Implement bigint shift intrinsics on x64.

runtime/vm/intrinsifier_x64.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intrinsifier.h"
 
 #include "vm/assembler.h"
@@ skipping 707 matching lines @@
   __ xorq(RAX, RCX);
   // BSR does not write the destination register if source is zero.  Put a 1 in
   // the Smi tag bit to ensure BSR writes to destination register.
   __ orq(RAX, Immediate(kSmiTagMask));
   __ bsrq(RAX, RAX);
   __ SmiTag(RAX);
   __ ret();
 }
 
 
+void Intrinsifier::Bigint_lsh(Assembler* assembler) {
+  // static void _lsh(Uint32List x_digits, int x_used, int n,
+  //                  Uint32List r_digits)
+
+  __ movq(RDI, Address(RSP, 4 * kWordSize));  // x_digits
+  __ movq(R8, Address(RSP, 3 * kWordSize));  // x_used is Smi
+  __ subq(R8, Immediate(2));  // x_used > 0, Smi. R8 = x_used - 1, round up.
+  __ sarq(R8, Immediate(2));  // R8 + 1 = number of digit pairs to read.
+  __ movq(RCX, Address(RSP, 2 * kWordSize));  // n is Smi
+  __ SmiUntag(RCX);
+  __ movq(RBX, Address(RSP, 1 * kWordSize));  // r_digits
+  __ movq(RSI, RCX);
+  __ sarq(RSI, Immediate(6));  // RSI = n ~/ (2*_DIGIT_BITS).
+  __ leaq(RBX, FieldAddress(RBX, RSI, TIMES_8, TypedData::data_offset()));
+  __ xorq(RAX, RAX);  // RAX = 0.
+  __ movq(RDX, FieldAddress(RDI, R8, TIMES_8, TypedData::data_offset()));
+  __ shldq(RAX, RDX, RCX);
+  __ movq(Address(RBX, R8, TIMES_8, 2 * Bigint::kBytesPerDigit), RAX);
+  Label last;
+  __ cmpq(R8, Immediate(0));
+  __ j(EQUAL, &last, Assembler::kNearJump);
+  Label loop;
+  __ Bind(&loop);
+  __ movq(RAX, RDX);
+  __ movq(RDX,
+          FieldAddress(RDI, R8, TIMES_8,
+                       TypedData::data_offset() - 2 * Bigint::kBytesPerDigit));
+  __ shldq(RAX, RDX, RCX);
+  __ movq(Address(RBX, R8, TIMES_8, 0), RAX);
+  __ decq(R8);
+  __ j(NOT_ZERO, &loop, Assembler::kNearJump);
+  __ Bind(&last);
+  __ xorq(RAX, RAX);  // RAX = 0.
+  __ shldq(RDX, RAX, RCX);
+  __ movq(Address(RBX, 0), RDX);
+  // Returning Object::null() is not required, since this method is private.
+  __ ret();
+}
+
+
+void Intrinsifier::Bigint_rsh(Assembler* assembler) {
+  // static void _rsh(Uint32List x_digits, int x_used, int n,
+  //                  Uint32List r_digits)
+
+  __ movq(RDI, Address(RSP, 4 * kWordSize));  // x_digits
+  __ movq(R8, Address(RSP, 3 * kWordSize));  // x_used is Smi
+  __ subq(R8, Immediate(2));  // x_used > 0, Smi. R8 = x_used - 1, round up.
+  __ sarq(R8, Immediate(2));
+  __ movq(RCX, Address(RSP, 2 * kWordSize));  // n is Smi
+  __ SmiUntag(RCX);
+  __ movq(RBX, Address(RSP, 1 * kWordSize));  // r_digits
+  __ movq(RSI, RCX);
+  __ sarq(RSI, Immediate(6));  // RSI = n ~/ (2*_DIGIT_BITS).
+  __ leaq(RDI, FieldAddress(RDI, RSI, TIMES_8, TypedData::data_offset()));
+  __ movq(RDX, Address(RDI, 0));
+  __ subq(R8, RSI);  // R8 + 1 = number of digit pairs to read.
+  Label last;
+  __ cmpq(R8, Immediate(0));
+  __ j(EQUAL, &last, Assembler::kNearJump);
+  __ xorq(R9, R9);  // R9 = 0.
+  Label loop;
+  __ Bind(&loop);
+  __ movq(RAX, RDX);
+  __ movq(RDX, Address(RDI, R9, TIMES_8, 2 * Bigint::kBytesPerDigit));
+  __ shrdq(RAX, RDX, RCX);
+  __ movq(FieldAddress(RBX, R9, TIMES_8, TypedData::data_offset()), RAX);
+  __ incq(R9);
+  __ cmpq(R9, R8);
+  __ j(NOT_EQUAL, &loop, Assembler::kNearJump);
+  __ Bind(&last);
+  __ xorq(RAX, RAX);  // RAX = 0.
+  __ shrdq(RDX, RAX, RCX);
+  __ movq(FieldAddress(RBX, R8, TIMES_8, TypedData::data_offset()), RDX);
+  // Returning Object::null() is not required, since this method is private.
+  __ ret();
+}
+
+
 void Intrinsifier::Bigint_absAdd(Assembler* assembler) {
   // static void _absAdd(Uint32List digits, int used,
   //                     Uint32List a_digits, int a_used,
   //                     Uint32List r_digits)
 
   __ movq(RDI, Address(RSP, 5 * kWordSize));  // digits
   __ movq(R8, Address(RSP, 4 * kWordSize));  // used is Smi
   __ addq(R8, Immediate(2));  // used > 0, Smi. R8 = used + 1, round up.
   __ sarq(R8, Immediate(2));  // R8 = number of digit pairs to process.
   __ movq(RSI, Address(RSP, 3 * kWordSize));  // a_digits
@@ skipping 1175 matching lines @@
   // Set return value to Isolate::current_tag_.
   __ movq(RAX, Address(RBX, Isolate::current_tag_offset()));
   __ ret();
 }
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64