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Author Topic: Masm32 debugger  (Read 9535 times)
pps
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Posts: 29


Masm32 debugger
« on: November 11, 2010, 08:26:27 AM »

When i wa using tasm i was having turbo debuger and i could see the results in memory. Here in masm i can't find something like this. I have the following code
Code:
; いいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいい
include \masm32\include\masm32rt.inc
; いいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいい

comment * -----------------------------------------------------
Build this console app with
"MAKEIT.BAT" on the PROJECT menu.
----------------------------------------------------- *

.data?
value dd ?

.data
item dd 0
sir DW 1,2,3

.code

start:

; いいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいい

call main
inkey
exit

; いいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいい

main proc

cls

mov si,0
mov bx,sir[si+4]
mov ax,sir[si+2]
mov sir[si+4],ax
mov ax,sir[si]
mov sir[si+2],ax
mov sir[si],bx


ret

main endp

; いいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいいい

end start

This cod assamble, link and generate the exe file but as you can see the result can't be seen. I shoult permute the values to the left, and i think it does. In tasm works fine but here i can't see the result.

Added code tags
« Last Edit: November 11, 2010, 08:41:31 AM by MichaelW » Logged
MichaelW
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Posts: 5161


Re: Masm32 debugger
« Reply #1 on: November 11, 2010, 08:49:43 AM »

The code you posted is not 16-bit DOS code. Was it supposed to be, or should I move this to the Campus?

Instead of using a debugger to view the results, you can display the results from the code by adding something like this:
Code:
movzx eax, sir
print str$(eax),13,10
movzx eax, sir+2
print str$(eax),13,10
movzx eax, sir+4
print str$(eax),13,10
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eschew obfuscation
pps
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Posts: 29


Re: Masm32 debugger
« Reply #2 on: November 11, 2010, 09:00:04 AM »

what is movzx? i tought it was mov only... Why isn't it 16 bit? I use only ax, bx and words not eax or doubles...?
I will try that, tanks!
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MichaelW
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Re: Masm32 debugger
« Reply #3 on: November 11, 2010, 09:53:26 AM »

It's not 16-bit code because it uses a 32-bit segment word size and a 32-bit memory model. Here are the first three statements in masm32rt.inc:
Code:
.486 ; create 32 bit code
.model flat, stdcall ; 32 bit memory model
option casemap :none ; case sensitive

You can verify this by trying to assemble a statement that tries to move a 32-bit address into a 16-bit register:

mov ax, OFFSET sir

For which ML will return:

error A2022: instruction operands must be the same size

Specifying SI in the indirect memory operands works because ML is actually encoding the instruction to use ESI. And the only reason that you are getting away with the:

mov si, 0

Instead of:

mov esi, 0

Is that ESI is initially zeroed.

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pps
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Posts: 29


Re: Masm32 debugger
« Reply #4 on: November 11, 2010, 07:17:41 PM »

sorry. I didn't knew that... what shoult I include for a 16 bit code?
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dedndave
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Re: Masm32 debugger
« Reply #5 on: November 11, 2010, 07:36:51 PM »

the masm32 library doesn't support 16-bit code
nor does link.exe - you have to use link16.exe, instead
attached is a zip that has all the stuff to try both   BigGrin

* hello.zip (2.25 KB - downloaded 311 times.)
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pps
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Re: Masm32 debugger
« Reply #6 on: November 12, 2010, 07:01:51 PM »

Ok, i got the ideea. I saw ur examples, and i solved some problems but i have some more. I should say that i started to make all the programs or problems(this is how we call them) that i have in masm32.
One problem is the next one. It works fine in tasm(16-bit) but here i have an error on mov ax,@DATA

the code:

Code:
;x=x-y+|x-|y||
TITLE pr11
.MODEL SMALL
.STACK 256
.DATA
x dw 5h
y dw 4h
.CODE
mov ax,@DATA
mov ds,ax

mov bx,offset x

mov ax,[bx+2]
cmp ax,0
jge salt1
neg ax
salt1:
neg ax
add ax,[bx]
cmp ax,0
jge salt2
neg ax
salt2:
sub ax,[bx+2]
add ax,[bx]
mov [bx],ax

mov ax,4c00h
int 21h
END
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dedndave
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Posts: 12523


Re: Masm32 debugger
« Reply #7 on: November 12, 2010, 07:47:56 PM »

that should work under masm
although - i have experienced something like it - lol
@DATA is actually an alias for DGROUP
DGROUP should be defined when .DATA is expanded in a SMALL model program
you might try _DATA or DGROUP
_DATA is the actual name of the data segment and DGROUP is DGROUP, without aliasing

also - the END directive should reference the program entry point - that may be the culprit

Code:
start:
mov ax,@DATA
.
.
.
END start

make sure you are using the right command line (i.e. batch file) to assemble
@DATA and the /coff switch aren't likely to get along well
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FORTRANS
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Imagine


Re: Masm32 debugger
« Reply #8 on: November 12, 2010, 08:00:08 PM »

Hi,

   Your code assembled fine with MASM 5.0.  So Dave may
have found your problem.

