arch/sparc/lib/locks.S

   1 /* $Id: locks.S,v 1.16 2000/02/26 11:02:47 anton Exp $
   2  * locks.S: SMP low-level lock primitives on Sparc.
   3  *
   4  * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
   5  * Copyright (C) 1998 Anton Blanchard (anton@progsoc.uts.edu.au)
   6  * Copyright (C) 1998 Jakub Jelinek   (jj@ultra.linux.cz)
   7  */
   8
   9 #include <asm/ptrace.h>
  10 #include <asm/psr.h>
  11 #include <asm/smp.h>
  12 #include <asm/spinlock.h>
  13
  14         .text
  15         .align  4
  16
  17         /* Read/writer locks, as usual this is overly clever to make it
  18          * as fast as possible.
  19          */
  20
  21         /* caches... */
  22 ___rw_read_enter_spin_on_wlock:
  23         orcc    %g2, 0x0, %g0
  24         be,a    ___rw_read_enter
  25          ldstub [%g1 + 3], %g2
  26         b       ___rw_read_enter_spin_on_wlock
  27          ldub   [%g1 + 3], %g2
  28 ___rw_read_exit_spin_on_wlock:
  29         orcc    %g2, 0x0, %g0
  30         be,a    ___rw_read_exit
  31          ldstub [%g1 + 3], %g2
  32         b       ___rw_read_exit_spin_on_wlock
  33          ldub   [%g1 + 3], %g2
  34 ___rw_write_enter_spin_on_wlock:
  35         orcc    %g2, 0x0, %g0
  36         be,a    ___rw_write_enter
  37          ldstub [%g1 + 3], %g2
  38         b       ___rw_write_enter_spin_on_wlock
  39          ld     [%g1], %g2
  40
  41         .globl  ___rw_read_enter
  42 ___rw_read_enter:
  43         orcc    %g2, 0x0, %g0
  44         bne,a   ___rw_read_enter_spin_on_wlock
  45          ldub   [%g1 + 3], %g2
  46         ld      [%g1], %g2
  47         add     %g2, 1, %g2
  48         st      %g2, [%g1]
  49         retl
  50          mov    %g4, %o7
  51
  52         .globl  ___rw_read_exit
  53 ___rw_read_exit:
  54         orcc    %g2, 0x0, %g0
  55         bne,a   ___rw_read_exit_spin_on_wlock
  56          ldub   [%g1 + 3], %g2
  57         ld      [%g1], %g2
  58         sub     %g2, 0x1ff, %g2
  59         st      %g2, [%g1]
  60         retl
  61          mov    %g4, %o7
  62
  63         .globl  ___rw_write_enter
  64 ___rw_write_enter:
  65         orcc    %g2, 0x0, %g0
  66         bne     ___rw_write_enter_spin_on_wlock
  67          ld     [%g1], %g2
  68         andncc  %g2, 0xff, %g0
  69         bne,a   ___rw_write_enter_spin_on_wlock
  70          stb    %g0, [%g1 + 3]
  71         retl
  72          mov    %g4, %o7