Implement bigint shift intrinsics on IA32.

runtime/vm/intrinsifier_ia32.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.
 //
 // The intrinsic code below is executed before a method has built its frame.
 // The return address is on the stack and the arguments below it.
 // Registers EDX (arguments descriptor) and ECX (function) must be preserved.
 // Each intrinsification method returns true if the corresponding
 // Dart method was intrinsified.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_IA32.
 #if defined(TARGET_ARCH_IA32)
 
 #include "vm/intrinsifier.h"
 
 #include "vm/assembler.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_compiler.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/os.h"
 #include "vm/regexp_assembler.h"
 #include "vm/symbols.h"
 
 namespace dart {
 
 DECLARE_FLAG(bool, enable_type_checks);
 
+// When entering intrinsics code:
+// ECX: IC Data
+// EDX: Arguments descriptor
+// TOS: Return address
+// The ECX, EDX registers can be destroyed only if there is no slow-path, i.e.
+// if the intrinsified method always executes a return.
+// The EBP register should not be modified, because it is used by the profiler.
 
 #define __ assembler->
 
 
 intptr_t Intrinsifier::ParameterSlotFromSp() { return 0; }
 
 
 static intptr_t ComputeObjectArrayTypeArgumentsOffset() {
   const Library& core_lib = Library::Handle(Library::CoreLibrary());
   const Class& cls = Class::Handle(
@@ skipping 526 matching lines @@
 
   __ Bind(&overflow);
   // Arguments are Smi but the shift produced an overflow to Mint.
   __ cmpl(EBX, Immediate(0));
   // TODO(srdjan): Implement negative values, for now fall through.
   __ j(LESS, &fall_through, Assembler::kNearJump);
   __ SmiUntag(EBX);
   __ movl(EAX, EBX);
   __ shll(EBX, ECX);
   __ xorl(EDI, EDI);
-  __ shldl(EDI, EAX);
+  __ shldl(EDI, EAX, ECX);
   // Result in EDI (high) and EBX (low).
   const Class& mint_class = Class::Handle(
       Isolate::Current()->object_store()->mint_class());
   __ TryAllocate(mint_class,
                  &fall_through,
                  Assembler::kNearJump,
                  EAX,  // Result register.
                  kNoRegister);
   // EBX and EDI are not objects but integer values.
   __ movl(FieldAddress(EAX, Mint::value_offset()), EBX);
@@ skipping 213 matching lines @@
   // 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.
   __ orl(EAX, Immediate(kSmiTagMask));
   __ bsrl(EAX, EAX);
   __ SmiTag(EAX);
   __ ret();
 }
 
 
 void Intrinsifier::Bigint_lsh(Assembler* assembler) {
-  // TODO(regis): Implement.
+  // static void _lsh(Uint32List x_digits, int x_used, int n,
+  //                  Uint32List r_digits)
+
+  __ movl(EDI, Address(ESP, 4 * kWordSize));  // x_digits
+  __ movl(ECX, Address(ESP, 2 * kWordSize));  // n is Smi
+  __ SmiUntag(ECX);
+  __ movl(EBX, Address(ESP, 1 * kWordSize));  // r_digits
+  __ movl(ESI, ECX);
+  __ sarl(ESI, Immediate(5));  // ESI = n ~/ _DIGIT_BITS.
+  __ leal(EBX, FieldAddress(EBX, ESI, TIMES_4, TypedData::data_offset()));
+  __ movl(ESI, Address(ESP, 3 * kWordSize));  // x_used > 0, Smi.
+  __ SmiUntag(ESI);
+  __ decl(ESI);
+  __ xorl(EAX, EAX);  // EAX = 0.
+  __ movl(EDX, FieldAddress(EDI, ESI, TIMES_4, TypedData::data_offset()));
+  __ shldl(EAX, EDX, ECX);
+  __ movl(Address(EBX, ESI, TIMES_4, Bigint::kBytesPerDigit), EAX);
+  Label last;
+  __ cmpl(ESI, Immediate(0));
+  __ j(EQUAL, &last, Assembler::kNearJump);
+  Label loop;
+  __ Bind(&loop);
+  __ movl(EAX, EDX);
+  __ movl(EDX,
+          FieldAddress(EDI, ESI, TIMES_4,
+                       TypedData::data_offset() - Bigint::kBytesPerDigit));
+  __ shldl(EAX, EDX, ECX);
+  __ movl(Address(EBX, ESI, TIMES_4, 0), EAX);
+  __ decl(ESI);
+  __ j(NOT_ZERO, &loop, Assembler::kNearJump);
+  __ Bind(&last);
+  __ shldl(EDX, ESI, ECX);  // ESI == 0.
+  __ movl(Address(EBX, 0), EDX);
+  // Returning Object::null() is not required, since this method is private.
+  __ ret();
 }
 
 
 void Intrinsifier::Bigint_rsh(Assembler* assembler) {
-  // TODO(regis): Implement.
+  // static void _rsh(Uint32List x_digits, int x_used, int n,
+  //                  Uint32List r_digits)
+
+  __ movl(EDI, Address(ESP, 4 * kWordSize));  // x_digits
+  __ movl(ECX, Address(ESP, 2 * kWordSize));  // n is Smi
+  __ SmiUntag(ECX);
+  __ movl(EBX, Address(ESP, 1 * kWordSize));  // r_digits
+  __ movl(EDX, ECX);
+  __ sarl(EDX, Immediate(5));  // EDX = n ~/ _DIGIT_BITS.
+  __ movl(ESI, Address(ESP, 3 * kWordSize));  // x_used > 0, Smi.
+  __ SmiUntag(ESI);
+  __ decl(ESI);
+  // EDI = &x_digits[x_used - 1].
+  __ leal(EDI, FieldAddress(EDI, ESI, TIMES_4, TypedData::data_offset()));
+  __ subl(ESI, EDX);
+  // EBX = &r_digits[x_used - 1 - (n ~/ 32)].
+  __ leal(EBX, FieldAddress(EBX, ESI, TIMES_4, TypedData::data_offset()));
+  __ negl(ESI);
+  __ movl(EDX, Address(EDI, ESI, TIMES_4, 0));
+  Label last;
+  __ cmpl(ESI, Immediate(0));
+  __ j(EQUAL, &last, Assembler::kNearJump);
+  Label loop;
+  __ Bind(&loop);
+  __ movl(EAX, EDX);
+  __ movl(EDX, Address(EDI, ESI, TIMES_4, Bigint::kBytesPerDigit));
+  __ shrdl(EAX, EDX, ECX);
+  __ movl(Address(EBX, ESI, TIMES_4, 0), EAX);
+  __ incl(ESI);
+  __ j(NOT_ZERO, &loop, Assembler::kNearJump);
+  __ Bind(&last);
+  __ shrdl(EDX, ESI, ECX);  // ESI == 0.
+  __ movl(Address(EBX, 0), EDX);
+  // 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)
 
   __ movl(EDI, Address(ESP, 5 * kWordSize));  // digits
   __ movl(EAX, Address(ESP, 4 * kWordSize));  // used is Smi
@@ skipping 1188 matching lines @@
                         Isolate::current_tag_offset());
   // Set return value to Isolate::current_tag_.
   __ movl(EAX, current_tag_addr);
   __ ret();
 }
 
 #undef __
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32