343 lines
6.8 KiB
C++
343 lines
6.8 KiB
C++
/*************************************************************************/
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/* safe_refcount.h */
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/*************************************************************************/
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/* This file is part of: */
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/* GODOT ENGINE */
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/* http://www.godotengine.org */
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/*************************************************************************/
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/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur. */
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/* */
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/* Permission is hereby granted, free of charge, to any person obtaining */
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/* a copy of this software and associated documentation files (the */
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/* "Software"), to deal in the Software without restriction, including */
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/* without limitation the rights to use, copy, modify, merge, publish, */
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/* distribute, sublicense, and/or sell copies of the Software, and to */
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/* permit persons to whom the Software is furnished to do so, subject to */
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/* the following conditions: */
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/* */
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/* The above copyright notice and this permission notice shall be */
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/* included in all copies or substantial portions of the Software. */
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/* */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
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/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
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/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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/*************************************************************************/
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#ifndef SAFE_REFCOUNT_H
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#define SAFE_REFCOUNT_H
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#include "os/mutex.h"
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/* x86/x86_64 GCC */
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#include "platform_config.h"
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#ifdef NO_THREADS
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struct SafeRefCount {
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int count;
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public:
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// destroy() is called when weak_count_ drops to zero.
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bool ref() { //true on success
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if (count == 0)
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return false;
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count++;
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return true;
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}
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int refval() { //true on success
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if (count == 0)
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return 0;
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count++;
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return count;
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}
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bool unref() { // true if must be disposed of
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if (count > 0)
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count--;
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return count == 0;
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}
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long get() const { // nothrow
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return static_cast<int const volatile &>(count);
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}
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void init(int p_value = 1) {
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count = p_value;
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};
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};
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#else
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#if defined(PLATFORM_REFCOUNT)
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#include "platform_refcount.h"
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#elif defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
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#define REFCOUNT_T volatile int
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#define REFCOUNT_GET_T int const volatile &
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static inline int atomic_conditional_increment(volatile int *pw) {
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// int rv = *pw;
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// if( rv != 0 ) ++*pw;
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// return rv;
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int rv, tmp;
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__asm__(
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"movl %0, %%eax\n\t"
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"0:\n\t"
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"test %%eax, %%eax\n\t"
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"je 1f\n\t"
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"movl %%eax, %2\n\t"
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"incl %2\n\t"
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"lock\n\t"
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"cmpxchgl %2, %0\n\t"
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"jne 0b\n\t"
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"1:"
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: "=m"(*pw), "=&a"(rv), "=&r"(tmp)
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: // outputs (%0, %1, %2)
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"m"(*pw)
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: // input (%3)
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"cc" // clobbers
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);
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return rv;
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}
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static inline int atomic_decrement(volatile int *pw) {
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// return --(*pw);
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unsigned char rv;
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__asm__(
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"lock\n\t"
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"decl %0\n\t"
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"setne %1"
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: "=m"(*pw), "=qm"(rv)
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: "m"(*pw)
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: "memory");
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return static_cast<int>(rv);
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}
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/* PowerPC32/64 GCC */
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#elif (defined(__GNUC__)) && (defined(__powerpc__) || defined(__ppc__))
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#define REFCOUNT_T int
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#define REFCOUNT_GET_T int const volatile &
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inline int atomic_conditional_increment(int *pw) {
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// if( *pw != 0 ) ++*pw;
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// return *pw;
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int rv;
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__asm__(
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"0:\n\t"
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"lwarx %1, 0, %2\n\t"
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"cmpwi %1, 0\n\t"
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"beq 1f\n\t"
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"addi %1, %1, 1\n\t"
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"1:\n\t"
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"stwcx. %1, 0, %2\n\t"
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"bne- 0b"
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:
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"=m"(*pw), "=&b"(rv)
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: "r"(pw), "m"(*pw)
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: "cc");
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return rv;
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}
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inline int atomic_decrement(int *pw) {
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// return --*pw;
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int rv;
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__asm__ __volatile__(
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"sync\n\t"
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"0:\n\t"
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"lwarx %1, 0, %2\n\t"
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"addi %1, %1, -1\n\t"
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"stwcx. %1, 0, %2\n\t"
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"bne- 0b\n\t"
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"isync"
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:
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"=m"(*pw), "=&b"(rv)
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: "r"(pw), "m"(*pw)
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: "memory", "cc");
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return rv;
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}
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/* CW ARM */
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#elif defined(__GNUC__) && (defined(__arm__))
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#define REFCOUNT_T int
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#define REFCOUNT_GET_T int const volatile &
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inline int atomic_conditional_increment(volatile int *v) {
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int t;
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int tmp;
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__asm__ __volatile__(
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"1: ldrex %0, [%2] \n"
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" cmp %0, #0 \n"
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" beq 2f \n"
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" add %0, %0, #1 \n"
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"2: \n"
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" strex %1, %0, [%2] \n"
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" cmp %1, #0 \n"
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" bne 1b \n"
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: "=&r"(t), "=&r"(tmp)
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: "r"(v)
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: "cc", "memory");
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return t;
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}
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inline int atomic_decrement(volatile int *v) {
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int t;
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int tmp;
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__asm__ __volatile__(
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"1: ldrex %0, [%2] \n"
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" add %0, %0, #-1 \n"
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" strex %1, %0, [%2] \n"
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" cmp %1, #0 \n"
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" bne 1b \n"
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: "=&r"(t), "=&r"(tmp)
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: "r"(v)
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: "cc", "memory");
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return t;
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}
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/* CW PPC */
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#elif (defined(__MWERKS__)) && defined(__POWERPC__)
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inline long atomic_conditional_increment(register long *pw) {
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register int a;
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asm {
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loop:
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lwarx a, 0, pw
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cmpwi a, 0
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beq store
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addi a, a, 1
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store:
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stwcx. a, 0, pw
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bne- loop
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}
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return a;
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}
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inline long atomic_decrement(register long *pw) {
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register int a;
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asm {
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sync
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loop:
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lwarx a, 0, pw
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addi a, a, -1
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stwcx. a, 0, pw
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bne- loop
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isync
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}
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return a;
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}
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/* Any Windows (MSVC) */
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#elif defined(_MSC_VER)
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// made functions to not pollute namespace..
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#define REFCOUNT_T long
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#define REFCOUNT_GET_T long const volatile &
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long atomic_conditional_increment(register long *pw);
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long atomic_decrement(register long *pw);
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#if 0
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#elif defined(__GNUC__) && defined(ARMV6_ENABLED)
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#endif
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#else
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#error This platform cannot use safe refcount, compile with NO_THREADS or implement it.
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#endif
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struct SafeRefCount {
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REFCOUNT_T count;
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public:
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// destroy() is called when weak_count_ drops to zero.
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bool ref() { //true on success
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return atomic_conditional_increment(&count) != 0;
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}
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int refval() { //true on success
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return atomic_conditional_increment(&count);
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}
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bool unref() { // true if must be disposed of
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if (atomic_decrement(&count) == 0) {
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return true;
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}
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return false;
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}
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long get() const { // nothrow
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return static_cast<REFCOUNT_GET_T>(count);
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}
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void init(int p_value = 1) {
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count = p_value;
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};
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};
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#endif // no thread safe
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#endif
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