diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..da382fb --- /dev/null +++ b/LICENSE @@ -0,0 +1,21 @@ +MIT License + +Copyright (c) 2020 Pavel Kirienko + +Permission is hereby granted, free of charge, to any person obtaining a copy +of this software and associated documentation files (the "Software"), to deal +in the Software without restriction, including without limitation the rights +to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +copies of the Software, and to permit persons to whom the Software is +furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in all +copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +SOFTWARE. diff --git a/o1heap.cpp b/o1heap.cpp index 93e2ab3..03ccbba 100644 --- a/o1heap.cpp +++ b/o1heap.cpp @@ -34,8 +34,11 @@ /// The assertion macro defaults to the standard assert(). /// It can be overridden to manually suppress assertion checks or use a different error handling policy. #ifndef O1HEAP_ASSERT -// Intentional violation of MISRA: the assertion check macro cannot be replaced with a function definition. -# define O1HEAP_ASSERT(x) assert(x) // NOSONAR + #if defined(AU_CFG_ID_DEBUG) || defined(AU_CFG_ID_INTERNAL) + #define O1HEAP_ASSERT(x) SysAssert(x) + #else + #define O1HEAP_ASSERT(x) + #endif #endif /// Branch probability annotations are used to improve the worst case execution time (WCET). They are entirely optional. @@ -43,7 +46,6 @@ /// If you are using a different compiler, consider overriding this value. #ifndef O1HEAP_LIKELY # if defined(__GNUC__) || defined(__clang__) || defined(__CC_ARM) -// Intentional violation of MISRA: branch hinting macro cannot be replaced with a function definition. # define O1HEAP_LIKELY(x) __builtin_expect((x), 1) // NOSONAR # else # define O1HEAP_LIKELY(x) x @@ -134,26 +136,27 @@ O1HEAP_PRIVATE bool isPowerOf2(const size_t x) } /// Special case: if the argument is zero, returns zero. -O1HEAP_PRIVATE uint8_t log2Floor(const size_t x); O1HEAP_PRIVATE uint8_t log2Floor(const size_t x) { - size_t tmp = x; - uint8_t y = 0; - // This is currently the only exception to the statement "routines contain neither loops nor recursion". - // It is unclear if there is a better way to compute the binary logarithm than this. - while (tmp > 1U) - { - tmp >>= 1U; - y++; - } - return y; + O1HEAP_ASSERT(x > 0); + AuUInt8 index {}; + AuBitScanReverse(index, x); + return (uint8_t)(((sizeof(x) * CHAR_BIT) - 1U) - index); } -/// Special case: if the argument is zero, returns zero. -O1HEAP_PRIVATE uint8_t log2Ceil(const size_t x); -O1HEAP_PRIVATE uint8_t log2Ceil(const size_t x) +O1HEAP_PRIVATE uint_fast8_t log2Ceil(const size_t x) { - return (uint8_t)(log2Floor(x) + (isPowerOf2(x) ? 0U : 1U)); + AuUInt8 index {}; + AuBitScanReverse(index, x - 1); + return (x <= 1U) ? 0U : (uint_fast8_t)((sizeof(x) * CHAR_BIT) - (index)); +} + +O1HEAP_PRIVATE size_t roundUpToPowerOf2(const size_t x) +{ + O1HEAP_ASSERT(x >= 2U); + AuUInt8 index {}; + AuBitScanReverse(index, x - 1); + return ((size_t)1U) << ((sizeof(x) * CHAR_BIT) - (index)); } /// Raise 2 into the specified power. @@ -316,11 +319,11 @@ void *o1heapAllocate(O1HeapInstance *const handle, const size_t amount) { // Add the header size and align the allocation size to the power of 2. // See "Timing-Predictable Memory Allocation In Hard Real-Time Systems", Herter, page 27. - const size_t fragment_size = pow2(log2Ceil(amount + O1HEAP_ALIGNMENT)); + const size_t fragment_size = roundUpToPowerOf2(amount + O1HEAP_ALIGNMENT); O1HEAP_ASSERT(fragment_size <= FRAGMENT_SIZE_MAX); O1HEAP_ASSERT(fragment_size >= FRAGMENT_SIZE_MIN); O1HEAP_ASSERT(fragment_size >= amount + O1HEAP_ALIGNMENT); - O1HEAP_ASSERT(isPowerOf2(fragment_size)); + O1HEAP_ASSERT((fragment_size & (fragment_size - 1U)) == 0U); // Is power of 2. const uint8_t optimal_bin_index = log2Ceil(fragment_size / FRAGMENT_SIZE_MIN); // Use CEIL when fetching. O1HEAP_ASSERT(optimal_bin_index < NUM_BINS_MAX); @@ -333,8 +336,8 @@ void *o1heapAllocate(O1HeapInstance *const handle, const size_t amount) const size_t smallest_bin_mask = suitable_bins & ~(suitable_bins - 1U); // Clear all bits but the lowest. if (O1HEAP_LIKELY(smallest_bin_mask != 0)) { - O1HEAP_ASSERT(isPowerOf2(smallest_bin_mask)); - const uint8_t bin_index = log2Floor(smallest_bin_mask); + O1HEAP_ASSERT((smallest_bin_mask & (smallest_bin_mask - 1U)) == 0U); // Is power of 2. + const uint_fast8_t bin_index = log2Floor(smallest_bin_mask); O1HEAP_ASSERT(bin_index >= optimal_bin_index); O1HEAP_ASSERT(bin_index < NUM_BINS_MAX); @@ -353,7 +356,7 @@ void *o1heapAllocate(O1HeapInstance *const handle, const size_t amount) O1HEAP_ASSERT(leftover % FRAGMENT_SIZE_MIN == 0U); // Alignment check. if (O1HEAP_LIKELY(leftover >= FRAGMENT_SIZE_MIN)) { - Fragment *const new_frag = (Fragment *)(void *)(((uint8_t *)frag) + fragment_size); + Fragment *const new_frag = (Fragment *)(void *)(((char *)frag) + fragment_size); O1HEAP_ASSERT(((size_t)new_frag) % O1HEAP_ALIGNMENT == 0U); new_frag->header.size = leftover; new_frag->header.used = false;