--- /dev/null
+// 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);
+}
+
+
+unsigned CountClearHalfWords(uint64_t imm, unsigned reg_size) {
+ VIXL_ASSERT((reg_size % 8) == 0);
+ int count = 0;
+ for (unsigned i = 0; i < (reg_size / 16); i++) {
+ if ((imm & 0xffff) == 0) {
+ count++;
+ }
+ imm >>= 16;
+ }
+ return count;
+}
+
+} // namespace vixl
Code Review / kvmfornfv.git / blobdiff