generate using lane literals

Author: jamierpond

inc/zoo/swar/SWAR.h

@@ -5,6 +5,7 @@
 #include "zoo/meta/log.h"
 
 #include <type_traits>
+#include <initializer_list>
 
 #ifdef _MSC_VER
 #include <iso646.h>
@@ -70,6 +71,19 @@ struct SWAR {
 
     constexpr T value() const noexcept { return m_v; }
 
+   constexpr static T baseFromLaneLiterals(std::initializer_list<T> args) noexcept {
+       T result = 0;
+       for (auto arg: args) {
+           result = (result << NBits) | arg;
+       }
+       return result;
+   }
+
+   constexpr static SWAR fromLaneLiterals(std::initializer_list<T> args) noexcept {
+       return SWAR(baseFromLaneLiterals(args));
+   }
+
+
     #define SWAR_UNARY_OPERATORS_X_LIST \
         X(SWAR, ~)
     //constexpr SWAR operator~() const noexcept { return SWAR{~m_v}; }

test/swar/BasicOperations.cpp

@@ -41,10 +41,12 @@ static_assert(
     multiplication_OverflowUnsafe_SpecificBitCount<3>(Micand, Mplier).value()
 );
 
+static_assert(0b00000010000000110000010100000110 == 0x02'03'05'06);
+
 TEST_CASE("Jamie's totally working exponentiation :D") {
-    constexpr auto base     = SWAR<8, u32>{0x02'01'05'06}; //   2 | 1 |  5 |   6
-    constexpr auto exponent = SWAR<8, u32>{0x07'00'02'03}; //   7 | 0 |  2 |   3
-    constexpr auto expected = SWAR<8, u32>{0x80'01'19'D8}; // 128 | 1 | 25 | 216
+    constexpr auto base     = SWAR<8, u32>::fromLaneLiterals({2, 3, 5, 6}); // {(2 << 24) + (3 << 16) + (5 << 8) + (6)};
+    constexpr auto exponent = SWAR<8, u32>::fromLaneLiterals({7, 0, 2, 3}); //   7 | 0 |  2 |   3
+    constexpr auto expected = SWAR<8, u32>::fromLaneLiterals({128, 1, 25, 216}); // 128 | 1 | 25 | 216
     constexpr auto actual = exponentiation_OverflowUnsafe(base, exponent);
     static_assert(expected.value() == actual.value());
     CHECK(expected.value() == actual.value());