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authorchai <chaifix@163.com>2019-08-14 22:50:43 +0800
committerchai <chaifix@163.com>2019-08-14 22:50:43 +0800
commit15740faf9fe9fe4be08965098bbf2947e096aeeb (patch)
treea730ec236656cc8cab5b13f088adfaed6bb218fb /Runtime/Allocator/tlsf/tlsfbits.h
+Unity Runtime codeHEADmaster
Diffstat (limited to 'Runtime/Allocator/tlsf/tlsfbits.h')
-rw-r--r--Runtime/Allocator/tlsf/tlsfbits.h184
1 files changed, 184 insertions, 0 deletions
diff --git a/Runtime/Allocator/tlsf/tlsfbits.h b/Runtime/Allocator/tlsf/tlsfbits.h
new file mode 100644
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+++ b/Runtime/Allocator/tlsf/tlsfbits.h
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+#ifndef INCLUDED_tlsfbits
+#define INCLUDED_tlsfbits
+
+#if defined(__cplusplus)
+#define tlsf_decl inline
+#else
+#define tlsf_decl static
+#endif
+
+/*
+** Architecture-specific bit manipulation routines.
+**
+** TLSF achieves O(1) cost for malloc and free operations by limiting
+** the search for a free block to a free list of guaranteed size
+** adequate to fulfill the request, combined with efficient free list
+** queries using bitmasks and architecture-specific bit-manipulation
+** routines.
+**
+** Most modern processors provide instructions to count leading zeroes
+** in a word, find the lowest and highest set bit, etc. These
+** specific implementations will be used when available, falling back
+** to a reasonably efficient generic implementation.
+**
+** NOTE: TLSF spec relies on ffs/fls returning value 0..31.
+** ffs/fls return 1-32 by default, returning 0 for error.
+*/
+
+/*
+** Detect whether or not we are building for a 32- or 64-bit (LP/LLP)
+** architecture. There is no reliable portable method at compile-time.
+*/
+
+// native client uses ILP32, even when building for x86_64, so make sure
+// that pointer sizes are treated as 32 bits.
+#if !defined(__native_client__)
+#if defined (__alpha__) || defined (__ia64__) || defined (__x86_64__) \
+ || defined (_WIN64) || defined (__LP64__) || defined (__LLP64__)
+#define TLSF_64BIT
+#endif
+#endif
+/*
+** gcc 3.4 and above have builtin support, specialized for architecture.
+** Some compilers masquerade as gcc; patchlevel test filters them out.
+*/
+#if defined (__GNUC__) && (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)) \
+ && defined (__GNUC_PATCHLEVEL__)
+
+tlsf_decl int tlsf_ffs(unsigned int word)
+{
+ return __builtin_ffs(word) - 1;
+}
+
+tlsf_decl int tlsf_fls(unsigned int word)
+{
+ const int bit = word ? 32 - __builtin_clz(word) : 0;
+ return bit - 1;
+}
+
+#elif defined (_MSC_VER) && defined (_M_IX86) && (_MSC_VER >= 1400)
+/* Microsoft Visual C++ 2005 support on x86 architectures. */
+
+#include <intrin.h>
+
+#pragma intrinsic(_BitScanReverse)
+#pragma intrinsic(_BitScanForward)
+
+tlsf_decl int tlsf_fls(unsigned int word)
+{
+ unsigned long index;
+ return _BitScanReverse(&index, word) ? index : -1;
+}
+
+tlsf_decl int tlsf_ffs(unsigned int word)
+{
+ unsigned long index;
+ return _BitScanForward(&index, word) ? index : -1;
+}
+
+#elif defined (_MSC_VER) && defined (_M_PPC)
+/* Microsoft Visual C++ support on PowerPC architectures. */
+
+#include <ppcintrinsics.h>
+
+tlsf_decl int tlsf_fls(unsigned int word)
+{
+ const int bit = 32 - _CountLeadingZeros(word);
+ return bit - 1;
+}
+
+tlsf_decl int tlsf_ffs(unsigned int word)
+{
+ const unsigned int reverse = word & (~word + 1);
+ const int bit = 32 - _CountLeadingZeros(reverse);
+ return bit - 1;
+}
+
+#elif defined (__ARMCC_VERSION)
+/* RealView Compilation Tools for ARM */
+
+tlsf_decl int tlsf_ffs(unsigned int word)
+{
+ const unsigned int reverse = word & (~word + 1);
+ const int bit = 32 - __clz(reverse);
+ return bit - 1;
+}
+
+tlsf_decl int tlsf_fls(unsigned int word)
+{
+ const int bit = word ? 32 - __clz(word) : 0;
+ return bit - 1;
+}
+
+#elif defined (__ghs__)
+/* Green Hills support for PowerPC */
+
+#include <ppc_ghs.h>
+
+tlsf_decl int tlsf_ffs(unsigned int word)
+{
+ const unsigned int reverse = word & (~word + 1);
+ const int bit = 32 - __CLZ32(reverse);
+ return bit - 1;
+}
+
+tlsf_decl int tlsf_fls(unsigned int word)
+{
+ const int bit = word ? 32 - __CLZ32(word) : 0;
+ return bit - 1;
+}
+
+#else
+/* Fall back to generic implementation. */
+
+tlsf_decl int tlsf_fls_generic(unsigned int word)
+{
+ int bit = 32;
+
+ if (!word) bit -= 1;
+ if (!(word & 0xffff0000)) { word <<= 16; bit -= 16; }
+ if (!(word & 0xff000000)) { word <<= 8; bit -= 8; }
+ if (!(word & 0xf0000000)) { word <<= 4; bit -= 4; }
+ if (!(word & 0xc0000000)) { word <<= 2; bit -= 2; }
+ if (!(word & 0x80000000)) { word <<= 1; bit -= 1; }
+
+ return bit;
+}
+
+/* Implement ffs in terms of fls. */
+tlsf_decl int tlsf_ffs(unsigned int word)
+{
+ return tlsf_fls_generic(word & (~word + 1)) - 1;
+}
+
+tlsf_decl int tlsf_fls(unsigned int word)
+{
+ return tlsf_fls_generic(word) - 1;
+}
+
+#endif
+
+/* Possibly 64-bit version of tlsf_fls. */
+#if defined (TLSF_64BIT)
+tlsf_decl int tlsf_fls_sizet(size_t size)
+{
+ int high = (int)(size >> 32);
+ int bits = 0;
+ if (high)
+ {
+ bits = 32 + tlsf_fls(high);
+ }
+ else
+ {
+ bits = tlsf_fls((int)size & 0xffffffff);
+
+ }
+ return bits;
+}
+#else
+#define tlsf_fls_sizet tlsf_fls
+#endif
+
+#undef tlsf_decl
+
+#endif