/// <summary cref="IBackendCodeGenerator.GenerateCode(AtomicCAS)"/>
public void GenerateCode(AtomicCAS atomicCAS)
{
var target = Load(atomicCAS.Target);
var value = Load(atomicCAS.Value);
var compare = Load(atomicCAS.CompareValue);
// The internal AtomicCAS value "returns" the old value that was stored
// at the memory location. If the emitted operation fails the comparison
// check, we will "return" the updated value stored in "targetVariable". If
// the operation succeeds we will return the old value stored in
// "targetVariable". Consequently, we will always assign the value stored in
// "targetVariable" the be the "result" of the computation.
var targetVariable = Allocate(atomicCAS);
// Copy the compare value into the target variable to avoid modifications of
// the input value
using (var statement = BeginStatement(targetVariable))
statement.Append(value);
// Perform the atomic operation and ignore the resulting bool value
using (var statement = BeginStatement(CLInstructions.AtomicCASOperation))
{
statement.BeginArguments();
statement.AppendAtomicCast(atomicCAS.ArithmeticBasicValueType);
statement.AppendArgument(target);
statement.AppendArgumentAddressWithCast(
targetVariable,
atomicCAS.ArithmeticBasicValueType);
statement.AppendArgumentWithCast(
compare,
atomicCAS.ArithmeticBasicValueType);
statement.EndArguments();
}
}
/// <summary cref="IBackendCodeGenerator.GenerateCode(AtomicCAS)"/>
public void GenerateCode(AtomicCAS atomicCAS)
{
var target = LoadHardware(atomicCAS.Target);
var value = LoadPrimitive(atomicCAS.Value);
var compare = LoadPrimitive(atomicCAS.CompareValue);
var targetRegister = AllocateHardware(atomicCAS);
using var command = BeginCommand(PTXInstructions.AtomicCASOperation);
command.AppendNonLocalAddressSpace(
(atomicCAS.Target.Type as AddressSpaceType).AddressSpace);
command.AppendSuffix(atomicCAS.BasicValueType);
command.AppendArgument(targetRegister);
command.AppendArgumentValue(target);
command.AppendArgument(value);
command.AppendArgument(compare);
}
/// <summary cref="IValueVisitor.Visit(AtomicCAS)"/>
public void Visit(AtomicCAS atomicCAS)
{
var target = Load(atomicCAS.Target);
var value = Load(atomicCAS.Value);
var compare = Load(atomicCAS.CompareValue);
var tempVariable = AllocateType(BasicValueType.Int1) as PrimitiveVariable;
var targetVariable = Allocate(atomicCAS);
using (var statement = BeginStatement(tempVariable))
{
statement.AppendCommand(CLInstructions.AtomicCASOperation);
statement.BeginArguments();
statement.AppendAtomicCast(atomicCAS.ArithmeticBasicValueType);
statement.AppendArgument(target);
statement.AppendArgumentAddressWithCast(value, $"{CLInstructions.GetAddressSpacePrefix(MemoryAddressSpace.Generic)} {CLTypeGenerator.GetBasicValueType(atomicCAS.ArithmeticBasicValueType)} {CLInstructions.DereferenceOperation}");
statement.AppendArgument(compare);
statement.EndArguments();
}
// The OpenCL way is not compatible with the internal CAS semantic
// We should adapt to the more general way of returning a bool in the future
// For now, check the result of the operation and emit an atomic load
// in the case of a failure.
using (var statement = BeginStatement(targetVariable))
{
statement.Append(tempVariable);
statement.AppendCommand(CLInstructions.SelectOperation1);
statement.Append(value);
statement.AppendCommand(CLInstructions.SelectOperation2);
statement.AppendCommand(CLInstructions.AtomicLoadOperation);
statement.BeginArguments();
statement.AppendAtomicCast(atomicCAS.ArithmeticBasicValueType);
statement.AppendArgument(target);
statement.EndArguments();
}
}
public void Visit(AtomicCAS atomicCAS)
{
}
/// <summary cref="IValueVisitor.Visit(AtomicCAS)"/> public void Visit(AtomicCAS atomicCAS) => CodeGenerator.GenerateCode(atomicCAS);
