mlemanczyk/even-perfect-numbers-scanner
1
0 Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Implement GPU-safe fast division helper

Browse Source
This commit is contained in:
Marek Lemańczyk committed 2025-09-24 21:07:43 +02:00
1 parent cc7cb12f86
commit e316c0055f
2 files changed
+108 -54
Download Patch File Download Diff File Expand all files Collapse all files

No files matched your search

PerfectNumbers.Core/Gpu/GpuKernelPool.cs
+19 -3
View File
@@ -275,7 +275,7 @@ public ref struct GpuKernelLease(IDisposable limiter, GpuContextLease gpu, Kerne
return;
}
ulong div = phi64.FastDiv64(exponent, divMul);
ulong div = FastDiv64Gpu(phi64, exponent, divMul);
GpuUInt128 divPow = GpuUInt128.Pow2Mod(div, q) - GpuUInt128.One;
if (GpuUInt128.BinaryGcd(divPow, q) != GpuUInt128.One)
{
@@ -311,7 +311,7 @@ public ref struct GpuKernelLease(IDisposable limiter, GpuContextLease gpu, Kerne
return;
}
ulong div = phi64.FastDiv64(exponent, divMul);
ulong div = FastDiv64Gpu(phi64, exponent, divMul);
GpuUInt128 divPow = GpuUInt128.Pow2Mod(div, q) - GpuUInt128.One;
if (GpuUInt128.BinaryGcd(divPow, q) != GpuUInt128.One)
{
@@ -432,6 +432,22 @@ public ref struct GpuKernelLease(IDisposable limiter, GpuContextLease gpu, Kerne
orders[index] = exponent;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static ulong FastDiv64Gpu(ulong value, ulong divisor, ulong mul)
{
ulong quotient = GpuUInt128.MulHigh(value, mul);
GpuUInt128 remainder = new(0UL, value);
GpuUInt128 product = new(GpuUInt128.MulHigh(quotient, divisor), quotient * divisor);
remainder.Sub(product);
if (remainder.High != 0UL || remainder.Low >= divisor)
{
quotient++;
}
return quotient;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static ulong Mod128By64(GpuUInt128 value, ulong modulus)
{
@@ -552,7 +568,7 @@ public ref struct GpuKernelLease(IDisposable limiter, GpuContextLease gpu, Kerne
return;
}
ulong div = phi64.FastDiv64(exponent, divMul);
ulong div = FastDiv64Gpu(phi64, exponent, divMul);
GpuUInt128 divPow = GpuUInt128.Pow2Mod(div, q) - GpuUInt128.One;
if (GpuUInt128.BinaryGcd(divPow, q) != GpuUInt128.One)
{