===================================================================
@@ -1,3 +1,7 @@
+2016-01-12 James Norris <jnorris@codesourcery.com>
+
+ * libgomp.texi: Updates for OpenACC.
+
2016-01-11 Alexander Monakov <amonakov@ispras.ru>
* plugin/plugin-nvptx.c (link_ptx): Do not set CU_JIT_TARGET.
===================================================================
@@ -99,6 +99,16 @@
interface.
* Environment Variables:: Influencing runtime behavior with environment
variables.
+* Enabling OpenACC:: How to enable OpenACC for your
+ applications.
+* OpenACC Runtime Library Routines:: The OpenACC runtime application
+ programming interface.
+* OpenACC Environment Variables:: Influencing OpenACC runtime behavior with
+ environment variables.
+* CUDA Streams Usage:: Notes on the implementation of
+ asynchronous operations.
+* OpenACC Library Interoperability:: OpenACC library interoperability with the
+ NVIDIA CUBLAS library.
* The libgomp ABI:: Notes on the external ABI presented by libgomp.
* Reporting Bugs:: How to report bugs in the GNU Offloading and
Multi Processing Runtime Library.
@@ -1790,6 +1800,1272 @@
@c ---------------------------------------------------------------------
+@c Enabling OpenACC
+@c ---------------------------------------------------------------------
+
+@node Enabling OpenACC
+@chapter Enabling OpenACC
+
+To activate the OpenACC extensions for C/C++ and Fortran, the compile-time
+flag @option{-fopenacc} must be specified. This enables the OpenACC directive
+@code{#pragma acc} in C/C++ and @code{!$accp} directives in free form,
+@code{c$acc}, @code{*$acc} and @code{!$acc} directives in fixed form,
+@code{!$} conditional compilation sentinels in free form and @code{c$},
+@code{*$} and @code{!$} sentinels in fixed form, for Fortran. The flag also
+arranges for automatic linking of the OpenACC runtime library
+(@ref{OpenACC Runtime Library Routines}).
+
+A complete description of all OpenACC directives accepted may be found in
+the @uref{http://www.openacc.org/, OpenACC} Application Programming
+Interface manual, version 2.0.
+
+Note that this is an experimental feature and subject to
+change in future versions of GCC. See
+@uref{https://gcc.gnu.org/wiki/OpenACC} for more information.
+
+
+
+@c ---------------------------------------------------------------------
+@c OpenACC Runtime Library Routines
+@c ---------------------------------------------------------------------
+
+@node OpenACC Runtime Library Routines
+@chapter OpenACC Runtime Library Routines
+
+The runtime routines described here are defined by section 3 of the OpenACC
+specifications in version 2.0.
+They have C linkage, and do not throw exceptions.
+Generally, they are available only for the host, with the exception of
+@code{acc_on_device}, which is available for both the host and the
+acceleration device.
+
+@menu
+* acc_get_num_devices:: Get number of devices for the given device
+ type.
+* acc_set_device_type:: Set type of device accelerator to use.
+* acc_get_device_type:: Get type of device accelerator to be used.
+* acc_set_device_num:: Set device number to use.
+* acc_get_device_num:: Get device number to be used.
+* acc_async_test:: Tests for completion of a specific asynchronous
+ operation.
+* acc_async_test_all:: Tests for completion of all asychronous
+ operations.
+* acc_wait:: Wait for completion of a specific asynchronous
+ operation.
+* acc_wait_all:: Waits for completion of all asyncrhonous
+ operations.
+* acc_wait_all_async:: Wait for completion of all asynchronous
+ operations.
+* acc_wait_async:: Wait for completion of asynchronous operations.
+* acc_init:: Initialize runtime for a specific device type.
+* acc_shutdown:: Shuts down the runtime for a specific device
+ type.
+* acc_on_device:: Whether executing on a particular device
+* acc_malloc:: Allocate device memory.
+* acc_free:: Free device memory.
+* acc_copyin:: Allocate device memory and copy host memory to
+ it.
+* acc_present_or_copyin:: If the data is not present on the device,
+ allocate device memory and copy from host
+ memory.
+* acc_create:: Allocate device memory and map it to host
+ memory.
+* acc_present_or_create:: If the data is not present on the device,
+ allocate device memory and map it to host
+ memory.
+* acc_copyout:: Copy device memory to host memory.
+* acc_delete:: Free device memory.
