dolphin/Source/UnitTests/Common/BitFieldTest.cpp

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// Copyright 2014 Dolphin Emulator Project
// Licensed under GPLv2
// Refer to the license.txt file included.
#include <gtest/gtest.h>
#include "Common/BitField.h"
#include "Common/CommonTypes.h"
union TestUnion
{
u64 hex;
BitField< 0,64,u64> full_u64; // spans whole storage
BitField< 0,64,s64> full_s64; // spans whole storage
BitField< 9, 3,u64> regular_field_unsigned; // a plain bitfield
BitField< 9, 3,u64> regular_field_unsigned2; // Just the very same bitfield again
BitField< 9, 3,s64> regular_field_signed; // Same bitfield, but different sign
BitField<30, 4,s64> at_dword_boundary; // goes over the boundary of two u32 values
BitField<15, 1,s64> signed_1bit; // allowed values: -1 and 0
};
// table of raw numbers to test with
u64 table[] =
{
0x0000000000000000ull, // all zero
0xffffffffffffffffull, // all one
0x7fffffffffffffffull, // all one apart from the sign bit
0x8000000000000000ull, // all zero apart from the sign bit
0x8000000000000048ull, // regular_field = 0b1001
// "random" numbers
0x0F7B8B1ABD9B8D3Full,
0xA8B86F73FDAADD2Dull,
0x1B17A557BFEB351Dull,
0xE3354268B0C2395Bull,
};
// Verify that bitfields in a union have the same underlying data
TEST(BitField, Storage)
{
TestUnion object;
EXPECT_EQ((void*)&object.hex, (void*)&object.regular_field_unsigned);
EXPECT_EQ(sizeof(TestUnion), sizeof(object.hex));
EXPECT_EQ(sizeof(TestUnion), sizeof(object.full_u64));
EXPECT_EQ(sizeof(TestUnion), sizeof(object.full_s64));
EXPECT_EQ(sizeof(TestUnion), sizeof(object.regular_field_unsigned));
EXPECT_EQ(sizeof(TestUnion), sizeof(object.regular_field_signed));
EXPECT_EQ(sizeof(TestUnion), sizeof(object.at_dword_boundary));
EXPECT_EQ(sizeof(TestUnion), sizeof(object.signed_1bit));
// Now write some values to one field and check if this reflects properly
// in the others.
for (u64 val : table)
{
object.hex = val;
EXPECT_EQ(object.hex, object.full_u64);
EXPECT_EQ(object.regular_field_unsigned, object.regular_field_unsigned2);
object.regular_field_unsigned = val & 0x3;
EXPECT_EQ(object.hex, object.full_u64);
EXPECT_EQ(object.regular_field_unsigned, object.regular_field_unsigned2);
}
}
TEST(BitField, Read)
{
TestUnion object;
for (u64 val : table)
{
object.hex = val;
// Make sure reading/casting does not behave completely idiotic
EXPECT_EQ(object.full_u64, (u64)object.full_u64);
EXPECT_EQ(object.full_s64, (s64)object.full_s64);
EXPECT_EQ(object.regular_field_unsigned, (u64)object.regular_field_unsigned);
EXPECT_EQ(object.regular_field_unsigned2, (u64)object.regular_field_unsigned2);
EXPECT_EQ(object.regular_field_signed, (s64)object.regular_field_signed);
EXPECT_EQ(object.at_dword_boundary, (s64)object.at_dword_boundary);
EXPECT_EQ(object.signed_1bit, (s64)object.signed_1bit);
// Now make sure the value is indeed correct
EXPECT_EQ(val, object.full_u64);
EXPECT_EQ(*(s64*)&val, object.full_s64);
EXPECT_EQ((val >> 9) & 0x7, object.regular_field_unsigned);
EXPECT_EQ((val >> 9) & 0x7, object.regular_field_unsigned2);
EXPECT_EQ(((s64)(object.hex << 52)) >> 61, object.regular_field_signed);
EXPECT_EQ(((s64)(object.hex << 30)) >> 60, object.at_dword_boundary);
EXPECT_EQ(((object.hex >> 15) & 1) ? -1 : 0, object.signed_1bit);
}
}
TEST(BitField, Assignment)
{
TestUnion object;
for (u64 val : table)
{
// Assignments with fixed values
object.full_u64 = val;
EXPECT_EQ(val, object.full_u64);
object.full_s64 = (s64)val;
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EXPECT_EQ(val, object.full_u64);
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object.regular_field_unsigned = val;
EXPECT_EQ(val & 0x7, object.regular_field_unsigned);
object.at_dword_boundary = val;
EXPECT_EQ(((s64)(val << 60)) >> 60, object.at_dword_boundary);
object.signed_1bit = val;
EXPECT_EQ((val & 1) ? -1 : 0, object.signed_1bit);
object.regular_field_signed = val;
EXPECT_EQ(((s64)(object.hex << 61)) >> 61, object.regular_field_signed);
// Assignment from other BitField
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object.at_dword_boundary = object.regular_field_signed;
EXPECT_EQ(object.regular_field_signed, object.at_dword_boundary);
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}
}
// Test class behavior on oddly aligned structures.
TEST(BitField, Alignment)
{
#pragma pack(1)
struct OddlyAlignedTestStruct
{
u8 padding;
TestUnion obj;
};
#pragma pack()
GC_ALIGNED16(OddlyAlignedTestStruct test_struct);
TestUnion& object = test_struct.obj;
static_assert(alignof(test_struct.obj.signed_1bit) == 1, "Incorrect variable alignment");
for (u64 val : table)
{
// Assignments with fixed values
object.full_u64 = val;
EXPECT_EQ(val, object.full_u64);
object.full_s64 = (s64)val;
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EXPECT_EQ(val, object.full_u64);
object.regular_field_unsigned = val;
EXPECT_EQ(val & 0x7, object.regular_field_unsigned);
object.at_dword_boundary = val;
EXPECT_EQ(((s64)(val << 60)) >> 60, object.at_dword_boundary);
object.signed_1bit = val;
EXPECT_EQ((val & 1) ? -1 : 0, object.signed_1bit);
object.regular_field_signed = val;
EXPECT_EQ(((s64)(object.hex << 61)) >> 61, object.regular_field_signed);
// Assignment from other BitField
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object.at_dword_boundary = object.regular_field_signed;
EXPECT_EQ(object.regular_field_signed, object.at_dword_boundary);
}
}