Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/* $Id: locks.S,v 1.16 2000/02/26 11:02:47 anton Exp $
 * locks.S: SMP low-level lock primitives on Sparc.
 *
 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
 * Copyright (C) 1998 Anton Blanchard (anton@progsoc.uts.edu.au)
 * Copyright (C) 1998 Jakub Jelinek   (jj@ultra.linux.cz)
 */

#include <asm/ptrace.h>
#include <asm/psr.h>
#include <asm/smp.h>
#include <asm/spinlock.h>

        .text
        .align  4

        /* Read/writer locks, as usual this is overly clever to make it
         * as fast as possible.
         */

        /* caches... */
___rw_read_enter_spin_on_wlock:
        orcc    %g2, 0x0, %g0
        be,a    ___rw_read_enter
         ldstub [%g1 + 3], %g2
        b       ___rw_read_enter_spin_on_wlock
         ldub   [%g1 + 3], %g2
___rw_read_try_spin_on_wlock:
        andcc   %g2, 0xff, %g0
        be,a    ___rw_read_try
         ldstub [%g1 + 3], %g2
        xnorcc  %g2, 0x0, %o0   /* if g2 is ~0, set o0 to 0 and bugger off */
        bne,a   ___rw_read_enter_spin_on_wlock
         ld     [%g1], %g2
        retl
         mov    %g4, %o7
___rw_read_exit_spin_on_wlock:
        orcc    %g2, 0x0, %g0
        be,a    ___rw_read_exit
         ldstub [%g1 + 3], %g2
        b       ___rw_read_exit_spin_on_wlock
         ldub   [%g1 + 3], %g2
___rw_write_enter_spin_on_wlock:
        orcc    %g2, 0x0, %g0
        be,a    ___rw_write_enter
         ldstub [%g1 + 3], %g2
        b       ___rw_write_enter_spin_on_wlock
         ld     [%g1], %g2

        .globl  ___rw_read_enter
___rw_read_enter:
        orcc    %g2, 0x0, %g0
        bne,a   ___rw_read_enter_spin_on_wlock
         ldub   [%g1 + 3], %g2
        ld      [%g1], %g2
        add     %g2, 1, %g2
        st      %g2, [%g1]
        retl
         mov    %g4, %o7

        .globl  ___rw_read_exit
___rw_read_exit:
        orcc    %g2, 0x0, %g0
        bne,a   ___rw_read_exit_spin_on_wlock
         ldub   [%g1 + 3], %g2
        ld      [%g1], %g2
        sub     %g2, 0x1ff, %g2
        st      %g2, [%g1]
        retl
         mov    %g4, %o7

        .globl  ___rw_read_try
___rw_read_try:
        orcc    %g2, 0x0, %g0
        bne     ___rw_read_try_spin_on_wlock
         ld     [%g1], %g2
        add     %g2, 1, %g2
        st      %g2, [%g1]
        set     1, %o1
        retl
         mov    %g4, %o7

        .globl  ___rw_write_enter
___rw_write_enter:
        orcc    %g2, 0x0, %g0
        bne     ___rw_write_enter_spin_on_wlock
         ld     [%g1], %g2
        andncc  %g2, 0xff, %g0
        bne,a   ___rw_write_enter_spin_on_wlock
         stb    %g0, [%g1 + 3]
        retl
         mov    %g4, %o7