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ms-dos-3.3/PROGREF/1E_CALLS.A

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_ _ | | _ _
_ ______________
Get Verify State (Function 54H)
Call:
AH = 54H
Return:
AL
0 = No verify after write
1 = Verify after write
Comments:
Function 54H checks whether MS-DOS verifies write operations to disk
files. The status returns in AL: 0 if verify is off, 1 if verify is on.
You can set the verify status with Function 2EH (Set/Reset Verify Flag).
Macro Definition:
get_verify macro
mov ah,54H
int 21H
endm
Example:
The following program displays the verify status:
message db "Verify ","$"
on db "on.",0DH,0AH,"$"
off db "off.",0DH,0AH,"$"
;
begin: display message ;See Function 09H
get_verify ;THIS FUNCTION
cmp al,0 ;Is flag off?
1
_ _ | | _ _
_ _ | | _ _
_ ______________
jg ver_on ;No, it's on
display off ;See Function 09H
jmp return ;Go home
ver_on: display on ;See Function 09H
2
_ _ | | _ _
_ _ | | _ _
_ ______________
Change Directory Entry (Function 56H)
Call:
AH = 56H
DS:DX
Pointer to pathname
ES:DI
Pointer to second pathname
Return:
Carry set:
AX
2 = File not found
3 = Path not found
5 = Access denied
17 = Not same device
Carry not set:
No error
Comments:
Function 56H renames a file by changing its directory entry. DX must
contain the offset (from the segment address in DS) of an ASCIZ string that
contains the pathname of the entry to be changed. DI must contain the
offset (from the segment address in ES) of an ASCIZ string that contains a
second pathname to which the first is to be changed.
If a directory entry for the first pathname exists, it is changed to the
second pathname.
The directory paths need not be the same; in effect, you can move the file
to another directory by renaming it. You cannot use this function request
to copy a file to another drive, however; if the second pathname specifies a
drive, the first pathname must specify or default to the same drive.
You cannot use this function request to rename an open file, a hidden file,
a system file, or a subdirectory, because it may corrupt your disk.
If there is an error, the carry flag (CF) is set and the error code returns in
AX.
Code
Meaning
_ ________________________________________________________________
2 One of files is invalid or not open
3
_ _ | | _ _
_ _ | | _ _
_ ______________
3 One of paths is invalid or not open
5 First pathname specifies a directory, second pathname specifies an
existing file; or second directory entry could not be opened
17 Both files not on the same drive
Macro Definition:
rename_file macro old_path,new_path
mov dx,offset old_path
push ds
pop es
mov di,offset new_path
mov ah,56H
int 21H
endm
Example:
The following program prompts for the name of a file and a new name,
then renames the file.
prompt1 db "Filename: $"
prompt2 db "New name: $"
old_path db 15,?,15 dup (?)
new_path db 15,?,15 dup (?)
crlf db 0DH,0AH,"$"
;
begin: display prompt1 ;See Function 09H
get_string 15,old_path ;See Function 0AH
xor bx,bx ;To use BL as index
mov bl,old_path[1] ;Get string length
mov old_path[bx+2],0 ;Make an ASCIZ string
display crlf ;See Function 09H
display prompt2 ;See Function 09H
get_string 15,new_path ;See Function 0AH
xor bx,bx ;To use BL as index
mov bl,new_path[1] ;Get string length
mov new_path[bx+2],0 ;Make an ASCIZ string
display crlf ;See Function 09H
rename_file old_path[2],new_path[2];THIS FUNCTION
jc error_rename ;Routine not shown
4
_ _ | | _ _
_ _ | | _ _
_ ______________
Get/Set Date/Time of File(Function 57H)
Call:
AH = 57H
AL = Function code
0 = Get date and time
1 = Set date and time
BX
Handle
CX (if AL = 1)
Time to be set
DX (if AL = 1)
Date to be set
Return:
Carry set:
AX
1 = Invalid function
6 = Invalid handle
Carry not set:
CX (if AL = 0)
Time file last written
DX (if AL = 0)
Date file last written
Comments:
Function 57H gets or sets the time and date when a file was last written.
To get the time and date, AL must contain 0; the time and date return in
CX and DX. To set the time and date, AL must contain 1; CX and DX
must contain the time and date. BX must contain the file handle. The time
and date are in the form described in "Fields of the FCB" in Section 1.9.1.
If there is an error, the carry flag (CF) is set and the error code returns in
AX:
Code
Meaning
_ ________________________________________________________________
1 AL not 0 or 1
6 Handle in BX invalid or not open
5
_ _ | | _ _
_ _ | | _ _
_ ______________
Macro Definition:
get_set_date_time macro handle,action,time,date
mov bx,handle
mov al,action
mov cx,word ptr time
mov dx,word ptr date
mov ah,57H
int 21H
endm
Example:
The following program gets the date of a file named report.asm in the
current directory on the disk in drive B, increments the day, increments
the month and/or year, if necessary, and sets the new date of the file.
month db 31,28,31,30,31,30,31,31,30,31,30,31
path db "b:report.asm",0
handle dw ?
time db 2 dup (?)
date db 2 dup (?)
;
begin: open_handle path,0 ;See Function 3DH
mov handle,ax ;Save handle
get_set_date_time handle,0,time,date ;THIS FUNCTION
jc error_time ;Routine not shown
mov word ptr time,cx ;Save time
mov word ptr date,dx ;Save date
convert_date date[-24] ;See end of chapter
inc dh ;Increment day
xor bx,bx ;To use BL as index
mov bl,dl ;Get month
cmp dh,month[bx-1] ;Past last day?
jle month_ok ;No, go home
mov dh,1 ;Yes, set day to 1
inc dl ;Increment month
cmp dl,12 ;Is it past December?
jle month_ok ;No, go home
mov dl,1 ;Yes, set month to 1
inc cx ;Increment year
month_ok: pack_date date ;See end of chapter
get_set_date_time handle,1,time,date ;THIS FUNCTION
jc error_time ;Routine not shown
close_handle handle ;See Function 3EH
jc error_close ;Routine not shown
6
_ _ | | _ _
_ _ | | _ _
_ ______________
Get/Set Allocation Strategy (Function 58H)
Call:
AH = 58H
AL
0 = Get strategy
1 = Set strategy
BX (AL = 1)
0 = First fit
1 = Best fit
2 = Last fit
Return:
Carry set:
AX
1 = Invalid function code
Carry not set:
AX (AL = 0)
0 = First fit
1 = Best fit
2 = Last fit
Comments:
Function 58H gets or sets the strategy that MS-DOS uses to allocate
memory when a process requests it. If AL contains 0, the strategy is
returned in AX. If AL contains 1, BX must contain the strategy. The three
possible strategies are:
7
_ _ | | _ _
_ _ | | _ _
_ ______________
Table 0.1
Allocation Strategy
_ _________________________________________________________________________
Value Name Description
_ _________________________________________________________________________
0 First fit
MS-DOS starts searching at the lowest available block and
allocates the first block it finds (the allocated memory is the
lowest available block). This is the default strategy.
1 Best fit
MS-DOS searches each available block and allocates the
smallest available block that satisfies the request.
2 Last fit
MS-DOS starts searching at the highest available block and
allocates the first block it finds (the allocated memory is the
highest available block).
_ _________________________________________________________________________
You can use this function request to control how MS-DOS uses its memory
resources.
