[libc-commits] [libc] 5b079af - [libc] add FXBits class (#82065)
via libc-commits
libc-commits at lists.llvm.org
Thu Feb 22 09:52:19 PST 2024
Author: Michael Jones
Date: 2024-02-22T09:52:16-08:00
New Revision: 5b079af169cd04b457465fd7ca31714efeefe6d9
URL: https://github.com/llvm/llvm-project/commit/5b079af169cd04b457465fd7ca31714efeefe6d9
DIFF: https://github.com/llvm/llvm-project/commit/5b079af169cd04b457465fd7ca31714efeefe6d9.diff
LOG: [libc] add FXBits class (#82065)
The FXBits class is what will be used to modify fixed point numbers on a
bit level. This patch adds a basic implementation as well as basic
tests.
Added:
libc/test/src/__support/fixed_point/CMakeLists.txt
libc/test/src/__support/fixed_point/fx_bits_test.cpp
Modified:
libc/src/__support/fixed_point/CMakeLists.txt
libc/src/__support/fixed_point/fx_bits.h
libc/test/src/__support/CMakeLists.txt
libc/test/src/__support/FPUtil/fpbits_test.cpp
Removed:
################################################################################
diff --git a/libc/src/__support/fixed_point/CMakeLists.txt b/libc/src/__support/fixed_point/CMakeLists.txt
index c6bb9e17adfa8e..64f9dacc7ba5f0 100644
--- a/libc/src/__support/fixed_point/CMakeLists.txt
+++ b/libc/src/__support/fixed_point/CMakeLists.txt
@@ -17,5 +17,7 @@ add_header_library(
libc.include.llvm-libc-macros.stdfix_macros
libc.src.__support.macros.attributes
libc.src.__support.macros.optimization
+ libc.src.__support.CPP.type_traits
libc.src.__support.CPP.bit
+ libc.src.__support.math_extras
)
diff --git a/libc/src/__support/fixed_point/fx_bits.h b/libc/src/__support/fixed_point/fx_bits.h
index b26be169a593a3..fcd47cd72cbb31 100644
--- a/libc/src/__support/fixed_point/fx_bits.h
+++ b/libc/src/__support/fixed_point/fx_bits.h
@@ -14,6 +14,7 @@
#include "src/__support/CPP/type_traits.h"
#include "src/__support/macros/attributes.h" // LIBC_INLINE
#include "src/__support/macros/optimization.h" // LIBC_UNLIKELY
+#include "src/__support/math_extras.h"
#include "fx_rep.h"
@@ -21,6 +22,83 @@
namespace LIBC_NAMESPACE::fixed_point {
+template <typename T> struct FXBits {
+private:
+ using fx_rep = FXRep<T>;
+ using StorageType = typename fx_rep::StorageType;
+
+ StorageType value;
+
+ static_assert(fx_rep::FRACTION_LEN > 0);
+
+ static constexpr size_t FRACTION_OFFSET = 0; // Just for completeness
+ static constexpr size_t INTEGRAL_OFFSET =
+ fx_rep::INTEGRAL_LEN == 0 ? 0 : fx_rep::FRACTION_LEN;
+ static constexpr size_t SIGN_OFFSET =
+ fx_rep::SIGN_LEN == 0
+ ? 0
+ : ((sizeof(StorageType) * CHAR_BIT) - fx_rep::SIGN_LEN);
+
+ static constexpr StorageType FRACTION_MASK =
+ mask_trailing_ones<StorageType, fx_rep::FRACTION_LEN>()
+ << FRACTION_OFFSET;
+ static constexpr StorageType INTEGRAL_MASK =
+ mask_trailing_ones<StorageType, fx_rep::INTEGRAL_LEN>()
+ << INTEGRAL_OFFSET;
+ static constexpr StorageType SIGN_MASK =
+ (fx_rep::SIGN_LEN == 0 ? 0 : StorageType(1) << SIGN_OFFSET);
+
+public:
+ LIBC_INLINE constexpr FXBits() = default;
+
+ template <typename XType> LIBC_INLINE constexpr explicit FXBits(XType x) {
+ using Unqual = typename cpp::remove_cv_t<XType>;
+ if constexpr (cpp::is_same_v<Unqual, T>) {
+ value = cpp::bit_cast<StorageType>(x);
+ } else if constexpr (cpp::is_same_v<Unqual, StorageType>) {
+ value = x;
+ } else {
+ // We don't want accidental type promotions/conversions, so we require
+ // exact type match.