+* acc_update_device:: Update device memory from mapped host memory.
+* acc_update_self:: Update host memory from mapped device memory.
+* acc_map_data:: Map previously allocated device memory to host
+ memory.
+* acc_unmap_data:: Unmap device memory from host memory.
+* acc_deviceptr:: Get device pointer associated with specific
+ host address.
+* acc_hostptr:: Get host pointer associated with specific
+ device address.
+* acc_is_present:: Indiciate whether host variable / array is
+ present on device.
+* acc_memcpy_to_device:: Copy host memory to device memory.
+* acc_memcpy_from_device:: Copy device memory to host memory.
+
+API routines for target platforms.
+
+* acc_get_current_cuda_device:: Get CUDA device handle.
+* acc_get_current_cuda_context::Get CUDA context handle.
+* acc_get_cuda_stream:: Get CUDA stream handle.
+* acc_set_cuda_stream:: Set CUDA stream handle.
+@end menu
+
+
+
+@node acc_get_num_devices
+@section @code{acc_get_num_devices} -- Get number of devices for given device type
+@table @asis
+@item @emph{Description}
+This function returns a value indicating the number of devices available
+for the device type specified in @var{devicetype}.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{int acc_get_num_devices(acc_device_t devicetype);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{integer function acc_get_num_devices(devicetype)}
+@item @tab @code{integer(kind=acc_device_kind) devicetype}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.1.
+@end table
+
+
+
+@node acc_set_device_type
+@section @code{acc_set_device_type} -- Set type of device accelerator to use.
+@table @asis
+@item @emph{Description}
+This function indicates to the runtime library which device typr, specified
+in @var{devicetype}, to use when executing a parallel or kernels region.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_set_device_type(acc_device_t devicetype);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{subroutine acc_set_device_type(devicetype)}
+@item @tab @code{integer(kind=acc_device_kind) devicetype}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.2.
+@end table
+
+
+
+@node acc_get_device_type
+@section @code{acc_get_device_type} -- Get type of device accelerator to be used.
+@table @asis
+@item @emph{Description}
+This function returns what device type will be used when executing a
+parallel or kernels region.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_device_t acc_get_device_type(void);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{function acc_get_device_type(void)}
+@item @tab @code{integer(kind=acc_device_kind) acc_get_device_type}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.3.
+@end table
+
+
+
+@node acc_set_device_num
+@section @code{acc_set_device_num} -- Set device number to use.
+@table @asis
+@item @emph{Description}
+This function will indicate to the runtime which device number,
+specified by @var{num}, associated with the specifed device
+type @var{devicetype}.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_set_device_num(int num, acc_device_t devicetype);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{subroutine acc_set_device_num(devicenum, devicetype)}
+@item @tab @code{integer devicenum}
+@item @tab @code{integer(kind=acc_device_kind) devicetype}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.4.
+@end table
+
+
+
+@node acc_get_device_num
+@section @code{acc_get_device_num} -- Get device number to be used.
+@table @asis
+@item @emph{Description}
+This function returns which device number associated with the specified device
+type @var{devicetype}, will be used when executing a parallel or kernels
+region.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{int acc_get_device_num(acc_device_t devicetype);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{function acc_get_device_num(devicetype)}
+@item @tab @code{integer(kind=acc_device_kind) devicetype}
+@item @tab @code{integer acc_get_device_num}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.5.
+@end table
+
+
+
+@node acc_async_test
+@section @code{acc_async_test} -- Test for completion of a specific asynchronous operation.
+@table @asis
+@item @emph{Description}
+This function tests for completion of the asynchrounous operation specified
+in @var{arg}. In C/C++, a non-zero value will be returned to indicate
+the specified asynchronous operation has completed. While Fortran will return
+a @code{true}. If the asynchrounous operation has not completed, C/C++ returns
+a zero and Fortran returns a @code{false}.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{int acc_async_test(int arg);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{function acc_async_test(arg)}
+@item @tab @code{integer(kind=acc_handle_kind) arg}
+@item @tab @code{logical acc_async_test}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.6.
+@end table
+
+
+
+@node acc_async_test_all
+@section @code{acc_async_test_all} -- Tests for completion of all asynchronous operations.
+@table @asis
+@item @emph{Description}
+This function tests for completion of all asynchrounous operations.