If there is an error, the carry flag (CF) is set and the error code returns in
AX:
Code
Meaning
_ ________________________________________________________________
1 AL doesn't contain 0 or 1, or BX doesn't contain 0, 1, or 2.
Macro Definition:
alloc_strat macro code,strategy
mov bx,strategy
mov al,code
mov ah,58H
int 21H
endm
Example:
The following program displays the memory-allocation strategy in effect,
then forces subsequent memory allocations to the top of memory by set-
ting the strategy to last fit (code 2).
get equ 0
set equ 1
stdout equ 1
last_fit equ 2
;
first db "First fit ",0DH,0AH
best db "Best fit ",0DH,0AH
last db "Last fit ",0DH,0AH
8
_ _ | | _ _
_ _ | | _ _
_ ______________
;
begin: alloc_strat get ;THIS FUNCTION
jc alloc_error ;routine not shown
mov cl,4 ;multiply code by 16
shl ax,cl ;to calculate offset
mov dx,offset first ;point to first msg
add dx,ax ;add to base address
mov bx,stdout ;handle for write
mov cs,16 ;write 16 bytes
mov ah,40h ;write handle
int 21H ;system call
; jc write_error ;routine not shown
alloc_strat set,last_fit ;THIS FUNCTION
; jc alloc_error ;routine not shown
9
_ _ | | _ _
_ _ | | _ _
_ ______________
Get Extended Error (Function 59H)
Call:
AH = 59H
BX = 0
Return:
AX
Extended-error code
BH
Error class (see text)
BL
Suggested action (see text)
CH
Locus (see text)
CL, DX, SI, DI, DS, ES destroyed
Comments:
Function 59H retrieves an extended-error code for the preceding system
call. Each release of MS-DOS extends the error codes to cover new capabil-
ities. These new codes are mapped to a simpler set of error codes based on
MS-DOS Version 2.0, so that existing programs can continue to operate
correctly. Note that this call destroys all registers except CS:IP and
SS:SP.
A user-written Interrupt 24H (Critical-Error Handler Address) can use
Function 59H to get detailed information about the error that caused the
interrupt to be issued.
The input BX is a version indicator that specifies for what level of error
handling the application was written. The current level is 0.
The extended-error code consists of four separate codes in AX, BH, BL,
and CH that give as much detail as possible about the error and suggest
how the issuing program should respond.
10
_ _ | | _ _
_ _ | | _ _
_ ______________
BH\(emError Class
BH returns a code that describes the class of error that occurred:
Class
Description
_ ________________________________________________________________
1 Out of a resource, such as storage or channels
2 Not an error, but a temporary situation (such as a locked region in
a file) that is expected to end
3 Authorization problem
4 Internal error in system software
5 Hardware failure
6 System software failure not the fault of the active process (could be
caused by missing or incorrect configuration files, for example)
7 Application program error
8 File or item not found
9 File or item of invalid format or type, or that is otherwise invalid
or unsuitable
10 Interlocked file or item
11 Wrong disk in drive, bad spot on disk, or other problem with
storage medium
12 Other error
11
_ _ | | _ _
_ _ | | _ _
_ ______________
BL\(emSuggested Action
BL returns a code that suggests how the issuing program can respond to
the error:
Action
Description
_ ________________________________________________________________
1 Retry, then prompt user
2 Retry after a Pause
3 If user entered data such as drive letter or filename, prompt for it
again
4 Terminate with cleanup
5 Terminate immediately; system so unhealthy that program should
exit as soon as possible without taking time to close files and
update indexes
6 Error is informational
7 Prompt user to perform some action, such as changing disks, then
retry operation
CH\(emLocus
CH returns a code that provides additional information to help locate the
area involved in the failure. This code is particularly useful for hardware
failures (BH=5).
Locus
Description
_ ________________________________________________________________
1 Unknown
2 Related to random-access block devices, such as a disk drive
3 Related to Network
4 Related to serial-access character devices, such as a printer
5 Related to random-access memory
Your programs should handle errors by noting the error return from the
original system call and then issuing this system call to get the extended-
error code. If the program does not recognize the extended-error code, it
should respond to the original error code.
This system call is available during Interrupt 24H and may be used to
return network-related errors.
12
_ _ | | _ _
_ _ | | _ _
_ ______________
Macro Definition:
get_error macro
mov ah, 59H
int 21H
endm
Example:
Since this function request provides such detailed information, a general
example is not practical. User programs can interpret the various codes to
determine what sort of messages or prompts should be displayed, what
action to take, and whether to terminate the program if recovery from the
errors isn't possible.
13
_ _ | | _ _
_ _ | | _ _
_ ______________
Create Temporary File (Function 5AH)
Call:
AH = 5AH
CX
Attribute
DS:DX
Pointer to pathname, followed by a
byte of 0, and then by 13 bytes of memory
Return:
Carry set:
AX
2 = File not found
3 = Path not found
4 = Too many open files
5 = Access denied
Carry not set:
AX
Handle
Comments:
Function 5AH creates a file with a unique name. DX must contain the
offset (from the segment address in DS) of an ASCIZ string that specifies a
pathname and 13 bytes of memory (to hold the filename). CX must con-
tain the attribute to be assigned to the file, as described in Section 1.5.5,
"File Attributes," earlier in this chapter.
MS-DOS creates a unique filename and appends it to the pathname
pointed to by DS:DX, creates the file and opens it in compatibility mode,
then returns the file handle in AX. A program that needs a temporary file
should use this function request to avoid name conflicts.
When the creating process exits, MS-DOS does not automatically delete a
file created with Function 5AH. When you no longer need the file you
should delete it.
If there is an error, the carry flag (CF) is set and the error code returns in
AX:
Code
Meaning
_ ________________________________________________________________
2 File is invalid or doesn't exist
14
_ _ | | _ _
_ _ | | _ _
_ ______________
3 Directory pointed to by DS:DX is invalid or doesn't exist
4 Too many open files (no handle available)
5 Access denied
Macro Definition:
create_temp macro pathname,attrib
mov cx,attrib
mov dx,offset pathname
mov ah,5AH
int 21H
endm
15
_ _ | | _ _
_ _ | | _ _
_ ______________
Example:
The following program creates a temporary file in the directory named
\wp\docs, copies a file named textfile.asc that is in the current directory
into the temporary file, and then closes both files.
stdout equ 1
;
file db "TEXTFILE.ASC",0
path db "\WP\DOCS",0
temp db 13 dup (0)
open_msg db " opened.",0DH,0AH
crl_msg db " created.",0DH,0AH
rd_msg db " read into buffer.",0DH,0AH
wr_msg db "Buffer written to "
cl_msg db "Files closed.",0DH,0AH
crlf db 0DH,0AH
handle1 dw ?
handle2 dw ?
buffer db 512 dup (?)
;
begin: open_handle file,0 ;see Function 3DH
jc open_error ;routine not shown
mov handle1,ax ;save handle
write_handle stdout,file,12 ;see Function 40H
jc write_error ;routine not shown
write_handle stdout,open_msg,10 ;see Function 40H
jc write_error ;routine not shown
create_temp path,0 ;THIS FUNCTION
jc create_error ;routine not shown
mov handle2,ax ;save handle
write_handle stdout,path,8 ;see Function 40H
jc write_error ;routine not shown
display_char "
write_handle stdout,temp,12 ;see Function 40H
jc write_error ;routine not shown
write_handle stdout,crl_msg,11 ;See Function 40H
jc write_error ;routine not shown
read_handle handle1,buffer,512 ;see Function 3FH
jc read_error ;routine not shown
write_handle stdout,file,12 ;see Function 40H
jc write_error ;routine not shown
write_handle stdout,rd_msg,20 ;see Function 40H
jc write_error ;routine not shown
write_handle handle2,buffer,512 ;see Function 40H
jc write_error ;routine not shown
write_handle stdout,wr_msg,18 ;see Function 40H
jc write_error ;routine not shown
write_handle stdout,temp,12 ;see Function 40H
jc write_error ;routine not shown
write_handle stdout,crlf,2 ;see Function 40H
jc write_error ;routine not shown
close_handle handle1 ;see Function 3EH
jc close_error ;routine not shown
close_handle handle2 ;see Function 3EH
16
_ _ | | _ _
_ _ | | _ _
_ ______________
jc close_error ;routine not shown
write_handle stdout,cl_msg,15 ;see Function 40H
jc write_error ;routine not shown
17
_ _ | | _ _
_ _ | | _ _
_ ______________
Create New File (Function 5BH)
Call:
AH = 5BH
CX
Attribute
DS:DX
Pointer to pathname
Return:
Carry set:
AX
2 = File not found
3 = Path not found
4 = Too many open files
5 = Access denied
80 = File already exists
Carry not set:
AX
Handle
Comments:
Function 5BH creates a new file. DX must contain the offset (from the seg-
ment address in DS) of an ASCIZ string that specifies a pathname. CX con-
tains the attribute to be assigned to the file, as described in Section 1.5.5,
"File Attributes."
