Move some inline functions from alMain.h to alnumeric.h

1 files changed, 235 insertions, 0 deletions

diff --git a/common/alnumeric.h b/common/alnumeric.h
index 08a4858d..a2bcd8ee 100644
--- a/common/alnumeric.h
+++ b/common/alnumeric.h
@@ -2,6 +2,15 @@
 #define AL_NUMERIC_H
 
 #include <stdint.h>
+#ifdef HAVE_INTRIN_H
+#include <intrin.h>
+#endif
+#ifdef HAVE_SSE_INTRINSICS
+#include <xmmintrin.h>
+#endif
+
+#include "opthelpers.h"
+
 
 inline constexpr int64_t operator "" _i64(unsigned long long int n) noexcept { return static_cast<int64_t>(n); }
 inline constexpr uint64_t operator "" _u64(unsigned long long int n) noexcept { return static_cast<uint64_t>(n); }
@@ -79,4 +88,230 @@ inline size_t RoundUp(size_t value, size_t r) noexcept
     return value - (value%r);
 }
 
+
+/* Define CTZ macros (count trailing zeros), and POPCNT macros (population
+ * count/count 1 bits), for 32- and 64-bit integers. The CTZ macros' results
+ * are *UNDEFINED* if the value is 0.
+ */
+#ifdef __GNUC__
+
+#define POPCNT32 __builtin_popcount
+#define CTZ32 __builtin_ctz
+#if SIZEOF_LONG == 8
+#define POPCNT64 __builtin_popcountl
+#define CTZ64 __builtin_ctzl
+#else
+#define POPCNT64 __builtin_popcountll
+#define CTZ64 __builtin_ctzll
+#endif
+
+#elif defined(HAVE_BITSCANFORWARD64_INTRINSIC)
+
+inline int msvc64_popcnt32(ALuint v)
+{ return (int)__popcnt(v); }
+#define POPCNT32 msvc64_popcnt32
+inline int msvc64_ctz32(ALuint v)
+{
+    unsigned long idx = 32;
+    _BitScanForward(&idx, v);
+    return (int)idx;
+}
+#define CTZ32 msvc64_ctz32
+
+inline int msvc64_popcnt64(uint64_t v)
+{ return (int)__popcnt64(v); }
+#define POPCNT64 msvc64_popcnt64
+inline int msvc64_ctz64(uint64_t v)
+{
+    unsigned long idx = 64;
+    _BitScanForward64(&idx, v);
+    return (int)idx;
+}
+#define CTZ64 msvc64_ctz64
+
+#elif defined(HAVE_BITSCANFORWARD_INTRINSIC)
+
+inline int msvc_popcnt32(ALuint v)
+{ return (int)__popcnt(v); }
+#define POPCNT32 msvc_popcnt32
+inline int msvc_ctz32(ALuint v)
+{
+    unsigned long idx = 32;
+    _BitScanForward(&idx, v);
+    return (int)idx;
+}
+#define CTZ32 msvc_ctz32
+
+inline int msvc_popcnt64(uint64_t v)
+{ return (int)(__popcnt((ALuint)v) + __popcnt((ALuint)(v>>32))); }
+#define POPCNT64 msvc_popcnt64
+inline int msvc_ctz64(uint64_t v)
+{
+    unsigned long idx = 64;
+    if(!_BitScanForward(&idx, v&0xffffffff))
+    {
+        if(_BitScanForward(&idx, v>>32))
+            idx += 32;
+    }
+    return (int)idx;
+}
+#define CTZ64 msvc_ctz64
+
+#else
+
+/* There be black magics here. The popcnt method is derived from
+ * https://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetParallel
+ * while the ctz-utilizing-popcnt algorithm is shown here
+ * http://www.hackersdelight.org/hdcodetxt/ntz.c.txt
+ * as the ntz2 variant. These likely aren't the most efficient methods, but
+ * they're good enough if the GCC or MSVC intrinsics aren't available.
+ */
+inline int fallback_popcnt32(ALuint v)
+{
+    v = v - ((v >> 1) & 0x55555555u);
+    v = (v & 0x33333333u) + ((v >> 2) & 0x33333333u);
+    v = (v + (v >> 4)) & 0x0f0f0f0fu;
+    return (int)((v * 0x01010101u) >> 24);
+}
+#define POPCNT32 fallback_popcnt32
+inline int fallback_ctz32(ALuint value)
+{ return fallback_popcnt32(~value & (value - 1)); }
+#define CTZ32 fallback_ctz32
+
+inline int fallback_popcnt64(uint64_t v)
+{
+    v = v - ((v >> 1) & 0x5555555555555555_u64);
+    v = (v & 0x3333333333333333_u64) + ((v >> 2) & 0x3333333333333333_u64);
+    v = (v + (v >> 4)) & 0x0f0f0f0f0f0f0f0f_u64;
+    return (int)((v * 0x0101010101010101_u64) >> 56);
+}
+#define POPCNT64 fallback_popcnt64
+inline int fallback_ctz64(uint64_t value)