+In C/C++, a non-zero value will be returned to indicate all asynchronous
+operations have completed. While Fortran will return a @code{true}. If
+any asynchronous operation has not completed, C/C++ returns a zero and
+Fortran returns a @code{false}.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{int acc_async_test_all(void);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{function acc_async_test()}
+@item @tab @code{logical acc_get_device_num}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.7.
+@end table
+
+
+
+@node acc_wait
+@section @code{acc_wait} -- Wait for completion of a specific asynchronous operation.
+@table @asis
+@item @emph{Description}
+This function waits for completion of the asynchronous operation
+specified in @var{arg}.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_wait(arg);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{subroutine acc_wait(arg)}
+@item @tab @code{integer(acc_handle_kind) arg}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.8.
+@end table
+
+
+
+@node acc_wait_all
+@section @code{acc_wait_all} -- Waits for completion of all asynchronous operations.
+@table @asis
+@item @emph{Description}
+This function waits for the completion of all asynchronous operations.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_wait_all(void);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{subroutine acc_wait_async()}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.10.
+@end table
+
+
+
+@node acc_wait_all_async
+@section @code{acc_wait_all_async} -- Wait for completion of all asynchronous operations.
+@table @asis
+@item @emph{Description}
+This function enqueues a wait operation on the queue @var{async} for any
+and all asynchronous operations that have been previously enqueued on
+any queue.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_wait_all_async(int async);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{subroutine acc_wait_all_async(async)}
+@item @tab @code{integer(acc_handle_kind) async}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.11.
+@end table
+
+
+
+@node acc_wait_async
+@section @code{acc_wait_async} -- Wait for completion of asynchronous operations.
+@table @asis
+@item @emph{Description}
+This function enqueues a wait operation on queue @var{async} for any and all
+asynchronous operations enqueued on queue @var{arg}.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_wait_async(int arg, int async);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{subroutine acc_wait_async(arg, async)}
+@item @tab @code{integer(acc_handle_kind) arg, async}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.9.
+@end table
+
+
+
+@node acc_init
+@section @code{acc_init} -- Initialize runtime for a specific device type.
+@table @asis
+@item @emph{Description}
+This function initializes the runtime for the device type specified in
+@var{devicetype}.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_init(acc_device_t devicetype);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{subroutine acc_init(devicetype)}
+@item @tab @code{integer(acc_device_kind) devicetype}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.12.
+@end table
+
+
+
+@node acc_shutdown
+@section @code{acc_shutdown} -- Shuts down the runtime for a specific device type.
+@table @asis
+@item @emph{Description}
+This function shuts down the runtime for the device type specified in
+@var{devicetype}.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_shutdown(acc_device_t devicetype);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{subroutine acc_shutdown(devicetype)}
+@item @tab @code{integer(acc_device_kind) devicetype}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.13.
+@end table
+
+
+
+@node acc_on_device
+@section @code{acc_on_device} -- Whether executing on a particular device
+@table @asis
+@item @emph{Description}:
+This function returns whether the program is executing on a particular
+device specified in @var{devicetype}. In C/C++ a non-zero value is
+returned to indicate the device is execiting on the specified device type.
+In Fortran, @code{true} will be returned. If the program is not executing
+on the specified device type C/C++ will return a zero, while Fortran will
+return @code{false}.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_on_device(acc_device_t devicetype);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{function acc_on_device(devicetype)}
+@item @tab @code{integer(acc_device_kind) devicetype}
+@item @tab @code{logical acc_on_device}
+@end multitable
+
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.14.
+@end table
+
+
+
+@node acc_malloc
+@section @code{acc_malloc} -- Allocate device memory.
+@table @asis
+@item @emph{Description}
+This function allocates @var{len} bytes of device memory. It returns
+the device address of the allocated memory.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{d_void* acc_malloc(size_t len);}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.15.
+@end table
+
+
+
+@node acc_free
+@section @code{acc_free} -- Free device memory.
+@table @asis
+@item @emph{Description}
+Free previously allocated device memory at the device address @code{a}.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_free(d_void *a);}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.16.
+@end table
+
+
+
+@node acc_copyin
+@section @code{acc_copyin} -- Allocate device memory and copy host memory to it.
+@table @asis
+@item @emph{Description}
+In C/C++, this function allocates @var{len} bytes of device memory
+and maps it to the specified host address in @var{a}. The device
+address of the newly allocated device memory is returned.
