Hi, I've got a newbie question about string handling:

ok, so let's say i'm writing a hello world program and have the following code:



ok, so my question is does dx contain the memory address for the string hello? when you do mov's on variables, does it just move the memory addresses?

-crackrock

hello is address, [hello] is the character that hello address contain. [hello]='H', [hello+1]='e' etc...

"mov dx,hello" puts a memory pointer to the hello world string into the DX register. When you do mov's it doesn't always move memory addresses, it depends on how you use the command, below are examples.

check my tutorial it's nicely explained there. Somewhat lot to read but you can be sure you understand it.

yes & no, yes

MOV DX,HELLO ;move offset adr of HELLO to DX reg

SEG:OFF = SEGMENT:OFFSET address=adr is the full adr required to
address memory for read/write, but in ASM the DS seg reg is default
so the adr of HELLO is held in DS:DX after your MOV DX,HELLO
but DS is not updated by the MOV,
so you have to set DS to your data segment where the HELLO data
is located before the INT 21h instruction.
In a .COM file DS=CS at startup
in an .EXE file, data seg is not= to CS=Code Segment = text

(You need a JMP OVERhello to get IP=Instruction Pointer over the
HELLO data during "run time" = program execution.)

There might be some stuff that interests you in this ENV thingie,
http://bitdog.home.att.net/files/fasmenv.zip
unzips to path and creates an environment/dir-tree.