84 lines
3 KiB
C++
84 lines
3 KiB
C++
// Copyright 2015, ARM Limited
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are met:
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//
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// * Redistributions of source code must retain the above copyright notice,
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// this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above copyright notice,
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// this list of conditions and the following disclaimer in the documentation
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// and/or other materials provided with the distribution.
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// * Neither the name of ARM Limited nor the names of its contributors may be
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// used to endorse or promote products derived from this software without
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// specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND
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// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
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// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#include "vixl/a64/macro-assembler-a64.h"
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#include "vixl/a64/instructions-a64.h"
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#include "vixl/globals.h"
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using namespace vixl;
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static const int kDefaultInstructionCount = 100000;
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// This program focuses on emitting branch instructions.
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//
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// This code will emit a given number of branch immediate to the next
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// instructions in a fixed size buffer, looping over the buffer if necessary.
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// This code therefore focuses on Emit and label binding/patching.
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int main(int argc, char* argv[]) {
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int instructions = 0;
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switch (argc) {
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case 1: instructions = kDefaultInstructionCount; break;
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case 2: instructions = atoi(argv[1]); break;
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default:
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printf("Usage: %s [#instructions]\n", argv[0]);
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exit(1);
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}
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const int buffer_size = 256 * KBytes;
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const int buffer_instruction_count = buffer_size / kInstructionSize;
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MacroAssembler masm(buffer_size);
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#define __ masm.
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// We emit a branch to the next instruction.
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int rounds = instructions / buffer_instruction_count;
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for (int i = 0; i < rounds; ++i) {
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{
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InstructionAccurateScope scope(&masm, buffer_instruction_count);
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for (int j = 0; j < buffer_instruction_count; ++j) {
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Label target;
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__ b(&target);
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__ bind(&target);
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}
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}
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masm.Reset();
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}
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int remaining = instructions % buffer_instruction_count;
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{
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InstructionAccurateScope scope(&masm, remaining);
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for (int i = 0; i < remaining; ++i) {
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Label target;
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__ b(&target);
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__ bind(&target);
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}
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}
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masm.FinalizeCode();
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return 0;
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}
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