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New Literals Utils #80

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merged 16 commits into from
Jun 10, 2024
Merged

New Literals Utils #80

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295d602
new literals
jamierpond Apr 16, 2024
dbf8115
PR feedback
jamierpond Apr 19, 2024
2327807
tidy tests
jamierpond Apr 19, 2024
7c10d29
tidy reused code for booleanswaer
jamierpond Apr 19, 2024
0b8b214
update name
jamierpond Apr 19, 2024
e3a802d
style
jamierpond Apr 19, 2024
7ed6e88
test style
jamierpond Apr 19, 2024
03edd02
fix
jamierpond Apr 19, 2024
0648bb1
undef util
jamierpond Apr 19, 2024
0d0a833
simplify again
jamierpond Apr 19, 2024
33183cd
fmt
jamierpond Apr 19, 2024
1cba60e
Add to Array
jamierpond Apr 19, 2024
8aa4ea5
from array
jamierpond Apr 19, 2024
2a383cb
rm unused
jamierpond Apr 19, 2024
1dc2d89
Finalizing PR
thecppzoo Jun 10, 2024
aabab90
Strange Windows fail on unmodified code of Variant
thecppzoo Jun 10, 2024
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46 changes: 43 additions & 3 deletions inc/zoo/swar/SWAR.h
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,15 @@

namespace zoo { namespace swar {

template <int NBits, typename T> struct SWAR;

template <int NumBits, typename BaseType> struct Literals_t {
constexpr static void (SWAR<NumBits, BaseType>::*value)() = nullptr;
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This is not in use, remove

};

template <int NumBits, typename BaseType>
constexpr Literals_t<NumBits, BaseType> Literals{};
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using u64 = uint64_t;
using u32 = uint32_t;
using u16 = uint16_t;
Expand Down Expand Up @@ -70,6 +79,18 @@ struct SWAR {
// "don't care" bits when non-power-of-two bit lane sizes are supported
LowerBits = MostSignificantBit - LeastSignificantBit;

template <typename Arg, std::size_t N, typename = std::enable_if_t<N == Lanes, int>>
constexpr
SWAR(Literals_t<NBits, T>, const Arg (&values)[N]) : m_v{0} {
auto result = T{0};
for (const auto arg : values) {
result = (result << NBits) | arg;
}
m_v = result;
}

constexpr static T MaxUnsignedLaneValue = ~(((~T{0}) << (NBits - 1)) << 1);
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I agree this constant is worth including, but not here, and not with this calculation. See there are a bunch of constants in SWAR, you may, for example, put it at the end of the list like this:

MaxUnsignedLaneValue = LeastSignificantLaneMask;


SWAR() = default;
constexpr explicit SWAR(T v): m_v(v) {}
constexpr explicit operator T() const noexcept { return m_v; }
Expand Down Expand Up @@ -161,6 +182,9 @@ struct SWAR {
T m_v;
};

template <int NBits, typename T, typename Arg>
SWAR(Literals_t<NBits, T>, const Arg (&values)[SWAR<NBits, T>::Lanes]) -> SWAR<NBits, T>;

/// Defining operator== on base SWAR types is entirely too error prone. Force a verbose invocation.
template<int NBits, typename T = uint64_t>
constexpr auto horizontalEquality(SWAR<NBits, T> left, SWAR<NBits, T> right) {
Expand Down Expand Up @@ -231,6 +255,19 @@ template<int NBits, typename T>
struct BooleanSWAR: SWAR<NBits, T> {
using Base = SWAR<NBits, T>;

constexpr auto toMsbBools(const bool (&values)[Base::Lanes]) {
constexpr auto msbOfFirstLane = T{1} << (NBits - 1);
auto result = T{0};
for (auto arg : values) {
auto bit = arg ? msbOfFirstLane : 0;
result = (result << NBits) | bit;
}
return BooleanSWAR{result};
}