+ static_assert(cpp::always_false<XType>);
+ }
+ }
+
+ LIBC_INLINE constexpr StorageType get_fraction() {
+ return (value & FRACTION_MASK) >> FRACTION_OFFSET;
+ }
+
+ LIBC_INLINE constexpr StorageType get_integral() {
+ return (value & INTEGRAL_MASK) >> INTEGRAL_OFFSET;
+ }
+
+ // TODO: replace bool with Sign
+ LIBC_INLINE constexpr bool get_sign() {
+ return static_cast<bool>((value & SIGN_MASK) >> SIGN_OFFSET);
+ }
+
+ // This represents the effective negative exponent applied to this number
+ LIBC_INLINE constexpr int get_exponent() { return fx_rep::FRACTION_LEN; }
+
+ LIBC_INLINE constexpr void set_fraction(StorageType fraction) {
+ value = (value & (~FRACTION_MASK)) |
+ ((fraction << FRACTION_OFFSET) & FRACTION_MASK);
+ }
+
+ LIBC_INLINE constexpr void set_integral(StorageType integral) {
+ value = (value & (~INTEGRAL_MASK)) |
+ ((integral << INTEGRAL_OFFSET) & INTEGRAL_MASK);
+ }
+
+ // TODO: replace bool with Sign
+ LIBC_INLINE constexpr void set_sign(bool sign) {
+ value = (value & (~SIGN_MASK)) |
+ ((static_cast<StorageType>(sign) << SIGN_OFFSET) & SIGN_MASK);
+ }
+
+ LIBC_INLINE constexpr T get_val() const { return cpp::bit_cast<T>(value); }
+};
+
// Bit-wise operations are not available for fixed point types yet.
template <typename T>
LIBC_INLINE constexpr cpp::enable_if_t<cpp::is_fixed_point_v<T>, T>
diff --git a/libc/test/src/__support/CMakeLists.txt b/libc/test/src/__support/CMakeLists.txt
index 493ef9ddabe1e0..9801621e6b3991 100644
--- a/libc/test/src/__support/CMakeLists.txt
+++ b/libc/test/src/__support/CMakeLists.txt
@@ -188,4 +188,5 @@ add_subdirectory(File)
add_subdirectory(RPC)
add_subdirectory(OSUtil)
add_subdirectory(FPUtil)
+add_subdirectory(fixed_point)
add_subdirectory(HashTable)
diff --git a/libc/test/src/__support/FPUtil/fpbits_test.cpp b/libc/test/src/__support/FPUtil/fpbits_test.cpp
index 46f7d250596873..4f9f53afe54785 100644
--- a/libc/test/src/__support/FPUtil/fpbits_test.cpp
+++ b/libc/test/src/__support/FPUtil/fpbits_test.cpp
@@ -1,4 +1,4 @@
-//===-- Unittests for the DyadicFloat class -------------------------------===//
+//===-- Unittests for the FPBits class ------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
diff --git a/libc/test/src/__support/fixed_point/CMakeLists.txt b/libc/test/src/__support/fixed_point/CMakeLists.txt
new file mode 100644
index 00000000000000..384cc9394ee79b
--- /dev/null
+++ b/libc/test/src/__support/fixed_point/CMakeLists.txt
@@ -0,0 +1,16 @@
+if(NOT LIBC_COMPILER_HAS_FIXED_POINT)
+ return()
+endif()
+
+add_custom_target(libc-fixed-point-tests)
+
+add_libc_test(
+ fx_bits_test
+ SUITE
+ libc-fixed-point-tests
+ SRCS
+ fx_bits_test.cpp
+ DEPENDS
+ libc.src.__support.fixed_point.fx_bits
+ libc.src.__support.integer_literals
+)
diff --git a/libc/test/src/__support/fixed_point/fx_bits_test.cpp b/libc/test/src/__support/fixed_point/fx_bits_test.cpp
new file mode 100644
index 00000000000000..58627816eb8d97
--- /dev/null
+++ b/libc/test/src/__support/fixed_point/fx_bits_test.cpp
@@ -0,0 +1,348 @@
+//===-- Unittests for the FXBits class ------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "include/llvm-libc-macros/stdfix-macros.h"
+
+#include "src/__support/fixed_point/fx_bits.h"
+#include "src/__support/integer_literals.h"
+#include "test/UnitTest/Test.h"
+
+using LIBC_NAMESPACE::fixed_point::FXBits;
+using LIBC_NAMESPACE::fixed_point::FXRep;
+
+using LIBC_NAMESPACE::operator""_u8;
+using LIBC_NAMESPACE::operator""_u16;
+using LIBC_NAMESPACE::operator""_u32;
+using LIBC_NAMESPACE::operator""_u64;
+
+// -------------------------------- SHORT TESTS --------------------------------
+
+TEST(LlvmLibcFxBitsTest, FXBits_UnsignedShortFract) {
+ auto bits_var = FXBits<unsigned short fract>(0b00000000_u8);
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x00_u8);
+ EXPECT_EQ(bits_var.get_fraction(), 0x00_u8);
+
+ // Since an unsigned fract has no sign or integral components, setting either
+ // should have no effect.
