home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Magnum One
/
Magnum One (Mid-American Digital) (Disc Manufacturing).iso
/
d1
/
dostech.arc
/
CHAP10
< prev
next >
Wrap
Text File
|
1989-02-04
|
71KB
|
1,384 lines
CHAPTER 10
Programming Technical Reference - IBM
Copyright 1988, Dave Williams
LOTUS-INTEL-MICROSOFT EXPANDED MEMORY SPECIFICATION
The Expanded Memory Manager ............................................ 10-
History ........................................................ 10-
Page Frames .................................................... 10-
Expanded Memory Services ............................................... 10-
AST/Quadram/Ashton-Tate Enhanced EMM ................................... 10-
Calling the Manager ............................................ 10-
Common EMS Functions (hex calls)
1 (40h) Get Manager Status ............................ 10-
2 (41h) Get Page Frame Segment ........................ 10-
3 (42h) Get Number of Pages ........................... 10-
4 (43h) Get Handle and Allocate Memory ................ 10-
5 (44h) Map Memory .................................... 10-
6 (45h) Release Handle and Memory ..................... 10-
7 (46h) Get EMM Version ............................... 10-
8 (47h) Save Mapping Context .......................... 10-
9 (48h) Restore Mapping Context ....................... 10-
10 (49h) Reserved ...................................... 10-
11 (4Ah) Reserved ...................................... 10-
12 (4Bh) Get Number of EMM Handles ..................... 10-
12 (4Ch) Get Pages Owned By Handle ..................... 10-
14 (4Dh) Get Pages for All Handles ..................... 10-
15 (4Eh) Get Or Set Page Map ........................... 10-
new LIM 4.0 specification:
16 (4Fh) Get/Set Partial Page Map ...................... 10-
17 (50h) Map/Unmap Multiple Pages ...................... 10-
18 (51h) Reallocate Pages .............................. 10-
19 (52h) Handle Attribute Functions .................... 10-
20 (53h) Get Handle Name ............................... 10-
21 (54h) Get Handle Directory .......................... 10-
22 (55h) Alter Page Map & Jump ......................... 10-
23 (56h) Alter Page Map & Call ......................... 10-
24 (57h) Move Memory Region ............................ 10-
25 (58h) Get Mappable Physical Address Array ........... 10-
26 (59h) Get Expanded Memory Hardware .................. 10-
27 (5Ah) Allocate Raw Pages ............................ 10-
28 (5Bh) Get Alternate Map Register Set ................ 10-
29 (5Ch) Prepare Expanded Memory Hardware .............. 10-
30 (5Dh) Enable OS/E Function Set ...................... 10-
31 (5Eh) Unknown ....................................... 10-
32 (5Fh) Unknown ....................................... 10-
33 (60h) Unknown ....................................... 10-
34 (61h) AST Generic Accelerator Card Support .......... 10-
Expanded Memory Manager Error Codes .................................... 10-
THE EXPANDED MEMORY MANAGER
History
The Lotus/Intel/Microsoft Expanded Memory Manager was originally a Lotus and
Intel project and was announced as version 3.0 in the second quarter of 1985
primarily as a means of running larger Lotus worksheets by transparently
paging unused sections to bank-switched memory. Shortly afterward Microsoft
announced support of the standard and version 3.2 was subsequently released
with support for Microsoft Windows. LIM 3.2 supported up to 8 megabytes of
paged memory. The LIM 4.0 supports up to 32 megabytes of paged memory.
AST/QUADRAM/ASHTON-TATE ENHANCED EXPANDED MEMORY SPECIFICATION
The AQA EEMS maintains upward compatibility with the LIM, but is a superset
of functions.
The AQA EEMS permits its pages to be scattered throughout the unused portion
of the machine's address space.
On August 19, 1987, the new version of the Expanded Memory Specification (EMS)
was announced by Lotus, Intel and Microsoft. This new version of the
specification includes many features of the Enhanced Expanded Memory
Specification (EEMS) originally developed by AST Reserach, Quadram and Ashton-
Tate, although the three original sponsoring companies elected not to make the
new specification upward compatible with EEMS. AST Research says that they will
endorse EMS 4.0 without reservation.
The definitive document for the LIM-EMS is Intel part number 300275-004,
August, 1987.
32M ┌──────────────┐
/│ │
│ │
/ │ │
│ │
/ │ │
│ │
/ │ │
│ Expanded │
/ │ Memory │
1024K ┌──────────────┐ │ │
│ / / / / / / │ / │ │
960K ├──────────────┤ │ │
│ Page Frame │ │ │
│ │ │ │
│ 12 16K-Byte │ │ │
│ Physical │ │ │
│ Pages │ │ │
768K ├──────────────┤ │ Divided into │
│ / / / / / / │ \ │ logical │
640K ├──────────────┤ │ pages │
│ │ \ │ │
│ │ │ │
│ │ \ │ │
│ │ │ │
│ 24 16K-Byte │ \ │ │
│ Physical │ │ │
│ Pages* │ \ │ │
│ │ │ │
│ │ \ │ │
│ │ │ │
│ │ \ │ │
256K ├──────────────┤ │ │
│ │ \ │ │
│ / / / / / / │ │ │
│ │ \ │ │
│ / / / / / / │ │ │
│ │ \ │ │
│ / / / / / / │ │ │
│ │ \ │ │
0 └──────────────┘ │ │
\ │ │
│ │
\ │ │
0 └──────────────┘
The page frame is located above the 640k system RAM area, anywhere from
0A000h to 0FFFFh. This area is used by the video adapters, network cards, and
add-on ROMs (as in hard disk controllers). The page frames are mapped around
areas that are in use.
WRITING PROGRAMS THAT USE EXPANDED MEMORY
In order to use expanded memory, applications must perform these steps in the
following order:
1. Determine if EMM is installed.
2. Determine if enough expanded memory pages exist for your application.
(Function 3)
3. Allocate expanded memory pages. (Function 4 or 18)
4. Get the page frame base address. (Function 2)
5. Map in expanded memory pages. (Function 5 or 17)
6. Read/write/execute data in expanded memory, just as if it were conventional
memory.
7. Return expanded memory pages to expanded memory pool before exiting. Function
6 or 18)
Programming Guidelines
The following section contains guidelines for programmers writing applications
that use EMM.
A) Do not put a program's stack in expanded memory.
B) Do not replace interrupt 67h. This is the interrupt vector the EMM uses.
Replacing interrupt 67h could result in disabling the Expanded Memory
Manager.
