Setting class variable from inline assembly

[Thomas Kuehne]

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pmoore schrieb am 2006-05-20:
> Hi,
>
> It seems that within inline assembly I can read a class variable but I can't set
> it. Is this a bug or is there a good reason for this?
>
> uint myvar;
>
> void main()
> {
> }
>
> class AClass
> {
> uint myvar2;
>
> this()
> {
> asm
> {
> mov EAX,myvar;
> mov myvar,EAX;  // this is fine
>
> mov EAX,myvar2; // no problem reading
> mov myvar2,EAX;	// doesn't compile - bad type/size of operands 'mov'
> }
> }
> }

mov EAX,myvar2; seems to move the offset of myvar2 - not the value:

# import std.stdio;
# 
# class C{
#    int i;
# 
#    void foo(){
#       int x;
#       
#       asm{
#          mov EAX, i;
#          mov x, EAX;
#       }
# 
#       writefln("%s at 0x%X -> 0x%X, %s", i, &i, x, x);
#       writefln("offset of i: %s", i.offsetof);
#    }
# }
# 
# int main(){
#    C c = new C();
#    c.foo();
# 
#    return 0;
# }

What you are looking for is:
#       void* p = this;
# 
#       asm{
#          mov EBX, p;
#          mov EAX, [EBX+myvar2];
#          // something productive here
#          mov [EBX+myvar2], EBX;
#       }

Thomas


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