If there is no existing file with the same filename, MS-DOS creates the file,
opens it in compatibility mode, and returns the file handle in AX.
This function request fails if the specified file exists, unlike Function 3CH
(Create Handle), which, under the same circumstances, truncates the file
to a length of 0. In a multitasking system, the existence of a file is used as
a semaphore; you can use this system call as a test-and-set semaphore.
18
_ _ | | _ _
_ _ | | _ _
_ ______________
If there is an error, the carry flag (CF) is set and the error code returns in
AX:
Code
Meaning
_ ________________________________________________________________
2 File is invalid or doesn't exist
3 Directory pointed to by DS:DX is invalid or doesn't exist
4 No free handles are available in the current process, or internal
system tables are full
5 Access denied
80 File with the same specification pointed to by DS:DX already exists
Macro Definition:
create_new macro pathname,attrib
mov cx, attrib
mov dx, offset pathname
mov ah, 5BH
int 21H
endm
Example:
The following program attempts to create a new file named report.asm in
the current directory. If the file already exists, the program displays an
error message and returns to MS-DOS. If the file doesn't exist and there
are no other errors, the program saves the handle and continues process-
ing.
err_msg db "FILE ALREADY EXISTS",0DH,0AH,"$"
path db "report.asm",0
handle dw ?
;
begin: create_new path,0 ;THIS FUNCTION
jnc continue ;further processing
cmp ax,80 ;file already exist?
jne error ;routine not shown
display err_msg ;see Function 09H
jmp return ;return to MS-DOS
continue: mov handle,ax ;save handle
;
; (further processing here)
19
_ _ | | _ _
_ _ | | _ _
_ ______________
Lock (Function 5CH, Code 00H)
Call:
AH = 5CH
AL = 00H
BX
Handle
CX:DX
Offset of region to be locked
SI:DI
Length of region to be locked
Return:
Carry set:
AX
1 = Invalid function code
6 = Invalid handle
33 = Lock violation
36 = Sharing buffer exceeded
Carry not set:
No error
Comments:
Function 5CH, Code 00H, denies all access (read or write) by any other
process to the specified region of the file. BX must contain the handle of
the file that contains the region to be locked. CX:DX (a four-byte integer)
must contain the offset in the file of the beginning of the region. SI:DI (a
four-byte integer) must contain the length of the region.
If another process attempts to use (read or write) a locked region, MS-DOS
retries three times; if the retries fail, MS-DOS issues Interrupt 24H for the
requesting process. You can change the number of retries with Function
44H, Code 0BH (IOCtl Retry).
The locked region can be anywhere in the file. For instance, locking
beyond the end of the file is not an error. A region should be locked for
only a brief period, so if it is locked for more than ten seconds you should
consider it to be an error.
Function 45H (Duplicate File Handle) and Function 46H (Force Duplicate
File Handle) duplicate access to any locked region. Passing an open file to
a child process with Function 4BH, Code 00H (Load and Execute Program)
does not duplicate access to locked regions.
_ ________________________________________________________________
20
_ _ | | _ _
_ _ | | _ _
_ ______________
Warning
If a program closes a file that contains a locked region or terminates
with an open file that contains a locked region, the result is undefined.
_ ________________________________________________________________
Programs that might be terminated by Interrupt 23H (CONTROL-C Handler
Address) or Interrupt 24H (Critical-Error-Handler Address) should trap
these interrupts and unlock any locked regions before exiting.
Programs should not rely on being denied access to a locked region. A
program can determine the status of a region (locked or unlocked) by
attempting to lock the region and examining the error code.
If there is an error, the carry flag (CF) is set and the error code is returned
in AX:
Code
Meaning
_ ________________________________________________________________
1 File sharing must be loaded to use this function request.
6 The handle in BX is not a valid, open handle.
33 All or part of the specified region is already locked.
36 There is no more room for lock entries in the buffer. Refer to the
share command in the MS-DOS User's Reference for information
on allocating more lock entries.
Macro Definition:
lock macro handle,start,bytes
mov bx, handle
mov cx, word ptr start
mov dx, word ptr start+2
mov si, word ptr bytes
mov di, word ptr bytes+2
mov al, 0
mov ah, 5CH
int 21H
endm
21
_ _ | | _ _
_ _ | | _ _
_ ______________
Example:
The following program opens a file named finalrpt in "Deny None" mode
and locks two portions of it: the first 128 bytes and bytes 1024 through
5119. After some (unspecified) processing, it unlocks the same portions and
closes the file.
stdout equ 1
;
start1 dd 0
lgth1 dd 128
start2 dd 1023
lgth2 dd 4096
file db "FINALRPT",0
op_msg db " opened.",0DH,0AH
11_msg db "First 128 bytes locked.",0DH,0AH
12_msg db "Bytes 1024-5119 locked.",0DH,0AH
u1_msg db "First 128 bytes unlocked.",0DH,0AH
u2_msg db "Bytes 1024-5119 unlocked.",0DH,0AH
cl_msg db " closed.:,0DH,0AH
handle dw ?
;
begin: open_handle file,01000010b ;see Function 3DH
jc open_error ;routine not shown
write_handle stdout,file,8 ;see Function 40H
jc write_error ;routine not shown
write_handle stdout,op_msg,10 ;see Function 40H
jc write_error ;routine not shown
mov handle,ax ;save handle
lock handle,start1,lgth1 ;THIS FUNCTION
jc lock_error ;routine not shown
write_handle stdout,11_msg,25 ;see Function 40H
jc write_error ;routine not shown
lock handle,start2,lgth2 ;THIS FUNCTION
jc lock_error ;routine not shown
write_handle stdout,12_msg,25 ;see Function 40H
jc write_error ;routine not shown
;
; ( Further processing here )
;
unlock handle,start1,lgth1 ;See Function 5C01H
jc unlock_error ;routine not shown
write_handle stdout,ul_msg,27 ;see Function 40H
jc write_error ;routine not shown
unlock handle,start2,lgth2 ;See Function 5C01H
jc unlock_error ;routine not shown
write_handle stdout,u2_msg,27 ;See Function 40H
jc write_error ;routine not shown
close_handle handle ;See Function 3EH
jc close_error ;routine not shown
write_handle stdout,file,8 ;see Function 40H
jc write_error ;routine not shown
write_handle stdout,cl_msg,10 ;see Function 40H
jc write_error ;routine not shown
22
_ _ | | _ _
_ _ | | _ _
_ ______________
Unlock (Function 5CH, Code 01H)
Call:
AH = 5CH
AL = 01H
BX
Handle
CX:DX
Offset of area to be unlocked
SI:DI
Length of area to be unlocked
Return:
Carry set:
AX
1 = Invalid function code
6 = Invalid handle
33 = Lock violation
36 = Sharing buffer exceeded
Carry not set:
No error
Comments:
Function 5CH, Code 01H, unlocks a region previously locked by the same
process. BX must contain the handle of the file that contains the region to
be unlocked. CX:DX (a four-byte integer) must contain the offset in the file
of the beginning of the region. SI:DI (a four-byte integer) must contain the
length of the region. The offset and length must be exactly the same as the
offset and length specified in the previous Function 5CH, Code 00H (Lock).
The description of Function 5CH, Code 00H (Lock) describes how to use
locked regions.
23
_ _ | | _ _
_ _ | | _ _
_ ______________
If there is an error, the carry flag (CF) is set and the error code returns in
AX:
Code
Meaning
_ ________________________________________________________________
1 File sharing must be loaded to use this function request.
6 The handle in BX is not a valid, open handle.
33 The region specified is not identical to one that was previously
locked by the same process.
