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 1998-2006 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/_interpreterRT_sparc.cpp.incl"
#define __ _masm->
// Implementation of SignatureHandlerGenerator
void InterpreterRuntime::SignatureHandlerGenerator::pass_word(int size_of_arg, int offset_in_arg) {
Argument jni_arg(jni_offset() + offset_in_arg, false);
Register Rtmp = O0;
__ ld(Llocals, Interpreter::local_offset_in_bytes(offset()), Rtmp);
__ store_argument(Rtmp, jni_arg);
}
void InterpreterRuntime::SignatureHandlerGenerator::pass_long() {
Argument jni_arg(jni_offset(), false);
Register Rtmp = O0;
#ifdef ASSERT
if (TaggedStackInterpreter) {
// check at least one tag is okay
Label ok;
__ ld_ptr(Llocals, Interpreter::local_tag_offset_in_bytes(offset() + 1), Rtmp);
__ cmp(Rtmp, G0);
__ brx(Assembler::equal, false, Assembler::pt, ok);
__ delayed()->nop();
__ stop("Native object has bad tag value");
__ bind(ok);
}
#endif // ASSERT
#ifdef _LP64
__ ldx(Llocals, Interpreter::local_offset_in_bytes(offset() + 1), Rtmp);
__ store_long_argument(Rtmp, jni_arg);
#else
__ ld(Llocals, Interpreter::local_offset_in_bytes(offset() + 1), Rtmp);
__ store_argument(Rtmp, jni_arg);
__ ld(Llocals, Interpreter::local_offset_in_bytes(offset() + 0), Rtmp);
Argument successor(jni_arg.successor());
__ store_argument(Rtmp, successor);
#endif
}
#ifdef _LP64
void InterpreterRuntime::SignatureHandlerGenerator::pass_float() {
Argument jni_arg(jni_offset(), false);
FloatRegister Rtmp = F0;
__ ldf(FloatRegisterImpl::S, Llocals, Interpreter::local_offset_in_bytes(offset()), Rtmp);
__ store_float_argument(Rtmp, jni_arg);
}
#endif
void InterpreterRuntime::SignatureHandlerGenerator::pass_double() {
Argument jni_arg(jni_offset(), false);
#ifdef _LP64
FloatRegister Rtmp = F0;
__ ldf(FloatRegisterImpl::D, Llocals, Interpreter::local_offset_in_bytes(offset() + 1), Rtmp);
__ store_double_argument(Rtmp, jni_arg);
#else
Register Rtmp = O0;
__ ld(Llocals, Interpreter::local_offset_in_bytes(offset() + 1), Rtmp);
__ store_argument(Rtmp, jni_arg);
__ ld(Llocals, Interpreter::local_offset_in_bytes(offset()), Rtmp);
Argument successor(jni_arg.successor());
__ store_argument(Rtmp, successor);
#endif
}
void InterpreterRuntime::SignatureHandlerGenerator::pass_object() {
Argument jni_arg(jni_offset(), false);
Argument java_arg( offset(), true);
Register Rtmp1 = O0;
Register Rtmp2 = jni_arg.is_register() ? jni_arg.as_register() : O0;
Register Rtmp3 = G3_scratch;
// the handle for a receiver will never be null
bool do_NULL_check = offset() != 0 || is_static();
Address h_arg = Address(Llocals, 0, Interpreter::local_offset_in_bytes(offset()));
__ ld_ptr(h_arg, Rtmp1);
#ifdef ASSERT
if (TaggedStackInterpreter) {
// check we have the obj and not the tag
Label ok;
__ mov(frame::TagReference, Rtmp3);
__ cmp(Rtmp1, Rtmp3);
__ brx(Assembler::notEqual, true, Assembler::pt, ok);
__ delayed()->nop();
__ stop("Native object passed tag by mistake");
__ bind(ok);
}
#endif // ASSERT
if (!do_NULL_check) {
__ add(h_arg, Rtmp2);
} else {
if (Rtmp1 == Rtmp2)
__ tst(Rtmp1);
else __ addcc(G0, Rtmp1, Rtmp2); // optimize mov/test pair
Label L;
__ brx(Assembler::notZero, true, Assembler::pt, L);
__ delayed()->add(h_arg, Rtmp2);
__ bind(L);
}
__ store_ptr_argument(Rtmp2, jni_arg); // this is often a no-op
}
void InterpreterRuntime::SignatureHandlerGenerator::generate(uint64_t fingerprint) {