Regards,

Steve N.
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pps
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Re: Masm32 debugger
« Reply #9 on: November 14, 2010, 06:12:20 PM »

i tried with DGROUP and _DATA, nothing. i tried with segments and the same. If in include masm32rc.inc it works but have a problem on mov bx,offset x...
here is the changed code

Code:
;x=x-y+|x-|y||
TITLE pr11
.MODEL SMALL
.STACK 256
data segment
x dw 5h
y dw 4h

data ends
cod segment
assume ds:data, cs:cod
start:

mov ax,DATA
mov ds,ax

mov bx,offset x

mov ax,[bx+2]
cmp ax,0
jge salt1
neg ax
salt1:
neg ax
add ax,[bx]
cmp ax,0
jge salt2
neg ax
salt2:
sub ax,[bx+2]
add ax,[bx]
mov [bx],ax

mov ax,4c00h
int 21h
cod ends
   END start
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Magnum
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Re: Masm32 debugger
« Reply #10 on: November 14, 2010, 06:40:14 PM »

Since you are using Tasm, here is some Tasm code.

It's fairly well commented and demonstrates a lot of things that Tasm uses.

Code:
; SHRED1.ASM  Ver 1i   B/W version     
;                   (c) Copywrong 1996 - 2004
;                           Tasm code
;        ***** FILE is NOT recoverable !!!!  ****
;               
;        Supports Long Filenames
;        Works in Win XP in a DOS box, with short or long filenames
;
;       Shreds a 331 Meg file in 80 secs on an AMD K-6 475 MHz
;
;        Overwrite a file with zero bytes, truncates it to zero bytes,
;        set file time and date to 12:59:58 pm  1/1/80,
;        renames it and then deletes it.
;        Single files only. (For Safety)
;
; Use SHORT (8.3) FILENAME when file is a LFN
;                               Ex. C:\PROGRA~1\VERYLO~1.ASM
;
; Works across drives, handles periods in the path names
;
;         Help from Stealth, Raymond, Bitrake, Rudy Weiser, Frank Kotler,
;         Fauzan Mirza, Robert Redelmeier, QvasiModo, and others
;
.MODEL       SMALL       
.386
.stack       200h

.data?   ; can contain ONLY un-initialized data, keeps executable small
         
random       db       64000 dup(?)
file_name    db       128 dup(?)  ; DOS maximum path length
storage      db       150 dup(?)
                               
.data

handle       dw           ?
file_size    dd           ?
name_size    dw           ?


;  Direct video writes, shows right after Version number !!
;
prompt       db       13,10,13,10,9,'File Shredder   Ver. 1h'  ,13,10
             db       13,10,9,'(c) Copyright 1996 - 2004',13,10
             db       13,10,9,'IF YOU USE THIS PROGRAM, OVERWRITTEN FILES',13,10
             db       13,10,9,'WILL BE GONE FOR GOOD.  THIS PROGRAM CAUSES',13,10
             db       13,10,9,'PERMANENT DATA LOSS. YOU HAVE BEEN WARNED!!',13,10
             db       13,10,9,'Use SHORT (8.3) FILENAME when file is a LFN.',13,10
             db       13,10,9,'Use full path when not in current DIR/DRIVE',13,10
             db       13,10,9,'Usage: C:\PROGRA~1\FILENAME.ASM',13,10,13,10
             db       13,10,9,'File name to SHRED --> $'

not_there    db       13,10,13,10,13,9,'File not present.',13,10,'$'
emsg2        db       13,10,13,10,'Error moving file pointer.',13,10,'$'
emsg3        db       13,10,13,10,'Error writing to file.',13,10,'$'
done_msg     db       13,10,13,10,'File has been shredded.',13,10,'$'
eraser_name  db      '珀矣粤肄.',0

