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+/* $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_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_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