C) Do not map into conventional memory address space your application doesn't
own. Applications that use the EMM to swap into conventional memory space,
must first allocate this space from the operating system. If the operating
system is not aware that a region of memory it manages is in use, it will
think it is available. This could have disastrous results. EMM should not be
used to "allocate" conventional memory. DOS is the proper manager of
conventional memory space. EMM should only be used to swap data in
conventional memory space previously allocated from DOS.
D) Applications that plan on using data aliasing in expanded memory must check
for the presence of expanded memory hardware. Data aliasing occurs when
mapping one logical page into two or more mappable segments. This makes one
16K-byte expanded memory page appear to be in more than one 16K-byte memory
address space. Data aliasing is legal and sometimes useful for applications.
Software-only expanded memory emulators cannot perform data aliasing. A
simple way to distinguish software emulators from actual expanded memory
hardware is to attempt data aliasing and check the results. For example, map
one logical page into four physical pages. Write to physical page 0. Read
physical pages 1-3 to see if the data is there as well. If the data appears
in all four physical pages, then expanded memory hardware is installed in the
system, and data aliasing is supported.
E) Applications should always return expanded memory pages to the expanded
memory manager upon termination. These pages will be made available for other
applications. If unneeded pages are not returned to the expanded memory
manager, the system could run out of expanded memory pages or expanded
memory handles.
F) Terminate and stay resident programs (TSRs) should always save the state of
the map registers before changing them. Since TSRs may interrupt other
programs which may be using expanded memory, they must not change the state
of the page mapping registers without first saving them. Before exiting, TSRs
must restore the state of the map registers.
The following sections describe the three ways to save and restore the state
of the map registers.
1) Save Page Map and Restore Page Map (Functions 8 and 9). This is the
simplest of the three methods. The EMM saves the map register contents in
its own data structures -- the application does not need to provide extra
storage locations for the mapping context. The last mapping context to be
saved, under a particular handle, will be restored when a call to Restore
Page Map is issued with the same handle. This method is limited to one
mapping context for each handle and saves the context for only LIM
standard 64K-byte page frames.
2) Get/Set Page Map (Function 15). This method requires the application to
allocate space for the storage array. The EMM saves the mapping context in
an array whose address is passed to the EMM. When restoring the mapping
context with this method, an application passes the address of an array
which contains a previously stored mapping context. This method is
preferable if an application needs to do more than one save before a
restore. It provides a mechanism for switching between more than one
mapping context.
3) Get/Set Partial Page Map (Function 16). This method provides a way for
saving a partial mapping context. It should be used when the application
does not need to save the context of all mappable memory. This function
also requires that the storage array be part of the application's data.
G) All functions using pointers to data structures must have those data
structures in memory which will not be mapped out. Functions 22 and 23
(Alter Map & Call and Alter Map & Jump) are the only exceptions.
EMS 4.0 SPECIFICATIONS
Page Frames
The bank switched memory chunks are referred to as "page frames". These frame
consist of four 16K memory blocks mapped into some of the normally unused
system ROM address area, 0C0000-0EFFFF. Each 16K page is independent of the
other and they can map to discrete or overlapping areas of the 8 megabyte
expanded memory address area. Most cards allow selection of addresses to prevent
conflict with other cards, such as hard disk controllers and other expanded
memory boards.
Calling the Manager
Applications programs communicate with the EMM device driver directly via user
interrupt 67h. All communication between the application program and the driver
bypasses DOS completely. To call the driver, register AH is loaded with the
number of the EMM service requested; DX is loaded with the file handle; and
interrupt 67h is called. ES:DI is used to pass the address of a buffer or array
if needed.
On return AH contains 0 if the call was successful or an error code from 80h to
8Fh if unsuccessful.
TESTING FOR THE PRESENCE OF THE EXPANDED MEMORY MANAGER
Before an application program can use the Expanded Memory Manager, it must
determine whether the manager is present. The two recommended methods are the
"open handle" technique and the "get interrupt vector" technique.
The majority of application programs can use either the "open handle" or the
"get interrupt vector" method. However, if your program is a device driver or
if it interrupts DOS during file system operations, you must use only the "get
interrupt vector" method.
Device drivers execute from within DOS and can't access the DOS file functions;
programs that interrupt DOS during file operations have a similar restriction.
During their interrupt processing procedures, they can't access the DOS file
functions because another program may be using the system. Since the "get
interrupt vector" method doesn't require the DOS file functions, you must use
it for programs of this type.
The "Open Handle" Method
Most application programs can use the DOS "Open Handle" method to test for
the presence of the EMM. To use this method, follow these steps in order:
1) Issue an "open handle" command (DOS function 3Dh) in "read only" access mode
(register AL = 0). This function requires your program to point to an ASCII
string which contains the path name of the file or device in which you're
interested (register set DS:DX contains the pointer). In this case the file
is actually the reserved name of the expanded memory manager.
you should format the ASCII string as follows:
ASCII_device_name DB 'EMMXXXX0', 0
The ASCII codes for the capital letters EMMXXXX0 are terminated by a byte
containing a value of zero.
2) If DOS returns no error code, skip Steps 3 and 4 and go to Step 5. If DOS
returns a "Too many open files" error code, go to Step 3. If DOS returns a
"File/Path not found" error code, skip Step 3 and go to Step 4.
3) If DOS returns a "Too many open files" (not enough handles) status code, your
program should invoke the "open file" command before it opens any other
files. This will guarantee that at least one file handle will be available to
perform the function without causing this error.
After the program performs the "open file" command, it should perform the
test described in Step 6 and close the "file handle" (DOS function 3Eh).
Don't keep the manager "open" after this status test is performed since
"manager" functions are not available through DOS. Go to Step 6.
4) If DOS returns a "File/Path not found," the memory manager is not installed.
If your application requires the memory manager, the user will have to reboot
the system with a disk containing the memory manager and the appropriate
CONFIG.SYS file before proceeding.
5) If DOS doesn't return an error status code you can assume that either a
device with the name EMMXXXX0 is resident in the system, or a file with this
name is on disk in the current disk drive. Go to Step 6.
6) Issue an "I/O Control for Devices" command (DOS function 44h) with a "get
device information" command (register AL = 0). DOS function 44h determines
whether EMMXXXX0 is a device or a file.
You must use the file handle (register BX) which you obtained in Step 1 to
access the "EMM" device.
This function returns the "device information" in a word (register DX).
Go to Step 7.
