--- libecb/ecb.h 2012/05/29 21:03:20 1.94 +++ libecb/ecb.h 2012/06/29 01:39:51 1.108 @@ -56,7 +56,6 @@ typedef uint32_t uintptr_t; typedef int32_t intptr_t; #endif - typedef intptr_t ptrdiff_t; #else #include #if UINTMAX_MAX > 0xffffffffU @@ -85,16 +84,25 @@ #define ECB_C99 (__STDC_VERSION__ >= 199901L) #define ECB_C11 (__STDC_VERSION__ >= 201112L) #define ECB_CPP (__cplusplus+0) -#define ECB_CPP98 (__cplusplus >= 199711L) #define ECB_CPP11 (__cplusplus >= 201103L) +#if ECB_CPP + #define ECB_EXTERN_C extern "C" + #define ECB_EXTERN_C_BEG ECB_EXTERN_C { + #define ECB_EXTERN_C_END } +#else + #define ECB_EXTERN_C extern + #define ECB_EXTERN_C_BEG + #define ECB_EXTERN_C_END +#endif + /*****************************************************************************/ /* ECB_NO_THREADS - ecb is not used by multiple threads, ever */ /* ECB_NO_SMP - ecb might be used in multiple threads, but only on a single cpu */ #if ECB_NO_THREADS -# define ECB_NO_SMP 1 + #define ECB_NO_SMP 1 #endif #if ECB_NO_SMP @@ -140,15 +148,13 @@ #ifndef ECB_MEMORY_FENCE #if ECB_GCC_VERSION(4,7) - /* see comment below about the C11 memory model. in short - avoid */ + /* see comment below (stdatomic.h) about the C11 memory model. */ #define ECB_MEMORY_FENCE __atomic_thread_fence (__ATOMIC_SEQ_CST) - #elif defined __clang && __has_feature (cxx_atomic) - /* see above */ - #define ECB_MEMORY_FENCE __c11_atomic_thread_fence (__ATOMIC_SEQ_CST) + /*#elif defined __clang && __has_feature (cxx_atomic)*/ + /* see comment below (stdatomic.h) about the C11 memory model. */ + /*#define ECB_MEMORY_FENCE __c11_atomic_thread_fence (__ATOMIC_SEQ_CST)*/ #elif ECB_GCC_VERSION(4,4) || defined __INTEL_COMPILER || defined __clang__ #define ECB_MEMORY_FENCE __sync_synchronize () - /*#define ECB_MEMORY_FENCE_ACQUIRE ({ char dummy = 0; __sync_lock_test_and_set (&dummy, 1); }) */ - /*#define ECB_MEMORY_FENCE_RELEASE ({ char dummy = 1; __sync_lock_release (&dummy ); }) */ #elif _MSC_VER >= 1400 /* VC++ 2005 */ #pragma intrinsic(_ReadBarrier,_WriteBarrier,_ReadWriteBarrier) #define ECB_MEMORY_FENCE _ReadWriteBarrier () @@ -172,10 +178,13 @@ /* we assume that these memory fences work on all variables/all memory accesses, */ /* not just C11 atomics and atomic accesses */ #include - /* unfortunately, the C11 memory model seems to be very limited, and unable to express */ - /* simple barrier semantics. That means we need to take out thor's hammer. */ + /* Unfortunately, neither gcc 4.7 nor clang 3.1 generate any instructions for */ + /* any fence other than seq_cst, which isn't very efficient for us. */ + /* Why that is, we don't know - either the C11 memory model is quite useless */ + /* for most usages, or gcc and clang have a bug */ + /* I *currently* lean towards the latter, and inefficiently implement */ + /* all three of ecb's fences as a seq_cst fence */ #define ECB_MEMORY_FENCE atomic_thread_fence (memory_order_seq_cst) - #endif #endif #endif @@ -461,14 +470,32 @@ #endif /* try to tell the compiler that some condition is definitely true */ -#define ecb_assume(cond) do { if (!(cond)) ecb_unreachable (); } while (0) +#define ecb_assume(cond) if (!(cond)) ecb_unreachable (); else 0 ecb_inline unsigned char ecb_byteorder_helper (void) ecb_const; ecb_inline unsigned char ecb_byteorder_helper (void) { - const uint32_t u = 0x11223344; - return *(unsigned char *)&u; + /* the union code still generates code under pressure in gcc, */ + /* but less than using pointers, and always seem to */ + /* successfully return a constant. */ + /* the reason why we have this horrible preprocessor mess */ + /* is to avoid it in all cases, at least on common architectures */ + /* and yes, gcc defines __BYTE_ORDER__, g++ does not */ +#if __i386 || __i386__ || _M_X86 || __amd64 || __amd64__ || _M_X64 + return 0x44; +#elif __BYTE_ORDER__ && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + return 0x44; +#elif __BYTE_ORDER__ && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ + retrurn 0x11; +#else + union + { + uint32_t i; + uint8_t