36 There is no more room for lock entries in the buffer. Refer to the
share command in the MS-DOS User's Reference for information
on allocating more lock entries.
You should issue Function 59H (Get Extended Error) to list the possible
errors returned by this function.
Macro Definition:
unlock macro handle,start,bytes
mov bx, handle
mov cx, word ptr start
mov dx, word ptr start+2
mov si, word ptr bytes
mov di, word ptr bytes+2
mov al, 1
mov ah, 5CH
int 21H
endm
Example:
The following program opens a file named finalrpt in "Deny None" mode
and locks two portions of it: the first 128 bytes and bytes 1024 through
5119. After some (unspecified) processing, it unlocks the same portions and
closes the file.
stdout equ 1
;
start1 dd 0
lgth1 dd 128
start2 dd 1023
lgth2 dd 4096
file db "FINALRPT",0
op_msg db " opened.",0DH,0AH
11_msg db "First 128 bytes locked.",0DH,0AH
12_msg db "Bytes 1024-5119 locked.",0DH,0AH
u1_msg db "First 128 bytes unlocked.",0DH,0AH
u2_msg db "Bytes 1024-5119 unlocked.",0DH,0AH
24
_ _ | | _ _
_ _ | | _ _
_ ______________
cl_msg db " closed.",0DH,0AH
handle dw ?
;
begin: open_handle file,01000010b ;see Function 3DH
jc open_error ;routine not shown
write_handle stdout,file,8 ;see Function 40H
jc write_error ;routine not shown
write_handle stdout,op_msg,10 ;see Function 40H
jc write_error ;routine not shown
mov handle,ax ;save handle
lock handle,start1,lgth1 ;See Function 5C00H
jc lock_error ;routine not shown
write_handle stdout,11_msg,25 ;see Function 40H
jc write_error ;routine not shown
lock handle,start2,lgth2 ;See Function 5C00H
jc lock_error ;routine not shown
write_handle stdout,12_msg,25 ;see Function 40H
jc write_error ;routine not shown
;
; ( Further processing here )
;
unlock handle,start1,lgth1 ;THIS FUNCTION
jc unlock_error ;routine not shown
write_handle stdout,u1_msg,27 ;see Function 40H
jc write_error ;routine not shown
unlock handle,start2,lgth2 ;THIS FUNCTION
jc unlock_error ;routine not shown
write_handle stdout,u2_msg,27 ;see Function 40H
jc write_error ;routine not shown
close_handle handle ;See Function 3EH
jc close_error ;routine not shown
write_handle stdout,file,8 ;see Function 40H
jc write_error ;routine not shown
write_handle stdout,cl_msg,10 ;see Function 40H
jc write_error ;routine not shown
25
_ _ | | _ _
_ _ | | _ _
_ ______________
Get Machine Name (Function 5EH, Code 00H)
Call:
AH = 5EH
AL = 0
DS:DX
Pointer to 16-byte buffer
Return:
Carry set:
AX
1 = Invalid function code
Carry not set:
CX
Identification number of local
computer
Comments:
Function 5EH, Code 0, retrieves the net name of the local computer. DX
must contain the offset (to the segment address in DS) of a 16-byte buffer.
Microsoft Networks must be running.
MS-DOS returns the local computer name (a 16-byte ASCIZ string, padded
with blanks) in the buffer pointed to by DS:DX. CX returns the
identification number of the local computer. If the network was never
installed, the CH register returns with zero and the value in the CL regis-
ter is invalid.
If there is an error, the carry flag (CF) is set and the error code returns in
AX:
Code
Meaning
_ ________________________________________________________________
1 Microsoft Networks must be running to use this function request.
26
_ _ | | _ _
_ _ | | _ _
_ ______________
Macro Definition:
get_machine_name macro buffer
mov dx,offset buffer
mov al,0
mov ah,5EH
int 21H
endm
Example:
The following program displays the name of a Microsoft Networks work-
station.
stdout equ 1
;
msg db "Netname: "
mac_name db 16 dup (?),0DH,0AH
;
begin: get_machine_name mac_name ;THIS FUNCTION
jc name_error ;routine not shown
write_handle stdout,msg,27 ;see Function 40H
jc write_error ;routine not shown
27
_ _ | | _ _
_ _ | | _ _
_ ______________
Printer Setup (Function 5EH, Code 02H)
Call:
AH = 5EH
AL = 02H
BX
Assign-list index
CX
Length of setup string
DS:SI
Pointer to setup string
Return:
Carry set:
AX
1 = Invalid function code
Carry not set:
No error
Comments:
Function 5EH, Code 02H, defines a string of control characters that
MS-DOS adds to the beginning of each file sent to the network printer. BX
must contain the index into the assign list that identifies the printer (entry
0 is the first entry). CX must contain the length of the string. SI must con-
tain the offset (to the segment address in DS) of the string itself. Microsoft
Networks must be running.
MS-DOS adds the setup string to the beginning of each file sent to the
printer, which is specified by the assign-list index in BX. This function
request lets each program that shares a printer have its own printer
configuration. You can use Function 5F02H (Get Assign-List Entry) to
determine which entry in the assign list refers to the printer.
If there is an error, the carry flag (CF) is set and the error code returns in
AX:
Code
Meaning
_ ________________________________________________________________
1 Microsoft Networks must be running to use this function request.
28
_ _ | | _ _
_ _ | | _ _
_ ______________
Macro Definition:
printer_setup macro index,lgth,string
mov bx, index
mov cx, lgth
mov dx, offset string
mov al, 2
mov ah, 5EH
int 21H
endm
Example:
The following program defines a printer-setup string that consists of the
control character to print expanded type on Epson-compatible printers.
The printer cancels this mode at the first carriage return, so the effect is to
print the first line of each file sent to the network printer as a title in
expanded characters. The setup string is one character. This example
assumes that the printer is the entry number 3 (the fourth entry) in the
assign list. Use Function 5F02H (Get Assign-List Entry) to determine this
value.
setup db 0EH
;
begin: printer_setup 3,1,setup ;THIS FUNCTION
jc error ;routine not shown
29
_ _ | | _ _
_ _ | | _ _
_ ______________
Get Assign-List Entry (Function 5FH, Code
02H)
Call:
AH = 5FH
AL = 02H
BX
Assign-list index
DS:SI
Pointer to buffer for local name
ES:DI
Pointer to buffer for remote name
Return:
Carry set:
AX
1 = Invalid function code
18 = No more files
Carry not set:
BL
3 = Printer
4 = Drive
CX
Stored user value
Comments:
Function 5FH, Code 02H, retrieves the specified entry from the network
list of assignments. BX must contain the assign-list index (entry 0 is the
first entry). SI must contain the offset (to the segment address in DS) of a
16-byte buffer for the local name. DI must contain the offset (to the seg-
ment address in ES) of a 128-byte buffer for the remote name. Microsoft
Networks must be running.
MS-DOS puts the local name in the buffer pointed to by DS:SI and the
remote name in the buffer pointed to by ES:DI. The local name can be a
null ASCIZ string. BL returns 3 if the local device is a printer or 4 if the
local device is a drive. CX returns the stored user value set with Function
5F03H (Make Assign-List Entry). The contents of the assign list can
change between calls.
You can use this function request to retrieve any entry, or to make a copy
of the complete list by stepping through the table. To detect the end of
the assign list, check for error code 18 (no more files), as you would when
stepping through a directory by using Functions 4EH (Find First File) and
30
_ _ | | _ _
_ _ | | _ _
_ ______________
4FH (Find Next File).
If there is an error, the carry flag (CF) is set and the error code returns in
AX:
Code
Meaning
_ ________________________________________________________________
1 Microsoft Networks must be running to use this function request.
18 The index passed in BX is greater than the number of entries in the
assign list.