7. If DOS returns any error code, you should assume that the memory manager
device driver is not installed. If your application requires the memory
manager, the user will have to reboot the system with a disk containing the
memory manager and the appropriate CONFIG.SYS file before proceeding.
8) If DOS didn't return an error status, test the contents of bit 7 (counting
from 0) of the "device information" word (register DX) the function
returned. Go to Step 9.
9) If bit 7 of the "device information" word contains a zero, then EMMXXXX0 is
a file, and the memory manager device driver is not present. If your
application requires the memory manager, the user will have to reboot the
system with a disk containing the memory manager and the appropriate
CONFIG.SYS file before proceeding.
If bit 7 contains a one, then EMMXXXX0 is a device. Go to Step 10.
10) Issue an "I/O Control for Devices" command (DOS function 44h) with a "get
output status" command (register AL = 7). You must use the file handle you
obtained in Step 1 to access the "EMM" device (register BX). Go to Step 11.
11) If the expanded memory device driver is ready, the memory manager passes
a status value of 0FFh in register AL. The status value is 00h if the device
driver is not ready.
If the memory manager device driver is "not ready" and your application
requires its presence, the user will have to reboot the system with a disk
containing the memory manager and the appropriate CONFIG.SYS file before
proceeding.
If the memory manager device driver is "ready," go to Step 12.
12) Issue a "Close File Handle" command (DOS function 3Eh) to close the expanded
memory device driver. You must use the file handle you obtained in Step 1 to
close the "EMM" device (register BX).
The "Get Interrupt Vector" technique
Any type of program can use this method to test for the presence of the EMM.
Use this method (not the "Open Handle" method) if your program is a device
driver or if it interrupts DOS during file system operations.
Follow these steps in order:
1) Issue a "get vector" command (DOS function 35h) to obtain the contents of
interrupt vector array entry number 67h (addresses 0000:019Ch thru
0000:019Fh).
The memory manager uses this interrupt vector to perform all manager
functions. The offset portion of this interrupt service routine address is
stored in the word located at address 0000:019Ch; the segment portion is
stored in the word located at address 0000:019Eh.
2) Compare the "device name field" with the contents of the ASCII string which
starts at the address specified by the segment portion of the contents of
interrupt vector address 67h and a fixed offset of 000Ah. If DOS loaded the
memory manager at boot time this name field will have the name of the device
in it.
Since the memory manager is implemented as a character device driver, its
program origin is 0000h. Device drivers are required to have a "device
header" located at the program origin. Within the "device header" is an 8
byte "device name field." For a character mode device driver this name field
is always located at offset 000Ah within the device header. The device name
field contains the name of the device which DOS uses when it references the
device.
If the result of the "string compare" in this technique is positive, the
memory manager is present.
Terminate and Stay Resident (TSR) Program Cooperation:
In order for TSR's to cooperate with each other and with other applications,
TSRs must follow this rule: a program may only remap the DOS partition it lives
in. This rule applies at all times, even when no expanded memory is present.
EXPANDED MEMORY SERVICES
FUNCTIONS DEFINED IN EMS 3.2 SPECIFICATION
Interrupt 67h
Function 40h Get Manager Status
LIM Function Call 1
Returns a status code indicating whether the memory manager is
present and the hardware is working correctly.
entry AH 40h
return AH error status: 00h, 80h, 81h, 84h
note 1) upward and downward compatible with both EMS and EEMS 3.2.
this call can be used only after establishing that the EMS driver is in
fact present
2) uses register AX
Function 41h Get Page Frame Segment
LIM Function Call 2
Obtain segment address of the page frame used by the EMM.
entry AH 41h
return AH error status: 00h, 80h, 81h, 84h
BX page frame segment address (error code 0)
note 1) upward and downward compatible with both EMS and EEMS 3.2.
2) uses registers AX & BX
Function 42h Get Unallocated Page Count
LIM Function Call 3
Obtain total number of logical expanded memory pages present in
the system and the number of those pages not already allocated.
entry AH 42h
return AH error status: 00h, 80h, 81h, 84h
BX number of unallocated pages currently availible
DX total number of pages
note 1) upward and downward compatible with both EMS and EEMS 3.2. Note that EMS
and EEMS 3.2 had no mechanism to return the maximum number of handles
that can be allocated by programs. This is handled by the EMS 4.0 new
function 54h/02h.
2) uses registers AX, BX, DX
Function 43h Get Handle and Allocate Memory
LIM Function Call 4
Notifies the EMM that a program will be using extended memory,
obtains a handle, and allocates a certain number of logical pages
of extended memory to be controlled by that handle
entry AH 43h
BX number of 16k logical pages requested (zero OK)
return AH error status: 00h, 80h, 81h, 84h, 85h, 87h, 88h, 89h
DX unique EMM handle (see note 2)
note 1) upward compatible with both EMS and EEMS 3.2; EMS and EEMS 3.2 do not
allow the allocation of zero pages (returns error status 89h). EMS 4.0
does allow zero pages to be requested for a handle, allocating pages
later using function 51h
2) your program must use this EMM handle as a parameter in any function
that requires it. You can use up to 255 handles. The uppermost byte of
the handle will be zero and cannot be used by the application.
3) regs AX & DX are used
Function 44h Map Memory
LIM Function Call 5
Maps one of the logical pages of expanded memory assigned to a
handle onto one of the four physical pages within the EMM's page
frame.
entry AH 44h
AL physical page to be mapped (0-3)
BX the logical page to be mapped (zero through [number of pages
allocated to the EMM handle - 1]). If the logical page number
is 0FFFFh, the physical page specified in AL will be unmapped
(made inaccessible for reading or writing).
DX the EMM handle your program received from Function 4 (Allocate
Pages).
return AH error status: 00h, 80h, 81h, 83h, 84h, 8Ah, 8Bh
note 1) downward compatible with both EMS and EEMS 3.2; EMS and EEMS 3.2 do not
support unmap (logical page 0FFFFh) capability. Also, EEMS 3.2
specified there were precisely four physical pages; EMS 4.0 uses the
subfunctions of function 58h to return the permitted number of physical
pages. This incorporates the functionality of function 69h ("function
42") of EEMS.
2) uses register AX
Function 45h Release Handle and Memory
LIM Function Call 6
Deallocates the logical pages of expanded memory currently
assigned to a handle and then releases the handle itself.
entry AH 45h
DX handle
return AH error status: 00h, 80h, 81h, 83h, 84h, 86h
note 1) upward and downward compatible with both EMS and EEMS 3.2.
