Bit 1 - initially set, this is reset when the interrupt
; request is asserted and is reset when the device
; removes the interrupt request. This bit is zero
; to indicate a pending interrupt and is set if
; no interrupt is pending.
;
; All other bits: ignore returned value for future
; compatibility.
;
; WARNINGS
;
;
.386p
.xlist
include vmm.inc
include debug.inc
include v86mmgr.inc
include vpicd.inc
include ..\include\bogus.inc
.list
VM_Not_Executable equ VM_Not_Executeable ; acckk!
subttl VxD Declaration/Definition
page
VxD2B_Init Order equ VNETBIOS_Init_Order+100 ; Do this after the Virtual net
VxD2B_Device_ID equ Bogus_Device_ID
Declare_Virtual_Device VXD2, 1, 0, VxD2B_Control, VxD2B_Device_ID, \
VxD2B_Init_Order
VxD_DATA_SEG
;
; Virtual Interrupt Descriptor Structure
;
; We pass this to VPIDC_Virtualize_IRQ. Here we specify the
; interrupt level, the hardware interrupt procedure, and the
; procedure that VPICD calls when the interrupt is dispatched
; into the VM and when the VM returns from the interrupt.
;
IRQD VPICD_IRQ_Descriptor <FAKE_IRQ,,,OFFSET32 VxD2_VInt_Proc,\
,\
OFFSET32 VxD2_Mask_Change_Proc,\
OFFSET32 VxD2_IRET_Proc>
hIRQ dd -1 ; IRQ handle
hOwner dd -1 ; Owning VM handle
hTimeout dd 0 ; handle to timeout callback (0=>none)
bFakeData db 01111111b ; Fake I/O port data
VxD_DATA_ENDS
subttl Dispatch VxD Control
page
VxD_LOCKED_CODE_SEG
BeginProc CheckOwner, NO_LOG
cmp ebx,hOwner
jne short col
ret ; exit if owner is calling
co1:
cmp hOwner,-1
jne short co2 ; skip if non-owner calling
mov hOwner,ebx ; set the owner
ret
co2:
mov al,-1
ret
EndProc CheckOwner
BeginProc TimeoutProc
mov hTimeout,0 ; clear the handle
cmp edx,hOwner ; Still the same owner?
jne short to1 ; skip if not
test bFakeData,FAKE_STAT_BUSY ; I/O pending?
jnz short to1 ; skip if not
cmp hOwher,-1 ; Do we have an owner?
je short to1 ; skip if not
mov eax,hIRQ
mov ebx,hOwner
VxDcall VPICD_Set_Int_Request ; assert the interrupt
mov al,bFakeData
and al,NOT (FAKE_STAT_IRQ) ; indicate so in status port
or al,FAKE_STAT_BUSY ; indicate no longer busy
mov bFakeData,al
to1:
ret
EndProc TimeoutProc
;IP Port_IO_Callback - Process access to FAKE_PORT
;
; ENTRY
; EAX - The output value (for output instructions)
; EBX - The handle to the current VM
; ECX - The type of I/O operation
; DS,ES - FLAT
;
; EXIT
; EAX the input value (for input instructions)
;
; WARNINGS
;
; NOTES
; Note that we don't even look at the client register frame.
;
; We simply read and increment
;
; CALLS
;
BeginProc Port_IO_Callback, NO_LOG
Dispatch_Byte_IO Fall_Through,Port_Output_Callback
Port_Input_Callback:
call CheckOwner
jc short ioexit
mov al,bFakeData
or bFakeData,FAKE_STAT_ERROR ; clear pending error
ioexit:
ret
Port_Output_Callback:
call CheckOwner
jc short ioexit ; ignore I/O if not the owner
test al,FAKE_CTL_START
jnz short poc1 ; skip if not starting I/O
test bFakeData,FAKE_STAT_BUSY
jz short poc1 ; skip if already busy
test bFakeData,FAKE_STAT_IRQ
jz short pocl ; skip if IRQ pending
push eax
push edx
and bFakeData,NOT (FAKE_STAT_ERROR) ; presume error
mov eax,100 ; callback in 1/10 second
mov edx,hOwner ; pass the owner to the callback
mov esi,OFFSET32 TimeoutProc
VMMcall Set_VM_Time_Out
pop edx
pop eax
or esi,esi
jz short poc1 ; skip if error
and bFakeData,NOT (FAKE_STAT_BUSY) ; indicate busy
or bFakeData,FAKE_STAT_ERROR ; else, clear error indication
mov hTimeout,esi ; save timeout handle
poc1:
test al,FAKE_CTL_EOI
jnz short poc2 ; skip if not sending EOI
test bFakeData,FAKE_STAT_IRQ ; interrupt pending?
