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TURBORUN.ASM
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Assembly Source File
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1985-12-13
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21KB
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451 lines
Page 60,132
Title TURBORUN a utility for Turbo Pascal, MS/PC-DOS v2.xx
Name TurboRun
;************************************************************************
;* *
;* T U R B O R U N *
;* Version 1.2 *
;* *
;* By John Cooper John Falconer *
;* (913) 262-8451 (415) 521-7245 *
;* CIS 74775,756 CIS 72435,1617 *
;* *
;* Update to Version 1.2 by *
;* *
;* Tom Devitt *
;* Pseudonym Software *
;* (818) 796-7933 *
;* *
;************************************************************************
Comment*
Revision History
Version 1.0 was successfully tested on 12/10/84.
By John Cooper
Updated to Version 1.0A on 12/22/84.
By John Falconer
1. Changed ssmax from a constant to a code-base-relative
value. This change allows Turborun to be used with
different versions of Turbo Pascal. Although undocumented,
the four versions of Turbo I tested all store their
maximum stack segment size as a word located seven bytes
ahead of the beginning of user code.
2. Added code to determine the length of the command line
which is passed to the child process. Moved the child's
command line starting point to PSP+081H as called for in
the DOS manual (Ver 2.0 page E-6) and placed the length
byte for the command line at PSP+080H. This allows the
command line passed to the child to be used as a string
with string[0] containing the valid length. Note that
a carriage return is placed at the end of the passed command
line but that it is not counted in the length. Note also
that this change corrupts the CmdLine variable passed
to Turborun by changing the last character of the file
name to the length of the child's CmdLine.
3. Changed original code so that all characters on the command
line are passed on to the child. This is as called for in
the DOS manual. Previously the first terminator (usually
a space) was skipped over.
4. Corrected a few minor documentation errors.
Note: The EXEC call does not support IO-Redirection on the command
line.
*
Page
Comment *
Updated to Version 1.0B January 10, 1985
By John Cooper
1. A note concerning the lack of IO-redirection support
by the MS/PC DOS EXEC function call, the call which is
at the heart of this program, was ammended, as it has
been determined that, at least in the case of MS-DOS 2.11,
EXEC does provide full IO-redirection, via the command line
symbols "> < |", if the command processor is envolked ahead
of the child.
<Child> [FCB-1 [FCB-2]] >PIPEOUT <PIPEIN
The above will NOT work, however,
[path][drive]COMMAND.COM /C <Child> [FCB-1 [FCB-2]] >PIPEOUT <PIPEIN
should work just fine.
2. Changed the way in which the program detects the end
of the childs name, to include all filename separators,
as listed on page 1-88 of MS-DOS v2.0 Programmer's
Reference, except the back-slash (\) and colon (:). These
two were excluded because the program needs to accept a
full-path name, which could include these symbols. Pre-
viously only a space or null was considered a terminator.
This change was recommended but not implemented in version
1.0A.
3. Added notes on installation concerning the requirement,
introduced by an enhancement made in 1.0A, that the
external declaration of this program be the first in the
Turbo source code. Also added some warnings and documentation
notes.
*
Page
Comment *
Updated to Version 1.1 March 17, 1985
By John Falconer
1. A "bug" in the way memory allocation is calculated and
set to protect Turbo's SSEG was fixed. The program is now
known to function with such large applications as 1-2-3 and
Dbase III.
Updated to Version 1.2 on April 28, 1985
By Tom Devitt
1. Made Version 1.2 compatible with the 2.0 AND 3.0 versions
of Turbo Pascal by modifying the method in which ssmax
is located. Under 3.0 TP stores the maximum stack segment
size 20 bytes ahead of the beginning of user code. However,
both versions store this value at CS:[101H] + 112H. This
change should make the placement of the EXTERNAL RUN proc
unimportant.
2. Acknowledgement: I owe a debt to the guys at Pathfinder
Software Inc., publishers of TurboLink. Although TL 2.0
contains a bug which makes it unusable on > 512k systems,
I was able to discover the above fact by analysing their
code.
3. With Turbo Pascal 2.0B, you must first compile in memory
and only then switch over to the com option, limiting
memory before the second compile. With Turbo Pascal
3.0B, you may skip the memory compile.
*
Page
Comment*
- - - W A R N I N G - - -
Although every effort has been made, by the two authors, to
ensure that this program will perform as specified, there are
may be programs which will not function correctly when envoked
from Turbo, via Turborun, but will do just fine if envoked
from COMMAND.COM. An excellent example is WordStar(tm). In
some, but not all, cases this can be solved by first envoking
COMMAND.COM and then envoking the child from COMMAND.COM.
Assume that there is a program, WORKING.COM, that will not
work from Turborun but does work from DOS. The following
command line might help;
COMMAND.COM /c WORKING.COM
This of course assume that there is not a shortage of
memory of some other explainable problem. The switch, /c,
is included to force COMMAND.COM to return control to the
parent after the processing of its, COMMAND.COM's, command line.