+{ return fallback_popcnt64(~value & (value - 1)); }
+#define CTZ64 fallback_ctz64
+#endif
+
+
+/**
+ * Fast float-to-int conversion. No particular rounding mode is assumed; the
+ * IEEE-754 default is round-to-nearest with ties-to-even, though an app could
+ * change it on its own threads. On some systems, a truncating conversion may
+ * always be the fastest method.
+ */
+inline int fastf2i(float f) noexcept
+{
+#if defined(HAVE_SSE_INTRINSICS)
+    return _mm_cvt_ss2si(_mm_set_ss(f));
+
+#elif defined(_MSC_VER) && defined(_M_IX86_FP)
+
+    int i;
+    __asm fld f
+    __asm fistp i
+    return i;
+
+#elif (defined(__GNUC__) || defined(__clang__)) && (defined(__i386__) || defined(__x86_64__))
+
+    int i;
+#ifdef __SSE_MATH__
+    __asm__("cvtss2si %1, %0" : "=r"(i) : "x"(f));
+#else
+    __asm__ __volatile__("fistpl %0" : "=m"(i) : "t"(f) : "st");
+#endif
+    return i;
+
+#else
+
+    return static_cast<int>(f);
+#endif
+}
+
+/** Converts float-to-int using standard behavior (truncation). */
+inline int float2int(float f) noexcept
+{
+#if defined(HAVE_SSE_INTRINSICS)
+    return _mm_cvtt_ss2si(_mm_set_ss(f));
+
+#elif ((defined(__GNUC__) || defined(__clang__)) && (defined(__i386__) || defined(__x86_64__)) && \
+       !defined(__SSE_MATH__)) || (defined(_MSC_VER) && defined(_M_IX86_FP) && _M_IX86_FP == 0)
+    int sign, shift, mant;
+    union {
+        float f;
+        int i;
+    } conv;
+
+    conv.f = f;
+    sign = (conv.i>>31) | 1;
+    shift = ((conv.i>>23)&0xff) - (127+23);
+
+    /* Over/underflow */
+    if(UNLIKELY(shift >= 31 || shift < -23))
+        return 0;
+
+    mant = (conv.i&0x7fffff) | 0x800000;
+    if(LIKELY(shift < 0))
+        return (mant >> -shift) * sign;
+    return (mant << shift) * sign;
+
+#else
+
+    return static_cast<int>(f);
+#endif
+}
+
+/**
+ * Rounds a float to the nearest integral value, according to the current
+ * rounding mode. This is essentially an inlined version of rintf, although
+ * makes fewer promises (e.g. -0 or -0.25 rounded to 0 may result in +0).
+ */
+inline float fast_roundf(float f) noexcept
+{
+#if (defined(__GNUC__) || defined(__clang__)) && (defined(__i386__) || defined(__x86_64__)) && \
+    !defined(__SSE_MATH__)
+
+    float out;
+    __asm__ __volatile__("frndint" : "=t"(out) : "0"(f));
+    return out;
+
+#else
+
+    /* Integral limit, where sub-integral precision is not available for
+     * floats.
+     */
+    static constexpr float ilim[2] = {
+         8388608.0f /*  0x1.0p+23 */,
+        -8388608.0f /* -0x1.0p+23 */
+    };
+    unsigned int sign, expo;
+    union {
+        float f;
+        unsigned int i;
+    } conv;
+
+    conv.f = f;
+    sign = (conv.i>>31)&0x01;
+    expo = (conv.i>>23)&0xff;
+
+    if(UNLIKELY(expo >= 150/*+23*/))
+    {
+        /* An exponent (base-2) of 23 or higher is incapable of sub-integral
+         * precision, so it's already an integral value. We don't need to worry
+         * about infinity or NaN here.
+         */
+        return f;
+    }
+    /* Adding the integral limit to the value (with a matching sign) forces a
+     * result that has no sub-integral precision, and is consequently forced to
+     * round to an integral value. Removing the integral limit then restores
+     * the initial value rounded to the integral. The compiler should not
+     * optimize this out because of non-associative rules on floating-point
+     * math (as long as you don't use -fassociative-math,
+     * -funsafe-math-optimizations, -ffast-math, or -Ofast, in which case this
+     * may break).
+     */
+    f += ilim[sign];
+    return f - ilim[sign];
+#endif
+}
+
 #endif /* AL_NUMERIC_H */