+
+In Fortran, two (2) forms are supported. In the first form, @var{a} specifies
+a contiguous array section. The second form @var{a} specifies a
+variable or array element and @var{len} specifies the length in bytes.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{void *acc_copyin(h_void *a, size_t len);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{subroutine acc_copyin(a)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @emph{Interface}: @tab @code{subroutine acc_copyin(a, len)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @tab @code{integer len}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.17.
+@end table
+
+
+
+@node acc_present_or_copyin
+@section @code{acc_present_or_copyin} -- If the data is not present on the device, allocate device memory and copy from host memory.
+@table @asis
+@item @emph{Description}
+This function tests if the host data specifed by @var{a} and of length
+@var{len} is present or not. If it is not present, then device memory
+will be allocated and the host memory copied. The device address of
+the newly allocated device memory is returned.
+
+In Fortran, two (2) forms are supported. In the first form, @var{a} specifies
+a contiguous array section. The second form @var{a} specifies a variable or
+array element and @var{len} specifies the length in bytes.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{void *acc_present_or_copyin(h_void *a, size_t len);}
+@item @emph{Prototype}: @tab @code{void *acc_pcopyin(h_void *a, size_t len);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{subroutine acc_present_or_copyin(a)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @emph{Interface}: @tab @code{subroutine acc_present_or_copyin(a, len)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @tab @code{integer len}
+@item @emph{Interface}: @tab @code{subroutine acc_pcopyin(a)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @emph{Interface}: @tab @code{subroutine acc_pcopyin(a, len)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @tab @code{integer len}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.18.
+@end table
+
+
+
+@node acc_create
+@section @code{acc_create} -- Allocate device memory and map it to host memory.
+@table @asis
+@item @emph{Description}
+This function allocates device memory and maps it to host memory specified
+by the host address @var{a} with a length of @var{len} bytes. In C/C++,
+the function returns the device address of the allocated device memory.
+
+In Fortran, two (2) forms are supported. In the first form, @var{a} specifies
+a contiguous array section. The second form @var{a} specifies a variable or
+array element and @var{len} specifies the length in bytes.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{void *acc_create(h_void *a, size_t len);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{subroutine acc_create(a)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @emph{Interface}: @tab @code{subroutine acc_create(a, len)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @tab @code{integer len}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.19.
+@end table
+
+
+
+@node acc_present_or_create
+@section @code{acc_present_or_create} -- If the data is not present on the device, allocate device memory and map it to host memory.
+@table @asis
+@item @emph{Description}
+This function tests if the host data specifed by @var{a} and of length
+@var{len} is present or not. If it is not present, then device memory
+will be allocated and mapped to host memory. In C/C++, the device address
+of the newly allocated device memory is returned.
+
+In Fortran, two (2) forms are supported. In the first form, @var{a} specifies
+a contiguous array section. The second form @var{a} specifies a variable or
+array element and @var{len} specifies the length in bytes.
+
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{void *acc_present_or_create(h_void *a, size_t len)}
+@item @emph{Prototype}: @tab @code{void *acc_pcreate(h_void *a, size_t len)}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{subroutine acc_present_or_create(a)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @emph{Interface}: @tab @code{subroutine acc_present_or_create(a, len)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @tab @code{integer len}
+@item @emph{Interface}: @tab @code{subroutine acc_pcreate(a)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @emph{Interface}: @tab @code{subroutine acc_pcreate(a, len)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @tab @code{integer len}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.20.
+@end table
+
+
+
+@node acc_copyout
+@section @code{acc_copyout} -- Copy device memory to host memory.
+@table @asis
+@item @emph{Description}
+This function copies mapped device memory to host memory which is specified
+by host address @var{a} for a length @var{len} bytes in C/C++.
+
+In Fortran, two (2) forms are supported. In the first form, @var{a} specifies
+a contiguous array section. The second form @var{a} specifies a variable or
+array element and @var{len} specifies the length in bytes.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_copyout(h_void *a, size_t len);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{subroutine acc_copyout(a)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @emph{Interface}: @tab @code{subroutine acc_copyout(a, len)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @tab @code{integer len}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.21.
+@end table
+
+
+
+@node acc_delete
+@section @code{acc_delete} -- Free device memory.
+@table @asis
+@item @emph{Description}
+This function frees previously allocated device memory specified by
+the device address @var{a} and the length of @var{len} bytes.