template <std::size_t N, typename = std::enable_if_t<N == Base::Lanes, T>>
constexpr BooleanSWAR(Literals_t<NBits, T>, const bool (&values)[N]) : Base(toMsbBools(values)) {}
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// Booleanness is stored in the MSBs
static constexpr auto MaskMSB =
broadcast<NBits, T>(Base(T(1) << (NBits -1)));
Expand All @@ -240,7 +277,7 @@ struct BooleanSWAR: SWAR<NBits, T> {
static constexpr auto MaskNonLSB = ~MaskLSB;
static constexpr auto MaskNonMSB = ~MaskMSB;
constexpr explicit BooleanSWAR(T v): Base(v) {}

constexpr BooleanSWAR clear(int bit) const noexcept {
constexpr auto Bit = T(1) << (NBits - 1);
return this->m_v ^ (Bit << (NBits * bit)); }
Expand All @@ -256,7 +293,7 @@ struct BooleanSWAR: SWAR<NBits, T> {
constexpr auto operator ~() const noexcept {
return BooleanSWAR(Base{Base::MostSignificantBit} ^ *this);
}

constexpr auto operator not() const noexcept {
return BooleanSWAR(MaskMSB ^ *this);
}
Expand Down Expand Up @@ -305,6 +342,9 @@ struct BooleanSWAR: SWAR<NBits, T> {
convertToBooleanSWAR(SWAR<NB, TT> arg) noexcept;
};

template <int NBits, typename T>
BooleanSWAR(Literals_t<NBits, T>, const bool (&values)[BooleanSWAR<NBits, T>::Lanes]) -> BooleanSWAR<NBits, T>;

template<int NBits, typename T>
constexpr BooleanSWAR<NBits, T>
convertToBooleanSWAR(SWAR<NBits, T> arg) noexcept {
Expand Down Expand Up @@ -381,7 +421,7 @@ greaterEqual(SWAR<NBits, T> left, SWAR<NBits, T> right) noexcept {
using S = swar::SWAR<NBits, T>;
const auto h = S::MostSignificantBit, x = left.value(), y = right.value(); // x=left, y= right is x < y
const auto z = (x|h) - (y&~h);
// bitwise ternary median!
// bitwise ternary median!
const auto t = h & ~median(x, ~y, z);
return ~BooleanSWAR<NBits, T>{static_cast<T>(t)}; // ~(x<y) === x >= y
}
Expand Down
32 changes: 26 additions & 6 deletions test/swar/BasicOperations.cpp
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Expand Up @@ -33,6 +33,26 @@ using S32_32 = SWAR<32, uint32_t>;

using S64_64 = SWAR<64, uint64_t>;

static_assert(SWAR<16, u64>::MaxUnsignedLaneValue == 65535);
static_assert(SWAR<16, u32>::MaxUnsignedLaneValue == 65535);
static_assert(SWAR<8, u32>::MaxUnsignedLaneValue == 255);
static_assert(SWAR<4, u32>::MaxUnsignedLaneValue == 15);
static_assert(SWAR<2, u32>::MaxUnsignedLaneValue == 3);
Comment on lines +32 to +36
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Decimal is not the natural base for these tests.
I know we ahve a mess of decimals and hex and binary in these tests, but let's stop the mess.
You may create an assign a PR to me to clean this up if you're upset about this request.

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I understand why we might want to have just one format, decimal makes the repo a little more approachable and understandable.


static_assert(SWAR{Literals<8, u32>, {0, 0, 0, 0}}.value() == 0);
static_assert(SWAR{Literals<8, u32>, {0, 0, 0, 1}}.value() == 1);
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static_assert(SWAR{Literals<8, u32>, {8, 3, 2, 1}}.value() == 0x08'03'02'01);
static_assert(SWAR{Literals<8, u32>, {42, 42, 42, 42}}.value() == 0x2A'2A'2A'2A);
static_assert(SWAR{Literals<4, u32>, {0, 0, 0, 0, 0, 0, 0, 0}}.value() == 0);
static_assert(SWAR{Literals<4, u32>, {0, 0, 0, 0, 0, 0, 0, 1}}.value() == 1);
static_assert(SWAR{Literals<4, u32>, {0, 0, 0, 0, 0, 0, 0, 0}}.value() == 0);
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static_assert(SWAR{Literals<4, u32>, {8, 7, 6, 5, 4, 3, 2, 1}}.value() == 0x8765'4321);
static_assert(SWAR{Literals<4, u32>, {8, 7, 6, 5, 4, 3, 2, 7}}.value() == 0x8765'4327);
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static_assert(BooleanSWAR{Literals<4, u16>, {false, false, false, false}}.value() == 0);
static_assert(BooleanSWAR{Literals<4, u16>, {true, true, true, true}}.value() == 0b1000'1000'1000'1000);
static_assert(BooleanSWAR{Literals<8, u32>, {true, true, true, true}}.value() == 0b10000000'10000000'10000000'10000000);
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namespace Multiplication {

