128 lines
3.1 KiB
C
128 lines
3.1 KiB
C
#ifndef _PRIVATE_ALPHA_ATOMIC_H
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#define _PRIVATE_ALPHA_ATOMIC_H
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#define mb() \
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__asm__ __volatile__("mb": : :"memory")
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#define rmb() \
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__asm__ __volatile__("mb": : :"memory")
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#define wmb() \
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__asm__ __volatile__("wmb": : :"memory")
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#define smp_mb() mb()
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#define smp_rmb() rmb()
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#define smp_wmb() wmb()
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/*
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* Atomic operations that C can't guarantee us. Useful for
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* resource counting etc...
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*
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* But use these as seldom as possible since they are much slower
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* than regular operations.
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*/
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/*
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* Counter is volatile to make sure gcc doesn't try to be clever
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* and move things around on us. We need to use _exactly_ the address
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* the user gave us, not some alias that contains the same information.
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*/
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typedef struct { volatile int counter; } ncpt_atomic_t;
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#define NCPT_ATOMIC_INIT(i) ( (ncpt_atomic_t) { (i) } )
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#define ncpt_atomic_read(v) ((v)->counter)
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#define ncpt_atomic_set(v,i) ((v)->counter = (i))
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/*
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* To get proper branch prediction for the main line, we must branch
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* forward to code at the end of this object's .text section, then
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* branch back to restart the operation.
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*/
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static __inline__ void ncpt_atomic_add(int i, ncpt_atomic_t * v)
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{
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unsigned long temp;
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__asm__ __volatile__(
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"1: ldl_l %0,%1\n"
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" addl %0,%2,%0\n"
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" stl_c %0,%1\n"
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" beq %0,2f\n"
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".subsection 2\n"
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"2: br 1b\n"
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".previous"
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:"=&r" (temp), "=m" (v->counter)
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:"Ir" (i), "m" (v->counter));
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}
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static __inline__ void ncpt_atomic_sub(int i, ncpt_atomic_t * v)
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{
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unsigned long temp;
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__asm__ __volatile__(
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"1: ldl_l %0,%1\n"
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" subl %0,%2,%0\n"
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" stl_c %0,%1\n"
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" beq %0,2f\n"
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".subsection 2\n"
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"2: br 1b\n"
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".previous"
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:"=&r" (temp), "=m" (v->counter)
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:"Ir" (i), "m" (v->counter));
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}
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/*
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* Same as above, but return the result value
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*/
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static __inline__ long ncpt_atomic_add_return(int i, ncpt_atomic_t * v)
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{
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long temp, result;
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__asm__ __volatile__(
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"1: ldl_l %0,%1\n"
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" addl %0,%3,%2\n"
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" addl %0,%3,%0\n"
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" stl_c %0,%1\n"
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" beq %0,2f\n"
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" mb\n"
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".subsection 2\n"
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"2: br 1b\n"
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".previous"
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:"=&r" (temp), "=m" (v->counter), "=&r" (result)
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:"Ir" (i), "m" (v->counter) : "memory");
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return result;
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}
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static __inline__ long ncpt_atomic_sub_return(int i, ncpt_atomic_t * v)
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{
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long temp, result;
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__asm__ __volatile__(
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"1: ldl_l %0,%1\n"
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" subl %0,%3,%2\n"
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" subl %0,%3,%0\n"
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" stl_c %0,%1\n"
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" beq %0,2f\n"
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" mb\n"
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".subsection 2\n"
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"2: br 1b\n"
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".previous"
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:"=&r" (temp), "=m" (v->counter), "=&r" (result)
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:"Ir" (i), "m" (v->counter) : "memory");
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return result;
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}
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#define ncpt_atomic_dec_return(v) ncpt_atomic_sub_return(1,(v))
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#define ncpt_atomic_inc_return(v) ncpt_atomic_add_return(1,(v))
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#define ncpt_atomic_sub_and_test(i,v) (ncpt_atomic_sub_return((i), (v)) == 0)
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#define ncpt_atomic_dec_and_test(v) (ncpt_atomic_sub_return(1, (v)) == 0)
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#define ncpt_atomic_inc(v) ncpt_atomic_add(1,(v))
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#define ncpt_atomic_dec(v) ncpt_atomic_sub(1,(v))
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#define smp_mb__before_ncpt_atomic_dec() smp_mb()
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#define smp_mb__after_ncpt_atomic_dec() smp_mb()
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#define smp_mb__before_ncpt_atomic_inc() smp_mb()
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#define smp_mb__after_ncpt_atomic_inc() smp_mb()
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#endif /* _ALPHA_ATOMIC_H */
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