.code

start:                             
             mov          ah,15     ; clear the screen
             int          10h
             mov          ah,0
             int          10h

             mov          ax,@data
             mov          ds,ax             
             mov          es,ax  ; need for LFN functions
             mov          bx,00h ; write zeros into memory

zero_out:   ; Set memory to zero
             mov           [random + bx],00h
             inc           bx
             cmp           bx,64000
             jnz           zero_out
           
             mov          dx, offset prompt
             mov          ah,9
             int          21h
 
             mov          file_name,128      ; max characters in input
             mov          dx,offset file_name; get filename
             mov          ah,0ch             ; flush keyboard buffer
             mov          al,0ah             ; buffered keyboard input
             int          21h
             mov          cl,[file_name + 1] ; how many bytes read in
             add          cl,2           ; find position after last character
             mov          ch,00
             mov          si,cx              ; move count to index register
             mov          [name_size],cx     ; save size
             mov          file_name[si],00   ; make into ASCII string
                             
; Change any read-only attribute

change:
             lea          dx,file_name  + 2
             mov          ax,4301h
             mov          bl,01h         ; set attributes
;Bitfields for file attributes:  (CX register)
;Bit(s) Description (Table 01420)
; 7 shareable (Novell NetWare)
; 7 pending deleted files (Novell DOS, OpenDOS)
; 6 unused
; 5 archive
; 4 directory
; 3 volume label
; execute-only (Novell NetWare)
; 2 system
; 1 hidden
; 0 read-only

             mov          cx,00000000b   ; remove read-only attribute
             int          21h

;INT 21 - Windows95 - LONG FILENAME - CREATE OR OPEN FILE
; AX = 716Ch
; BX = access mode and sharing flags (see #01782,also AX=6C00h);
; CX = attributes
; DX = action (see #01781)
; DS:SI -> ASCIZ filename

open_it:

mov ax,716Ch ; create file
xor cx,cx ; file attributes

; file access modes (bits) BX register
;     000 read-only
;     001 write-only
;     010 read-write
;     100 read-only, do not modify file's last-access time

; Bitfields for Windows95 long-name open action: DX Register
; Bit(s) Description (Table 01781)
; 0 open file (fail if file does not exist)
; 1 truncate file if it already exists (fail if file does not exist)
; 4 create new file if file does not already exist (fail if exists)
; Note: the only valid combinations of multiple flags are bits 4&0 and 4&1


             mov          bx,00000001b       ; access mode - write only
             mov          dx,00000001b       ; open file
             lea          si,file_name + 2   ; sets the file name
             int          21h
             mov          [handle],ax        ; Save file handle
             jnc          short get_size     ; No errors, go on
no_file:             
             mov          dx,offset not_there; Get error message
             jmp          error              ; and go display/exit
get_size:
             mov          ax,4202h           ; Set file pointer
             mov          bx,[handle]        ; for this file
             xor          cx,cx              ; relative to end of file
             xor          dx,dx              ; offset 0 bytes
             int          21h
             jnc          save_size           
err2:
             mov          dx,offset emsg2    ; Get error message
             jmp          error              ; and go display/exit

save_size:
             mov          word ptr [file_size],ax     ; Save low word of file size
             mov          word ptr [file_size + 2],dx ; Save high word

             mov          ax,4200h           ; Move file pointer
             mov          bx,[handle]        ; for this file
             xor          cx,cx              ; relative to beginning of file
             xor          dx,dx              ; offset 0 bytes
             int          21h
             jc           err2               ; Errors: go handle

next_bunch:
             mov          cx,64000           ; Assume 64,000 bytes or more
                                             ; left to do

             sub          word ptr [file_size],cx   ; Is there ? - subtract it
             sbb          word ptr [file_size + 2],0 ; from saved file size

             jae          wipe                ; There were 64,000 bytes or
                                              ; more left
             
             mov          cx,word ptr [file_size] ; Get number of bytes left
             add          cx,64000                ; back CX (undo subtraction)

wipe:
             mov          ah,40h             ; Write file
             mov          bx,[handle]        ; Handle
             lea          dx,random   ; Write the random bytes
             int          21h
             jnc          check_size         ; No errors, go on

err3:
             mov          dx,offset emsg3    ; Get appropriate error message
             jmp          error              ; and go display/exit

check_size:
             cmp          ax,cx               
             jnz          err3               
             cmp          ax,64000           ; Full 64,000 bytes written,
             je           next_bunch         ; yes, go check for more
             jmp          SHORT $+2          ; short delay cuz sometimes
                                             ; file isn't renamed
                                             ;
             mov          bx,[handle]        ; close file
             mov          ah,3eh
             int          21h

trunc:

; Truncate file to zero bytes

             mov          ah,3ch        ; truncate file to zero bytes
             mov          cx,0
             mov          dx,offset file_name + 2
             int          21h
                       
             mov          bx,[handle]   ; close file
             mov          ah,3eh
             int          21h
             
