gem5 / public / gem5 / f278b1ea3657a8cccb6ebdf73d3632257fe11e9a / . / src / base / condcodes.test.cc

/* | |

* Copyright (c) 2019 The Regents of the University of California | |

* All rights reserved | |

* | |

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* documentation and/or other materials provided with the distribution; | |

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* 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 | |

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*/ | |

#include <gtest/gtest.h> | |

#include "base/condcodes.hh" | |

using namespace gem5; | |

/* | |

* Add 0x80 + 0x80 to get 0x100. findCarry should report a carry flag after | |

* this operation. | |

*/ | |

TEST(CondCodes, FindCarryWithNoCarryIn8Bit) | |

{ | |

EXPECT_TRUE(findCarry(8, 0x100, 0x80, 0x80)); | |

} | |

/* | |

* Add 0xf0 + 0x0f to get 0xff. findCarry should not report a carry flag after | |

* this operation. | |

*/ | |

TEST(CondCodes, FindNoCarryWithNoCarryIn8Bit) | |

{ | |

EXPECT_FALSE(findCarry(8, 0xff, 0xf0, 0x0f)); | |

} | |

/* | |

* Add 0x7f + 0x80 + 0x01 to get 0x100. findCarry should report a carry flag | |

* after this operation. | |

*/ | |

TEST(CondCodes, FindCarryWithCarryIn8Bit) | |

{ | |

EXPECT_TRUE(findCarry(8, 0x100, 0x80, 0x7f)); | |

} | |

/* | |

* Add 0x80 + 0x7e + 0x01 to get 0xff. findCarry should not report a carry | |

* flag after this operation. | |

*/ | |

TEST(CondCodes, FindNoCarryWithCarryIn8Bit) | |

{ | |

EXPECT_FALSE(findCarry(8, 0xff, 0x80, 0x7e)); | |

} | |

/* | |

* Add 0x80000000 + 0x80000000 to get 0x100000000. findCarry should report a | |

* carry flag after this operation. | |

*/ | |

TEST(CondCodes, FindCarryWithNoCarryIn32Bit) | |

{ | |

EXPECT_TRUE(findCarry(32, 0x100000000, 0x80000000, 0x80000000)); | |

} | |

/* | |

* Add 0xffff0000 + 0x0000ffff to get 0xffffffff. findCarry should not report a | |