Macro Definition:
get_list macro index,local,remote
mov bx, index
mov si, offset local
mov di, offset remote
mov al,2
mov ah, 5FH
int 21H
endm
Example:
The following program displays the assign list on a Microsoft Networks
workstation, showing the local name, remote name, and device type (drive
or printer) for each entry.
stdout equ 1
printer equ 3
;
local_nm db 16 dup (?),2 dup (20h)
remote_nm db 128 dup (?),2 dup (20h)
header db "Local name",8 dup (20h)
db "Remote name",7 dup (20h)
db "Device Type"
crlf db 0dh,0ah,0dh,0ah
drive_msg db "drive"
print_msg db "printer"
index dw ?
;
begin: write_handle stdout,header,51 ;see Function 40H
jc write_error ;routine not shown
mov index,0 ;assign list index
ck_list: get_list index,local_nm,remote_nm ;THIS FUNCTION
jnc got_one ;got an entry
error: cmp ax,18
je last_one ;yes
jmp error ;routine not shown
got_one: push bx ;save device type
31
_ _ | | _ _
_ _ | | _ _
_ ______________
write_handle stdout,local_nm,148 ;see Function 40H
jc write_error ;routine not shown
pop bx ;get device type
cmp bl,printer ;is it a printer?
je prntr ;yes
write_handle stdout,drive_msg,5 ;see Function 40H
jc write_error ;routine not shown
jmp get_next ;finish message
prntr: write_handle stdout,print_msg,7 ;see Function 40H
jc write_error ;routine not shown
get_next: write_handle stdout,crlf,2 ;see Function 40H
jc write_error ;routine not shown
inc index ;bump index
jmp ck_list ;get next entry
last_one: write_handle stdout,crlf,4 ;see Function 40H
jc write_error ;routine not shown
;
32
_ _ | | _ _
_ _ | | _ _
_ ______________
Make Assign-List Entry (Function 5FH, Code
03H)
Call:
AH = 5FH
AL = 03H
BL
3 = Printer
4 = Drive
CX
User value
DS:SI
Pointer to name of source device
ES:DI
Pointer to name of destination
device
Return:
Carry set:
AX
1 = Invalid function code
5 = Access denied
3 = Path not found
8 = Insufficient memory
(Other errors particular to the
network may occur.)
Carry not set:
No error
Comments:
Function 5FH, Code 03H, redirects a printer or disk drive (source device)
to a network directory (destination device). BL must contain 3 if the
source device is a printer or 4 if it is a disk drive. SI must contain the
offset (to the segment address in DS) of an ASCIZ string that specifies the
name of the printer, or a drive letter followed by a colon, or a null string
(one byte of 00H). DI must contain the offset (to the segment address in
ES) of an ASCIZ string that specifies the name of a network directory. CX
contains a user-specified 16-bit value that MS-DOS maintains. Microsoft
Networks must be running.
The destination string must be an ASCIZ string of the following form:
machine-name pathname 00H password 00H
33
_ _ | | _ _
_ _ | | _ _
_ ______________
where:
Machine-name is the net name of the server that contains the network
directory;
Pathname is the alias of the network directory (not the directory path) to
which the source device is to be redirected;
00H is a null byte; and
Password is the password for access to the network directory. If no pass-
word is specified, both null bytes must immediately follow the pathname.
If BL=3, the source string must be PRN, LPT1, LPT2, or LPT3. This
function buffers and sends all output for the named printer to the remote-
printer spooler named in the destination string.
If BL=4, the source string can be either a drive letter followed by a colon,
or a null string. If the source string contains a valid drive letter and colon,
this call redirects all subsequent drive-letter references to the network
directory named in the destination string. If the source string is a null
string, MS-DOS attempts to grant access to the network directory with
the specified password.
The maximum length of the destination string is 128 bytes. You can
retrieve the value in CX by using Function 5FH, Code 02H (Get Assign-
List Entry).
If there is an error, the carry flag (CF) is set and the error code returns in
AX:
Code
Meaning
_ ________________________________________________________________
1 Microsoft Networks must be running to use this function request;
the value in BX is not 1 to 4, the source string is in the wrong for-
mat; the destination string is in the wrong format; or the source
device is already redirected.
3 The network directory path is invalid or doesn't exist.
5 The network directory/password combination is not valid. This
does not mean that the password itself was invalid; the directory
might not exist on the server.
8 There is not enough memory for string substitutions.
34
_ _ | | _ _
_ _ | | _ _
_ ______________
Macro Definition:
redir macro device,value,source,destination
mov bl, device
mov cx, value
mov si, offset source
mov es, seg destination
mov di, offset destination
mov al, 03H
mov ah, 5FH
int 21H
endm
35
_ _ | | _ _
_ _ | | _ _
_ ______________
Example:
The following program redirects two drives and a printer from a worksta-
tion to a server named harold. It assumes the machine name, directory
names, and driver letters shown:
Local drive Netname
or printer on server Password
E: WORD none
F: COMM fred
PRN: PRINTER quick
printer equ 3
drive equ 4
;
local_1 db "e:",0
local_2 db "f:",0
local_3 db "prn",0
remote_1 db "\harold\word",0,0
remote_2 db "\harold\comm",0,"fred",0
remote_3 db "\harold\printer",0,"quick",0
;
begin: redir local_1,remote_1,drive,0 ;THIS FUNCTION
jc error ;routine not shown
redir local_2,remote_2,drive,0 ;THIS FUNCTION
jc error ;routine not shown
redir local_3,remote_3,printer,0 ;THIS FUNCTION
jc error ;routine not shown
36
_ _ | | _ _
_ _ | | _ _
_ ______________
Cancel Assign-List Entry (Function 5FH, Code
04H)
Call:
AH = 5FH
AL = 04H
DS:SI
Pointer to name of source device
Return:
Carry set:
AX
1 = Invalid function code
15 = Redirection paused on server
(Other errors particular to the network
may occur.)
Carry not set:
No error
Comments:
Function 5FH, Code 04H, cancels the redirection of a printer or disk drive
(source device) to a network directory (destination device) made with
Function 5FH, Code 03H (Make Assign-List Entry). SI must contain the
offset (to the segment address in DS) of an ASCIZ string that specifies the
name of the printer or drive whose redirection is to be canceled. Microsoft
Networks must be running.
The ASCIZ string pointed to by DS:SI can contain one of three values:
o The letter of a redirected drive, followed by a colon. Cancels the
redirection and restores the drive to its physical meaning.
o The name of a redirected printer (PRN, LPT1, LPT2, LPT3, or
their machine-specific equivalents). Cancels the redirection and
restores the printer name to its physical meaning.
o A string starting with \\ (2 backslashes). Terminates the connec-
tion between the local machine and the network directory.
If there is an error, the carry flag (CF) is set and the error code returns in
AX:
Code
37
_ _ | | _ _
_ _ | | _ _
_ ______________
Meaning
_ ________________________________________________________________
1 Microsoft Networks must be running to use this function request;
or the ASCIZ string names a nonexistent source device.
15 Disk or printer redirection on the network server is paused.
Macro Definition:
cancel_redir macro local
mov si, offset local
mov al, 4
mov ah, 5FH
int 21H
endm
Example:
The following program cancels the redirection of drives E and F and the
printer (PRN) of a Microsoft Networks workstation. It assumes that these
local devices were redirected previously.
local_1 db "e:",0
local_2 db "f:",0
local_3 db "prn",0
;
begin: cancel_redir local_1 ;THIS FUNCTION
jc error ;routine not shown
cancel_redir local_2 ;THIS FUNCTION
jc error ;routine not shown
cancel_redir local_3 ;THIS FUNCTION
jc error ;routine not shown
38
_ _ | | _ _
_ _ | | _ _
_ ______________
Get PSP (Function 62H)
Call:
AH = 62H
Return:
BX
Segment address of the Program
Segment Prefix of the current process
Comments:
Function 62H retrieves the segment address of the currently active process
(the start of the Program Segment Prefix). The address returns in BX.