; Store the path

scan:
             lea      si,[file_name + 2]
             xor      cx,cx
             mov      di,si
             mov      cx,[name_size]

             mov      al,'\'             
             add      di,cx
             std                          ; scan from right to left
             dec      di
             repne    scasb               
             jnz      short no_path       ;  No slash is present
             add      cx,1                ;

no_path:
             mov      di,offset storage
             cld                          ; change directions and scan
             rep      movsb               ; from left to right
             mov      al,00
             stosb                        ; make path ASCIZ
             ;STOP
; Add on eraser_name to end of storage

add_eraser:

             mov      cx,[name_size]
             mov      si,cx
             lea      di,storage
             mov      al,00             ; stops at the byte after the "00"
             repnz    scasb
             dec      di                ; backup one

             xor      cx,cx
             mov      si,offset eraser_name
             mov      cx,9  ; # of characters
             rep      movsb

; Rename and delete file   (LFN)

rename:
             mov          dx,offset file_name + 2  ; old file name
             mov          di,offset storage
             mov          ax,7156h                 ; LFN support
             int          21h

; Change file date and time

        mov     ax,716Ch        ; open file
        xor     cx,cx   ; file attributes

; file access modes (bits) FOR BX Register
;       000 read-only
; 001 write-only
; 010 read-write
; 100 read-only, do not modify file's last-access time
;       set bit 14 - commit file after every write operation

        mov     bx,00000000000000010b         ; access mode (R/W)
                                           
        mov     dx,1              ; open file
        lea     si,storage        ; sets the file name
        int     21h
        mov     bx,ax             ; save file handle
        push    bx

        mov     ax,5701h ; change file date
                         ; BITS 5-10 are minutes, 11-15 are hours
        mov     cx,677dh ; 12:59:58 pm  110011101111101b
                         ;
                         ; BITS 0-4 are day, 5-8 are month, 9-15 (year - 1980)
        mov     dx,021h  ; 1/1/80    0000000000100001b
        int     21h

        pop     bx

;INT 21 U - DOS 4.0+ - COMMIT FILE
; AH = 6Ah
; BX = file handle

        mov     ah,6ah   ; make sure this file is written to disk
        int     21h

        mov     ah,3eh   ; close file
        int     21h

; INT 21 - Windows95 - LONG FILENAME - DELETE FILE
;           AX = 7141h
;           DS:DX -> ASCIZ long name of file to delete

             mov          dx,offset storage    ; delete file
             mov          ax,7141h
             xor          si,si
             int          21h
                                               ; idea from Fauzan Mirza
             xor          ax,ax                ; Zero out file_name
             mov          di,offset storage + 2
             mov          cx,150
             rep          stosb

finito:
             mov          ah,9
             mov          dx,offset done_msg
             int          21h
             mov          ax,4c00h           ; Set errorlevel to 0
             int          21h
error:
             mov          ah,9
             int          21h
             mov          ax,4c01h           ; Set errorlevel to 1
             int          21h

end     start


Have a great day,
                          Andy

http://intouch.org/magazine/daily-devotional
http://www.happynews.com
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Have a great day,
Andy
dedndave
Member
*****
Posts: 12523


Re: Masm32 debugger
« Reply #11 on: November 14, 2010, 06:57:26 PM »

ok - let's get you where you can assemble - lol

the program you posted assembles fine for me (although, you should stay with @DATA)
so, you are probably using a different linker or batch file than i am

here is how i have my system set up

1) i have installed masm32 as C:\masm32

2) in the masm32 folder, a subfolder is created called bin (C:\masm32\bin)
this is where executables go, including batch files
make sure you have A16.BAT and LINK16.EXE in that folder
i have attached a zip than contains all the files you need
note: my copy of A16.BAT has been modified to create assembler listings

3) there is an environment variable called PATH
this variable is likely already created, and includes a few to several path-names
these paths are seperated by a semicolon
somewhere in that variable, you want to add C:\masm32\bin seperated from the other paths with semicolons

a) My Computer - Properties
Advanced tab
Environment Variables button
the bottom window is for System variables - this is the best place to add this path
find the Path variable in that list and modify it as mentioned above

4) in the masm32 folder, i have created a woking folder named Asm (C:\masm32\Asm)
this is where i play around with programs that are too small to require a project folder of their own
place the ASM file in that folder
open a console window and change to that directory
from there, you should be able to use A16 to assemble 16 bit programs:

A16 MyProg

the .ASM file extension is not required

from there, you may use a debugger to step through the program
i have included SymDeb.exe
place it in the masm32\bin folder, as well

SymDeb MyProg.exe

after that, you may use the "T" command to step through the program - "Q" to exit

note: in the attached archive, i have included your program
i have changed it to use .DATA, .CODE, and @DATA

* MyProg.zip (26.27 KB - downloaded 326 times.)
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