Installation Notes:
The enhancement to provide for a version-independent SSMAX,
provided by John F., has introduced the additional requirement
that this external be the first code generating structute in
the Turbo Pascal source code, i.e. make TurboRun the first
procedure, following the Const, Type, and Var blocks, in the
main program. Turborun assumes it is the first and can,
therefore, find the SSMAX word exactly seven bytes prior to
its own base address.
Note: Under Version 1.2, the above requirement may be relaxed.
- TD
Memory Compiles.
The use of this program in "memory mode" is not recom-
mended. Turbo seems to dislike having its memory
limited, which is required to run the child. It may
work but it is, at best, risky! The prefered method
is to do a memory-compile, if possible, then switch to
Com and limit the Maximum Stack Size and compile again,
this time producing a COM file. If compilation to memory
is not possible, due to lack of memory or the use of
Overlays, you MUST implement some sort of patch to
work around Turbo Pascal 2.0B's known "bug" in its handling
of externals greater that 128-bytes in length. The "bug"
is easy to work around, by either loading the external
at run-time(recommended) or converting it to an INLINE
$Include file.
Note: Above bug appears to have been fixed in Turbo
Pascal 3.0B - TD
*
Page
Comment *
Limiting the Stack Segment for Turbo Pascal.
If the Stack Size is not limited, at compile-time, then
Turbo Pascal may want to consume all of the system's
available RAM. Of course, that precludes the use of child
processes because the BLOCK call will fail, due to a lack
of resources. It is, therefore, recommended that you limit
Maximum Stack Size to just enough memory to allow the Pascal
program to operate, this will leave the balance of your
system's resources available for child processes.
Terminate But Stay Resident.
Programs which use "Terminate but stay resident" or
"Keep process" to terminate but keep itself in memory should
not be run from Turborun. The reason is that will cause
DOS to attempt to set the allocation block map to prevent
overlaying of the child. If the system survives this, it
still leave DOS in an unpredictable state.
Exit codes.
In order for the parent to correctly detect the reason the
child terminated the child must pass that infomation back,
so that the Get Return Code can find it. Many currently,
available programs do not provide this and hence the code
value passed back to RetCode may not reflect the actual
reason the child was terminated. An example is COMMAND.COM.
"BUGS".
If you encounter difficulties using this program or you find
"bugs" in it, please contact either author or the latest
revisor.
After this source code is assembled, linked, and converted to
a COM file it should be included as an external procedure
within the Turbo Pascal source file. The external should be
of the form shown below.
Procedure GoForIt(Var RetCode:Integer; Var Cmdline);
External 'TurboRun.com';
Cmdline can be either type-CHAR or type-STRING. If the latter
is used you should pass CmdLine[1] to skip the length byte.
Format of CmdLine:
path-name-to-child [<sp> First-FCB [<sp> Second-FCB [<sp> switchs and/or IO redirection]]] #0
Notice that the Cmdline to followed by a byte of 0, this is binary 0
not ASCII 0. <-- VERY IMPORTANT!
*
Page
Comment *
The variable, RetCode, will contain the return code from the
child process. RetCode is actually used as two, seperate,
byte-length variables. The table below explains how to interpret
this variable in terms of its high and low bytes.
High byte
0 : Normal Termination, No error
1 : Child was terminated via by CONTROL-C
2 : Child was aborted because of a DOS Hard Error
3 : Child used terminate-but-stay-resident
(System needs to be rebooted)
4 : EXEC call failed.
8 : Memory allocation error, EXEC was not attempted
In the cases of 0,1,2, and 3 the low byte has the value passed
back by the child. Any of these values indicate that the EXEC
call was successful. Programs which use terminate-but-stay-
resident should not be called by the program.
In the case of 4 the low byte has the reason the EXEC failed.
2 : The path specified was invalid or not found.
8 : There was not enough memory for the process to be created.
11 : The process was an EXE format file and contained information
that was internally inconsistent.
In the case of 8 the low byte has the reason the memory allocation
request failed.
7 : The arena was trashed because a user program has changed
memory that does not belong to it. System needs to be Rebooted.
8 : Insufficient memory.