Macro Definition:
get_psp macro
mov ah, 62H
int 21H
endm
Example:
The following program displays the segment address of its Program Seg-
ment Prefix (PSP) in hexadecimal.
msg db "PSP segment address: H",0DH,0AH,"$"
;
begin: get_psp ;THIS FUNCTION
convert bx,16,msg[21] ;see end of chapter
display msg ;see Function 09H
39
_ _ | | _ _
_ _ | | _ _
_ ______________
Get Extended Country Information (Function
65H)
Call:
AH = 65H
AL
Function (minor) code
BX
Code page (-1 = active CON device)
CX
Amount of data to return
DX
Country ID for which information is to be returned
(-1=default country)
ES:DI
Address of country information buffer
Return:
1 = Buffer has been filled
2 = File not found
Comments:
Function 65H retrieves standard country information. This information
includes country ID, code page, date and time format, currency symbol,
separators (for thousands, decimals, data list, date and time) currency for-
mat flags, digits in currency, and case-mapping information.
The function code passed in AL may be one of the following:
Code
Description
_ ________________________________________________________________
1 Return standard information
2 Return pointer to uppercase table
3 Return pointer to filename uppercase table
4 Return pointer to collating table
5 Reserved (no entry)
6 Return pointer to collating sequence
40
_ _ | | _ _
_ _ | | _ _
_ ______________
MS-DOS 3.3 provides more country-dependent information than previous
versions of MS-DOS. Only the information for the default country is kept
in the kernel. Country-dependent information for all other countries is
contained in the country.sys file. The MS-DOS nlsfunc command is used
to access the country-dependent information in country.sys using this call.
If the country code and code page number do not match, or if either is
invalid, error code 2 is returned to AX. If CX is less than 5, error code 1 is
returned. If the amount of information requested is greater than the value
of CX, only CX bytes are returned and no error is reported.
If AL = 1, the buffer is filled with the following information:
db 1 ; Information ID
dw ? ; Size (<=38)
dw ? ; Country ID
dw ? ; Code page
If AL = 2, the buffer is filled with the following information:
db 2 ; Information ID
dd ? ; Double-word pointer to uppercase table
If AL = 4, the buffer is filled with the following information:
db 4 ; Information ID
dd ? ; Double-word pointer to filename uppercase table
Both of these tables consist of a length field (two bytes) followed by 128
uppercase values for the upper 128 ASCII characters. The following for-
mula is used to compute the address of an uppercase equivalent in the
table:
Address of outchar = inchar - (256-table_len) = table_start
where:
Parameter
Meaning
_ ________________________________________________________________
inchar Character to be generated
table_len Length of list of uppercase values (two bytes)
table_start Starting address of uppercase table
outchar Uppercase value for inchar
If inchar is greater than or equal to (256 - table_len), there is an uppercase
equivalent in the table; otherwise, there is not.
41
_ _ | | _ _
_ _ | | _ _
_ ______________
If AL = 6, the buffer is filled with the following information:
db 6 ; Information ID
dd ? ; Double-word pointer to collating sequence
The table is 258 bytes long. The first word is the length of the table. The
rest of the table is 256 ASCII values in the appropriate order.
42
_ _ | | _ _
_ _ | | _ _
_ ______________
Get/Set Global Code Page (Function 66H)
Call:
AH = 66H
AL
Function (minor) code
BX
Code page to set (AL = 2)
Return:
Carry set:
AX
02 = File not found
65 = Device not selected
Carry not set:
No error
Comments:
Function 66H gets or sets the code page used by the kernel and all devices.
If no other code page has been set, this function gets the default code page
from DX. If another code page is set, this function retrieves the active
code page from BX.
The MS-DOS nlsfunc command and country.sys must be on the system if
this function is to be used to change the global code page.
The function code may be one of the following:
Code
Description
_ ________________________________________________________________
1 Get code page
2 Set code page
MS-DOS gets the new code page from the country.sys file. Devices must be
prepared for code page switching before a code page can be selected. To
prepare a device, a device driver that supports code page switching must
be installed by using the device command in the config.sys file. The user
43
_ _ | | _ _
_ _ | | _ _
_ ______________
must also use the prepare keyword with the MS-DOS mode command to
prepare the device for code page switching.
The code page selected must be compatible with the country code specified
in the config.sys file. If MS-DOS cannot read country.sys or other specified
country information file, error code 02 is returned to AX.
44
_ _ | | _ _
_ _ | | _ _
_ ______________
Set Handle Count (Function 67H)
Call:
AH = 67H
BX
Number of allowed handles
Return:
Carry set:
AX
Carry not set:
No error
Comments:
Function 67H increases or decreases the number of files a program can
have open at one time. The maximum number of files handles is 64K. If
less than 20 are specified, the minimum handle number, 20, is assumed. If
this call is used to reduce the number of allowed handles, the new limit
does not take affect until any handles above the new limit are closed.
The user should use Call 4AH (Set Block) to allocate memory for the
extended handle list if BX is greater than 255. The maximum number for
the value of the config.sys command files is 255.
45
_ _ | | _ _
_ _ | | _ _
_ ______________
Commit File (Function 68H)
Call:
AH = 68H
BX
File handle
Return:
Carry set:
AX = error
Carry not set
No error
Comments:
Function 68H flushes all buffered data for a file without closing it. Using
this call is more efficient than using the traditional close-open sequence,
and is more effective for network environments. This call makes sure that
the disk image of a file is current.
46
_ _ | | _ _
_ _ | | _ _
_ ______________
; Macro Definitions for MS-DOS System Call Examples
;
;*******************
; Interrupts
;*******************
; Interrupt 25H
ABS_DISK_READ macro disk,buffer,num_sectors,first_sector
mov al,disk
mov bx,offset buffer
mov cx,num_sectors
mov dx,first_sector
int 25H
popf
endm
; Interrupt 26H
ABS_DISK_WRITE macro disk,buffer,num_sectors,first_sector
mov al,disk
mov bx,offset buffer
mov cx,num_sectors
mov dx,first_sector
int 26H
popf
endm
; Interrupt 27H
STAY_RESIDENT macro last_instruc