2) uses register AX
3) when a handle is deallocated, its name is set to all ASCII nulls
(binary zeros).
4) a program must perform this function before it exits to DOS or no other
programs can use these pages or the EMM handle.
Function 46h Get EMM Version
LIM Function Call 7
Returns the version number of the Expanded Memory Manager software.
entry AH 46h
return AH error status: 00h, 80h, 81h, 84h
AL version number byte (if AL=00h)
binary coded decimal (BCD) format if version byte:
high nibble: integer digit of the version number
low nibble : fractional digit of version number
i.e., version 4.0 is represented like this:
0100 0000
/ \
4 . 0
note 1) upward and downward compatible with both EMS and EEMS 3.2. It appears
that the intended use for this function is to return the version of the
vendor implementation of the expanded memory manager instead of the
specification version.
2) uses register AX
Function 47h Save Mapping Context
LIM Function Call 8
Save the contents of the expanded memory page-mapping registers on
the expanded memory boards, associating those contents with a
specific EMM handle.
entry AH 47h
DX caller's EMM handle (NOT current EMM handle)
return AH error status: 00h, 80h, 81h, 83h, 84h, 8Ch, 8Dh
note 1) upward and downward compatible with both EMS and EEMS 3.2.
2) This only saves the context saved in EMS 3.2 specification; if a driver,
interrupt routine or TSR needs to do more, functions 4Eh (Page Map
functions) or 4Fh (Partial Page Map functions) should be used.
3) no mention is made about the number of save contexts to provide. AST
recommends in their Rampage AT manual one save context for each handle
plus one per possible interrupt (5 + <handles>).
4) uses register AX
5) this function saves the state of the map registers for only the 64K page
frame defined in versions 3.x of the LIM. Since all applications written
to LIM versions 3.x require saving the map register state of only this
64K page frame, saving the entire mapping state for a large number of
mappable pages would be inefficient use of memory. Applications that use
a mappable memory region outside the LIM 3.x page frame should use
functions 15 or 16 to save and restore the state of the map registers.
Function 48h Restore Page Map
LIM Function Call 9
Restores the contents of all expanded memory hardwere page-mapping
registers to the values associated with the given handle by a
previous function 08h (Save Mapping Context).
entry AH 48h
DX caller's EMM handle (NOT current EMM handle)
return AH error status: 00h, 80h, 81h, 83h, 84h, 8Eh
note 1) upward and downward compatible with both EMS and EEMS 3.2.
2) This only restores the context saved in EMS 3.2 specification; if a
driver, interrupt routine or TSR needs to do more, functions 4Eh (Page
Map functions) or 4Fh (Partial Page Map functions) should be used.
3) uses register AX
4) this function saves the state of the map registers for only the 64K page
frame defined in versions 3.x of the LIM. Since all applications written
to LIM versions 3.x require saving the map register state of only this
64K page frame, saving the entire mapping state for a large number of
mappable pages would be inefficient use of memory. Applications that use
a mappable memory region outside the LIM 3.x page frame should use
functions 15 or 16 to save and restore the state of the map registers.
Function 49h Reserved
LIM Function Call 10
This function was used in EMS 3.0, but was no longer documented in
EMS 3.2. It formerly returned the page mapping register I/O port
array. Use of this function is discouraged, and in EMS 4.0 may
conflict with the use of the new functions 16 through 30 (4Fh
through 5Dh) and functions 10 and 11. Functions 10 and 11 are
specific to the hardware on Intel expanded memory boards and may
not work correctly on all vendors' expanded memory boards.
Function 4Ah Reserved
LIM Function Call 11
This function was used in EMS 3.0, but was no longer documented in
EMS 3.2. It was formerly Get Page Translation Array. Use of this
function is discouraged, and in EMS 4.0 may conflict with the use
of the new functions (4Fh through 5Dh).
Function 4Bh Get Number of EMM Handles
LIM Function Call 12
The Get Handle Count function returns the number of open EMM
handles (including the operating system handle 0) in the system.
entry AH 4Bh
return AH error status: 00h, 80h, 81h, 84h
BX handle count (AH=00h) (including the operating system handle
[0]). max 255.
note 1) upward and downward compatible with EMS and EEMS 3.2.
2) uses registers AX and BX
Function 4Ch Get Pages Owned by Handle
LIM Function Call 13
Returns number of logical expanded memory pages allocated to a
specific EMM handle.
entry AH 4Ch
DX handle
return AH error status: 00h, 80h, 81h, 83h, 84h
BX pages allocated to handle, max 2048 because the EMM allows a
maximum of 2048 pages (32M bytes) of expanded memory.
note 1) This function is upward compatible with EMS and EEMS 3.2.
2) programmers should compare the number returned in BX with the maximum
number of pages returned by function 42h register DX, total number of
EMM pages. This should be an UNSIGNED comparison, just in case the spec
writers decide to use 16 bit unsigned numbers (for a maximum space of
one gigabyte) instead of signed numbers (for a maximum space of 512
megabytes). Unsigned comparisons will work properly in either case
3) uses registers AX and BX
Function 4Dh Get Pages for All Handles
LIM Function Call 14
Returns an array containing all active handles and the number of
logical expanded memory pages associated with each handle.
entry AH 4Dh
ES:DI pointer to 1020 byte array to receive information on an array of
structures where a copy of all open EMM handles and the number
of pages allocated to each will be stored.
return AH error status: 00h, 80h, 81h, 84h
BX number of active handles (1-255); array filled with 2-word
entries, consisting of a handle and the number of pages
allocated to that handle. (including the operating system handle
[0]). BX cannot be zero because the operating system handle is
always active and cannot be deallocated.
note 1) NOT COMPATIBLE with EMS or EEMS 3.2, since the new special OS handle
0000h is returned as part of the array. Unless benign use of this
information is used (such as displaying the handle and count of pages
associated with the handle) code should be changed to only work with
handles between 01h and FFh and to specifically ignore handle 00h.
2) The array consists of an array of 255 elements. The first word of each
element is the handle number, the second word contains the number of
pages allocated.
3) There are two types of handles, "standard" and "raw". The specification
does not talk about how this function works when both raw and standard
handles exist in a given system. There is no currently known way to
differentiate between a standard handle and a raw handle in EMS 4.0.
4) uses registers AX and BX
Function 4Eh Get or Set Page Map
LIM Function Call 15
Gets or sets the contents of the EMS page-mapping registers on the
expanded memory boards.