* carry flag after this operation. | |

*/ | |

TEST(CondCodes, FindNoCarryWithNoCarryIn32Bit) | |

{ | |

EXPECT_FALSE(findCarry(32, 0xffffffff, 0xffff0000, 0x0000ffff)); | |

} | |

TEST(CondCodes, FindCarryWithCarryIn32Bit) | |

{ | |

/* | |

* Add 0x80000000 + 0x7fffffff + 0x00000001 to get 0x100000000, | |

* resulting in a carry | |

*/ | |

EXPECT_TRUE(findCarry(32, 0x100000000, 0x80000000, 0x7fffffff)); | |

// Add 0x80000000 + 0x7ffffffe + 0x00000001 to get 0xffffffff, | |

// resulting in no carry | |

EXPECT_FALSE(findCarry(32, 0xffffffff, 0x80000000, 0x7ffffffe)); | |

// Add 0xffffffff + 0x00000000 + 0x00000001 to get 0x100000000, | |

// resulting in a carry | |

EXPECT_TRUE(findCarry(32, 0x100000000, 0xffffffff, 0x00000000)); | |

} | |

TEST(CondCodes, FindCarryWithNoCarryIn64Bit) | |

{ | |

// Add 0x8000000000000000 + 0x8000000000000000 to get 0x10000000000000000, | |

// (unrepresentable with uint64_t), resulting in a carry | |

EXPECT_TRUE(findCarry(64, 0x0000000000000000, | |

0x8000000000000000, | |

0x8000000000000000)); | |

/* | |

* Add 0x0000000000000000 + 0x0000000000000000 to get 0x0000000000000000 | |

* resulting in no carry | |

* We get the same sum as above case due to unrepresentability, but we | |

* should still expect no carry | |

*/ | |

EXPECT_FALSE(findCarry(64, 0x0000000000000000, | |

0x0000000000000000, | |

0x0000000000000000)); | |

/* | |

* Add 0x8000000000000000 + 0x7fffffffffffffff to get 0xffffffffffffffff, | |

* resulting in no carry | |

*/ | |

EXPECT_FALSE(findCarry(64, 0xffffffffffffffff, | |

0x8000000000000000, | |

0x7fffffffffffffff)); | |

/* | |

* Add 0xffffffff00000000 + 0x00000000ffffffff to get 0xffffffffffffffff, | |

* resulting in no carry | |

*/ | |

EXPECT_FALSE(findCarry(64, 0xffffffffffffffff, | |

0xffffffff00000000, | |

0x00000000ffffffff)); | |

} | |

TEST(CondCodes, FindCarryWithCarryIn64Bit) | |

{ | |

/* Add 0x8000000000000000 + 0x8000000000000000 + 0x0000000000000001 | |

* to get 0x1 000000000000001 (unrepresentable with uint64_t), | |

* resulting in a carry | |

*/ | |

EXPECT_TRUE(findCarry(64, 0x0000000000000000, | |

0x8000000000000000, | |

0x7fffffffffffffff)); | |

/* | |

* Add 0x0000000000000000 + 0x0000000000000000 + 0x0000000000000001 | |

* resulting in no carry | |

* We get the same sum as the above case due to unrepresentability, but we | |

* should still expect no carry | |

*/ | |

EXPECT_FALSE(findCarry(64, 0x0000000000000001, | |

0x0000000000000000, | |

0x0000000000000000)); | |

/* | |

* Add 0x8000000000000000 + 0x7fffffffffffffff + 0x0000000000000001 | |

* to get 0x1 0000000000000000 (unrepresentable with uint64_t), | |

* resulting in a carry | |

*/ | |

EXPECT_TRUE(findCarry(64, 0x0000000000000000, | |

0x8000000000000000, | |

0x7fffffffffffffff)); | |

/* | |

* Add 0xffffffff00000000 + 0x000000000000000 + 0x0000000000000001 | |

* to get 0x1 0000000000000000 (unrepresentable with uint64_t), | |

* resulting in a carry | |

*/ | |

EXPECT_TRUE(findCarry(64, 0x0000000000000000, | |

0xffffffffffffffff, | |

0x0000000000000001)); | |

} | |

TEST(CondCodes, FindOverflow8Bit) | |

{ | |

/* | |

* Addition of 127 + 1 = 128 or -128 as signed two's complement. | |

* Overflow occurs in this case | |

*/ | |

EXPECT_TRUE(findOverflow(8, 0x80, 0x7f, 0x01)); | |

/* | |

* Addition of 64 + 63 = 127, or 127 as signed two's complement. | |

* No overflow occurs | |

*/ | |

EXPECT_FALSE(findOverflow(8, 0x7f, 0x40, 0x3f)); | |

} | |

TEST(CondCodes, FindOverflow32Bit) | |

{ | |

/* | |

* Addition of 2,147,483,647 + 1 = 2,147,483,648, or -2,147,483,648 as | |

* signed two's complement. Overflow occurs in this case | |

*/ | |

EXPECT_TRUE(findOverflow(32, 0x80000000, 0x7fffffff, 0x00000001)); | |

/* | |

* Addition of 1,073,741,824 + 1,073,741,823 = 2,147,483,647, or | |

* 2,147,483,647 as signed two's complement. No overflow occurs | |

*/ | |

EXPECT_FALSE(findOverflow(32, 0x7fffffff, 0x40000000, 0x3fffffff)); | |

} | |

TEST(CondCodes, FindOverflow64Bit) | |

{ | |

/* | |

* Addition of 0x7fffffffffffffff + 0x0000000000000001 = | |

* 0x8000000000000000, or -9,223,372,036,854,775,808 as signed two's | |

* complement. Overflow occurs in this case | |

*/ | |

EXPECT_TRUE(findOverflow(64, 0x8000000000000000, | |

0x7fffffffffffffff, | |

0x0000000000000001)); | |

/* Addition of 0x4000000000000000 + 0x3fffffffffffffff = | |

* 0x7fffffffffffffff, or 9,223,372,036,854,775,807 as signed two's | |

* complement. No overflow occurs | |

*/ | |

EXPECT_FALSE(findOverflow(64, 0x7fffffffffffffff, | |

0x4000000000000000, | |

0x3fffffffffffffff)); | |

} | |

TEST(CondCodes, OddParity) | |

{ | |

EXPECT_EQ(1, findParity(8, 1)); | |

} | |

TEST(CondCodes, EvenParity) | |

{ | |

EXPECT_EQ(0, findParity(8, 3)); | |

} | |

TEST(CondCodes, OddParityOverflow) | |

{ | |

EXPECT_EQ(1, findParity(8, 0x102)); | |

} | |

TEST(CondCodes, EvenParityOverflow) | |

{ | |

EXPECT_EQ(0, findParity(4,0x43)); | |

} | |

TEST(CondCodes, IsNegative) | |

{ | |

EXPECT_EQ(1, findNegative(8, 128)); | |

} | |

TEST(CondCodes, IsNotNegative) | |

{ | |

EXPECT_EQ(0, findNegative(8, 127)); | |

} | |

TEST(CondCodes, IsZero) | |

{ | |

EXPECT_EQ(1, findZero(8, 0)); | |

} | |

TEST(CondCodes, IsNotZero) | |

{ | |

EXPECT_EQ(0, findZero(8, 1)); | |

} | |

TEST(CondCodes, IsZeroOverflow) | |

{ | |

EXPECT_EQ(1, findZero(8,0x100)); | |

} |