michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: // Shared utility functions for and macros parallel operations in `Array.js`
michael@0: // and `TypedObject.js`.
michael@0: 
michael@0: #ifdef ENABLE_PARALLEL_JS
michael@0: 
michael@0: /* The mode asserts options object. */
michael@0: #define TRY_PARALLEL(MODE) \
michael@0:   ((!MODE || MODE.mode !== "seq"))
michael@0: #define ASSERT_SEQUENTIAL_IS_OK(MODE) \
michael@0:   do { if (MODE) AssertSequentialIsOK(MODE) } while(false)
michael@0: 
michael@0: /**
michael@0:  * The ParallelSpew intrinsic is only defined in debug mode, so define a dummy
michael@0:  * if debug is not on.
michael@0:  */
michael@0: #ifndef DEBUG
michael@0: #define ParallelSpew(args)
michael@0: #endif
michael@0: 
michael@0: #define MAX_SLICE_SHIFT 6
michael@0: #define MAX_SLICE_SIZE 64
michael@0: #define MAX_SLICES_PER_WORKER 8
michael@0: 
michael@0: /**
michael@0:  * Macros to help compute the start and end indices of slices based on id. Use
michael@0:  * with the object returned by ComputeSliceInfo.
michael@0:  */
michael@0: #define SLICE_START_INDEX(shift, id) \
michael@0:     (id << shift)
michael@0: #define SLICE_END_INDEX(shift, start, length) \
michael@0:     std_Math_min(start + (1 << shift), length)
michael@0: 
michael@0: /**
michael@0:  * ForkJoinGetSlice acts as identity when we are not in a parallel section, so
michael@0:  * pass in the next sequential value when we are in sequential mode. The
michael@0:  * reason for this odd API is because intrinsics *need* to be called during
michael@0:  * ForkJoin's warmup to fill the TI info.
michael@0:  */
michael@0: #define GET_SLICE(sliceStart, sliceEnd, id) \
michael@0:     ((id = ForkJoinGetSlice((InParallelSection() ? -1 : sliceStart++) | 0)) < sliceEnd)
michael@0: 
michael@0: /**
michael@0:  * Determine the number and size of slices. The info object has the following
michael@0:  * properties:
michael@0:  *
michael@0:  *  - shift: amount to shift by to compute indices
michael@0:  *  - count: number of slices
michael@0:  */
michael@0: function ComputeSlicesInfo(length) {
michael@0:   var count = length >>> MAX_SLICE_SHIFT;
michael@0:   var numWorkers = ForkJoinNumWorkers();
michael@0:   if (count < numWorkers)
michael@0:     count = numWorkers;
michael@0:   else if (count >= numWorkers * MAX_SLICES_PER_WORKER)
michael@0:     count = numWorkers * MAX_SLICES_PER_WORKER;
michael@0: 
michael@0:   // Round the slice size to be a power of 2.
michael@0:   var shift = std_Math_max(std_Math_log2(length / count) | 0, 1);
michael@0: 
michael@0:   // Recompute count with the rounded size.
michael@0:   count = length >>> shift;
michael@0:   if (count << shift !== length)
michael@0:     count += 1;
michael@0: 
michael@0:   return { shift: shift, count: count };
michael@0: }
michael@0: 
michael@0: #endif // ENABLE_PARALLEL_JS