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 1998-2008 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.
*
*/
# include "incls/_precompiled.incl"
# include "incls/_relocInfo_sparc.cpp.incl"
void Relocation::pd_set_data_value(address x, intptr_t o) {
NativeInstruction* ip = nativeInstruction_at(addr());
jint inst = ip->long_at(0);
assert(inst != NativeInstruction::illegal_instruction(), "no breakpoint");
switch (Assembler::inv_op(inst)) {
case Assembler::ldst_op:
#ifdef ASSERT
switch (Assembler::inv_op3(inst)) {
case Assembler::lduw_op3:
case Assembler::ldub_op3:
case Assembler::lduh_op3:
case Assembler::ldd_op3:
case Assembler::ldsw_op3:
case Assembler::ldsb_op3:
case Assembler::ldsh_op3:
case Assembler::ldx_op3:
case Assembler::ldf_op3:
case Assembler::lddf_op3:
case Assembler::stw_op3:
case Assembler::stb_op3:
case Assembler::sth_op3:
case Assembler::std_op3:
case Assembler::stx_op3:
case Assembler::stf_op3:
case Assembler::stdf_op3:
case Assembler::casa_op3:
case Assembler::casxa_op3:
break;
default:
ShouldNotReachHere();
}
goto do_non_sethi;
#endif
case Assembler::arith_op:
#ifdef ASSERT
switch (Assembler::inv_op3(inst)) {
case Assembler::or_op3:
case Assembler::add_op3:
case Assembler::jmpl_op3:
break;
default:
ShouldNotReachHere();
}
do_non_sethi:;
#endif
{
guarantee(Assembler::inv_immed(inst), "must have a simm13 field");
int simm13 = Assembler::low10((intptr_t)x) + o;
guarantee(Assembler::is_simm13(simm13), "offset can't overflow simm13");
inst &= ~Assembler::simm( -1, 13);
inst |= Assembler::simm(simm13, 13);
ip->set_long_at(0, inst);
}
break;
case Assembler::branch_op:
{
#ifdef _LP64
jint inst2;
guarantee(Assembler::inv_op2(inst)==Assembler::sethi_op2, "must be sethi");
if (format() != 0) {
assert(type() == relocInfo::oop_type, "only narrow oops case");
jint np = oopDesc::encode_heap_oop((oop)x);
inst &= ~Assembler::hi22(-1);
inst |= Assembler::hi22((intptr_t)np);
ip->set_long_at(0, inst);
inst2 = ip->long_at( NativeInstruction::nop_instruction_size );
guarantee(Assembler::inv_op(inst2)==Assembler::arith_op, "arith op");
ip->set_long_at(NativeInstruction::nop_instruction_size, ip->set_data32_simm13( inst2, (intptr_t)np));
break;
}
ip->set_data64_sethi( ip->addr_at(0), (intptr_t)x );
#ifdef COMPILER2
// [RGV] Someone must have missed putting in a reloc entry for the
// add in compiler2.
inst2 = ip->long_at( NativeMovConstReg::add_offset );
guarantee(Assembler::inv_op(inst2)==Assembler::arith_op, "arith op");
ip->set_long_at(NativeMovConstReg::add_offset,ip->set_data32_simm13( inst2, (intptr_t)x+o));
#endif
#else
guarantee(Assembler::inv_op2(inst)==Assembler::sethi_op2, "must be sethi");
inst &= ~Assembler::hi22( -1);
inst |= Assembler::hi22((intptr_t)x);
// (ignore offset; it doesn't play into the sethi)
ip->set_long_at(0, inst);
#endif
}
break;
default:
guarantee(false, "instruction must perform arithmetic or memory access");
}
}
address Relocation::pd_call_destination(address orig_addr) {
intptr_t adj = 0;
if (orig_addr != NULL) {
// We just moved this call instruction from orig_addr to addr().
// This means its target will appear to have grown by addr() - orig_addr.
adj = -( addr() - orig_addr );
}
if (NativeCall::is_call_at(addr())) {
NativeCall* call = nativeCall_at(addr());
return call->destination() + adj;
}
if (NativeFarCall::is_call_at(addr())) {
NativeFarCall* call = nativeFarCall_at(addr());
return call->destination() + adj;
}
// Special case: Patchable branch local to the code cache.
// This will break badly if the code cache grows larger than a few Mb.
NativeGeneralJump* br = nativeGeneralJump_at(addr());
return br->jump_destination() + adj;
}
void Relocation::pd_set_call_destination(address x) {
if (NativeCall::is_call_at(addr())) {
NativeCall* call = nativeCall_at(addr());
call->set_destination(x);
return;
}
if (NativeFarCall::is_call_at(addr())) {
NativeFarCall* call = nativeFarCall_at(addr());
call->set_destination(x);
return;
}
// Special case: Patchable branch local to the code cache.
// This will break badly if the code cache grows larger than a few Mb.
NativeGeneralJump* br = nativeGeneralJump_at(addr());
br->set_jump_destination(x);
}
address* Relocation::pd_address_in_code() {
// SPARC never embeds addresses in code, at present.
//assert(type() == relocInfo::oop_type, "only oops are inlined at present");
return (address*)addr();
}
address Relocation::pd_get_address_from_code() {
// SPARC never embeds addresses in code, at present.
//assert(type() == relocInfo::oop_type, "only oops are inlined at present");
return *(address*)addr();
}
int Relocation::pd_breakpoint_size() {
// minimum breakpoint size, in short words
return NativeIllegalInstruction::instruction_size / sizeof(short);
}
void Relocation::pd_swap_in_breakpoint(address x, short* instrs, int instrlen) {
Untested("pd_swap_in_breakpoint");
// %%% probably do not need a general instrlen; just use the trap size
if (instrs != NULL) {
assert(instrlen * sizeof(short) == NativeIllegalInstruction::instruction_size, "enough instrlen in reloc. data");
for (int i = 0; i < instrlen; i++) {
instrs[i] = ((short*)x)[i];
}
}
NativeIllegalInstruction::insert(x);
}
void Relocation::pd_swap_out_breakpoint(address x, short* instrs, int instrlen) {
Untested("pd_swap_out_breakpoint");
assert(instrlen * sizeof(short) == sizeof(int), "enough buf");
union { int l; short s[1]; } u;
for (int i = 0; i < instrlen; i++) {
u.s[i] = instrs[i];
}
NativeInstruction* ni = nativeInstruction_at(x);
ni->set_long_at(0, u.l);
}
void poll_Relocation::fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) {
}
void poll_return_Relocation::fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) {
}