This group of four subfunctions is provided for context switching
required by operating environments and systems. These functions are
upward and downward compatible with both EMS and EEMS 3.2; in
addition, these functions now include the functionality of EEMS
function 6Ah ("function 43") involving all pages.
The size and contents of the map register array will vary from
system to system based on hardware vendor, software vendor, number
of boards and the capacity of each board in the system. Note the
array size can be determined by function 4Eh/03h.
Use these functions (except for 03h) instead of Functions 8 and 9
if you need to save or restore the mapping context but don't want
(or have) to use a handle.
00h Get Page Map
This call saves the mapping context for all mappable memory regions
(conventional and expanded) by copying the contents of the mapping
registers from each expanded memory board to a destination array.
The application must pass a pointer to the destination array.
entry AH 4Eh
AL 00h
ES:DI pointer to target array
return AH error status: 00h, 80h, 81h, 84h, 8Fh
note 1) uses register AX
2) does not use an EMM handle
01h Set Page Map
This call the mapping context for all mappable memory regions
(conventional and expanded) by copying the contents of a source
array into the mapping registers on each expanded memory board in
the system. The application must pass a pointer to the source array.
entry AH 4Eh
AL 01h
DS:SI pointer to source array
return AH error status: 00h, 80h, 81h, 84h, 8Fh, 0A3h
note 1) uses register AX
2) does not use an EMM handle
02h Get & Set Page Map
This call simultaneously saves the current mapping context and
restores a previous mapping context for all mappable memory regions
(both conventional and expanded). It first copies the contents of
the mapping registers from each expanded memory board in the system
into a destination array. Then the subfunction copies the contents
of a source array into the mapping registers on each of the
expanded memory boards.
entry AH 4Eh
AL 02h
DS:SI pointer to source array
ES:DI pointer to target array
return AH error status: 00h, 80h, 81h, 84h, 8Fh, 0A3h
note 1) uses register AX
03h Get Size of Page Map Save Array
entry AH 4Eh
AL 03h
return AH error status: 00h, 80h, 81h, 84h, 8Fh
AL size in bytes of array
note 1) this subfunction does not require an EMM handle
2) uses register AX
FUNCTIONS NEW TO EMS 4.0
Function 4Eh Get or Set Page Map
LIM Function Call 16
entry AH 4Eh
AL 00h if getting mapping registers
01h if setting mapping registers
02h if getting and setting mapping registers at once
03h if getting size of page-mapping array
DS:SI pointer to array holding information (AL=01/02)
ES:DI pointer to array to receive information (AL=00/02)
return AH error status: 00h, 80h, 81h, 84h, 8Fh, 0A3h
note 1) this function was designed to be used by multitasking operating systems
and should not ordinarily be used by appplication software.
Function 4Fh Get/Set Partial Page Map
LIM Function Call 16
These four subfunctions are provided for context switching required
by interrupt routines, operating environments and systems. This set
of functions provides extended functionality over the EEMS function
6Ah (function 43) involving subsets of pages. In EEMS, a subset of
pages could be specified by starting position and number of pages;
in this function a list of pages is specified, which need not be
contiguous.
Interrupt routines can use this function in place of functions 47h
and 48h, especially if the interrupt routine wants to use more than
the standard four physical pages.
AH 4Fh
AL subfunction
00h get partial page map
DS:SI pointer to structure containing list of
segments whose mapping contexts are to be saved
ES:DI pointer to array to receive page map
01h set partial page map
DS:SI pointer to structure containing saved partial
page map
02h get size of partial page map
BX number of mappable segments in the partial map
to be saved
return AH error status (00h): 00h, 80h, 81h, 84h, 8Bh, 8Fh, 0A3h
error status (01h): 00h, 80h, 81h, 84h, 8Fh, 0A3h
error status (02h): 00h, 80h, 81h, 84h, 8Bh, 8Fh
AL size of partial page map for subfunction 02h
DS:SI (call 00h) pointer to array containing the partial mapping
context and any additional information necessary to restore this
context to its original state when the program invokes a Set
subfunction.
note uses register AX
Function 50h Map/Unmap Multiple Pages
LIM Function Call 17
entry AH 50h
AL 00h (by physical page)
01h (by segment number)
CX contains the number of entries in the array. For example, if the
array contained four pages to map or unmap, then CX would
contain 4.
DX handle
DS:SI pointer to an array of structures that contains the information
necessary to map the desired pages.
return AH error status: 00h, 80h, 81h, 83h, 84h, 8Ah, 8Bh, 8Fh
note 1) New function permits multiple logical-to-physical assignments to be made
in a single call.(faster than mapping individual pages)
2) The source map array is an array of word pairs. The first word of a
pair contains the logical page to map (0FFFFh if the physical page is
to be totally unmapped) and the second word of a pair contains the
physical page number (subfunction 00h) or the segment selector
(subfunction 01h) of the physical page in which the logical page shall
be mapped.
3) A map of available physical pages (by physical page number and segment
selectors) can be obtained using function 58h/00h, Get Mappable
Physical Address Array.
4) uses register AX
5) Both mapping and unmapping pages can be done simultaneously.
6) If a request to map or unmap zero pages is made, nothing is done and no
error is returned.
7) Pages can be mapped or unmapped using one of two methods. Both methods
produce identical results.
A) A logical page and a physical page at which the logical page is to
be mapped. This method is an extension of Function 5 (Map Handle
Page).
B) Specifys both a logical page and a corresponding segment address at
which the logical page is to be mapped. While functionally the same
as the first method, it may be easier to use the actual segment
address of a physical page than to use a number which only
represents its location. The memory manager verifies whether the
specified segment address falls on the boundary of a mappable
physical page. The manager then translates the segment address
passed to it into the necessary internal representation to map the
pages.
Function 51h Reallocate pages
LIM Function Call 18
This function allows an application to change the number of logical
pages allocated to an EMM handle.
entry AH 51h
BX number of pages desired at return
DX handle
return AH error status: 00h, 80h, 81h, 83h, 84h, 87h, 88h
BX number of pages now associated with handle
note 1) uses registers AX, BX
2) Logical pages which were originally allocated with Function 4 are called
pages and are 16K bytes long. Logical pages which were allocated with
Function 27 are called raw pages and might not be the same size as pages
allocated with Function 4.
3) If the status returned in BX is not zero, the value in BX is equal to
the number of pages allocated to the handle prior to calling this
function. This information can be used to verify that the request
generated the expected results.
