text: // Copyright 2017 the V8 project authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #include "src/builtins/builtins-bigint-gen.h"
  #include "src/builtins/builtins-utils-gen.h"
  #include "src/builtins/builtins.h"
  #include "src/codegen/code-stub-assembler.h"
  
  namespace v8 {
  namespace internal {
  
  // https://tc39.github.io/proposal-bigint/#sec-to-big-int64
  TF_BUILTIN(BigIntToI64, CodeStubAssembler) {
    if (!Is64()) {
      Unreachable();
      return;
    }
  
    TNode<Object> value = CAST(Parameter(Descriptor::kArgument));
    TNode<Context> context = CAST(Parameter(Descriptor::kContext));
    TNode<BigInt> bigint = ToBigInt(context, value);
  
    TVARIABLE(UintPtrT, var_low);
    TVARIABLE(UintPtrT, var_high);
  
    // 2. Let int64bit be n modulo 2^64.
    // 3. If int64bit ≥ 2^63, return int64bit - 2^64;
    BigIntToRawBytes(bigint, &var_low, &var_high);
    ReturnRaw(var_low.value());
  }
  
  // https://tc39.github.io/proposal-bigint/#sec-bigint-constructor-number-value
  TF_BUILTIN(I64ToBigInt, CodeStubAssembler) {
    if (!Is64()) {
      Unreachable();
      return;
    }
  
    TNode<IntPtrT> argument =
        UncheckedCast<IntPtrT>(Parameter(Descriptor::kArgument));
  
    Return(BigIntFromInt64(argument));
  }
  
  }  // namespace internal
  }  // namespace v8
  