static_assert(~int64_t(0) == negate(S4_64{S4_64::LeastSignificantBit}).value());
Expand Down Expand Up @@ -357,23 +377,23 @@ TEST_CASE(
const auto left = S2_16{0}.blitElement(1, i);
const auto right = S2_16{S2_16::AllOnes}.blitElement(1, i-1);
const auto test = S2_16{0}.blitElement(1, 2);
CHECK(test.value() == greaterEqual<2, u16>(left, right).value());
CHECK(test.value() == greaterEqual<2, u16>(left, right).value());
}
}
SECTION("single") {
for (uint32_t i = 1; i < 15; i++) {
const auto large = S4_32{0}.blitElement(1, i+1);
const auto small = S4_32{S4_32::AllOnes}.blitElement(1, i-1);
const auto test = S4_32{0}.blitElement(1, 8);
CHECK(test.value() == greaterEqual<4, u32>(large, small).value());
CHECK(test.value() == greaterEqual<4, u32>(large, small).value());
}
}
SECTION("allLanes") {
for (uint32_t i = 1; i < 15; i++) {
const auto small = S4_32(S4_32::LeastSignificantBit * (i-1));
const auto large = S4_32(S4_32::LeastSignificantBit * (i+1));
const auto test = S4_32(S4_32::LeastSignificantBit * 8);
CHECK(test.value() == greaterEqual<4, u32>(large, small).value());
CHECK(test.value() == greaterEqual<4, u32>(large, small).value());
}
}
}
Expand Down Expand Up @@ -425,7 +445,7 @@ TEST_CASE(
"BooleanSWAR MSBtoLaneMask",
"[swar]"
) {
// BooleanSWAR as a mask:
// BooleanSWAR as a mask:
auto bswar =BooleanSWAR<4, u32>(0x0808'0000);
auto mask = S4_32(0x0F0F'0000);
CHECK(bswar.MSBtoLaneMask().value() == mask.value());
Expand All @@ -452,6 +472,6 @@ TEST_CASE(
CHECK(SWAR<4, u16>(0x0400).value() == saturatingUnsignedAddition(SWAR<4, u16>(0x0100), SWAR<4, u16>(0x0300)).value());
CHECK(SWAR<4, u16>(0x0B00).value() == saturatingUnsignedAddition(SWAR<4, u16>(0x0800), SWAR<4, u16>(0x0300)).value());
CHECK(SWAR<4, u16>(0x0F00).value() == saturatingUnsignedAddition(SWAR<4, u16>(0x0800), SWAR<4, u16>(0x0700)).value());
CHECK(SWAR<4, u16>(0x0F00).value() == saturatingUnsignedAddition(SWAR<4, u16>(0x0800), SWAR<4, u16>(0x0800)).value());
CHECK(S4_32(0x0F0C'F000).value() == saturatingUnsignedAddition(S4_32(0x0804'F000), S4_32(0x0808'F000)).value());
CHECK(SWAR<4, u16>(0x0F00).value() == saturatingUnsignedAddition(SWAR<4, u16>(0x0800), SWAR<4, u16>(0x0800)).value());
CHECK(S4_32(0x0F0C'F000).value() == saturatingUnsignedAddition(S4_32(0x0804'F000), S4_32(0x0808'F000)).value());
}