Function 52h Get/Set Handle Attributes
LIM Function Call 19
entry AH 52h
AL subfunction
00h get handle attributes
01h set handle attributes
BL new attribute
00h make handle volatile
01h make handle non-volatile
02h get attribute capability
DX handle
return AH error status: (function 00h) 00h, 80h, 81h, 83h, 84h, 8Fh, 91h
error status: (function 01h) 00h, 80h, 81h, 83h, 84h, 8Fh, 90h,
91h
error status: (function 02h) 00h, 80h, 81h, 84h, 8Fh
AL attribute (for subfunction 00h)
00h handle is volatile
01h handle is nonvolatile
AL attribute capability (for subfunction 02h)
00h only volatile handles supported
01h both volatile and non-volatile supported
note 1) uses register AX
2) A volatile handle attribute instructs the memory manager to deallocate
both the handle and the pages allocated to it after a warm boot. If all
handles have the volatile attribute (default) at warm boot the handle
directory will be empty and all expanded memory will be initialized to
zero immediately after a warm boot.
3) If the handle's attribute has been set to non-volatile, the handle, its
name (if it is assigned one), and the contents of the pages allocated to
the handle are all maintained after a warm boot.
4) Most PCs disable RAM refresh signals for a considerable period during a
warm boot. This can corrupt some of the data in memory boards. Non-
volatile handles should not be used unless it is definitely known that
the EMS board will retain proper function through a warm boot.
5) subfunction 02h can be used to determine whether the memory manager can
support the non-volatile attribute.
6) Currently the only attribute supported is non-volatile handles and
pages, indicated by the least significant bit.
Function 53h Handle Name Functions
LIM Function Call 20
EMS handles may be named. Each name may be any eight characters.
At installation, all handles have their name initialized to ASCII
nulls (binary zeros). There is no restriction on the characters
which may be used in the handle name (ASCII chars 00h through
0FFh). A name of eight nulls (zeroes) is special, and indicates a
handle has no name. Nulls have no special significance, and they
can appear in the middle of a name. The handle name is 64 bits of
binary information to the EMM.
Functions 53h and 54h provide a way of setting and reading the
names associated with a particular handle. Function 53h manipulates
names by number.
When a handle is assigned a name, at least one character in the
name must be a non-null character in order to distinguish it from
a handle without a name.
00h Get Handle Name
This subfunction gets the eight character name currently
assigned to a handle.
The handle name is initialized to ASCII nulls (binary zeros)
three times: when the memory manager is installed, when a handle
is allocated, and when a handle is deallocated.
entry AH 53h
AL 00h
DX handle
ES:DI pointer to 8-byte handle name array into which the name
currently assigned to the handle will be copied.
return AH error status: 00h, 80h, 81h, 83h, 84h, 8Fh
note uses register AX
01h Set Handle Name
This subfunction assigns an eight character name to a handle.
A handle can be renamed at any time by setting the handle's
name to a new value. When a handle is deallocated, its name is
removed (set to ASCII nulls).
entry AH 53h
AL 01h
DX handle
DS:SI pointer to 8-byte handle name array that is to be assigned to
the handle. The handle name must be padded with nulls if the
name is less than eight characters long.
return AH error status: 00h, 80h, 81h, 83h, 84h, 8Fh, 0A1h
note uses register AX
Function 54h Handle Directory Functions
LIM Function Call 21
Function 54h manipulates handles by name.
00h Get Handle Directory
Returns an array which contains all active handles and the names
associated with each.
entry AH 54h
AL 00h
ES:DI pointer to 2550 byte target array
return AH error status: 00h, 80h, 81h, 84h, 8Fh
AL number of active handles
note 1) The name array consists of 10 byte entries; each entry has a word
containing the handle number, followed by the eight byte (64 bit) name.
2) uses register AX
3) The number of bytes required by the target array is:
10 bytes * total number of handles
4) The maximum size of this array is:
(10 bytes/entry) * 255 entries = 2550 bytes.
01h Search for Named Handle
Searches the handle name directory for a handle with a particular
name. If the named handle is found, this subfunction returns the
handle number associated with the name.
entry AH 54h
AL 01h
DS:SI pointer to an 8-byte string that contains the name of the
handle being searched for
return AH error status: 00h, 80h, 81h, 84h, 8Fh, A0h, 0A1h
DX handle number
note 1) uses registers AX and DX
02h Get Total Handles
Returns the total number of handles the EMM supports, including
the operating system handle (handle value 0).
entry AH 54h
AL 02h
return AH error status: 00h, 80h, 81h, 84h, 8Fh
BX total number of handles availible
note 1) This is NOT the current number of handles defined, but the maximum
number of handles that can be supported in the current environment.
2) uses registers AX and BX
Function 55h Alter Page Map and Jump (cross page branch)
LIM Function Call 22
Alters the memory mapping context and transfers control to the
specified address. Analogous to the FAR JUMP in the 8086 family
architecture. The memory mapping context which existed before
calling function is lost.
entry AH 55h
AL 00h physical page numbers provided by caller
01h segment addresses provided by caller
DX handle
DS:SI pointer to structure containing map and jump address
return AH error status: 00h, 80h, 81h, 83h, 84h, 8Ah, 8Bh, 8Fh
note 1) Flags and all registers except AX are preserved across the jump.
2) uses register AX
3) Values in registers which don't contain required parameters maintain the
values across the jump. The values in registers (with the exception of
AX) and the flag state at the beginning of the function are still in the
registers and flags when the target address is reached.
4) Mapping no pages and jumping is not considered an error. If a request to
map zero pages and jump is made, control is transferred to the target
address, and this function performs a far jump.
Function 56h Alter Page Map and Call (cross page call)
LIM Function Call 23
00h and 01h
This subfunction saves the current memory mapping context,
alters the specified memory mapping context, and transfers
control to the specified address.
entry AH 56h
AL 00h physical page numbers provided by caller
01h segment addresses provided by caller
DS:SI pointer to structure containing page map and call address
DX handle
return AH error status: 00h, 80h, 81h, 83h, 84h, 8Ah, 8Bh, 8Fh
note 1) Flags and all registers except AX are preserved to the called routine.
On return, flags and all registers except AX are preserved; AL is set to
zero and AX is undefined.
2) uses register AX
3) Values in registers which don't contain required parameters maintain
the values across the call. The values in registers (with the exception
of AX) and the flag state at the beginning of the function are still in
the registers and flags when the target address is reached.
4) Developers using this subfunction must make allowances for the
additional stack space this subfunction will use.