// generate code to handle arguments
iterate(fingerprint);
// return result handler
Address result_handler(Lscratch, Interpreter::result_handler(method()->result_type()));
__ sethi(result_handler);
__ retl();
__ delayed()->add(result_handler, result_handler.base());
__ flush();
}
// Implementation of SignatureHandlerLibrary
void SignatureHandlerLibrary::pd_set_handler(address handler) {}
class SlowSignatureHandler: public NativeSignatureIterator {
private:
address _from;
intptr_t* _to;
intptr_t* _RegArgSignature; // Signature of first Arguments to be passed in Registers
uint _argcount;
enum { // We need to differenciate float from non floats in reg args
non_float = 0,
float_sig = 1,
double_sig = 2,
long_sig = 3
};
#ifdef ASSERT
void verify_tag(frame::Tag t) {
assert(!TaggedStackInterpreter ||
*(intptr_t*)(_from+Interpreter::local_tag_offset_in_bytes(0)) == t, "wrong tag");
}
#endif // ASSERT
virtual void pass_int() {
*_to++ = *(jint *)(_from+Interpreter::local_offset_in_bytes(0));
debug_only(verify_tag(frame::TagValue));
_from -= Interpreter::stackElementSize();
add_signature( non_float );
}
virtual void pass_object() {
// pass address of from
intptr_t *from_addr = (intptr_t*)(_from + Interpreter::local_offset_in_bytes(0));
*_to++ = (*from_addr == 0) ? NULL : (intptr_t) from_addr;
debug_only(verify_tag(frame::TagReference));
_from -= Interpreter::stackElementSize();
add_signature( non_float );
}
#ifdef _LP64
virtual void pass_float() {
*_to++ = *(jint *)(_from+Interpreter::local_offset_in_bytes(0));
debug_only(verify_tag(frame::TagValue));
_from -= Interpreter::stackElementSize();
add_signature( float_sig );
}
virtual void pass_double() {
*_to++ = *(intptr_t*)(_from+Interpreter::local_offset_in_bytes(1));
debug_only(verify_tag(frame::TagValue));
_from -= 2*Interpreter::stackElementSize();
add_signature( double_sig );
}
virtual void pass_long() {
_to[0] = *(intptr_t*)(_from+Interpreter::local_offset_in_bytes(1));
debug_only(verify_tag(frame::TagValue));
_to += 1;
_from -= 2*Interpreter::stackElementSize();
add_signature( long_sig );
}
#else
// pass_double() is pass_long() and pass_float() only _LP64
virtual void pass_long() {
_to[0] = *(intptr_t*)(_from+Interpreter::local_offset_in_bytes(1));
_to[1] = *(intptr_t*)(_from+Interpreter::local_offset_in_bytes(0));
debug_only(verify_tag(frame::TagValue));
_to += 2;
_from -= 2*Interpreter::stackElementSize();
add_signature( non_float );
}
#endif // _LP64
virtual void add_signature( intptr_t sig_type ) {
if ( _argcount < (sizeof (intptr_t))*4 ) {
*_RegArgSignature |= (sig_type << (_argcount*2) );
_argcount++;
}
}
public:
SlowSignatureHandler(methodHandle method, address from, intptr_t* to, intptr_t *RegArgSig) : NativeSignatureIterator(method) {
_from = from;
_to = to;
_RegArgSignature = RegArgSig;
*_RegArgSignature = 0;
_argcount = method->is_static() ? 2 : 1;
}
};
IRT_ENTRY(address, InterpreterRuntime::slow_signature_handler(
JavaThread* thread,
methodOopDesc* method,
intptr_t* from,
intptr_t* to ))
methodHandle m(thread, method);
assert(m->is_native(), "sanity check");
// handle arguments
// Warning: We use reg arg slot 00 temporarily to return the RegArgSignature
// back to the code that pops the arguments into the CPU registers
SlowSignatureHandler(m, (address)from, m->is_static() ? to+2 : to+1, to).iterate(UCONST64(-1));
// return result handler
return Interpreter::result_handler(m->result_type());
IRT_END