mov dx,offset last_instruc
inc dx
int 27H
endm
;
;
;*******************
; Function Requests
;*******************
; Function Request 00H
TERMINATE_PROGRAM macro
xor ah,ah
int 21H
endm
; Function Request 01H
READ_KBD_AND_ECHO macro
mov ah,01H
int 21H
endm
; Function Request 02H
DISPLAY_CHAR macro character
mov dl,character
mov ah,02H
int 21H
endm
; Function Request 03H
AUX_INPUT macro
mov ah,03H
int 21H
endm
; Function Request 04H
47
_ _ | | _ _
_ _ | | _ _
_ ______________
AUX_OUTPUT macro
mov ah,04H
int 21H
endm
; Function Request 05H
PRINT_CHAR macro character
mov dl,character
mov ah,05H
int 21H
endm
; Function Request 06H
DIR_CONSOLE_IO macro switch
mov dl,switch
mov ah,06H
int 21H
endm
; Function Request 07H
DIR_CONSOLE_INPUT macro
mov ah,07H
int 21H
endm
; Function Request 08H
READ_KBD macro
mov ah,08H
int 21H
endm
; Function Request 09H
DISPLAY macro string
mov dx,offset string
mov ah,09H
int 21H
endm
; Function Request 0AH
GET_STRING macro limit,string
mov dx,offset string
mov string,limit
mov ah,0AH
int 21H
endm
; Function Request 0BH
CHECK_KBD_STATUS macro
mov ah,0BH
int 21H
endm
; Function Request 0CH
FLUSH_AND_READ_KBD macro switch
mov al,switch
mov ah,0CH
int 21H
endm
; Function Request 0DH
RESET_DISK macro
mov ah,0DH
int 21H
endm
; Function Request 0EH
48
_ _ | | _ _
_ _ | | _ _
_ ______________
SELECT_DISK macro disk
mov dl,disk[-65]
mov ah,0EH
int 21H
endm
; Function Request 0FH
OPEN macro fcb
mov dx,offset fcb
mov ah,0FH
int 21H
endm
; Function Request 10H
CLOSE macro fcb
mov dx,offset fcb
mov ah,10H
int 21H
endm
; Function Request 11H
SEARCH_FIRST macro fcb
mov dx,offset fcb
mov ah,11H
int 21H
endm
; Function Request 12H
SEARCH_NEXT macro fcb
mov dx,offset fcb
mov ah,12H
int 21H
endm
; Function Request 13H
DELETE macro fcb
mov dx,offset fcb
mov ah,13H
int 21H
endm
; Function Request 14H
READ_SEQ macro fcb
mov dx,offset fcb
mov ah,14H
int 21H
endm
; Function Request 15H
WRITE_SEQ macro fcb
mov dx,offset fcb
mov ah,15H
int 21H
endm
; Function Request 16H
CREATE macro fcb
mov dx,offset fcb
mov ah,16H
int 21H
endm
; Function Request 17H
RENAME macro fcb,newname
mov dx,offset fcb
49
_ _ | | _ _
_ _ | | _ _
_ ______________
mov ah,17H
int 21H
endm
; Function Request 19H
CURRENT_DISK macro
mov ah,19H
int 21H
endm
; Function Request 1AH
SET_DTA macro buffer
mov dx,offset buffer
mov ah,1AH
endm
; Function Request 1BH
DEF_DRIVE_DATA macro
mov ah,1BH
int 21H
endm
; Function Request 1CH
DRIVE_DATA macro drive
mov dl,drive
mov ah,1CH
int 21H
endm
; Function Request 21H
READ_RAN macro fcb
mov dx,offset fcb
mov ah,21H
int 21H
endm
; Function Request 22H
WRITE_RAN macro fcb
mov dx,offset fcb
mov ah,22H
int 21H
endm
; Function Request 23H
FILE_SIZE macro fcb
mov dx,offset fcb
mov ah,23H
int 21H
endm
; Function Request 24H
SET_RELATIVE_RECORD macro fcb
mov dx,offset fcb
mov ah,24H
int 21H
endm
; Function Request 25H
SET_VECTOR macro interrupt,handler_start
mov al,interrupt
mov dx,offset handler_start
mov ah,25H
int 21H
endm
; Function Request 26H
50
_ _ | | _ _
_ _ | | _ _
_ ______________
CREATE_PSP macro seg_addr
mov dx,offset seg_addr
mov ah,26H
int 21H
endm
; Function Request 27H
RAN_BLOCK_READ macro fcb,count,rec_size
mov dx,offset fcb
mov cx,count
mov word ptr fcb[14],rec_size
mov ah,27H
int 21H
endm
; Function Request 28H
RAN_BLOCK_WRITE macro fcb,count,rec_size
mov dx,offset fcb
mov cx,count
mov word ptr fcb[14],rec_size
mov ah,28H
int 21H
endm
; Function Request 29H
PARSE macro string,fcb
mov si,offset string
mov di,offset fcb
push es
push ds
pop es
mov al,0FH
mov ah,29H
int 21H
pop es
endm
; Function Request 2AH
GET_DATE macro
mov ah,2AH
int 21H
endm
; Function Request 2BH
SET_DATE macro year,month,day
mov cx,year
mov dh,month
mov dl,day
mov ah,2BH
int 21H
endm
; Function Request 2CH
GET_TIME macro
mov ah,2CH
int 21H
endm
; Function Request 2DH
SET_TIME macro hour,minutes,seconds,hundredths
mov ch,hour
mov cl,minutes
mov dh,seconds
51
_ _ | | _ _
_ _ | | _ _
_ ______________
mov dl,hundredths
mov ah,2DH
int 21H
endm
; Function Request 2EH
VERIFY macro switch
mov al,switch
mov ah,2EH
int 21H
endm
; Function Request 2FH
GET_DTA macro
mov ah,2FH
int 21H
endm
; Function Request 30H
GET_VERSION macro
mov ah,30H
int 21H
endm
; Function Request 31H
KEEP_PROCESS macro return_code,last_byte
mov al,return_code
mov dx,offset last_byte
mov cl,4
shr dx,cl
inc dx
mov ah,31H
int 21H
endm
; Function Request 33H
CTRL_C_CK macro action,state
mov al,action
mov dl,state
mov ah,33H
int 21H
endm
; Function Request 35H
GET_VECTOR macro interrupt
mov al,interrupt
mov ah,35H
int 21H
endm
; Function Request 36H
GET_DISK_SPACE macro drive
mov dl,drive
mov ah,36H
int 21H
endm
; Function Request 38H
GET_COUNTRY macro country,buffer
local gc_01
mov dx,offset buffer
mov ax,country
cmp ax,0FFH
jl gc_01
52
_ _ | | _ _
_ _ | | _ _
_ ______________
mov al,0ffh
mov bx,country
gc_01: mov ah,38H
int 21H
endm
; Function Request 38H
SET_COUNTRY macro country
local sc_01
mov dx,0FFFFH
mov ax,country
cmp ax,0FFH
jl sc_01
mov al,0ffh
mov bx,country
sc_01: mov ah,38H
int 21H
endm
; Function Request 39H
MAKE_DIR macro path
mov dx,offset path
mov ah,39H
int 21H
endm
; Function Request 3AH
REM_DIR macro path
mov dx,offset path
mov ah,3AH
int 21H
endm
; Function Request 3BH
CHANGE_DIR macro path
mov dx,offset path
mov ah,3BH
int 21H
endm
; Function Request 3CH
CREATE_HANDLE macro path,attrib
mov dx,offset path
mov cx,attrib
mov ah,3CH
int 21H
endm
; Function Request 3DH
OPEN_HANDLE macro path,access
mov dx,offset path
mov al,access
mov ah,3DH
int 21H
endm
; Function Request 3EH
CLOSE_HANDLE macro handle
mov bx,handle
mov ah,3EH
int 21H
endm
; Function Request 3FH
53
_ _ | | _ _
_ _ | | _ _
_ ______________
READ_HANDLE macro handle,buffer,bytes
mov bx,handle
mov dx,offset buffer
mov cx,bytes
mov ah,3FH
int 21H
endm
; Function Request 40H
WRITE_HANDLE macro handle,buffer,bytes
mov bx,handle
mov dx,offset buffer
mov cx,bytes
mov ah,40H
int 21H
endm
; Function Request 41H
DELETE_ENTRY macro path
mov dx,offset path
mov ah,41H
int 21H
endm
; Function Request 42H
MOVE_PTR macro handle,high,low,method
mov bx,handle
mov cx,high
mov dx,low
mov al,method
mov ah,42H
int 21H
endm
; Function Request 43H
CHANGE_MODE macro path,action,attrib
mov dx,offset path
mov al,action
mov cx,attrib
mov ah,43H
int 21H
endm
; Function Request 4400H,01H
IOCTL_DATA macro code,handle
mov bx,handle
mov al,code
mov ah,44H
int 21H
endm
; Function Request 4402H,03H
IOCTL_CHAR macro code,handle,buffer
mov bx,handle
mov dx,offset buffer
mov al,code
mov ah,44H
int 21H
endm
; Function Request 4404H,05H