+
+In Fortran, two (2) forms are supported. In the first form, @var{a} specifies
+a contiguous array section. The second form @var{a} specifies a variable or
+array element and @var{len} specifies the length in bytes.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_delete(h_void *a, size_t len);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{subroutine acc_delete(a)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @emph{Interface}: @tab @code{subroutine acc_delete(a, len)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @tab @code{integer len}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.22.
+@end table
+
+
+
+@node acc_update_device
+@section @code{acc_update_device} -- Update device memory from mapped host memory.
+@table @asis
+@item @emph{Description}
+This function updates the device copy from the previously mapped host memory.
+The host memory is specified with the host address @var{a} and a length of
+@var{len} bytes.
+
+In Fortran, two (2) forms are supported. In the first form, @var{a} specifies
+a contiguous array section. The second form @var{a} specifies a variable or
+array element and @var{len} specifies the length in bytes.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_update_device(h_void *a, size_t len);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{subroutine acc_update_device(a)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @emph{Interface}: @tab @code{subroutine acc_update_device(a, len)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @tab @code{integer len}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.23.
+@end table
+
+
+
+@node acc_update_self
+@section @code{acc_update_self} -- Update host memory from mapped device memory.
+@table @asis
+@item @emph{Description}
+This function updates the host copy from the previously mapped device memory.
+The host memory is specified with the host address @var{a} and a length of
+@var{len} bytes.
+
+In Fortran, two (2) forms are supported. In the first form, @var{a} specifies
+a contiguous array section. The second form @var{a} specifies a variable or
+array element and @var{len} specifies the length in bytes.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_update_self(h_void *a, size_t len);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{subroutine acc_update_self(a)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @emph{Interface}: @tab @code{subroutine acc_update_self(a, len)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @tab @code{integer len}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.24.
+@end table
+
+
+
+@node acc_map_data
+@section @code{acc_map_data} -- Map previously allocated device memory to host memory.
+@table @asis
+@item @emph{Description}
+This function maps previously allocated device and host memory. The device
+memory is specified with the device address @var{d}. The host memory is
+specified with the host address @var{h} and a length of @var{len}.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_map_data(h_void *h, d_void *d, size_t len);}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.25.
+@end table
+
+
+
+@node acc_unmap_data
+@section @code{acc_unmap_data} -- Unmap device memory from host memory.
+@table @asis
+@item @emph{Description}
+This function unmaps previously mapped device and host memory. The latter
+specified by @var{h}.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_unmap_data(h_void *h);}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.26.
+@end table
+
+
+
+@node acc_deviceptr
+@section @code{acc_deviceptr} -- Get device pointer associated with specific host address.
+@table @asis
+@item @emph{Description}
+This function returns the device address that has been mapped to the
+host address specified by @var{h}.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{void *acc_deviceptr(h_void *h);}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.27.
+@end table
+
+
+
+@node acc_hostptr
+@section @code{acc_hostptr} -- Get host pointer associated with specific device address.
+@table @asis
+@item @emph{Description}
+This function returns the host address that has been mapped to the
+device address specified by @var{d}.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{void *acc_hostptr(d_void *d);}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.28.
+@end table
+
+
+
+@node acc_is_present
+@section @code{acc_is_present} -- Indicate whether host variable / array is present on device.
+@table @asis
+@item @emph{Description}
+This function indicates whether the specified host address in @var{a} and a
+length of @var{len} bytes is present on the device. In C/C++, a non-zero
+value is returned to indicate the presence of the mapped memory on the
+device. A zero is returned to indicate the memory is not mapped on the
+device.
+
+In Fortran, two (2) forms are supported. In the first form, @var{a} specifies
+a contiguous array section. The second form @var{a} specifies a variable or
+array element and @var{len} specifies the length in bytes. If the host
+memory is mapped to device memory, then a @code{true} is returned. Otherwise,
+a @code{false} is return to indicate the mapped memory is not present.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{int acc_is_present(h_void *a, size_t len);}
+@end multitable
+
+@item @emph{Fortran}:
+@multitable @columnfractions .20 .80
+@item @emph{Interface}: @tab @code{function acc_is_present(a)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @tab @code{logical acc_is_present}
+@item @emph{Interface}: @tab @code{function acc_is_present(a, len)}
+@item @tab @code{type, dimension(:[,:]...) :: a}
+@item @tab @code{integer len}
+@item @tab @code{logical acc_is_present}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.29.