02h Get Page Map Stack Space Size
Since the Alter Page Map & Call function pushes additional
information onto the stack, this subfunction returns the number of
bytes of stack space the function requires.
entry AH 56h
AL 02h
return: BX number of bytes of stack used per call
AH error status: 00h, 80h, 81h, 84h, 8Fh
note 1) if successful, the target address is called. Use a RETF to return and
restore mapping context
2) uses registers AX, BX
Function 57h Move/Exchange Memory Region
LIM Function Call 24
00h Move Memory Region
Moves data between two memory areas. Includes moves between paged
and non-paged areas, or between two different paged areas.
entry AH 57h
AL 00h
SI offset to request block
DS segment selector to request block
return AH error status: 00h, 80h, 81h, 83h, 84h, 8Ah, 8Fh, 92h, 93h, 94h,
95h, 96h, 98h, 0A2h
note 1) uses register AX
01h Exchange Memory Region
Exchanges data between two memory areas. Includes exchanges between
paged and non-paged areas, or between two different paged areas.
entry AH 57h
AL 01h
DS:SI pointer to the data structure which contains the source and
destination information for the exchange.
return AH error status: 00h, 80h, 81h, 83h, 84h, 8Ah, 8Fh, 93h, 94h, 95h,
96h, 97h, 98h, 0A2h
note 1) The request block is a structure with the following format:
dword region length in bytes
byte 0=source in conventional memory
1=source in expanded memory
word source handle
word source offset in page or selector
word source logical page (expanded) or selector (conventional)
byte 0=target in conventional memory
1=target in expanded memory
word target handle
word target offset in page or selector
word target logical page (expanded) or selector (conventional)
2) Expanded memory allocated to a handle is considered to be a linear
array, starting from logical page 0 and progressing through logical page
1, 2, ... n, n+1, ... up to the last logical page in the handle.
3) uses register AX
Function 58h Mappable Physical Address Array
LIM Function Call 25
These functions let you obtain a complete map of the way physical
memory is laid out in a vendor independent manner. This is a
functional equivalent of EEMS function 68h ("function 41"). EEMS
function 60h ("function 33") is a subset call of 68h.
00h Get Array
Returns an array containing the segment address and physical page
number for each mappable physical page in a system. This array
provides a cross reference between physical page numbers and the
actual segment addresses for each mappable page in the system.
entry AH 58h
AL 00h
ES:DI pointer to target array
return AH error status: 00h, 80h, 81h, 84h, 8Fh
CX entries in target array
note 1) The information returned is in an array composed of word pairs. The
first word is the physical page's segment selector, the second word the
physical page number. Note that values are not necessarily returned in a
particular order, either ascending/decending segment selector values or
as ascending/decending physical page number.
2) For compatibility with earlier EMS specifications, physical page zero
contains the segment selector value returned by function 41h, and
physical pages 1, 2 and 3 return segment selector values that corrospond
to the physical 16 KB blocks immediately following physical page zero.
3) uses registers AX and CX
4) The array is sorted in ascending segment order. This does not mean that
the physical page numbers associated with the segment addresses are
also in ascending order.
01h Get Physical Page Address Array Entries.
Returns a word which represents the number of entries in the
array returned by the previous subfunction. This number also
indicates the number of mappable physical pages in a system.
entry AH 58h
AL 01h
return AH error status: 00h, 80h, 81h, 84h, 8Fh
CX number of entries returned by 58h/00h
note 1) multiply CX by 4 for the byte count.
2) uses registers AX and CX
Function 59h Get Expanded Memory Hardware Information
LIM Function Call 26
These functions return information specific to a given hardware
implementation and to use of raw pages as opposed to standard
pages. The intent is that only operating system code ever need use
these functions.
00h Get EMS Hardware Info
Returns an array containing expanded memory hardware configuration
information for use by an operating system.
entry AH 59h
AL 00h
ES:DI pointer to 10 byte target array
The target array has the following format:
word: raw page size in paragraphs (multiples of 16 bytes)
word: number of alternate register sets
word: size of page maps (function 4Eh [15])
word: number of alternate registers sets for DMA
word: DMA operation -- see full specification
return AH error status: 00h, 80h, 81h, 84h, 8Fh, 0A4h
note 1) uses register AX
2) This function is for use by operating systems only.
3) This function can be disabled at any time by the operating system.
01h Get Unallocated Raw Page Count
Returns the number of unallocated non-standard length mappable
pages as well as the total number of non-standard length mappable
pages of expanded memory
entry AH 59h
AL 01h
return AH error status: 00h, 80h, 81h, 84h, 8Fh
BX unallocated raw pages availible for use
DX total raw 16k pages of expanded memory
note 1) uses registers AX, BX, CX
2) An expanded memory page which is a sub-multiple of 16K is termed a raw
page. An operating system may deal with mappable physical page sizes
which are sub-multiples of 16K bytes.
3) If the expanded memory board supplies pages in exact multiples of 16K
bytes, the number of pages this function returns is identical to the
number Function 3 (Get Unallocated Page Count) returns. In this case,
there is no difference between a page and a raw page.
Function 5Ah Allocate Raw Pages
LIM Function Call 27
Allocates the number of nonstandard size pages that the operating
system requests and assigns a unique EMM handle to these pages.
entry AH 5Ah
AL 00h allocate standard pages
01h allocate raw pages
BX number of pages to allocate
return AH error status: 00h, 80h, 81h, 84h, 85h, 87h, 88h
DX unique raw EMM handle (1-255)
note 1) it is intended this call be used only by operating systems
2) uses registers AX and DX
3) For all functions using the raw handle returned in DX, the length of
the physical and logical pages allocated to it are some nonstandard
length (that is, not 16K bytes).
4) this call is primarily for use by operating systems or EMM drivers
supporting hardware with a nonstandard EMS page size.
