synchronized vs. C volatile

[SK]

On Mon, Aug 9, 2010 at 9:55 AM, Lutger <lutger.blijdestijn at gmail.com> wrote:
>
> I'm not an expert on this, but if I am not mistaken the shared type
qualifier
> will handle the barriers, require atomic ops and prevent reordering
compiler
> optimizations so it looks like this one will take care of what volatile
used to
> do, right?
>
>

Seems the latest dmd in svn hasn't implemented shared atomics yet anyway.
If it had, we'd see a lock prefix in use.

$ cat main.d
shared int x = 1;
int main()
{
 x = x + 1;
 ++x;
 return 0;
}
$ dmd -O -w -wi main.d
$ objdump -d main.o

main.o:     file format elf32-i386


Disassembly of section .text:

00000000 <.text>:
   0:   c3                      ret
   1:   60                      pusha
   2:   b8 14 00 00 00          mov    $0x14,%eax
   7:   b9 00 00 00 00          mov    $0x0,%ecx
   c:   8b 11                   mov    (%ecx),%edx
   e:   89 10                   mov    %edx,(%eax)
  10:   89 01                   mov    %eax,(%ecx)
  12:   61                      popa
  13:   c3                      ret

Disassembly of section .text._Dmain:

00000000 <_Dmain>:
   0:   55                      push   %ebp
   1:   a1 00 00 00 00          mov    0x0,%eax
   6:   40                      inc    %eax
   7:   a3 00 00 00 00          mov    %eax,0x0
   c:   8b ec                   mov    %esp,%ebp
   e:   31 c0                   xor    %eax,%eax
  10:   83 05 00 00 00 00 01    addl   $0x1,0x0
  17:   5d                      pop    %ebp
  18:   c3                      ret
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