+
+ bits_var.set_sign(true);
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x00_u8);
+ EXPECT_EQ(bits_var.get_fraction(), 0x00_u8);
+
+ bits_var.set_integral(0xab);
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x00_u8);
+ EXPECT_EQ(bits_var.get_fraction(), 0x00_u8);
+
+ // but setting the fraction should work
+
+ bits_var.set_fraction(0xcd);
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x00_u8);
+ EXPECT_EQ(bits_var.get_fraction(), 0xcd_u8);
+}
+
+TEST(LlvmLibcFxBitsTest, FXBits_UnsignedShortAccum) {
+ auto bits_var = FXBits<unsigned short accum>(0b00000000'00000000_u16);
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x0000_u16);
+ EXPECT_EQ(bits_var.get_fraction(), 0x0000_u16);
+
+ bits_var.set_sign(true); // 0 sign bits used
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x0000_u16);
+ EXPECT_EQ(bits_var.get_fraction(), 0x0000_u16);
+
+ bits_var.set_integral(0xabcd); // 8 integral bits used
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x00cd_u16);
+ EXPECT_EQ(bits_var.get_fraction(), 0x0000_u16);
+
+ bits_var.set_fraction(0x21fe); // 8 fractional bits used
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x00cd_u16);
+ EXPECT_EQ(bits_var.get_fraction(), 0x00fe_u16);
+}
+
+TEST(LlvmLibcFxBitsTest, FXBits_ShortFract) {
+ auto bits_var = FXBits<short fract>(0b0'0000000_u8);
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x00_u8);
+ EXPECT_EQ(bits_var.get_fraction(), 0x00_u8);
+
+ bits_var.set_sign(true); // 1 sign bit used
+
+ EXPECT_EQ(bits_var.get_sign(), true);
+ EXPECT_EQ(bits_var.get_integral(), 0x00_u8);
+ EXPECT_EQ(bits_var.get_fraction(), 0x00_u8);
+
+ bits_var.set_integral(0xab); // 0 integral bits used
+
+ EXPECT_EQ(bits_var.get_sign(), true);
+ EXPECT_EQ(bits_var.get_integral(), 0x00_u8);
+ EXPECT_EQ(bits_var.get_fraction(), 0x00_u8);
+
+ bits_var.set_fraction(0xcd); // 7 fractional bits used
+
+ EXPECT_EQ(bits_var.get_sign(), true);
+ EXPECT_EQ(bits_var.get_integral(), 0x00_u8);
+ EXPECT_EQ(bits_var.get_fraction(), 0x4d_u8);
+}
+
+TEST(LlvmLibcFxBitsTest, FXBits_ShortAccum) {
+ auto bits_var = FXBits<short accum>(0b0'00000000'0000000_u16);
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x0000_u16);
+ EXPECT_EQ(bits_var.get_fraction(), 0x0000_u16);
+
+ bits_var.set_sign(true); // 1 sign bit used
+
+ EXPECT_EQ(bits_var.get_sign(), true);
+ EXPECT_EQ(bits_var.get_integral(), 0x0000_u16);
+ EXPECT_EQ(bits_var.get_fraction(), 0x0000_u16);
+
+ bits_var.set_integral(0xabcd); // 8 integral bits used
+
+ EXPECT_EQ(bits_var.get_sign(), true);
+ EXPECT_EQ(bits_var.get_integral(), 0x00cd_u16);
+ EXPECT_EQ(bits_var.get_fraction(), 0x0000_u16);
+
+ bits_var.set_fraction(0x21fe); // 7 fractional bits used
+
+ EXPECT_EQ(bits_var.get_sign(), true);
+ EXPECT_EQ(bits_var.get_integral(), 0x00cd_u16);
+ EXPECT_EQ(bits_var.get_fraction(), 0x007e_u16);
+}
+
+TEST(LlvmLibcFxBitsTest, FXBits_UnsignedFract) {
+ auto bits_var = FXBits<unsigned fract>(0b0000000000000000_u16);
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x0000_u16);
+ EXPECT_EQ(bits_var.get_fraction(), 0x0000_u16);
+
+ bits_var.set_sign(true); // 0 sign bits used
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x0000_u16);
+ EXPECT_EQ(bits_var.get_fraction(), 0x0000_u16);
+
+ bits_var.set_integral(0xabcd); // 0 integral bits used