Function 5Bh Alternate Map Register Set - DMA Registers
LIM Function Call 28
entry AH 00h Get Alternate Map Register Set
01h Set Alternate Map Register Set
BL new alternate map register set number
ES:DI pointer to map register context save area if
BL=0
02h Get Alternate Map Save Array Size
03h Allocate Alternate Map Register Set
04h Deallocate Alternate Map Register Set
BL number of alternate map register set
05h Allocate DMA Register Set
06h Enable DMA on Alternate Map Register Set
BL DMA register set number
DL DMA channel number
07h Disable DMA on Alternate Map Register Set
BL DMA register set number
08h Deallocate DMA Register Set
BL DMA register set number
return AH status: 00h, 02h 00h, 80h, 84h, 81h, 8Fh, 0A4h
01h 00h, 80h, 81h, 84h, 8Fh, 9Ah, 9Ch, 9Dh,
0A3h, 0A4h
03h, 05h 00h 80h 81h 84h, 8Fh, 9Bh, 0A4h
04h 00h, 80h, 81h, 84h, 8Fh, 9Ch, 9Dh, 0A4h
06h, 07h 00h, 80h, 81h, 84h, 8Fh, 9Ah, 9Ch, 9Dh, 9Eh,
9Fh, 0A4h
BL current active alternate map register set number if nonzero
(AL=0)
BL number of alternate map register set; zero if not supported
(AL=3)
DX array size in bytes (subfunction 02h)
ES:DI pointer to a map register context save area if BL=0 (AL=0)
note 1) this call is for use by operating systems only, and can be enabled
or disabled at any time by the operating system
2) This set of functions performs the same functions at EEMS function 6Ah
subfunctions 04h and 05h ("function 43").
3) 00h uses registers AX, BX, ES:DI
01h uses register AX
02h uses registers AX and DX
03h uses registers AX and BX
04h uses register AX
05h uses registers AX, BX
06h uses register AX
07h uses register AX
Function 5Ch Prepare EMS Hardware for Warm Boot
LIM Function Call 29
Prepares the EMM hardware for a warm boot.
entry AH 5Ch
return AH error status: 00h, 80h, 81h, 84h
note 1) uses register AX
2) this function assumes that the next operation that the operating system
performs is a warm boot of the system.
3) in general, this function will affect the current mapping context, the
alternate register set in use, and any other expanded memory hardware
dependencies which need to be initialized at boot time.
4) if an application decides to map memory below 640K, the application must
trap all possible conditions leading to a warm boot and invoke this
function before performing the warm boot itself.
Function 5Dh Enable/Disable OS Function Set Functions
LIM Function Call 30
Lets the OS allow other programs or device drivers to use the OS
specific functions. This capability is provided only for an OS
which manages regions of mappable conventional memory and cannot
permit programs to use any of the functions which affect that
memory, but must be able to use these functions itself.
entry AH 5Dh
AL 00h enable OS function set
01h disable OS function set
02h return access key (resets memory manager, returns access
key at next invocation)
BX,CX access key returned by first invocation
return BX,CX access key, returned only on first invocation of function
AH status 00h, 80h, 81h, 84h, 8Fh, 0A4h
note 1) this function is for use by operating systems only. The operating system
can disable this function at any time.
2) 00h uses registers AX, BX, CX
01h uses registers AX, BX, CX
02h uses register AX
3) 00h, 01h: The OS/E (Operating System/Environment) functions these
subfunctions affect are:
Function 26. Get Expanded Memory Hardware Information.
Function 28. Alternate Map Register Sets.
Function 30. Enable/Disable Operating System Functions.
Function 5Eh Unknown
LIM Function call (not defined under LIM)
Function 5Fh Unknown
LIM Function call (not defined under LIM)
Function 60h EEMS - Get Physical Window Array
LIM Function call (not defined under LIM)
entry AH 60h
ES:DI pointer to buffer
return AH status
AL number of entries
buffer at ES:DI filled
Function 61h Generic Accelerator Card Support
LIM Function Call 34
Contact AST Research for a copy of the Generic Accelerator Card
Driver (GACD) Specification
note Can be used by accelerator card manufacturer to flush RAM cache,
ensuring that the cache accurately reflects what the processor would
see without the cache.
Function 68h EEMS - Get Addresses of All Page Frames in System
LIM Function Call (not defined under LIM)
entry AH 68h
ES:DI pointer to buffer
return AH status
AL number of entries
buffer at ES:DI filled
note Equivalent to LIM 4.0 function 58h
Function 69h EEMS - Map Page Into Frame
LIM Function Call (not defined under LIM)
entry AH 69h
AL frame number
BX page number
DX handle
return AH status
note Similar to EMS function 44h
Function 6Ah EEMS - Page Mapping
LIM Function Call (not defined under LIM)
entry AH 6Ah
AL 00h save partial page map
CH first page frame
CL number of frames
ES:DI pointer to buffer which is to be filled
01h restore partial page map
CH first page frame
CL number of frames
DI:SI pointer to previously saved page map
02h save and restore partial page map
CH first page frame
CL number of frames
ES:DI buffer for current page map
DI:SI new page map
03h get size of save array
CH first page frame
CL number of frames
return AL size of array in bytes
04h switch to standard map register setting
05h switch to alternate map register setting
06h deallocate pages mapped to frames in conventional memory
CH first page frame
CL number of frames
return AH status
note Similar to LIM function 4Eh, except that a subrange of pages can
be specified
EXPANDED MEMORY MANAGER ERROR CODES
EMM error codes are returned in AH after a call to the EMM (int 67h).
code meaning
00h function successful
80h internal error in EMM software (possibly corrupted driver)
81h hardware malfunction
82h EMM busy (dropped in EEMS 3.2)
83h invalid EMM handle
84h function requested not defined - unknown function code in AH.
85h no more EMM handles availible
86h error in save or restore of mapping context
87h more pages requested than exist
88h allocation request specified more logical pages than currently
availible in system (request does not exceed actual physical number of
pages, but some are already allocated to other handles); no pages
allocated
89h zero pages; cannot be allocated (dropped in EMS 4.0)
8Ah logical page requested to be mapped outside range of logical pages
assigned to handle
8Bh illegal page number in mapping request (valid numbers are 0 to 3)
8Ch page-mapping hardware state save area full
8Dh save of mapping context failed; save area already contains context
associated with page handle
8Eh retore of mapping context failed; save area does not contain context
for requested handle
8Fh subfunction parameter not defined (unknown function)
LIM 4.0 extended error codes:
90h attribute type undefined
91h warm boot data save not implemented
92h move overlaps memory
93h move/exchange larger than allocated region
94h conventional/expanded regions overlap
95h logical page offset outside of logical page
96h region larger than 1 MB
97h exchange source/destination overlap
98h source/destination undefined or not supported
99h (no status assigned)
9Ah alternate map register sets supported, specified set is not
9Bh all alternate map & DMA register sets allocated
9Ch alternate map & DMA register sets not supported
9Dh alternate map register or DMA set not defined, allocated or is currently
defined set
9Eh dedicated DMA channels not supported
9Fh dedicated DMA channels supported; specifed channel is not
0A0h named handle could not be found
0A1h handle name already exists
0A2h move/exchange wraps around 1 MB boundry
0A3h data structure contains corrupted data
0A4h access denied