c; + } u = { 0x11223344 }; + return u.c; +#endif } ecb_inline ecb_bool ecb_big_endian (void) ecb_const; @@ -509,5 +536,177 @@ #define ecb_array_length(name) (sizeof (name) / sizeof (name [0])) #endif +/*******************************************************************************/ +/* floating point stuff, can be disabled by defining ECB_NO_LIBM */ + +/* basically, everything uses "ieee pure-endian" floating point numbers */ +/* the only noteworthy exception is ancient armle, which uses order 43218765 */ +#if 0 \ + || __i386 || __i386__ \ + || __amd64 || __amd64__ || __x86_64 || __x86_64__ \ + || __powerpc__ || __ppc__ || __powerpc64__ || __ppc64__ \ + || defined __arm__ && defined __ARM_EABI__ \ + || defined __s390__ || defined __s390x__ \ + || defined __mips__ \ + || defined __alpha__ \ + || defined __hppa__ \ + || defined __ia64__ \ + || defined _M_IX86 || defined _M_AMD64 || defined _M_IA64 + #define ECB_STDFP 1 + #include /* for memcpy */ +#else + #define ECB_STDFP 0 +#endif + +#ifndef ECB_NO_LIBM + + /* convert a float to ieee single/binary32 */ + ecb_function_ uint32_t ecb_float_to_binary32 (float x) ecb_const; + ecb_function_ uint32_t + ecb_float_to_binary32 (float x) + { + uint32_t r; + + #if ECB_STDFP + memcpy (&r, &x, 4); + #else + /* slow emulation, works for anything but -0 */ + ECB_EXTERN_C float frexpf (float v, int *e); + uint32_t m; + int e; + + if (x == 0e0f ) return 0x00000000U; + if (x > +3.40282346638528860e+38f) return 0x7f800000U; + if (x < -3.40282346638528860e+38f) return 0xff800000U; + if (x != x ) return 0x7fbfffffU; + + m = frexpf (x, &e) * 0x1000000U; + + r = m & 0x80000000U; + + if (r) + m = -m; + + if (e <= -126) + { + m &= 0xffffffU; + m >>= (-125 - e); + e = -126; + } + + r |= (e + 126) << 23; + r |= m & 0x7fffffU; + #endif + + return r; + } + + /* converts an ieee single/binary32 to a float */ + ecb_function_ float ecb_binary32_to_float (uint32_t x) ecb_const; + ecb_function_ float + ecb_binary32_to_float (uint32_t x) + { + float r; + + #if ECB_STDFP + memcpy (&r, &x, 4); + #else + /* emulation, only works for normals and subnormals and +0 */ + ECB_EXTERN_C float ldexpf (float x, int e); + + int neg = x >> 31; + int e = (x >> 23) & 0xffU; + + x &= 0x7fffffU; + + if (e) + x |= 0x800000U; + else + e = 1; + + /* we distrust ldexpf a bit and do the 2**-24 scaling by an extra multiply */ + r = ldexpf (x * (0.5f / 0x800000U), e - 126); + + r = neg ? -r : r; + #endif + + return r; + } + + /* convert a double to ieee double/binary64 */ + ecb_function_ uint64_t ecb_double_to_binary64 (double x) ecb_const; + ecb_function_ uint64_t + ecb_double_to_binary64 (double x) + { + uint64_t r; + + #if ECB_STDFP + memcpy (&r, &x, 8); + #else + /* slow emulation, works for anything but -0 */ + ECB_EXTERN_C double frexp (double v, int *e); + uint64_t m; + int e; + + if (x == 0e0 ) return 0x0000000000000000U; + if (x > +1.79769313486231470e+308) return 0x7ff0000000000000U; + if (x < -1.79769313486231470e+308) return 0xfff0000000000000U; + if (x != x ) return 0X7ff7ffffffffffffU; + + m = frexp (x, &e) * 0x20000000000000U; + + r = m & 0x8000000000000000;; + + if (r) + m = -m; + + if (e <= -1022) + { + m &= 0x1fffffffffffffU; + m >>= (-1021 - e); + e = -1022; + } + + r |= ((uint64_t)(e + 1022)) << 52; + r |= m & 0xfffffffffffffU; + #endif + + return r; + } + + /* converts an ieee double/binary64 to a double */ + ecb_function_ double ecb_binary64_to_double (uint64_t x) ecb_const; + ecb_function_ double + ecb_binary64_to_double (uint64_t x) + { + double r; + + #if ECB_STDFP + memcpy (&r, &x, 8); + #else + /* emulation, only works for normals and subnormals and +0 */ + ECB_EXTERN_C double ldexp (double x, int e); + + int neg = x >> 63; + int e = (x >> 52) & 0x7ffU; + + x &= 0xfffffffffffffU; + + if (e) + x |= 0x10000000000000U; + else + e = 1; + + /* we distrust ldexp a bit and do the 2**-53 scaling by an extra multiply */ + r = ldexp (x * (0.5 / 0x10000000000000U), e - 1022); + + r = neg ? -r : r; + #endif + + return r; + } + +#endif + #endif