initial commit, 4.5 stable

thirdparty/astcenc/astcenc_mathlib.h

@@ -0,0 +1,505 @@
+// SPDX-License-Identifier: Apache-2.0
+// ----------------------------------------------------------------------------
+// Copyright 2011-2025 Arm Limited
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not
+// use this file except in compliance with the License. You may obtain a copy
+// of the License at:
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations
+// under the License.
+// ----------------------------------------------------------------------------
+
+/*
+ * This module implements a variety of mathematical data types and library
+ * functions used by the codec.
+ */
+
+#ifndef ASTC_MATHLIB_H_INCLUDED
+#define ASTC_MATHLIB_H_INCLUDED
+
+#include <cassert>
+#include <cstdint>
+#include <cmath>
+
+#ifndef ASTCENC_POPCNT
+  #if defined(__POPCNT__)
+    #define ASTCENC_POPCNT 1
+  #else
+    #define ASTCENC_POPCNT 0
+  #endif
+#endif
+
+#ifndef ASTCENC_F16C
+  #if defined(__F16C__)
+    #define ASTCENC_F16C 1
+  #else
+    #define ASTCENC_F16C 0
+  #endif
+#endif
+
+#ifndef ASTCENC_SSE
+  #if defined(__SSE4_2__)
+    #define ASTCENC_SSE 42
+  #elif defined(__SSE4_1__)
+    #define ASTCENC_SSE 41
+  #elif defined(__SSE2__) || (defined(_M_AMD64) && !defined(_M_ARM64EC))
+    #define ASTCENC_SSE 20
+  #else
+    #define ASTCENC_SSE 0
+  #endif
+#endif
+
+#ifndef ASTCENC_AVX
+  #if defined(__AVX2__)
+    #define ASTCENC_AVX 2
+    #define ASTCENC_X86_GATHERS 1
+  #elif defined(__AVX__)
+    #define ASTCENC_AVX 1
+    #define ASTCENC_X86_GATHERS 1
+  #else
+    #define ASTCENC_AVX 0
+  #endif
+#endif
+
+#ifndef ASTCENC_NEON
+  #if defined(__aarch64__) || defined(_M_ARM64) || defined(_M_ARM64EC)
+    #define ASTCENC_NEON 1
+  #else
+    #define ASTCENC_NEON 0
+  #endif
+#endif
+
+#ifndef ASTCENC_SVE
+  #if defined(__ARM_FEATURE_SVE)
+    #if defined(__ARM_FEATURE_SVE_BITS) && __ARM_FEATURE_SVE_BITS == 256
+      #define ASTCENC_SVE 8
+    // Auto-detected SVE can only assume vector width of 4 is available, but
+    // must also allow for hardware being longer and so all use of intrinsics
+    // must explicitly use predicate masks to limit to 4-wide.
+    #else
+      #define ASTCENC_SVE 4
+    #endif
+    #else
+    #define ASTCENC_SVE 0
+  #endif
+#endif
+
+// Force vector-sized SIMD alignment
+#if ASTCENC_AVX || ASTCENC_SVE == 8
+  #define ASTCENC_VECALIGN 32
+#elif ASTCENC_SSE || ASTCENC_NEON || ASTCENC_SVE == 4
+  #define ASTCENC_VECALIGN 16
+// Use default alignment for non-SIMD builds
+#else
+  #define ASTCENC_VECALIGN 0
+#endif
+
+// C++11 states that alignas(0) should be ignored but GCC doesn't do
+// this on some versions, so workaround and avoid emitting alignas(0)
+#if ASTCENC_VECALIGN > 0
+	#define ASTCENC_ALIGNAS alignas(ASTCENC_VECALIGN)
+#else
+	#define ASTCENC_ALIGNAS
+#endif
+
+#if ASTCENC_SSE != 0 || ASTCENC_AVX != 0 || ASTCENC_POPCNT != 0
+	#include <immintrin.h>
+#endif
+
+/* ============================================================================
+  Fast math library; note that many of the higher-order functions in this set
+  use approximations which are less accurate, but faster, than <cmath> standard
+  library equivalents.
