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