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/* atomic.S: Move this stuff here for better ICACHE hit rates.
*
* Copyright (C) 1996 David S. Miller (davem@caipfs.rutgers.edu)
*/
#include <asm/cprefix.h>
#include <asm/ptrace.h>
#include <asm/psr.h>
.text
.align 4
#ifndef __SMP__
.globl ___xchg32_sun4c
___xchg32_sun4c:
rd %psr, %g3
andcc %g3, PSR_PIL, %g0
bne 1f
nop
wr %g3, PSR_PIL, %psr
nop; nop; nop
1:
andcc %g3, PSR_PIL, %g0
ld [%g1], %g7
bne 1f
st %g2, [%g1]
wr %g3, 0x0, %psr
nop; nop; nop
1:
mov %g7, %g2
jmpl %o7 + 8, %g0
mov %g4, %o7
.globl ___xchg32_sun4md
___xchg32_sun4md:
swap [%g1], %g2
jmpl %o7 + 8, %g0
mov %g4, %o7
#endif
/* Read asm-sparc/atomic.h carefully to understand how this works for SMP.
* Really, some things here for SMP are overly clever, go read the header.
*/
.globl ___atomic_add
___atomic_add:
rd %psr, %g3 ! Keep the code small, old way was stupid
nop; nop; nop; ! Let the bits set
or %g3, PSR_PIL, %g7 ! Disable interrupts
wr %g7, 0x0, %psr ! Set %psr
nop; nop; nop; ! Let the bits set
#ifdef __SMP__
1: ldstub [%g1 + 3], %g7 ! Spin on the byte lock for SMP.
orcc %g7, 0x0, %g0 ! Did we get it?
bne 1b ! Nope...
ld [%g1], %g7 ! Load locked atomic_t
sra %g7, 8, %g7 ! Get signed 24-bit integer
add %g7, %g2, %g2 ! Add in argument
sll %g2, 8, %g7 ! Transpose back to atomic_t
st %g7, [%g1] ! Clever: This releases the lock as well.
#else
ld [%g1], %g7 ! Load locked atomic_t
add %g7, %g2, %g2 ! Add in argument
st %g2, [%g1] ! Store it back
#endif
wr %g3, 0x0, %psr ! Restore original PSR_PIL
nop; nop; nop; ! Let the bits set
jmpl %o7, %g0 ! NOTE: not + 8, see callers in atomic.h
mov %g4, %o7 ! Restore %o7
.globl ___atomic_sub
___atomic_sub:
rd %psr, %g3 ! Keep the code small, old way was stupid
nop; nop; nop; ! Let the bits set
or %g3, PSR_PIL, %g7 ! Disable interrupts
wr %g7, 0x0, %psr ! Set %psr
nop; nop; nop; ! Let the bits set
#ifdef __SMP__
1: ldstub [%g1 + 3], %g7 ! Spin on the byte lock for SMP.
orcc %g7, 0x0, %g0 ! Did we get it?
bne 1b ! Nope...
ld [%g1], %g7 ! Load locked atomic_t
sra %g7, 8, %g7 ! Get signed 24-bit integer
sub %g7, %g2, %g2 ! Subtract argument
sll %g2, 8, %g7 ! Transpose back to atomic_t
st %g7, [%g1] ! Clever: This releases the lock as well
#else
ld [%g1], %g7 ! Load locked atomic_t
sub %g7, %g2, %g2 ! Subtract argument
st %g2, [%g1] ! Store it back
#endif
wr %g3, 0x0, %psr ! Restore original PSR_PIL
nop; nop; nop; ! Let the bits set
jmpl %o7, %g0 ! NOTE: not + 8, see callers in atomic.h
mov %g4, %o7 ! Restore %o7
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