computecpp-sdk/samples/accessors.cpp at master · codeplaysoftware/computecpp-sdk · GitHub

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/***************************************************************************

* Licensed under the Apache License, Version 2.0 (the "License");

* you may not use this file except in compliance with the License.

* You may obtain a copy of the License at

* http://www.apache.org/licenses/LICENSE-2.0

* For your convenience, a copy of the License has been included in this

* repository.

* Unless required by applicable law or agreed to in writing, software

* distributed under the License is distributed on an "AS IS" BASIS,

* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

* See the License for the specific language governing permissions and

* limitations under the License.

* Codeplay's ComputeCpp SDK

* accessor.cpp

* Description:

* Sample code that illustrates how to make data available on a device

* using accessors in SYCL.

**************************************************************************/

#include <CL/sycl.hpp>

#include <iostream>

class multiply;

int main() {

using namespace cl::sycl;

/* We define the data to be passed to the device. */

int data = 5;

/* The scope we create here defines the lifetime of the buffer object, in SYCL

* the lifetime of the buffer object dictates synchronization using RAII. */

try {

/* We can also create a queue that uses the default selector in

* the queue's default constructor. */

queue myQueue;

/* We define a buffer in order to maintain data across the host and one or

* more devices. We construct this buffer with the address of the data

* defined above and a range specifying a single element. */

buffer<int, 1> buf(&data, range<1>(1));

myQueue.submit([&](handler& cgh) {

/* We define accessors for requiring access to a buffer on the host or on

* a device. Accessors are are like pointers to data we can use in

* kernels to access the data. When constructing the accessor you must

* specify the access target and mode. SYCL also provides the

* get_access() as a buffer member function, which only requires an

* access mode - in this case access::mode::read_write.

* (make_access<>() has a second template argument which defaults

* to access::mode::global) */

auto ptr = buf.get_access<access::mode::read_write>(cgh);

cgh.single_task<multiply>([=]() {

/* We use the subscript operator of the accessor constructed above to

* read the value, multiply it by itself and then write it back to the

* accessor again. */

ptr[0] = ptr[0] * ptr[0];

});

/* queue::wait() will block until kernel execution finishes,

* successfully or otherwise. */

myQueue.wait();

} catch (exception const& e) {

std::cout << "SYCL exception caught: " << e.what() << '\n';

return 1;

}

constexpr int expectedResult = 5 * 5;

/* We check that the result is correct. */

if (data != expectedResult) {

std::cout << "Oops! Something went wrong... " << expectedResult

<< " != " << data << '\n';

return 1;

}

std::cout << "Hurray! 5 * 5 is " << data << '\n';

return 0;

}

computecpp-sdk/samples/accessors.cpp at master · codeplaysoftware/computecpp-sdk · GitHub

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