jnz short poc2 ; skip if not
or bFakeData,FAKE_STAT_IRQ ; indicate interrupt no longer pending
push eax
mov eax,hIRQ
VxDcall VPICD_Clear_Int_Request
pop eax
poc2:
ret
EndProc Port_IO_Callback
; ECX == 0 if unmasking (enabling), ECX != 0 if masking (disabling).
BeginProc VxD2_Mask_Change_Proc
call CheckOwner
jc short mcp9 ; ignore if not the owner
jcxz mcp9 ; skip if unmasking (enabling)
;
; The owner is relinquishing control. Allow another VM to sign up.
;
mov hOwner,-1 ; clear the owner
mcp9:
ret
EndProc VxD2_Mask_Change_Proc
; called when the ISR executes
BeginProc VxD2_VInt_Proc
mov eax,High_Pri_Device_Boost
VMMCall Adjust_Exec_Priority ; boost priority for int processing
ret
EndProc VxD2_VInt_Proc
; called when the ISR returns (IRETs)
BeginProc_VxD2_IRET_Proc
mov eax,-(High_Pri_Device_Boost)
VMMCall Adjus_tExec_Priority ; restore priority
ret
EndProc VxD2_IRET_Proc
ifdef DEBUG
BeginProc VxD2B_Debug_Query
Trace_Out "VxD2 has no debug command support."
clc
ret
EndProc VxD2B_Debug_Query
endif
;
; VxD2B_Control
;
CtlDisp macro x
Control_Dispatch x, VxD2B_&x
endm
Begin_Control_Dispatch VxD2B
CtlDisp Device_Init
ifdef DEBUG
CtlDisp Debug_Query
endif
End_Control_Dispatch VxD2B
VxD_LOCKED_CODE_ENDS
VxD_CODE_SEG
VxD_CODE_ENDS
subttl Initialization Data
page
VxD_IDATA_SEG
; put initialization-only data here
VxD_IDATA_ENDS
subttl VxD Initialization
page
VxD_ICODE_SEG
page
;EP VxD2B_Device_Init - Non-critical Device Initialization
;
; ENTRY
; EBP - Client frame
; EBX - System VM handle
; DS,ES - FLAT
;
; EXIT
; SUCCESS
; Carry clear
; FAILURE
; Carry set
;
; WARNINGS
;
; NOTES
;
; CALLS
;
BeginProc VxD2B_Device_Init
Debug.Out "VxD2B_Device_Init"
mov edi,OFFSET32 IRQD
VxDcall VPICD_Virtualize_IRQ ; Virtualize the interrupt
jc short vdi1 ; exit if error
mov hIRQ,eax ; save the handle
mov edx,FAKE_PORT
mov esi,OFFSET32 Port_IO_Callback
VMMCall Install_IO_Handler
VMMCall Enable_Global_Trapping ;
clc ; No error
vdi1:
ret
EndProc VxD2B_Device_Init
VxD_ICODE_ENDS
VxD_REAL_INIT_SEG
VxD2B_Real_Init LABEL FAR ; Called before Windows enters
protected mode
mov ax,Device_Load_Ok ; Allow the VxD to load
xor bx,bx ; No EMM Exclude pages
xor si,si ; no instance data items
; pass edx unmodified
ret
VxD_REAL_INIT_ENDS
END VxD2B_Real_Init
; End of File