Assume with different structures?

[LordAdef]

Hi everyone,

I am trying to compress some code.
I've got a single procedure that I need to invoke from different places, and I need to "assume edi: ptr *different structures", depending from where it's called.

I tried using "equ" but...it doens't work:

before calling:
current_structure equ ptr struct_foo

and in the proc:
assume edi: current_structure

I am using a very poor workaround, but it's very unreliable, I think.

Any ideas?
Alex

[NoCforMe]

MASM?
So far as I know, ASSUME was only used to control segment register usage in 16-bit code. I've never heard of it being used in the way you propose.

What are you trying to do here? Why not just use EDI with the name of the structure as a pointer?

Code Select Expand

SOMETHING STRUC
   a DD ?
   b DD ?
   c DD ?
SOMETHING ENDS

; set EDI to point to a structure element,
; then address it thus:
MOV EAX, [EDI].SOMETHING.a
MOV ECX, [EDI].SOMETHING.b
MOV EDX, [EDI].SOMETHING.c


[sinsi]

Or, alternatively

Code Select Expand

SOMETHING STRUC
   a1 DD ?
   b2 DD ?
   c3 DD ?
SOMETHING ENDS

ASSUME EDI:PTR SOMETHING
MOV EAX, [EDI].a1
MOV ECX, [EDI].b2
MOV EDX, [EDI].c3
        ...
ASSUME EDI:NOTHING


[NoCforMe]

So all this is to avoid typing 10 characters per statement.
OK.

[sinsi]

So all this is to avoid typing 10 characters per statement.
OK.

It's a PITA to fill a WNDCLASSEX structure - an extra 120 characters. Better things to do

[zedd151]

Looks cleaner and less messy as well. 
If it was nested structures though, the other way would prolly be better?

[sinsi]

Sometimes the explicit way is better, you are in no doubt.

Code Select Expand

  mov eax,[edi].nCount  ;a bit ambiguous
  mov eax,[edi].MYSTRUCT.nCount  ;obvious
A bit hypocritical, but I use the long version by habit - no ASSUME in ML64

[NoCforMe]

So all this is to avoid typing 10 characters per statement.
OK.

It's a PITA to fill a WNDCLASSEX structure - an extra 120 characters. Better things to do

Ever hear of copy & paste?

[sinsi]

Ever hear of copy & paste?

Ever heard of intellisense? Or auto-complete?

Maybe we should wait for Alex to reply, I'm not sure I understood his question.
Let's try and avoid polluting the topic eh?

[_japheth]

before calling:
current_structure equ ptr struct_foo

and in the proc:
assume edi: current_structure

That's not possible with ASSUME. ASSUME is an assembly-time thing, and the assembler, when assembling your PROC, simply doesn't know in what context your PROC is called. You'd have to differentiate the cases inside the procedure and then use multiple ASSUMES inside it - definitely not a good "solution".

[daydreamer]

Sometimes the explicit way is better, you are in no doubt.

Code Select Expand

  mov eax,[edi].nCount  ;a bit ambiguous
  mov eax,[edi].MYSTRUCT.nCount  ;obvious
A bit hypocritical, but I use the long version by habit - no ASSUME in ML64

Alternative Solution with create a macro and use it multiple times in source saves typing ?
David using macros as production tool predates windows 3.11 copy and paste
Or  built up library of .inc files

[jj2007]

Hi Alex,
What do you mean with "equ doesn't work"?

Code Select Expand

LOCAL rc1:RECT, rc2:RECT
...
push esi
push edi
lea esi, rc1
lea edi, rc2
invoke GetWindowRect, hMain, esi ; addr rcw
invoke GetClientRect, hMain, edi ; addr rcc
rcw equ [esi.RECT]
rcc equ [edi.RECT]
print chr$(13, 10)
print str$(rcw.left), 9, "WinRect left", 13, 10
print str$(rcw.top), 9, "WinRect top", 13, 10
print str$(rcw.right), 9, "WinRect right", 13, 10
print str$(rcw.bottom), 9, "WinRect bottom", 13, 10
print str$(rcc.left), 9, "ClientRect left", 13, 10
print str$(rcc.top), 9, "ClientRect top", 13, 10
print str$(rcc.right), 9, "ClientRect right", 13, 10
print str$(rcc.bottom), 9, "ClientRect bottom", 13, 10
pop edi
pop esi


[ognil]

Alternative Solution with create a macro and use it multiple times in source saves typing ?

In pure MASM64 I use:

Code Select Expand

It_is_WM_NOTIFY:
                        mov     rax, r9                               ; lParam                   
                        mov     rcx, hEdit
                        cmp     (NMHDR ptr [rax])._code, EN_SELCHANGE ; nphdr->code = EN_SELCHANGE = 702h   
                        jnz     @Ret                                               
                        cmp     (NMHDR ptr [rax]).hwndFrom, rcx       ; nphdr->hwndFrom = hEdit           
                        jnz     @Ret 

[jj2007]

Code Select Expand

                        mov     rax, r9                               ; lParam                   
                        mov     rcx, hEdit
                        cmp     (NMHDR ptr [rax])._code, EN_SELCHANGE
Any good reason not to use NMHDR ptr [r9]?

[ognil]

Any good reason not to use NMHDR ptr [r9]?

Code Select Expand

WndProc           proc
                        cmp     rdx, WM_NOTIFY
                        je      It_is_WM_NOTIFYI prefer to use registers RCX, RDX, R8 and R9 whenever possible instead of variables and so I need to duplicate R9 in RAX for its use with modification in subsequent code.
I am deeply sorry that using RAX instead of R9 has caused you so much trouble.