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x0000_u16);
+ EXPECT_EQ(bits_var.get_fraction(), 0x0000_u16);
+
+ bits_var.set_fraction(0xef12); // 16 fractional bits used
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x0000_u16);
+ EXPECT_EQ(bits_var.get_fraction(), 0xef12_u16);
+}
+
+// -------------------------------- NORMAL TESTS -------------------------------
+
+TEST(LlvmLibcFxBitsTest, FXBits_UnsignedAccum) {
+ auto bits_var =
+ FXBits<unsigned accum>(0b0000000000000000'0000000000000000_u32);
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x00000000_u32);
+ EXPECT_EQ(bits_var.get_fraction(), 0x00000000_u32);
+
+ bits_var.set_sign(true); // 0 sign bits used
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x00000000_u32);
+ EXPECT_EQ(bits_var.get_fraction(), 0x00000000_u32);
+
+ bits_var.set_integral(0xabcd); // 16 integral bits used
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x0000abcd_u32);
+ EXPECT_EQ(bits_var.get_fraction(), 0x00000000_u32);
+
+ bits_var.set_fraction(0xef12); // 16 fractional bits used
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x0000abcd_u32);
+ EXPECT_EQ(bits_var.get_fraction(), 0x0000ef12_u32);
+}
+
+TEST(LlvmLibcFxBitsTest, FXBits_Fract) {
+ auto bits_var = FXBits<fract>(0b0'000000000000000_u16);
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x0000_u16);
+ EXPECT_EQ(bits_var.get_fraction(), 0x0000_u16);
+
+ bits_var.set_sign(true); // 1 sign bit used
+
+ EXPECT_EQ(bits_var.get_sign(), true);
+ EXPECT_EQ(bits_var.get_integral(), 0x0000_u16);
+ EXPECT_EQ(bits_var.get_fraction(), 0x0000_u16);
+
+ bits_var.set_integral(0xabcd); // 0 integral bits used
+
+ EXPECT_EQ(bits_var.get_sign(), true);
+ EXPECT_EQ(bits_var.get_integral(), 0x0000_u16);
+ EXPECT_EQ(bits_var.get_fraction(), 0x0000_u16);
+
+ bits_var.set_fraction(0xef12); // 15 fractional bits used
+
+ EXPECT_EQ(bits_var.get_sign(), true);
+ EXPECT_EQ(bits_var.get_integral(), 0x0000_u16);
+ EXPECT_EQ(bits_var.get_fraction(), 0x6f12_u16);
+}
+
+TEST(LlvmLibcFxBitsTest, FXBits_Accum) {
+ auto bits_var = FXBits<accum>(0b0'0000000000000000'000000000000000_u32);
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x00000000_u32);
+ EXPECT_EQ(bits_var.get_fraction(), 0x00000000_u32);
+
+ bits_var.set_sign(true); // 1 sign bit used
+
+ EXPECT_EQ(bits_var.get_sign(), true);
+ EXPECT_EQ(bits_var.get_integral(), 0x00000000_u32);
+ EXPECT_EQ(bits_var.get_fraction(), 0x00000000_u32);
+
+ bits_var.set_integral(0xabcd); // 16 integral bits used
+
+ EXPECT_EQ(bits_var.get_sign(), true);
+ EXPECT_EQ(bits_var.get_integral(), 0x0000abcd_u32);
+ EXPECT_EQ(bits_var.get_fraction(), 0x00000000_u32);
+
+ bits_var.set_fraction(0xef12); // 15 fractional bits used
+
+ EXPECT_EQ(bits_var.get_sign(), true);
+ EXPECT_EQ(bits_var.get_integral(), 0x0000abcd_u32);
+ EXPECT_EQ(bits_var.get_fraction(), 0x00006f12_u32);
+}
+
+// --------------------------------- LONG TESTS --------------------------------
+
+TEST(LlvmLibcFxBitsTest, FXBits_UnsignedLongFract) {
+ auto bits_var =
+ FXBits<unsigned long fract>(0b00000000000000000000000000000000_u32);
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x00000000_u32);
+ EXPECT_EQ(bits_var.get_fraction(), 0x00000000_u32);
+
+ bits_var.set_sign(true); // 0 sign bits used
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x00000000_u32);
