Computed gotos on Reddit

[Walter Bright]

On 7/25/2012 2:55 PM, Dmitry Olshansky wrote:
>>>>> std\regex.d(5118): Error: undefined identifier 'L_jumptable'
>>>>>
>>>>
>>>> I was afraid of that. You may have to approximate it by loading the
>>>> address of L_jumptable into a register and adding it in instead of using
>>>> the addressing mode.
>
> I failed to load it in any register or interact with it in any way.
> I think I've stalled. There has to be a way to get label address somehow, I got
> tired of guess and shot :(
>
> BTW that would allow us to do computed gotos but only in inline asm.
>

How to get an address:

      call jump_table
L1:

      ...
jump_table:
      pop EAX
      jmp L1
      .. the rest of the jump table ...

Yes, it's awful, but we're just trying to take some measurements here, so it 
doesn't matter.

What I meant was add these extra instructions in to the switch version as 
dummies in order to make the extra time they take irrelevant to looking at the 
difference.