test/cctest/test-diy-fp.cc

// Copyright 2006-2008 the V8 project authors. All rights reserved.
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#include <stdlib.h>

#include "src/v8.h"

#include "src/base/platform/platform.h"
#include "src/diy-fp.h"
#include "test/cctest/cctest.h"

namespace v8 {
namespace internal {

TEST(Subtract) {
  DiyFp diy_fp1 = DiyFp(3, 0);
  DiyFp diy_fp2 = DiyFp(1, 0);
  DiyFp diff = DiyFp::Minus(diy_fp1, diy_fp2);

  CHECK_EQ(2, diff.f());
  CHECK_EQ(0, diff.e());
  diy_fp1.Subtract(diy_fp2);
  CHECK_EQ(2, diy_fp1.f());
  CHECK_EQ(0, diy_fp1.e());
}


TEST(Multiply) {
  DiyFp diy_fp1 = DiyFp(3, 0);
  DiyFp diy_fp2 = DiyFp(2, 0);
  DiyFp product = DiyFp::Times(diy_fp1, diy_fp2);

  CHECK_EQ(0, product.f());
  CHECK_EQ(64, product.e());
  diy_fp1.Multiply(diy_fp2);
  CHECK_EQ(0, diy_fp1.f());
  CHECK_EQ(64, diy_fp1.e());

  diy_fp1 = DiyFp(V8_2PART_UINT64_C(0x80000000, 00000000), 11);
  diy_fp2 = DiyFp(2, 13);
  product = DiyFp::Times(diy_fp1, diy_fp2);
  CHECK_EQ(1, product.f());
  CHECK_EQ(11 + 13 + 64, product.e());

  // Test rounding.
  diy_fp1 = DiyFp(V8_2PART_UINT64_C(0x80000000, 00000001), 11);
  diy_fp2 = DiyFp(1, 13);
  product = DiyFp::Times(diy_fp1, diy_fp2);
  CHECK_EQ(1, product.f());
  CHECK_EQ(11 + 13 + 64, product.e());

  diy_fp1 = DiyFp(V8_2PART_UINT64_C(0x7FFFFFFF, FFFFFFFF), 11);
  diy_fp2 = DiyFp(1, 13);
  product = DiyFp::Times(diy_fp1, diy_fp2);
  CHECK_EQ(0, product.f());
  CHECK_EQ(11 + 13 + 64, product.e());

  // Halfway cases are allowed to round either way. So don't check for it.

  // Big numbers.
  diy_fp1 = DiyFp(V8_2PART_UINT64_C(0xFFFFFFFF, FFFFFFFF), 11);
  diy_fp2 = DiyFp(V8_2PART_UINT64_C(0xFFFFFFFF, FFFFFFFF), 13);
  // 128bit result: 0xFFFFFFFFFFFFFFFE0000000000000001
  product = DiyFp::Times(diy_fp1, diy_fp2);
  CHECK(V8_2PART_UINT64_C(0xFFFFFFFF, FFFFFFFE) == product.f());
  CHECK_EQ(11 + 13 + 64, product.e());
}

}  // namespace internal
}  // namespace v8