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Switch GpuUInt128 internals to in-place shifts

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Marek Lemańczyk committed 2025-10-20 13:58:16 +02:00
1 parent 50d2e462d7
commit de8e769f48
1 file changed
+11 -10
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PerfectNumbers.Core/Gpu/GpuUInt128.cs
+11 -10
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@@ -753,7 +753,8 @@ public struct GpuUInt128 : IComparable<GpuUInt128>, IEquatable<GpuUInt128>
GpuUInt128 remainder = dividend; GpuUInt128 remainder = dividend;
GpuUInt128 shiftedDivisor = divisor; GpuUInt128 shiftedDivisor = divisor;
shiftedDivisor.ShiftLeft(shift); shiftedDivisor.ShiftLeft(shift);
GpuUInt128 quotientBit = One << shift; GpuUInt128 quotientBit = One;
quotientBit.ShiftLeft(shift);
while (true) while (true)
{ {
@@ -1113,8 +1114,8 @@ public struct GpuUInt128 : IComparable<GpuUInt128>, IEquatable<GpuUInt128>
// TODO: Can we modify these loops to process multiple bits at a time? E.g. 64-bit chunks. // TODO: Can we modify these loops to process multiple bits at a time? E.g. 64-bit chunks.
for (bit = 63; bit >= 0; bit--) for (bit = 63; bit >= 0; bit--)
{ {
remainder <<= 1; remainder.ShiftLeft(1);
remainder = new(remainder.High, remainder.Low | ((p3 >> bit) & 1UL)); remainder.Low |= (p3 >> bit) & 1UL;
if (remainder.CompareTo(modulus) >= 0) if (remainder.CompareTo(modulus) >= 0)
{ {
remainder.Sub(modulus); remainder.Sub(modulus);
@@ -1123,8 +1124,8 @@ public struct GpuUInt128 : IComparable<GpuUInt128>, IEquatable<GpuUInt128>
for (bit = 63; bit >= 0; bit--) for (bit = 63; bit >= 0; bit--)
{ {
remainder <<= 1; remainder.ShiftLeft(1);
remainder = new(remainder.High, remainder.Low | ((p2 >> bit) & 1UL)); remainder.Low |= (p2 >> bit) & 1UL;
if (remainder.CompareTo(modulus) >= 0) if (remainder.CompareTo(modulus) >= 0)
{ {
remainder.Sub(modulus); remainder.Sub(modulus);
@@ -1133,8 +1134,8 @@ public struct GpuUInt128 : IComparable<GpuUInt128>, IEquatable<GpuUInt128>
for (bit = 63; bit >= 0; bit--) for (bit = 63; bit >= 0; bit--)
{ {
remainder <<= 1; remainder.ShiftLeft(1);
remainder = new(remainder.High, remainder.Low | ((p1 >> bit) & 1UL)); remainder.Low |= (p1 >> bit) & 1UL;
if (remainder.CompareTo(modulus) >= 0) if (remainder.CompareTo(modulus) >= 0)
{ {
remainder.Sub(modulus); remainder.Sub(modulus);
@@ -1143,8 +1144,8 @@ public struct GpuUInt128 : IComparable<GpuUInt128>, IEquatable<GpuUInt128>
for (bit = 63; bit >= 0; bit--) for (bit = 63; bit >= 0; bit--)
{ {
remainder <<= 1; remainder.ShiftLeft(1);
remainder = new(remainder.High, remainder.Low | ((p0 >> bit) & 1UL)); remainder.Low |= (p0 >> bit) & 1UL;
if (remainder.CompareTo(modulus) >= 0) if (remainder.CompareTo(modulus) >= 0)
{ {
remainder.Sub(modulus); remainder.Sub(modulus);
@@ -1173,7 +1174,7 @@ public struct GpuUInt128 : IComparable<GpuUInt128>, IEquatable<GpuUInt128>
result.MulMod(baseValue, modulus); result.MulMod(baseValue, modulus);
} }
exponent >>= 1; exponent.ShiftRight(1);
baseValue.MulMod(baseValue, modulus); baseValue.MulMod(baseValue, modulus);
} }