home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
C!T ROM 2
/
ctrom_ii_b.zip
/
ctrom_ii_b
/
PROGRAM
/
PASCAL
/
PASTUT34
/
ASSEMBLY.TXT
< prev
next >
Wrap
Text File
|
1990-03-24
|
3KB
|
44 lines
ASSEMBLY LANGUAGE EXAMPLE.
--------------------------
This simple example shows how to place numerical values into a chosen
part of the data segment of memory. The offset values, starting at
0400, are seen below in the MOV WORD PTR [0400] statement.
The whole process is controlled from the DEBUG utility.
A:>debug
-a 0100
4DFC:0100 mov word ptr [0400],1234 {
4DFC:0106 mov word ptr [0402],5678 { Four lines for placing words
4DFC:010C mov byte ptr [0404],90 { or byte in consecutive memory
4DFC:0111 mov word ptr [0405],abcd { locations.
4DFC:0117 int 20 { Interrupt to terminate program.
4DFC:0119
-r cx { To check value in CX register.
CX 0000
:19 { New value of 19 entered.
-n assem.com { Program named ASSEM.COM
-w { Program written to disk.
Writing 0019 bytes
-g { Program run.
Program terminated normally
-d ds:0400 { 'Dump' of part of data segment.
4DFC:0400 34 12 78 56 90 CD AB 00-00 00 00 00 00 00 00 00 4.xV............
4DFC:0410 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................
4DFC:0420 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................
4DFC:0430 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................
4DFC:0440 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................
4DFC:0450 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................
4DFC:0460 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................
4DFC:0470 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................
-q
It can clearly be seen that the appropriate numerical values have been
placed in memory. Note that the low byte always appears first, so that
1234 appears as 34 12. Note also that debug dump attempts to interpret
the contents of memory. 34 is the ASCII value for decimal value 4 and
78 is ASCII value for x, etc.