+
+  Note: Many of these are not necessarily faster than simple C versions when
+  used on a single scalar value, but are included for testing purposes as most
+  have an option based on SSE intrinsics and therefore provide an obvious route
+  to future vectorization.
+============================================================================ */
+
+// Union for manipulation of float bit patterns
+typedef union
+{
+	uint32_t u;
+	int32_t s;
+	float f;
+} if32;
+
+// These are namespaced to avoid colliding with C standard library functions.
+namespace astc
+{
+
+static const float PI          = 3.14159265358979323846f;
+static const float PI_OVER_TWO = 1.57079632679489661923f;
+
+/**
+ * @brief SP float absolute value.
+ *
+ * @param v   The value to make absolute.
+ *
+ * @return The absolute value.
+ */
+static inline float fabs(float v)
+{
+	return std::fabs(v);
+}
+
+/**
+ * @brief Test if a float value is a nan.
+ *
+ * @param v    The value test.
+ *
+ * @return Zero is not a NaN, non-zero otherwise.
+ */
+static inline bool isnan(float v)
+{
+	return v != v;
+}
+
+/**
+ * @brief Return the minimum of two values.
+ *
+ * For floats, NaNs are turned into @c q.
+ *
+ * @param p   The first value to compare.
+ * @param q   The second value to compare.
+ *
+ * @return The smallest value.
+ */
+template<typename T>
+static inline T min(T p, T q)
+{
+	return p < q ? p : q;
+}
+
+/**
+ * @brief Return the minimum of three values.
+ *
+ * For floats, NaNs are turned into @c r.
+ *
+ * @param p   The first value to compare.
+ * @param q   The second value to compare.
+ * @param r   The third value to compare.
+ *
+ * @return The smallest value.
+ */
+template<typename T>
+static inline T min(T p, T q, T r)
+{
+	return min(min(p, q), r);
+}
+
+/**
+ * @brief Return the minimum of four values.
+ *
+ * For floats, NaNs are turned into @c s.
+ *
+ * @param p   The first value to compare.
+ * @param q   The second value to compare.
+ * @param r   The third value to compare.
+ * @param s   The fourth value to compare.
+ *
+ * @return The smallest value.
+ */
+template<typename T>
+static inline T min(T p, T q, T r, T s)
+{
+	return min(min(p, q), min(r, s));
+}
+
+/**
+ * @brief Return the maximum of two values.
+ *
+ * For floats, NaNs are turned into @c q.
+ *
+ * @param p   The first value to compare.
+ * @param q   The second value to compare.
+ *
+ * @return The largest value.
+ */
+template<typename T>
+static inline T max(T p, T q)
+{
+	return p > q ? p : q;
+}
+
+/**
+ * @brief Return the maximum of three values.
+ *
+ * For floats, NaNs are turned into @c r.
+ *
+ * @param p   The first value to compare.
+ * @param q   The second value to compare.
+ * @param r   The third value to compare.
+ *
+ * @return The largest value.
+ */
+template<typename T>
+static inline T max(T p, T q, T r)
+{
+	return max(max(p, q), r);
+}
+
+/**
+ * @brief Return the maximum of four values.
+ *
+ * For floats, NaNs are turned into @c s.
+ *
+ * @param p   The first value to compare.
+ * @param q   The second value to compare.
+ * @param r   The third value to compare.
+ * @param s   The fourth value to compare.
+ *
+ * @return The largest value.
+ */
+template<typename T>
+static inline T max(T p, T q, T r, T s)
+{
+	return max(max(p, q), max(r, s));
+}
+
+/**
+ * @brief Clamp a value value between @c mn and @c mx.
+ *
+ * For floats, NaNs are turned into @c mn.
+ *
+ * @param v      The value to clamp.
+ * @param mn     The min value (inclusive).
+ * @param mx     The max value (inclusive).
