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src/share/vm/runtime/atomic.cpp@8c95980d0b66 (annotated)

src/share/vm/runtime/atomic.cpp

Sat, 07 Nov 2020 10:30:02 +0800

author

aoqi

date

Sat, 07 Nov 2020 10:30:02 +0800

changeset 10026

8c95980d0b66

parent 6876

710a3c8b516e

permissions

-rw-r--r--

Added tag mips-jdk8u275-b01 for changeset d3b4d62f391f

aoqi@0	1	/*
aoqi@0	2	* Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved.
aoqi@0	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0	4	*
aoqi@0	5	* This code is free software; you can redistribute it and/or modify it
aoqi@0	6	* under the terms of the GNU General Public License version 2 only, as
aoqi@0	7	* published by the Free Software Foundation.
aoqi@0	8	*
aoqi@0	9	* This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
aoqi@0	12	* version 2 for more details (a copy is included in the LICENSE file that
aoqi@0	13	* accompanied this code).
aoqi@0	14	*
aoqi@0	15	* You should have received a copy of the GNU General Public License version
aoqi@0	16	* 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0	18	*
aoqi@0	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0	20	* or visit www.oracle.com if you need additional information or have any
aoqi@0	21	* questions.
aoqi@0	22	*
aoqi@0	23	*/
aoqi@0	24
aoqi@0	25	#include "precompiled.hpp"
aoqi@0	26	#include "runtime/atomic.hpp"
aoqi@0	27	#ifdef TARGET_OS_FAMILY_linux
aoqi@0	28	# include "os_linux.inline.hpp"
aoqi@0	29	#endif
aoqi@0	30	#ifdef TARGET_OS_FAMILY_solaris
aoqi@0	31	# include "os_solaris.inline.hpp"
aoqi@0	32	#endif
aoqi@0	33	#ifdef TARGET_OS_FAMILY_windows
aoqi@0	34	# include "os_windows.inline.hpp"
aoqi@0	35	#endif
aoqi@0	36	#ifdef TARGET_OS_FAMILY_aix
aoqi@0	37	# include "os_aix.inline.hpp"
aoqi@0	38	#endif
aoqi@0	39	#ifdef TARGET_OS_FAMILY_bsd
aoqi@0	40	# include "os_bsd.inline.hpp"
aoqi@0	41	#endif
aoqi@0	42
aoqi@0	43	#include "runtime/atomic.inline.hpp"
aoqi@0	44
aoqi@0	45	jbyte Atomic::cmpxchg(jbyte exchange_value, volatile jbyte* dest, jbyte compare_value) {
aoqi@0	46	assert(sizeof(jbyte) == 1, "assumption.");
aoqi@0	47	uintptr_t dest_addr = (uintptr_t)dest;
aoqi@0	48	uintptr_t offset = dest_addr % sizeof(jint);
aoqi@0	49	volatile jint* dest_int = (volatile jint*)(dest_addr - offset);
aoqi@0	50	jint cur = *dest_int;
aoqi@0	51	jbyte* cur_as_bytes = (jbyte*)(&cur);
aoqi@0	52	jint new_val = cur;
aoqi@0	53	jbyte* new_val_as_bytes = (jbyte*)(&new_val);
aoqi@0	54	new_val_as_bytes[offset] = exchange_value;
aoqi@0	55	while (cur_as_bytes[offset] == compare_value) {
aoqi@0	56	jint res = cmpxchg(new_val, dest_int, cur);
aoqi@0	57	if (res == cur) break;
aoqi@0	58	cur = res;
aoqi@0	59	new_val = cur;
aoqi@0	60	new_val_as_bytes[offset] = exchange_value;
aoqi@0	61	}
aoqi@0	62	return cur_as_bytes[offset];
aoqi@0	63	}
aoqi@0	64
aoqi@0	65	unsigned Atomic::xchg(unsigned int exchange_value, volatile unsigned int* dest) {
aoqi@0	66	assert(sizeof(unsigned int) == sizeof(jint), "more work to do");
aoqi@0	67	return (unsigned int)Atomic::xchg((jint)exchange_value, (volatile jint*)dest);
aoqi@0	68	}
aoqi@0	69
aoqi@0	70	unsigned Atomic::cmpxchg(unsigned int exchange_value,
aoqi@0	71	volatile unsigned int* dest, unsigned int compare_value) {
aoqi@0	72	assert(sizeof(unsigned int) == sizeof(jint), "more work to do");
aoqi@0	73	return (unsigned int)Atomic::cmpxchg((jint)exchange_value, (volatile jint*)dest,
aoqi@0	74	(jint)compare_value);
aoqi@0	75	}
aoqi@0	76
aoqi@0	77	jlong Atomic::add(jlong add_value, volatile jlong* dest) {
aoqi@0	78	jlong old = load(dest);
aoqi@0	79	jlong new_value = old + add_value;
aoqi@0	80	while (old != cmpxchg(new_value, dest, old)) {
aoqi@0	81	old = load(dest);
aoqi@0	82	new_value = old + add_value;
aoqi@0	83	}
aoqi@0	84	return old;
aoqi@0	85	}
aoqi@0	86
aoqi@0	87	void Atomic::inc(volatile short* dest) {
aoqi@0	88	// Most platforms do not support atomic increment on a 2-byte value. However,
aoqi@0	89	// if the value occupies the most significant 16 bits of an aligned 32-bit
aoqi@0	90	// word, then we can do this with an atomic add of 0x10000 to the 32-bit word.
aoqi@0	91	//
aoqi@0	92	// The least significant parts of this 32-bit word will never be affected, even
aoqi@0	93	// in case of overflow/underflow.
aoqi@0	94	//
aoqi@0	95	// Use the ATOMIC_SHORT_PAIR macro to get the desired alignment.
aoqi@0	96	#ifdef VM_LITTLE_ENDIAN
aoqi@0	97	assert((intx(dest) & 0x03) == 0x02, "wrong alignment");
aoqi@0	98	(void)Atomic::add(0x10000, (volatile int*)(dest-1));
aoqi@0	99	#else
aoqi@0	100	assert((intx(dest) & 0x03) == 0x00, "wrong alignment");
aoqi@0	101	(void)Atomic::add(0x10000, (volatile int*)(dest));
aoqi@0	102	#endif
aoqi@0	103	}
aoqi@0	104
aoqi@0	105	void Atomic::dec(volatile short* dest) {
aoqi@0	106	#ifdef VM_LITTLE_ENDIAN
aoqi@0	107	assert((intx(dest) & 0x03) == 0x02, "wrong alignment");
aoqi@0	108	(void)Atomic::add(-0x10000, (volatile int*)(dest-1));
aoqi@0	109	#else
aoqi@0	110	assert((intx(dest) & 0x03) == 0x00, "wrong alignment");
aoqi@0	111	(void)Atomic::add(-0x10000, (volatile int*)(dest));
aoqi@0	112	#endif
aoqi@0	113	}
aoqi@0	114