internal sealed override void CompileIKVM(IKVMCompilationContext context, IKVM.Reflection.Universe universe)
{
var stack = context.Stack;
if (stack.Count < 1)
{
throw new StackTooSmallException(OpCode.Int64CountTrailingZeroes, 1, stack.Count);
}
var type = stack.Peek(); //Assuming validation passes, the remaining type will be this.
if (type != ValueType.Int64)
{
throw new StackTypeInvalidException(OpCode.Int64CountTrailingZeroes, ValueType.Int64, type);
}
context.Emit(IKVM.Reflection.Emit.OpCodes.Call, context[HelperMethod.Int64CountTrailingZeroes, (helper, c) =>
{
Assert(c != null);
var result = context.ExportsBuilder.DefineMethod(
"☣ Int64CountTrailingZeroes",
IKVMCompilationContext.HelperMethodAttributes,
universe.Import(typeof(long)),
new[] { universe.Import(typeof(ulong)) });
//All modern CPUs have a fast instruction specifically for this process, but there's no way to use it from .NET.
//Based on the algorithm found here: http://aggregate.org/MAGIC/#Trailing%20Zero%20Count
var il = result.GetILGenerator();
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldarg_0);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldarg_0);
il.Emit(IKVM.Reflection.Emit.OpCodes.Neg);
il.Emit(IKVM.Reflection.Emit.OpCodes.And);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldc_I4_1);
il.Emit(IKVM.Reflection.Emit.OpCodes.Conv_I8);
il.Emit(IKVM.Reflection.Emit.OpCodes.Sub);
il.Emit(IKVM.Reflection.Emit.OpCodes.Call, Int64CountOneBits.IKVMCreateHelper(HelperMethod.Int64CountOneBits, context, universe));
il.Emit(IKVM.Reflection.Emit.OpCodes.Ret);
return(result);
}
]);
}
internal sealed override void CompileIKVM(IKVMCompilationContext context, IKVM.Reflection.Universe universe)
{
var stack = context.Stack;
if (stack.Count < 1)
{
throw new StackTooSmallException(OpCode.Int64CountLeadingZeroes, 1, stack.Count);
}
var type = stack.Peek(); //Assuming validation passes, the remaining type will be this.
if (type != ValueType.Int64)
{
throw new StackTypeInvalidException(OpCode.Int64CountLeadingZeroes, ValueType.Int64, type);
}
context.Emit(IKVM.Reflection.Emit.OpCodes.Call, context[HelperMethod.Int64CountLeadingZeroes, (helper, c) =>
{
Assert(c != null);
var result = context.ExportsBuilder.DefineMethod(
"☣ Int64CountLeadingZeroes",
IKVMCompilationContext.HelperMethodAttributes,
universe.Import(typeof(ulong)),
new[] { universe.Import(typeof(ulong)) });
//All modern CPUs have a fast instruction specifically for this process, but there's no way to use it from .NET.
//This algorithm is extended from https://stackoverflow.com/questions/10439242/count-leading-zeroes-in-an-int32
var il = result.GetILGenerator();
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldarg_0);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldarg_0);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldc_I4_1);
il.Emit(IKVM.Reflection.Emit.OpCodes.Shr_Un);
il.Emit(IKVM.Reflection.Emit.OpCodes.Or);
il.Emit(IKVM.Reflection.Emit.OpCodes.Starg_S, 0);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldarg_0);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldarg_0);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldc_I4_2);
il.Emit(IKVM.Reflection.Emit.OpCodes.Shr_Un);
il.Emit(IKVM.Reflection.Emit.OpCodes.Or);
il.Emit(IKVM.Reflection.Emit.OpCodes.Starg_S, 0);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldarg_0);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldarg_0);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldc_I4_4);
il.Emit(IKVM.Reflection.Emit.OpCodes.Shr_Un);
il.Emit(IKVM.Reflection.Emit.OpCodes.Or);
il.Emit(IKVM.Reflection.Emit.OpCodes.Starg_S, 0);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldarg_0);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldarg_0);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldc_I4_8);
il.Emit(IKVM.Reflection.Emit.OpCodes.Shr_Un);
il.Emit(IKVM.Reflection.Emit.OpCodes.Or);
il.Emit(IKVM.Reflection.Emit.OpCodes.Starg_S, 0);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldarg_0);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldarg_0);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldc_I4_S, 16);
il.Emit(IKVM.Reflection.Emit.OpCodes.Shr_Un);
il.Emit(IKVM.Reflection.Emit.OpCodes.Or);
il.Emit(IKVM.Reflection.Emit.OpCodes.Starg_S, 0);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldarg_0);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldarg_0);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldc_I4_S, 32);
il.Emit(IKVM.Reflection.Emit.OpCodes.Shr_Un);
il.Emit(IKVM.Reflection.Emit.OpCodes.Or);
il.Emit(IKVM.Reflection.Emit.OpCodes.Starg_S, 0);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldc_I4_S, 64);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ldarg_0);
il.Emit(IKVM.Reflection.Emit.OpCodes.Call, Int64CountOneBits.IKVMCreateHelper(HelperMethod.Int64CountOneBits, context, universe));
il.Emit(IKVM.Reflection.Emit.OpCodes.Sub);
il.Emit(IKVM.Reflection.Emit.OpCodes.Ret);
return(result);
}
]);
}
