6800154: Add comments to long_by_long_mulhi() for better understandability
Summary: This patch adds a comment pointing to the Hacker's Delight version of the algorithm plus a verbatim copy of it. Furthermore it adds inline comments.
Reviewed-by: kvn, jrose
/*
* Copyright 1999-2005 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*
*/
void pd_init() { /* nothing to do */ }
public:
void try_allocate(
Register obj, // result: pointer to object after successful allocation
Register var_size_in_bytes, // object size in bytes if unknown at compile time; invalid otherwise
int con_size_in_bytes, // object size in bytes if known at compile time
Register t1, // temp register
Register t2, // temp register
Label& slow_case // continuation point if fast allocation fails
);
void initialize_header(Register obj, Register klass, Register len, Register t1, Register t2);
void initialize_body(Register base, Register index);
// locking/unlocking
void lock_object (Register Rmark, Register Roop, Register Rbox, Register Rscratch, Label& slow_case);
void unlock_object(Register Rmark, Register Roop, Register Rbox, Label& slow_case);
void initialize_object(
Register obj, // result: pointer to object after successful allocation
Register klass, // object klass
Register var_size_in_bytes, // object size in bytes if unknown at compile time; invalid otherwise
int con_size_in_bytes, // object size in bytes if known at compile time
Register t1, // temp register
Register t2 // temp register
);
// allocation of fixed-size objects
// (can also be used to allocate fixed-size arrays, by setting
// hdr_size correctly and storing the array length afterwards)
void allocate_object(
Register obj, // result: pointer to object after successful allocation
Register t1, // temp register
Register t2, // temp register
Register t3, // temp register
int hdr_size, // object header size in words
int obj_size, // object size in words
Register klass, // object klass
Label& slow_case // continuation point if fast allocation fails
);
enum {
max_array_allocation_length = 0x01000000 // sparc friendly value, requires sethi only
};
// allocation of arrays
void allocate_array(
Register obj, // result: pointer to array after successful allocation
Register len, // array length
Register t1, // temp register
Register t2, // temp register
Register t3, // temp register
int hdr_size, // object header size in words
int elt_size, // element size in bytes
Register klass, // object klass
Label& slow_case // continuation point if fast allocation fails
);
// invalidates registers in this window
void invalidate_registers(bool iregisters, bool lregisters, bool oregisters,
Register preserve1 = noreg, Register preserve2 = noreg);