jdk-24/test/hotspot/gtest/utilities/test_byteswap.cpp
Justin King a9dba56568 8300783: Consolidate byteswap implementations
Reviewed-by: kbarrett, kvn
2023-03-09 19:39:07 +00:00

85 lines
2.9 KiB
C++

/*
* Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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#include "precompiled.hpp"
#include "utilities/byteswap.hpp"
#include "utilities/globalDefinitions.hpp"
#include "unittest.hpp"
template<typename T>
static inline void test_byteswap() {
const int NBIT = sizeof(T) * 8;
const bool IS_U = (T)-1 > 0;
const int XOR_REV_BITS = (NBIT - 1);
const int XOR_REV_BITS_IN_BYTES = 7; // only flip position in byte
const int XOR_REV_BYTES = XOR_REV_BITS ^ XOR_REV_BITS_IN_BYTES;
ASSERT_EQ(byteswap<T>((T)0), (T)0);
ASSERT_EQ(byteswap<T>((T)-1), (T)-1);
for (int i1 = 0; i1 < NBIT; i1++) {
T mask1 = (T)1 << i1;
T rbym1 = (T)1 << (i1 ^ XOR_REV_BYTES);
for (int i2 = 0; i2 <= i1; i2++) {
T mask2 = (T)1 << i2;
T rbym2 = (T)1 << (i2 ^ XOR_REV_BYTES);
T mask = mask1|mask2;
#define STUFF (IS_U?"u":"s") << NBIT << "@" << i1 << "," << i2
ASSERT_EQ(byteswap<T>(mask), rbym1|rbym2) << STUFF;
ASSERT_EQ((T)~byteswap<T>((T)~mask), rbym1|rbym2) << STUFF;
}
}
}
TEST_VM(utilities, byteswap) {
test_byteswap<int64_t>();
test_byteswap<uint64_t>();
test_byteswap<int32_t>();
test_byteswap<uint32_t>();
test_byteswap<int16_t>();
test_byteswap<uint16_t>();
test_byteswap<int8_t>();
test_byteswap<uint8_t>();
}
// Here is some object code to look at if we want to do a manual
// study. One could find the build file named test_byteswap.o.cmdline
// and hand-edit the command line to produce assembly code in
// test_byteswap.s.
//
// Or, given the two empty "fence functions", one could do a
// quick scan like this:
//
// $ objdump -D $(find build/*release -name test_byteswap.o) \
// | sed -n '/start_code_quality/,$p;/end_code_quality/q' \
// | egrep -B10 bswap # or grep -B20 cfi_endproc
void start_code_quality_byteswap() { }
int32_t code_quality_reverse_bytes_32(int32_t x) {
return byteswap(x);
}
int64_t code_quality_reverse_bytes_64(int64_t x) {
return byteswap(x);
}