[Issue 2076] New: offset doesn't work in asm

[d-bugmail at puremagic.com]

http://d.puremagic.com/issues/show_bug.cgi?id=2076

           Summary: offset doesn't work in asm
           Product: D
           Version: 1.028
          Platform: PC
        OS/Version: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla at digitalmars.com
        ReportedBy: clugdbug at yahoo.com.au


I wanted to get the address of a label into a register. This seems to be
impossible at present. I tried various things, including the code below, which
prints:
-----
Error: offset deprecated, use offsetof

which (a) gives no line number; and (b) in the spec, 'offset' is permitted in
asm (and offsetof is not mentioned).
-----

void main()
{
    asm {
        mov EAX, offset L1;
    L1:
    ;
    }
}

Finally,
bug(c):
mov EAX, $; doesn't work either. It seems that $ only works in jmp
instructions?
This is either a compiler bug, or should be mentioned in the spec.

So it seems that there is no way to get the current address into a register.
This limitation means that there's no way to (efficiently) implement duff's
device in asm. But it's probably a side-effect of there being no way to take
the address of a label in normal D code.


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