IOCTL_STATUS macro code,drive,buffer
mov bl,drive
54
_ _ | | _ _
_ _ | | _ _
_ ______________
mov dx,offset buffer
mov al,code
mov ah,44H
int 21H
endm
; Function Request 4406H,07H
IOCTL_STATUS macro code,handle
mov bx,handle
mov al,code
mov ah,44H
int 21H
endm
; Function Request 4408H
IOCTL_CHANGE macro drive
mov bl,drive
mov al,08H
mov ah,44H
int 21H
endm
; Function Request 4409H
IOCTL_RBLOCK macro drive
mov bl,drive
mov al,09H
mov ah,44H
int 21H
endm
; Function Request 440AH
IOCTL_RHANDLE macro handle
mov bx,handle
mov al,0AH
mov ah,44H
int 21H
endm
; Function Request 440BH
IOCTL_RETRY macro retries,wait
mov dx,retries
mov cx,wait
mov al,0BH
mov ah,44H
int 21H
endm
; Function Request 440CH
GENERIC_IOCTL_HANDLES macro handle,function,category,buffer
mov ch,05H
mov cl,function
mov dx,offset buffer
mov bx,handle
mov ah,44H
mov al,0CH
int 21H
endm
; Function Request 440DH
GENERIC_IOCTL_BLOCK macro drive_num,function,category,parm_blk
mov ch,08H
mov cl,function
mov dx,offset parm_blk - 1
55
_ _ | | _ _
_ _ | | _ _
_ ______________
mov bx,drive_num
mov ah,44H
mov al,0DH
int 21H
endm
; Function Request 440EH
IOCTL_GET_DRIVE_MAP macro logical_drv
mov bx,logical_drv
mov ah,44H
mov al,0EH
int 21H
endm
; Function Request 440FH
IOCTL_SET_DRIVE_MAP macro logical_drv
mov bx,logical_drv
mov ah,44H
mov al,0FH
int 21H
endm
; Function Request 45H
XDUP macro handle
mov bx,handle
mov ah,45H
int 21H
endm
; Function Request 46H
XDUP2 macro handle1,handle2
mov bx,handle1
mov cx,handle2
mov ah,46H
int 21H
endm
; Function Request 47H
GET_DIR macro drive,buffer
mov dl,drive
mov si,offset buffer
mov ah,47H
int 21H
endm
; Function Request 48H
ALLOCATE_MEMORY macro bytes
mov bx,bytes
mov cl,4
shr bx,cl
inc bx
mov ah,48H
int 21H
endm
; Function Request 49H
FREE_MEMORY macro seg_addr
mov ax,seg_addr
mov es,ax
mov ah,49H
int 21H
endm
; Function Request 4AH
56
_ _ | | _ _
_ _ | | _ _
_ ______________
SET_BLOCK macro last_byte
mov bx,offset last_byte
mov cl,4
shr bx,cl
add bx,17
mov ah,4AH
int 21H
mov ax,bx
shl ax,cl
dec ax
mov sp,ax
mov bp,sp
endm
; Function Request 4B00H
EXEC macro path,command,parms
mov dx,offset path
mov bx,offset parms
mov word ptr parms[02h],offset command
mov word ptr parms[04h],cs
mov word ptr parms[06h],5ch
mov word ptr parms[08h],es
mov word ptr parms[0ah],6ch
mov word ptr parms[0ch],es
mov al,0
mov ah,4BH
int 21H
endm
; Function Request 4B03H
EXEC_OVL macro path,parms,seg_addr
mov dx,offset path
mov bx,offset parms
mov parms,seg_addr
mov parms[02H],seg_addr
mov al,3
mov ah,4BH
int 21H
endm
; Function Request 4CH
END_PROCESS macro return_code
mov al,return_code
mov ah,4CH
int 21H
endm
; Function Request 4DH
RET_CODE macro
mov ah,4DH
int 21H
endm
; Function Request 4EH
FIND_FIRST_FILE macro path,attrib
mov dx,offset path
mov cx,attrib
mov ah,4EH
int 21H
endm
; Function Request 4FH
57
_ _ | | _ _
_ _ | | _ _
_ ______________
FIND_NEXT_FILE macro
mov ah,4FH
int 21H
endm
; Function Request 54H
GET_VERIFY macro
mov ah,54H
int 21H
endm
; Function Request 56H
RENAME_FILE macro old_path,new_path
mov dx,offset old_path
push ds
pop es
mov di,offset new_path
mov ah,56H
int 21H
endm
; Function Request 57H
GET_SET_DATE_TIME macro handle,action,time,date
mov bx,handle
mov al,action
mov cx,word ptr time
mov dx,word ptr date
mov ah,57H
int 21H
endm
; Function Request 58H
ALLOC_STRAT macro code,strategy
mov bx,strategy
mov al,code
mov ah,58H
int 21H
endm
; Function Request 59H
GET_ERROR macro
mov ah,59
int 21H
endm
; Function Request 5AH
CREATE_TEMP macro pathname,attrib
mov cx,attrib
mov dx,offset pathname
mov ah,5AH
int 21H
endm
; Function Request 5BH
CREATE_NEW macro pathname,attrib
mov cx,attrib
mov dx,offset pathname
mov ah,5BH
int 21H
endm
; Function Request 5C00H
LOCK macro handle,start,bytes
mov bx,handle
58
_ _ | | _ _
_ _ | | _ _
_ ______________
mov cx,word ptr start
mov dx,word ptr start+2
mov si,word ptr bytes
mov di,word ptr bytes+2
mov al,0
mov ah,5CH
int 21H
endm
; Function Request 5C01H
UNLOCK macro handle,start,bytes
mov bx,handle
mov cx,word ptr start
mov dx,word ptr start+2
mov si,word ptr bytes
mov di,word ptr bytes+2
mov al,1
mov ah,5CH
int 21H
endm
; Function Request 5E00H
GET_MACHINE_NAME macro buffer
mov dx,offset buffer
mov al,0
mov ah,5EH
int 21H
endm
; Function Request 5E02H
PRINTER_SETUP macro index,lgth,string
mov bx,index
mov cx,lgth
mov dx,offset string
mov al,2
mov ah,5EH
int 21H
endm
; Function Request 5F02H
GET_LIST macro index,local,remote
mov bx,index
mov si,offset local
mov di,offset remote
mov al,2
mov ah,5FH
int 21H
endm
; Function Request 5F03H
REDIR macro device,value,source,destination
mov bl,device
mov cx,value
mov si,offset source
mov es,seg destination
mov di,offset destination
mov al,03H
mov ah,5FH
int 21H
endm
; Function Request 5F04H
59
_ _ | | _ _
_ _ | | _ _
_ ______________
CANCEL_REDIR macro local
mov si,offset local
mov al,4
mov ah,5FH
int 21H
endm
; Function Request 62H
GET_PSP macro
mov ah,62H
int 21H
endm
;
;
;*******************
; General
;*******************
;
DISPLAY_ASCIIZ macro asciiz_string
local search,found_it
mov bx,offset asciiz_string
search:
cmp byte ptr [bx],0
je found_it
inc bx
jmp short search
found_it:
mov byte ptr [bx],"$"
display asciiz_string
mov byte ptr [bx],0
display_char 0DH
display_char 0AH
endm
;
MOVE_STRING macro source,destination,count
push es
push ds
pop es
assume es:code
mov si,offset source
mov di,offset destination
mov cx,count
rep movs es:destination,source
assume es:nothing
pop es
endm
;
CONVERT macro value,base,destination
local table,start
jmp start
table db "0123456789ABCDEF"
start:
push ax
push bx
60
_ _ | | _ _
_ _ | | _ _
_ ______________
push dx
mov al,value
xor ah,ah
xor bx,bx
div base
mov bl,al
mov al,cs:table[bx]
mov destination,al
mov bl,ah
mov al,cs:table[bx]
mov destination[1],al
pop dx
pop bx
pop ax
endm
;
CONVERT_TO_BINARY macro string,number,value
local ten,start,calc,mult,no_mult
jmp start
ten db 10
start:
mov value,0
xor cx,cx
mov cl,number
xor si,si
calc:
xor ax,ax
mov al,string[si]
sub al,48
cmp cx,2
jl no_mult
push cx
dec cx
mult:
mul cs:ten
loop mult
pop cx
no_mult:
add value,ax
inc si
loop calc
endm
;
CONVERT_DATE macro dir_entry
mov dx,word ptr dir_entry[24]
mov cl,5
shr dl,cl
mov dh,dir_entry[24]
and dh,1FH
xor cx,cx
mov cl,dir_entry[25]
shr cl,1
61
_ _ | | _ _
_ _ | | _ _
_ ______________
add cx,1980
endm
;
PACK_DATE macro date
local set_bit
;
; On entry: DH=day, DL=month, CX=(year-1980)
;
sub cx,1980
push cx
mov date,dh
mov cl,5
shl dl,cl
pop cx
jnc set_bit
or cl,80h
set_bit:
or date,dl
rol cl,1
mov date[1],cl
endm
;
62
_ _ | | _ _