Getting Started with Masm 32

[WayneSallee]

I'm working on converting a 16 bit program to a 32 bit program. Fun fun :-) What role can the segment registers play. Can I use them freely as 16 registers, or is the use of them prohibited. Or what role do they play if any in 32 bit programing?

Wayne Sallee
Wayne@WayneSallee.com

[hutch--]

Wayne,

You don't use segment registers in 32 bit code as they are set to the same starting address for FLAT memory model. Count it as a blessing.  :toothy

[Mark Jones]

Hello Wayne, welcome to the forum. :)

Please see this thread about the 16-bit registers: http://www.masmforum.com/simple/index.php?topic=1362.0

I found that information by using the little search box above.

That said, I would not recommend starting your 32-bit journey with such a complex task. Look at the Iczelion tutorials included with MASM32, that's probably your best way to get accustomed to this new style of coding.

Good luck and have fun.

[GregL]

Wayne,

Are you talking about the DOS-based IDE that came with MASM 6.1?. Wasn't it called 'Programmer's Workbench'? It's been more than a decade since I used it. There are IDEs for MASM that run on 32-bit Windows. The one that comes with MASM32 is QEdit, some others are WinAsm and RadAsm. Otherwise it's done from the command-line.

[pbrennick]

[Shameless Plug]Don't forget EasyCode.[/Shameless Plug]

Paul

[Mark Jones]

I was thinking the same thing Paul, but you beat me to it. :)

[WayneSallee]

.DATA

.CODE

.DATA

.CODE

.DATA

This is getting old. did not have to do it when programing in 16 bit. Is there a way around having to tell it every time that it's now data, or now code?

Also what's a good book to buy that would be best for me with my move from 16 bit to 32 bit, preferably one without a lot of higher code, but a rather pure assebly language code?

Wayne Sallee
Wayne@WayneSallee.com

[hutch--]

 :bg

Wayne,

Yes there is a way around it, write all of you data to the data section in one ".data" notation. The capacity to use,

Code Select Expand


.data
  somedata dd 0
.code


is there if you need to split up code and data.

[AeroASM]

Iczelions Win32 tutorials are very good:

http://win32assembly.online.fr/tutorials.html

[WayneSallee]

:bg


is there if you need to split up code and data.

I like putting the data with the subrotines that use it. That's my prefered way to organize it, and it was simple with masm16, but with masm32 I find that I have to insert .code, and .data.  So I thought I would check to see if there was a way to still do it without having to inset .code, and .data.

Is there some reasoning behind this that I don't understand? It seems so much simpler to mix the code with the data instead of having it segmented. Is there some reasoning behind this that I don't understand?

Wayne Sallee
Wayne@WayneSallee.com

[QvasiModo]

Hi all :)

Is there some reasoning behind this that I don't understand? It seems so much simpler to mix the code with the data instead of having it segmented. Is there some reasoning behind this that I don't understand?

The main reason is the fact that under modern OSs the code section is read-only.

Speed is another reason. For old processors it used to be all the same, but now mixing code and data is bad: it makes the processor waste bandwidth fetching data into the code cache, and invalid opcodes are slower to decode.

[AeroASM]

INside procedures you can use stack space for local variables like this:

Code Select Expand


MyProc proc arg1:DWORD,arg2:DWORD

LOCAL Var1:DWORD
LOCAL Var2:DWORD

...

ret

MyProc endp


[WayneSallee]

Still working on changing my code over to 32 bit.

I can't even get a PUSH   EBX to work. I don't get any errors on assembly, but when I run it, microsoft gives an error that it has to be shut down. I can put ret's before push statements, but if a push is read, it errors.

Is there some kind of stack preperation that I have to do that I didn't have to mess with on 16 bit?

Wayne Sallee
Wayne@WayneSallee.com

[AeroASM]

The only way that push ebx could fail at the OS level is if you mess up the stack pointer esp.

Please could you post the offending code?

[WayneSallee]

No microsoft does not have to shut down. Microsoft shuts down my program.

Now I found the problem. It's erroring on that fact that I ret without poping the stack to ballance it out. So it's the ret that is creating the error, not the push

I was using the ret to debug, and was actualy creating a bug.

Ok back to de work :-)

Wayne Sallee
Wayne@WayneSallee.com