+@end table
+
+
+
+@node acc_memcpy_to_device
+@section @code{acc_memcpy_to_device} -- Copy host memory to device memory.
+@table @asis
+@item @emph{Description}
+This function copies host memory specified by host address of @var{src} to
+device memory specified by the device address @var{dest} for a length of
+@var{bytes} bytes.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_memcpy_to_device(d_void *dest, h_void *src, size_t bytes);}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.30.
+@end table
+
+
+
+@node acc_memcpy_from_device
+@section @code{acc_memcpy_from_device} -- Copy device memory to host memory.
+@table @asis
+@item @emph{Description}
+This function copies host memory specified by host address of @var{src} from
+device memory specified by the device address @var{dest} for a length of
+@var{bytes} bytes.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_memcpy_from_device(d_void *dest, h_void *src, size_t bytes);}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+3.2.31.
+@end table
+
+
+
+@node acc_get_current_cuda_device
+@section @code{acc_get_current_cuda_device} -- Get CUDA device handle.
+@table @asis
+@item @emph{Description}
+This function returns the CUDA device handle. This handle is the same
+as used by the CUDA Runtime or Driver API's.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{void *acc_get_current_cuda_device(void);}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+A.2.1.1.
+@end table
+
+
+
+@node acc_get_current_cuda_context
+@section @code{acc_get_current_cuda_context} -- Get CUDA context handle.
+@table @asis
+@item @emph{Description}
+This function returns the CUDA context handle. This handle is the same
+as used by the CUDA Runtime or Driver API's.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_get_current_cuda_context(void);}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+A.2.1.2.
+@end table
+
+
+
+@node acc_get_cuda_stream
+@section @code{acc_get_cuda_stream} -- Get CUDA stream handle.
+@table @asis
+@item @emph{Description}
+This function returns the CUDA stream handle. This handle is the same
+as used by the CUDA Runtime or Driver API's.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_get_cuda_stream(void);}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+A.2.1.3.
+@end table
+
+
+
+@node acc_set_cuda_stream
+@section @code{acc_set_cuda_stream} -- Set CUDA stream handle.
+@table @asis
+@item @emph{Description}
+This function associates the stream handle specified by @var{stream} with
+the asynchronous value specified by @var{async}.
+
+@item @emph{C/C++}:
+@multitable @columnfractions .20 .80
+@item @emph{Prototype}: @tab @code{acc_set_cuda_stream(int async void *stream);}
+@end multitable
+
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+A.2.1.4.
+@end table
+
+
+
+@c ---------------------------------------------------------------------
+@c OpenACC Environment Variables
+@c ---------------------------------------------------------------------
+
+@node OpenACC Environment Variables
+@chapter OpenACC Environment Variables
+
+The variables @env{ACC_DEVICE_TYPE} and @env{ACC_DEVICE_NUM}
+are defined by section 4 of the OpenACC specification in version 2.0.
+The variable @env{GCC_ACC_NOTIFY} is used for diagnostic purposes.
+
+@menu
+* ACC_DEVICE_TYPE::
+* ACC_DEVICE_NUM::
+* GCC_ACC_NOTIFY::
+@end menu
+
+
+
+@node ACC_DEVICE_TYPE
+@section @code{ACC_DEVICE_TYPE}
+@table @asis
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+4.1.
+@end table
+
+
+
+@node ACC_DEVICE_NUM
+@section @code{ACC_DEVICE_NUM}
+@table @asis
+@item @emph{Reference}:
+@uref{http://www.openacc.org/, OpenACC specification v2.0}, section
+4.2.
+@end table
+
+
+
+@node GCC_ACC_NOTIFY
+@section @code{GCC_ACC_NOTIFY}
+@table @asis
+@item @emph{Description}:
+Print debug information pertaining to the accelerator.
+@end table
+
+
+
+@c ---------------------------------------------------------------------
+@c CUDA Streams Usage
+@c ---------------------------------------------------------------------
+
+@node CUDA Streams Usage
+@chapter CUDA Streams Usage
+
+This applies to the @code{nvptx} plugin only.
+
+The library provides elements that perform asynchronous movement of
+data and asynchronous operation of computing constructs. This
+asynchronous functionality is implemented by making use of CUDA
+streams@footnote{See "Stream Management" in "CUDA Driver API",
+TRM-06703-001, Version 5.5, for additional information}.
