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@digitalmars.com
        ReportedBy: clugdbug@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.


-- 

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


clugdbug@yahoo.com.au changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|offset doesn't work in asm  |asm: offset has wrong docs
                   |                            |and error without line
                   |                            |number




------- Comment #1 from clugdbug@yahoo.com.au  2008-06-24 08:06 -------
The inability to get the address of a label is the same bug as 1829.
Changing this to be a documentation bug:
* spec mentions offset, should be offsetof.
* spec mentions seg, which doesn't seem to work (and has no purpose in any
32-bit OS which I know of)
* spec should state that $ only works in jump instructions.

Also has an error without line number. (Note that it would also be possible to remove the 'offset deprecated' message entirely. It's been years since it was valid.)


-- 

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


clugdbug@yahoo.com.au changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED




------- Comment #2 from clugdbug@yahoo.com.au  2008-07-09 07:15 -------
Fixed DMD1.032


-- 

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





------- Comment #3 from bugzilla@digitalmars.com  2008-07-09 22:42 -------
Fixed dmd 2.016


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