What's wrong with this MOV?

[frktons]

Hi.
I'm wondering why this MOV gives me an error during compilation:

Code Select Expand


    mov NumFmt.lpDecimalSep,  lpSep  ; Pointer to NULL terminated string with the decimal separator
    mov NumFmt.lpThousandSep, lpTsep ; Pointer to NULL terminated string with the thousand separator


error:

Code Select Expand


Microsoft (R) Macro Assembler Version 10.00.30319.01
Copyright (C) Microsoft Corporation.  All rights reserved.

Assembling: C:\masm32\examples\format_number2.asm
C:\masm32\examples\format_number2.asm(45) : error A2070:invalid instruction operands
C:\masm32\examples\format_number2.asm(46) : error A2070:invalid instruction operands
_
Assembly Error
. . .


and this version is accepted and works:

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    mov NumFmt.lpDecimalSep,  offset Sep  ; Pointer to NULL terminated string with the decimal separator
    mov NumFmt.lpThousandSep, offset Tsep ; Pointer to NULL terminated string with the thousand separator


I define lpSep and lpTsep this way:

Code Select Expand


.data
    Sep         DB  ",",0
    lpSep       DD  Sep
    Tsep        DD  ".",0
    lpTsep      DD  Tsep 


and the input fields are defined:

Code Select Expand


    lpDecimalSep      DWORD      ?
    lpThousandSep     DWORD      ?

inside the NumFmt structure.  ::)

[redskull]

The first version is a memory-to-memory MOV (the value at the address 'lpSep' trying to be moved to the address of "NumFmt+lpDecimalSep').  The second way is proper (moving the address of Sep into the address of "NumFmt+lpDecimalSep'.  Or, alternatively, you could move lpSep into a register first.

-r

[frktons]

The first version is a memory-to-memory MOV (the value at the address 'lpSep' trying to be moved to the address of "NumFmt+lpDecimalSep').  The second way is proper (moving the address of Sep into the address of "NumFmt+lpDecimalSep'.  Or, alternatively, you could move lpSep into a register first.

-r

Woops!!! memory to memory.  :red
Thanks redskull  :U

[Farabi]

If you want to save bytes on moving memory to memory use push and pop instruction, or use M2M macro, but it slower compared to mov, if Im not mistaken.

[frktons]

If you want to save bytes on moving memory to memory use push and pop instruction, or use M2M macro, but it slower compared to mov, if Im not mistaken.

Thanks Farabi. I know how to do it, but I forgot it in this occasion  :P