test-diy-fp.cc 3.24 KB
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// Copyright 2006-2008 the V8 project authors. All rights reserved.
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// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
//       copyright notice, this list of conditions and the following
//       disclaimer in the documentation and/or other materials provided
//       with the distribution.
//     * Neither the name of Google Inc. nor the names of its
//       contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#include <stdlib.h>

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#include "src/base/numbers/diy-fp.h"
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#include "src/base/platform/platform.h"
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#include "src/init/v8.h"
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#include "test/cctest/cctest.h"
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namespace v8 {
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namespace base {
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TEST(Subtract) {
  DiyFp diy_fp1 = DiyFp(3, 0);
  DiyFp diy_fp2 = DiyFp(1, 0);
  DiyFp diff = DiyFp::Minus(diy_fp1, diy_fp2);

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

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

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  diy_fp1 = DiyFp(0x8000'0000'0000'0000, 11);
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  diy_fp2 = DiyFp(2, 13);
  product = DiyFp::Times(diy_fp1, diy_fp2);
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  CHECK_EQ(1, product.f());
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  CHECK_EQ(11 + 13 + 64, product.e());

  // Test rounding.
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  diy_fp1 = DiyFp(0x8000'0000'0000'0001, 11);
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  diy_fp2 = DiyFp(1, 13);
  product = DiyFp::Times(diy_fp1, diy_fp2);
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  CHECK_EQ(1, product.f());
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  CHECK_EQ(11 + 13 + 64, product.e());

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  diy_fp1 = DiyFp(0x7FFF'FFFF'FFFF'FFFF, 11);
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  diy_fp2 = DiyFp(1, 13);
  product = DiyFp::Times(diy_fp1, diy_fp2);
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  CHECK_EQ(0, product.f());
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  CHECK_EQ(11 + 13 + 64, product.e());

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

  // Big numbers.
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  diy_fp1 = DiyFp(0xFFFF'FFFF'FFFF'FFFF, 11);
  diy_fp2 = DiyFp(0xFFFF'FFFF'FFFF'FFFF, 13);
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  // 128bit result: 0xFFFFFFFFFFFFFFFE0000000000000001
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  product = DiyFp::Times(diy_fp1, diy_fp2);
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  CHECK_EQ(0xFFFF'FFFF'FFFF'FFFE, product.f());
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  CHECK_EQ(11 + 13 + 64, product.e());
}
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}  // namespace base
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}  // namespace v8