windows-nt/Source/XPSP1/NT/base/busdrv/agp/agplib/utils.c
2020-09-26 16:20:57 +08:00

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/*++
Copyright (c) 1996-2000 Microsoft Corporation
Module Name:
utils.c
Abstract:
This module contains assorted utility functions for PCI.SYS.
Author:
Peter Johnston (peterj) 20-Nov-1996
Revision History:
Eric Nelson (enelson) 20-Mar-2000 - kidnap registry function
--*/
#include "agplib.h"
#ifdef ALLOC_PRAGMA
#pragma alloc_text(PAGE, AgpOpenKey)
#pragma alloc_text(PAGE, AgpStringToUSHORT)
#endif
ULONGLONG
AgpGetDeviceFlags(
IN PAGP_HACK_TABLE_ENTRY AgpHackTable,
IN USHORT VendorID,
IN USHORT DeviceID,
IN USHORT SubVendorID,
IN USHORT SubSystemID,
IN UCHAR RevisionID
)
/*++
Description:
Look in the registry for any flags for this VendorId/DeviceId.
Arguments:
VendorId PCI Vendor ID (16 bits) of the manufacturer of the
device.
DeviceId PCI Device ID (16 bits) of the device.
SubVendorID PCI SubVendorID representing the manufacturer of the
subsystem
SubSystemID PCI SubSystemID representing subsystem
RevisionID PCI Revision denoting the revision of the device
Return Value:
64 bit flags value or 0 if not found.
--*/
{
PAGP_HACK_TABLE_ENTRY current;
ULONGLONG hackFlags = 0;
ULONG match, bestMatch = 0;
if (AgpHackTable == NULL) {
return hackFlags;
}
//
// We want to do a best-case match:
// VVVVDDDDSSSSssssRR
// VVVVDDDDSSSSssss
// VVVVDDDDRR
// VVVVDDDD
//
// List is currently unsorted, so keep updating current best match.
//
for (current = AgpHackTable; current->VendorID != 0xFFFF; current++) {
match = 0;
//
// Must at least match vendor/dev
//
if ((current->DeviceID != DeviceID) ||
(current->VendorID != VendorID)) {
continue;
}
match = 1;
//
// If this entry specifies a revision, check that it is consistent.
//
if (current->Flags & AGP_HACK_FLAG_REVISION) {
if (current->RevisionID == RevisionID) {
match += 2;
} else {
continue;
}
}
//
// If this entry specifies subsystems, check that they are consistent
//
if (current->Flags & AGP_HACK_FLAG_SUBSYSTEM) {
if (current->SubVendorID == SubVendorID &&
current->SubSystemID == SubSystemID) {
match += 4;
} else {
continue;
}
}
if (match > bestMatch) {
bestMatch = match;
hackFlags = current->DeviceFlags;
}
}
return hackFlags;
}
BOOLEAN
AgpOpenKey(
IN PWSTR KeyName,
IN HANDLE ParentHandle,
OUT PHANDLE Handle,
OUT PNTSTATUS Status
)
/*++
Description:
Open a registry key.
Arguments:
KeyName Name of the key to be opened.
ParentHandle Pointer to the parent handle (OPTIONAL)
Handle Pointer to a handle to recieve the opened key.
Return Value:
TRUE is key successfully opened, FALSE otherwise.
--*/
{
UNICODE_STRING nameString;
OBJECT_ATTRIBUTES nameAttributes;
NTSTATUS localStatus;
PAGED_CODE();
RtlInitUnicodeString(&nameString, KeyName);
InitializeObjectAttributes(&nameAttributes,
&nameString,
OBJ_CASE_INSENSITIVE,
ParentHandle,
(PSECURITY_DESCRIPTOR)NULL
);
localStatus = ZwOpenKey(Handle,
KEY_READ,
&nameAttributes
);
if (Status != NULL) {
//
// Caller wants underlying status.
//
*Status = localStatus;
}
//
// Return status converted to a boolean, TRUE if
// successful.
//
return NT_SUCCESS(localStatus);
}
BOOLEAN
AgpStringToUSHORT(
IN PWCHAR String,
OUT PUSHORT Result
)
/*++
Description:
Takes a 4 character hexidecimal sting and converts it into a USHORT.
Arguments:
String - the string
Result - the USHORT
Return Value:
TRUE is success, FASLE otherwise
--*/
{
ULONG count;
USHORT number = 0;
PWCHAR current;
current = String;
for (count = 0; count < 4; count++) {
number <<= 4;
if (*current >= L'0' && *current <= L'9') {
number |= *current - L'0';
} else if (*current >= L'A' && *current <= L'F') {
number |= *current + 10 - L'A';
} else if (*current >= L'a' && *current <= L'f') {
number |= *current + 10 - L'a';
} else {
return FALSE;
}
current++;
}
*Result = number;
return TRUE;
}