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| author | David S. Miller <davem@davemloft.net> | 2005-09-15 08:47:01 +0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2005-09-15 08:47:01 +0400 |
| commit | 4db2ce0199f04b6e99999f22e28ef9a0ae5f0d2f (patch) | |
| tree | 87a00c97e02a77cdfec517398caa3f1d8f6a2f0d /arch/sparc64/lib/dec_and_lock.S | |
| parent | 4a805e863d6b9466baf7084e1d6fdbe6e0628d8e (diff) | |
| download | linux-4db2ce0199f04b6e99999f22e28ef9a0ae5f0d2f.tar.xz | |
[LIB]: Consolidate _atomic_dec_and_lock()
Several implementations were essentialy a common piece of C code using
the cmpxchg() macro. Put the implementation in one spot that everyone
can share, and convert sparc64 over to using this.
Alpha is the lone arch-specific implementation, which codes up a
special fast path for the common case in order to avoid GP reloading
which a pure C version would require.
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/sparc64/lib/dec_and_lock.S')
| -rw-r--r-- | arch/sparc64/lib/dec_and_lock.S | 80 |
1 files changed, 0 insertions, 80 deletions
diff --git a/arch/sparc64/lib/dec_and_lock.S b/arch/sparc64/lib/dec_and_lock.S deleted file mode 100644 index 8ee288dd0afc..000000000000 --- a/arch/sparc64/lib/dec_and_lock.S +++ /dev/null @@ -1,80 +0,0 @@ -/* $Id: dec_and_lock.S,v 1.5 2001/11/18 00:12:56 davem Exp $ - * dec_and_lock.S: Sparc64 version of "atomic_dec_and_lock()" - * using cas and ldstub instructions. - * - * Copyright (C) 2000 David S. Miller (davem@redhat.com) - */ -#include <linux/config.h> -#include <asm/thread_info.h> - - .text - .align 64 - - /* CAS basically works like this: - * - * void CAS(MEM, REG1, REG2) - * { - * START_ATOMIC(); - * if (*(MEM) == REG1) { - * TMP = *(MEM); - * *(MEM) = REG2; - * REG2 = TMP; - * } else - * REG2 = *(MEM); - * END_ATOMIC(); - * } - */ - - .globl _atomic_dec_and_lock -_atomic_dec_and_lock: /* %o0 = counter, %o1 = lock */ -loop1: lduw [%o0], %g2 - subcc %g2, 1, %g7 - be,pn %icc, start_to_zero - nop -nzero: cas [%o0], %g2, %g7 - cmp %g2, %g7 - bne,pn %icc, loop1 - mov 0, %g1 - -out: - membar #StoreLoad | #StoreStore - retl - mov %g1, %o0 -start_to_zero: -#ifdef CONFIG_PREEMPT - ldsw [%g6 + TI_PRE_COUNT], %g3 - add %g3, 1, %g3 - stw %g3, [%g6 + TI_PRE_COUNT] -#endif -to_zero: - ldstub [%o1], %g3 - membar #StoreLoad | #StoreStore - brnz,pn %g3, spin_on_lock - nop -loop2: cas [%o0], %g2, %g7 /* ASSERT(g7 == 0) */ - cmp %g2, %g7 - - be,pt %icc, out - mov 1, %g1 - lduw [%o0], %g2 - subcc %g2, 1, %g7 - be,pn %icc, loop2 - nop - membar #StoreStore | #LoadStore - stb %g0, [%o1] -#ifdef CONFIG_PREEMPT - ldsw [%g6 + TI_PRE_COUNT], %g3 - sub %g3, 1, %g3 - stw %g3, [%g6 + TI_PRE_COUNT] -#endif - - b,pt %xcc, nzero - nop -spin_on_lock: - ldub [%o1], %g3 - membar #LoadLoad - brnz,pt %g3, spin_on_lock - nop - ba,pt %xcc, to_zero - nop - nop |