+ EXPECT_EQ(bits_var.get_fraction(), 0x00000000_u32);
+
+ bits_var.set_integral(0xabcdef12); // 0 integral bits used
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x00000000_u32);
+ EXPECT_EQ(bits_var.get_fraction(), 0x00000000_u32);
+
+ bits_var.set_fraction(0xfedcba98); // 32 integral bits used
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x00000000_u32);
+ EXPECT_EQ(bits_var.get_fraction(), 0xfedcba98_u32);
+}
+
+TEST(LlvmLibcFxBitsTest, FXBits_UnsignedLongAccum) {
+ auto bits_var = FXBits<unsigned long accum>(
+ 0b00000000000000000000000000000000'00000000000000000000000000000000_u64);
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x0000000000000000_u64);
+ EXPECT_EQ(bits_var.get_fraction(), 0x0000000000000000_u64);
+
+ bits_var.set_sign(true); // 0 sign bits used
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x0000000000000000_u64);
+ EXPECT_EQ(bits_var.get_fraction(), 0x0000000000000000_u64);
+
+ bits_var.set_integral(0xabcdef12); // 32 integral bits used
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x00000000abcdef12_u64);
+ EXPECT_EQ(bits_var.get_fraction(), 0x0000000000000000_u64);
+
+ bits_var.set_fraction(0xfedcba98); // 32 fractional bits used
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x00000000abcdef12_u64);
+ EXPECT_EQ(bits_var.get_fraction(), 0x00000000fedcba98_u64);
+}
+
+TEST(LlvmLibcFxBitsTest, FXBits_LongFract) {
+ auto bits_var = FXBits<long fract>(0b0'0000000000000000000000000000000_u32);
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x00000000_u32);
+ EXPECT_EQ(bits_var.get_fraction(), 0x00000000_u32);
+
+ bits_var.set_sign(true); // 1 sign bit used
+
+ EXPECT_EQ(bits_var.get_sign(), true);
+ EXPECT_EQ(bits_var.get_integral(), 0x00000000_u32);
+ EXPECT_EQ(bits_var.get_fraction(), 0x00000000_u32);
+
+ bits_var.set_integral(0xabcdef12); // 0 integral bits used
+
+ EXPECT_EQ(bits_var.get_sign(), true);
+ EXPECT_EQ(bits_var.get_integral(), 0x00000000_u32);
+ EXPECT_EQ(bits_var.get_fraction(), 0x00000000_u32);
+
+ bits_var.set_fraction(0xfedcba98); // 31 fractional bits used
+
+ EXPECT_EQ(bits_var.get_sign(), true);
+ EXPECT_EQ(bits_var.get_integral(), 0x00000000_u32);
+ EXPECT_EQ(bits_var.get_fraction(), 0x7edcba98_u32);
+}
+
+TEST(LlvmLibcFxBitsTest, FXBits_LongAccum) {
+ auto bits_var = FXBits<long accum>(
+ 0b0'00000000000000000000000000000000'0000000000000000000000000000000_u64);
+
+ EXPECT_EQ(bits_var.get_sign(), false);
+ EXPECT_EQ(bits_var.get_integral(), 0x0000000000000000_u64);
+ EXPECT_EQ(bits_var.get_fraction(), 0x0000000000000000_u64);
+
+ bits_var.set_sign(true); // 1 sign bit used
+
+ EXPECT_EQ(bits_var.get_sign(), true);
+ EXPECT_EQ(bits_var.get_integral(), 0x0000000000000000_u64);
+ EXPECT_EQ(bits_var.get_fraction(), 0x0000000000000000_u64);
+
+ bits_var.set_integral(0xabcdef12); // 32 integral bits used
+
+ EXPECT_EQ(bits_var.get_sign(), true);
+ EXPECT_EQ(bits_var.get_integral(), 0x00000000abcdef12_u64);
+ EXPECT_EQ(bits_var.get_fraction(), 0x0000000000000000_u64);
+
+ bits_var.set_fraction(0xfedcba98); // 31 fractional bits used
+
+ EXPECT_EQ(bits_var.get_sign(), true);
+ EXPECT_EQ(bits_var.get_integral(), 0x00000000abcdef12_u64);
+ EXPECT_EQ(bits_var.get_fraction(), 0x000000007edcba98_u64);
+}
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