*
Page
Subttl Main Program
;
;------------------- E Q U A T E S --------------------
;
spsave equ cs:00fch ;Storage for SP register
sssave equ cs:00feh ;Storage for SS register
;
;-------------------- M A C R O S ---------------------
;
MsDos Macro function
If function lt 256
mov ah,function
Else
mov ax,function
EndIf
int 21h
EndM
;
;
;------------------ M A I N P R O G R A M -----------------
;
code segment para public 'CODE'
assume cs:code,ds:nothing,es:code,ss:nothing
org 00h
run proc near
call entry ;Find out where we were loaded
;There is no return from this CALL
separate db ';,=+"[]><| ',9,0 ;Filename separators
;Excluding ":" and "\" which cannot appear in
;a filename but can appear in a pathname.
child db 128 dup(?) ;Path to child (with filename extension)
fcb1 db 16 dup(?) ;Optional fcb
fcb2 db 16 dup(?) ;Optional fcb
parablk dw 0,12 dup(?) ;Parameter block (DOS 2.0 Manual p. D-45)
cmdstrt dw 0 ;Offset to first char in child's CmdLine
ssmax dw 0 ;Storage for parent's maximum stack size,
;in paragraphs
entry: pop bx ;Offset+3
sub bx,3 ;Actual offset address of RUN.COM
pop dx ;Turbo(tm) return address
pop si ;Offset to command string
pop cx ;Segment address of command string
push dx ;Restore turbo's RET address
mov dx,si
push ds
push bp
pushf
push bx ;Save bx temporarily
mov ax,112h ;Offest of ssmax
mov bx,CS:[101H] ;pointer to user code
add bx,ax ;bx = addr ssmax
mov ax,cs:[bx] ;Move it to ax
pop bx ;Recover bx
mov [ssmax+bx],ax ;Save the max stack size for SETBLOCK call
mov ds,cx ;Point to command string segment
push cs ;Make ES=CS
pop es
mov di,offset child ;Child process path name
add di,bx ;Relocation offset
cld ;Force direction
cmdlp: lodsb ;Get character
push di ;Save DI
mov cx,13 ;look for any of 13 filename separators
mov di,offset separate
add di,bx ;Relocation offset
repnz scasb ;Look for match
jz endstr ;Exit if a separator is found
pop di ;Otherwise, retrieve DI and continue
stosb ;Store byte
jmp cmdlp ;Try next character
endstr: pop di ;Retrieve DI
mov [cmdstrt+bx],si ;Pointer to first char in child's CmdLine
mov al,0 ;Put terminating 0 in child path
stosb
dec si ;Back up one for stosb
dec si ;Back up one for the length byte
;ds:si point to the childs command line
u1: mov [parablk+2+bx],si ;Store offset address
inc si ;Start parsing at head of child's CmdLine
mov cx,ds
mov [parablk+4+bx],cx ;Store segment address
mov di,offset fcb1 ;Setup to parse first filename
add di,bx ;Relocation
;di has offset from cs to default FCB passed at 5Ch
mov [parablk+6+bx],di
MsDos 2901h ;Ignore leading separators
mov di,offset fcb2 ;Parse second filename
add di,bx ;Relocation
;di has offset from cs to default FCB passed at 6Ch
mov [parablk+10+bx],di
MsDos 2901h
;
;Place <cr> at end of CmdLine, calculate and store child's CmdLine length
;
u2: cmp byte ptr ds:[si],0 ;Look for end of line
jz u3
inc si
jmp u2
u3: mov byte ptr ds:[si],13
mov ax,[cmdstrt+bx] ;Get pointer to first char in child's CmdLine
xchg ax,si ;Swap it with current pointer
dec si ;We don't include the <cr> in our length
sub ax,si ;Calculate the length
dec si ;Point to the length byte
mov byte ptr ds:[si],al ;Store calculated length there
mov cx,cs ;Setup segments in parameter block
mov [parablk+8+bx],cx
mov [parablk+12+bx],cx
mov [parablk+bx],0 ;Pass environment to child, unchanged
;Now the childs parameter block is setup.
;All that remains is to allocate memory and go for it.
push bx ;Save reloc register
mov bx,[ssmax+bx]
push cx
mov cx,ss
add bx,cx
pop cx
sub bx,cx
MsDos 4ah ;Modify memory allocation
jnc $+5
jmp alocer ;Allocation error, Exit
pop bx ;Recover reloc register
push bx ;Save a copy on stack
mov dx,bx
add bx,offset parablk
mov [spsave],sp ;Save SP
mov [sssave],ss ;Save SS
push cs ;Point ds:sx to child
pop ds
add dx,offset child
MsDos 4b00h ;Go for it
cli ;Prevent interuption
mov sp,[spsave] ;Recover SP
mov ss,[sssave] ;Recover SS
sti
jnc $+5
jmp runerr ;Problems, Exit
pop bx ;Get reloc register
MsDos 4dh ;Get return code from child
getbac: popf ;Turbo's Flags
pop bp ;Turbo's BP
pop ds ;Turbo's DS
pop cx ;Return address
pop di ;Offset to RC Variable
pop es ;Segment of RC Variable
mov es:[di],ax ;Store return code
push cx ;Restore return address
ret ;Back to Turbo
alocer: pop bx ;Reloc register
mov ah,8 ;Indicate Allocation error
jmp getbac
runerr: pop bx
mov ah,4 ;Indicate RUN error
jmp getbac
run endp
code ends
end run