+
+The primary means by that the asychronous functionality is accessed
+is through the use of those OpenACC directives which make use of the
+@code{async} and @code{wait} clauses. When the @code{async} clause is
+first used with a directive, it creates a CUDA stream. If an
+@code{async-argument} is used with the @code{async} clause, then the
+stream is associated with the specified @code{async-argument}.
+
+Following the creation of an association between a CUDA stream and the
+@code{async-argument} of an @code{async} clause, both the @code{wait}
+clause and the @code{wait} directive can be used. When either the
+clause or directive is used after stream creation, it creates a
+rendezvous point whereby execution waits until all operations
+associated with the @code{async-argument}, that is, stream, have
+completed.
+
+Normally, the management of the streams that are created as a result of
+using the @code{async} clause, is done without any intervention by the
+caller. This implies the association between the @code{async-argument}
+and the CUDA stream will be maintained for the lifetime of the program.
+However, this association can be changed through the use of the library
+function @code{acc_set_cuda_stream}. When the function
+@code{acc_set_cuda_stream} is called, the CUDA stream that was
+originally associated with the @code{async} clause will be destroyed.
+Caution should be taken when changing the association as subsequent
+references to the @code{async-argument} refer to a different
+CUDA stream.
+
+
+
+@c ---------------------------------------------------------------------
+@c OpenACC Library Interoperability
+@c ---------------------------------------------------------------------
+
+@node OpenACC Library Interoperability
+@chapter OpenACC Library Interoperability
+
+@section Introduction
+
+The OpenACC library uses the CUDA Driver API, and may interact with
+programs that use the Runtime library directly, or another library
+based on the Runtime library, e.g., CUBLAS@footnote{See section 2.26,
+"Interactions with the CUDA Driver API" in
+"CUDA Runtime API", Version 5.5, and section 2.27, "VDPAU
+Interoperability", in "CUDA Driver API", TRM-06703-001, Version 5.5,
+for additional information on library interoperability.}.
+This chapter describes the use cases and what changes are
+required in order to use both the OpenACC library and the CUBLAS and Runtime
+libraries within a program.
+
+@section First invocation: NVIDIA CUBLAS library API
+
+In this first use case (see below), a function in the CUBLAS library is called
+prior to any of the functions in the OpenACC library. More specifically, the
+function @code{cublasCreate()}.
+
+When invoked, the function initializes the library and allocates the
+hardware resources on the host and the device on behalf of the caller. Once
+the initialization and allocation has completed, a handle is returned to the
+caller. The OpenACC library also requires initialization and allocation of
+hardware resources. Since the CUBLAS library has already allocated the
+hardware resources for the device, all that is left to do is to initialize
+the OpenACC library and acquire the hardware resources on the host.
+
+Prior to calling the OpenACC function that initializes the library and
+allocate the host hardware resources, you need to acquire the device number
+that was allocated during the call to @code{cublasCreate()}. The invoking of the
+runtime library function @code{cudaGetDevice()} accomplishes this. Once
+acquired, the device number is passed along with the device type as
+parameters to the OpenACC library function @code{acc_set_device_num()}.
+
+Once the call to @code{acc_set_device_num()} has completed, the OpenACC
+library uses the context that was created during the call to
+@code{cublasCreate()}. In other words, both libraries will be sharing the
+same context.
+
+@smallexample
+ /* Create the handle */
+ s = cublasCreate(&h);
+ if (s != CUBLAS_STATUS_SUCCESS)
+ @{
+ fprintf(stderr, "cublasCreate failed %d\n", s);
+ exit(EXIT_FAILURE);
+ @}
+
+ /* Get the device number */
+ e = cudaGetDevice(&dev);
+ if (e != cudaSuccess)
+ @{
+ fprintf(stderr, "cudaGetDevice failed %d\n", e);
+ exit(EXIT_FAILURE);
+ @}
+
+ /* Initialize OpenACC library and use device 'dev' */
+ acc_set_device_num(dev, acc_device_nvidia);
+
+@end smallexample
+@center Use Case 1
+
+@section First invocation: OpenACC library API
+
+In this second use case (see below), a function in the OpenACC library is
+called prior to any of the functions in the CUBLAS library. More specificially,
+the function @code{acc_set_device_num()}.
