src/backend/port/tas/sunstudio_sparc.s

   1 !-------------------------------------------------------------------------
   2 !
   3 ! sunstudio_sparc.s
   4 !         compare and swap for Sun Studio on Sparc
   5 !
   6 ! Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
   7 ! Portions Copyright (c) 1994, Regents of the University of California
   8 !
   9 ! IDENTIFICATION
  10 !         $PostgreSQL$
  11 !
  12 !-------------------------------------------------------------------------
  13
  14 ! Fortunately the Sun compiler can process cpp conditionals with -P
  15
  16 ! '/' is the comment for x86, while '!' is the comment for Sparc
  17
  18 #if defined(__sparcv9) || defined(__sparc)
  19
  20         .section        ".text"
  21         .align  8
  22         .skip   24
  23         .align  4
  24
  25         .global pg_atomic_cas
  26 pg_atomic_cas:
  27
  28         ! "cas" only works on sparcv9 and sparcv8plus chips, and
  29         ! requies a compiler targeting these CPUs.  It will fail
  30         ! on a compiler targeting sparcv8, and of course will not
  31         ! be understood by a sparcv8 CPU.  gcc continues to use
  32         ! "ldstub" because it targets sparcv7.
  33         !
  34         ! There is actually a trick for embedding "cas" in a
  35         ! sparcv8-targeted compiler, but it can only be run
  36         ! on a sparcv8plus/v9 cpus:
  37         !
  38         !   http://cvs.opensolaris.org/source/xref/on/usr/src/lib/libc/sparc/threads/sparc.il
  39         !
  40
  41 #if defined(__sparcv9) || defined(__sparcv8plus)
  42         cas     [%o0],%o2,%o1
  43 #else
  44         ldstub [%o0],%o1
  45 #endif
  46         mov     %o1,%o0
  47         retl
  48         nop
  49         .type   pg_atomic_cas,2
  50         .size   pg_atomic_cas,(.-pg_atomic_cas)
  51 #endif