jdk-sandbox: src/hotspot/os_cpu/solaris_sparc/count_trailing_zeros_solaris

46437 cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	1	/*
53244 9807daeb47c4 8216167: Update include guards to reflect correct directories coleenp parents: 47216 diff changeset	2	* Copyright (c) 2017, 2019, Oracle and/or its affiliates. All rights reserved.
46437 cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	4	*
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	5	* This code is free software; you can redistribute it and/or modify it
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	6	* under the terms of the GNU General Public License version 2 only, as
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	7	* published by the Free Software Foundation.
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	8	*
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	9	* This code is distributed in the hope that it will be useful, but WITHOUT
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	12	* version 2 for more details (a copy is included in the LICENSE file that
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	13	* accompanied this code).
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	14	*
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	15	* You should have received a copy of the GNU General Public License version
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	16	* 2 along with this work; if not, write to the Free Software Foundation,
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	18	*
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	20	* or visit www.oracle.com if you need additional information or have any
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	21	* questions.
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	22	*
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	23	*/
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	24
53244 9807daeb47c4 8216167: Update include guards to reflect correct directories coleenp parents: 47216 diff changeset	25	#ifndef OS_CPU_SOLARIS_SPARC_COUNT_TRAILING_ZEROS_SOLARIS_SPARC_HPP
9807daeb47c4 8216167: Update include guards to reflect correct directories coleenp parents: 47216 diff changeset	26	#define OS_CPU_SOLARIS_SPARC_COUNT_TRAILING_ZEROS_SOLARIS_SPARC_HPP
46437 cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	27
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	28	#include "utilities/globalDefinitions.hpp"
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	29
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	30	inline unsigned count_trailing_zeros(uintx x) {
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	31	assert(x != 0, "precondition");
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	32	// Reduce to mask with ones in all positions below the least
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	33	// significant set bit of x, and zeros otherwise.
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	34	uintx rx = (x - 1) & ~x; // sub x, 1, rx; andn rx, x, rx;
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	35	// Then count the set bits in the reduction.
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	36	uintx result;
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	37	__asm__(" popc %1, %0\n\t" : "=r" (result) : "r" (rx));
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	38	return result;
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	39	}
cda23e690843 8179004: Add an efficient implementation of the "count trailing zeros" operation kbarrett parents: diff changeset	40
53244 9807daeb47c4 8216167: Update include guards to reflect correct directories coleenp parents: 47216 diff changeset	41	#endif // OS_CPU_SOLARIS_SPARC_COUNT_TRAILING_ZEROS_SOLARIS_SPARC_HPP

author	darcy
	Tue, 12 Nov 2019 10:45:23 -0800
changeset 59037	3d2575331a41
parent 53244	9807daeb47c4
permissions	-rw-r--r--