+
+In the use case presented here, the function @code{acc_set_device_num()}
+is used to both initialize the OpenACC library and allocate the hardware
+resources on the host and the device. In the call to the function, the
+call parameters specify which device to use and what device
+type to use, i.e., @code{acc_device_nvidia}. It should be noted that this
+is but one method to initialize the OpenACC library and allocate the
+appropriate hardware resources. Other methods are available through the
+use of environment variables and these will be discussed in the next section.
+
+Once the call to @code{acc_set_device_num()} has completed, other OpenACC
+functions can be called as seen with multiple calls being made to
+@code{acc_copyin()}. In addition, calls can be made to functions in the
+CUBLAS library. In the use case a call to @code{cublasCreate()} is made
+subsequent to the calls to @code{acc_copyin()}.
+As seen in the previous use case, a call to @code{cublasCreate()}
+initializes the CUBLAS library and allocates the hardware resources on the
+host and the device. However, since the device has already been allocated,
+@code{cublasCreate()} will only initialize the CUBLAS library and allocate
+the appropriate hardware resources on the host. The context that was created
+as part of the OpenACC initialization is shared with the CUBLAS library,
+similarly to the first use case.
+
+@smallexample
+ dev = 0;
+
+ acc_set_device_num(dev, acc_device_nvidia);
+
+ /* Copy the first set to the device */
+ d_X = acc_copyin(&h_X[0], N * sizeof (float));
+ if (d_X == NULL)
+ @{
+ fprintf(stderr, "copyin error h_X\n");
+ exit(EXIT_FAILURE);
+ @}
+
+ /* Copy the second set to the device */
+ d_Y = acc_copyin(&h_Y1[0], N * sizeof (float));
+ if (d_Y == NULL)
+ @{
+ fprintf(stderr, "copyin error h_Y1\n");
+ exit(EXIT_FAILURE);
+ @}
+
+ /* Create the handle */
+ s = cublasCreate(&h);
+ if (s != CUBLAS_STATUS_SUCCESS)
+ @{
+ fprintf(stderr, "cublasCreate failed %d\n", s);
+ exit(EXIT_FAILURE);
+ @}
+
+ /* Perform saxpy using CUBLAS library function */
+ s = cublasSaxpy(h, N, &alpha, d_X, 1, d_Y, 1);
+ if (s != CUBLAS_STATUS_SUCCESS)
+ @{
+ fprintf(stderr, "cublasSaxpy failed %d\n", s);
+ exit(EXIT_FAILURE);
+ @}
+
+ /* Copy the results from the device */
+ acc_memcpy_from_device(&h_Y1[0], d_Y, N * sizeof (float));
+
+@end smallexample
+@center Use Case 2
+
+@section OpenACC library and environment variables
+
+There are two environment variables associated with the OpenACC library
+that may be used to control the device type and device number:
+@env{ACC_DEVICE_TYPE} and @env{ACC_DEVICE_NUM}, respecively. These two
+environement variables can be used as an alternative to calling
+@code{acc_set_device_num()}. As seen in the second use case, the device
+type and device number were specified using @code{acc_set_device_num()}.
+If however, the aforementioned environment variables were set, then the
+call to @code{acc_set_device_num()} would not be required.
+
+
+The use of the environment variables is only relevant when an OpenACC function
+is called prior to a call to @code{cudaCreate()}. If @code{cudaCreate()}
+is called prior to a call to an OpenACC function, then you must call
+@code{acc_set_device_num()}@footnote{More complete information
+about @env{ACC_DEVICE_TYPE} and @env{ACC_DEVICE_NUM} can be found in
+sections 4.1 and 4.2 of the @uref{http://www.openacc.org/, OpenACC}
+Application Programming Interface”, Version 2.0.}
+
+
+
+@c ---------------------------------------------------------------------
@c The libgomp ABI
@c ---------------------------------------------------------------------
@@ -1814,6 +3090,7 @@
* Implementing ORDERED construct::
* Implementing SECTIONS construct::
* Implementing SINGLE construct::
+* Implementing OpenACC's PARALLEL construct::
@end menu
@@ -2178,6 +3455,15 @@
+@node Implementing OpenACC's PARALLEL construct
+@section Implementing OpenACC's PARALLEL construct
+
+@smallexample
+ void GOACC_parallel ()
+@end smallexample
+
+
+
@c ---------------------------------------------------------------------
@c Reporting Bugs
@c ---------------------------------------------------------------------