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Diffstat (limited to 'qemu/disas/libvixl/utils.cc')
| -rw-r--r-- | qemu/disas/libvixl/utils.cc | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/qemu/disas/libvixl/utils.cc b/qemu/disas/libvixl/utils.cc new file mode 100644 index 000000000..80b132a11 --- /dev/null +++ b/qemu/disas/libvixl/utils.cc @@ -0,0 +1,151 @@ +// 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 |