6aea44fc2b
Update our copy of libvixl to upstream 1.6. There are no changes of any particular interest to QEMU, so this is simply keeping up with current upstream. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1412091418-25744-1-git-send-email-peter.maydell@linaro.org
139 lines
4.0 KiB
C++
139 lines
4.0 KiB
C++
// Copyright 2013, 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
|
|
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
|
|
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
|
|
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
|
|
#include "utils.h"
|
|
#include <stdio.h>
|
|
|
|
namespace vixl {
|
|
|
|
uint32_t float_to_rawbits(float value) {
|
|
uint32_t bits = 0;
|
|
memcpy(&bits, &value, 4);
|
|
return bits;
|
|
}
|
|
|
|
|
|
uint64_t double_to_rawbits(double value) {
|
|
uint64_t bits = 0;
|
|
memcpy(&bits, &value, 8);
|
|
return bits;
|
|
}
|
|
|
|
|
|
float rawbits_to_float(uint32_t bits) {
|
|
float value = 0.0;
|
|
memcpy(&value, &bits, 4);
|
|
return value;
|
|
}
|
|
|
|
|
|
double rawbits_to_double(uint64_t bits) {
|
|
double value = 0.0;
|
|
memcpy(&value, &bits, 8);
|
|
return value;
|
|
}
|
|
|
|
|
|
int CountLeadingZeros(uint64_t value, int width) {
|
|
VIXL_ASSERT((width == 32) || (width == 64));
|
|
int count = 0;
|
|
uint64_t bit_test = UINT64_C(1) << (width - 1);
|
|
while ((count < width) && ((bit_test & value) == 0)) {
|
|
count++;
|
|
bit_test >>= 1;
|
|
}
|
|
return count;
|
|
}
|
|
|
|
|
|
int CountLeadingSignBits(int64_t value, int width) {
|
|
VIXL_ASSERT((width == 32) || (width == 64));
|
|
if (value >= 0) {
|
|
return CountLeadingZeros(value, width) - 1;
|
|
} else {
|
|
return CountLeadingZeros(~value, width) - 1;
|
|
}
|
|
}
|
|
|
|
|
|
int CountTrailingZeros(uint64_t value, int width) {
|
|
VIXL_ASSERT((width == 32) || (width == 64));
|
|
int count = 0;
|
|
while ((count < width) && (((value >> count) & 1) == 0)) {
|
|
count++;
|
|
}
|
|
return count;
|
|
}
|
|
|
|
|
|
int CountSetBits(uint64_t value, int width) {
|
|
// TODO: Other widths could be added here, as the implementation already
|
|
// supports them.
|
|
VIXL_ASSERT((width == 32) || (width == 64));
|
|
|
|
// Mask out unused bits to ensure that they are not counted.
|
|
value &= (UINT64_C(0xffffffffffffffff) >> (64-width));
|
|
|
|
// Add up the set bits.
|
|
// The algorithm works by adding pairs of bit fields together iteratively,
|
|
// where the size of each bit field doubles each time.
|
|
// An example for an 8-bit value:
|
|
// Bits: h g f e d c b a
|
|
// \ | \ | \ | \ |
|
|
// value = h+g f+e d+c b+a
|
|
// \ | \ |
|
|
// value = h+g+f+e d+c+b+a
|
|
// \ |
|
|
// value = h+g+f+e+d+c+b+a
|
|
const uint64_t kMasks[] = {
|
|
UINT64_C(0x5555555555555555),
|
|
UINT64_C(0x3333333333333333),
|
|
UINT64_C(0x0f0f0f0f0f0f0f0f),
|
|
UINT64_C(0x00ff00ff00ff00ff),
|
|
UINT64_C(0x0000ffff0000ffff),
|
|
UINT64_C(0x00000000ffffffff),
|
|
};
|
|
|
|
for (unsigned i = 0; i < (sizeof(kMasks) / sizeof(kMasks[0])); i++) {
|
|
int shift = 1 << i;
|
|
value = ((value >> shift) & kMasks[i]) + (value & kMasks[i]);
|
|
}
|
|
|
|
return value;
|
|
}
|
|
|
|
|
|
uint64_t LowestSetBit(uint64_t value) {
|
|
return value & -value;
|
|
}
|
|
|
|
|
|
bool IsPowerOf2(int64_t value) {
|
|
return (value != 0) && ((value & (value - 1)) == 0);
|
|
}
|
|
|
|
} // namespace vixl
|