+ *
+ * @return The clamped value.
+ */
+template<typename T>
+inline T clamp(T v, T mn, T mx)
+{
+	// Do not reorder; correct NaN handling relies on the fact that comparison
+	// with NaN returns false and will fall-though to the "min" value.
+	if (v > mx) return mx;
+	if (v > mn) return v;
+	return mn;
+}
+
+/**
+ * @brief Clamp a float value between 0.0f and 1.0f.
+ *
+ * NaNs are turned into 0.0f.
+ *
+ * @param v   The value to clamp.
+ *
+ * @return The clamped value.
+ */
+static inline float clamp1f(float v)
+{
+	return astc::clamp(v, 0.0f, 1.0f);
+}
+
+/**
+ * @brief Clamp a float value between 0.0f and 255.0f.
+ *
+ * NaNs are turned into 0.0f.
+ *
+ * @param v  The value to clamp.
+ *
+ * @return The clamped value.
+ */
+static inline float clamp255f(float v)
+{
+	return astc::clamp(v, 0.0f, 255.0f);
+}
+
+/**
+ * @brief SP float round-down.
+ *
+ * @param v   The value to round.
+ *
+ * @return The rounded value.
+ */
+static inline float flt_rd(float v)
+{
+	return std::floor(v);
+}
+
+/**
+ * @brief SP float round-to-nearest and convert to integer.
+ *
+ * @param v   The value to round.
+ *
+ * @return The rounded value.
+ */
+static inline int flt2int_rtn(float v)
+{
+
+	return static_cast<int>(v + 0.5f);
+}
+
+/**
+ * @brief SP float round down and convert to integer.
+ *
+ * @param v   The value to round.
+ *
+ * @return The rounded value.
+ */
+static inline int flt2int_rd(float v)
+{
+	return static_cast<int>(v);
+}
+
+/**
+ * @brief SP float bit-interpreted as an integer.
+ *
+ * @param v   The value to bitcast.
+ *
+ * @return The converted value.
+ */
+static inline int float_as_int(float v)
+{
+	union { int a; float b; } u;
+	u.b = v;
+	return u.a;
+}
+
+/**
+ * @brief Integer bit-interpreted as an SP float.
+ *
+ * @param v   The value to bitcast.
+ *
+ * @return The converted value.
+ */
+static inline float int_as_float(int v)
+{
+	union { int a; float b; } u;
+	u.a = v;
+	return u.b;
+}
+
+/**
+ * @brief Fast approximation of 1.0 / sqrt(val).
+ *
+ * @param v   The input value.
+ *
+ * @return The approximated result.
+ */
+static inline float rsqrt(float v)
+{
+	return 1.0f / std::sqrt(v);
+}
+
+/**
+ * @brief Fast approximation of sqrt(val).
+ *
+ * @param v   The input value.
+ *
+ * @return The approximated result.
+ */
+static inline float sqrt(float v)
+{
+	return std::sqrt(v);
+}
+
+/**
+ * @brief Extract mantissa and exponent of a float value.
+ *
+ * @param      v      The input value.
+ * @param[out] expo   The output exponent.
+ *
+ * @return The mantissa.
+ */
+static inline float frexp(float v, int* expo)
+{
+	if32 p;
+	p.f = v;
+	*expo = ((p.u >> 23) & 0xFF) - 126;
+	p.u = (p.u & 0x807fffff) | 0x3f000000;
+	return p.f;
+}
+
+/**
+ * @brief Initialize the seed structure for a random number generator.
+ *
+ * Important note: For the purposes of ASTC we want sets of random numbers to
+ * use the codec, but we want the same seed value across instances and threads
+ * to ensure that image output is stable across compressor runs and across
+ * platforms. Every PRNG created by this call will therefore return the same
+ * sequence of values ...
+ *
+ * @param state The state structure to initialize.
+ */
+void rand_init(uint64_t state[2]);
+
+/**
+ * @brief Return the next random number from the generator.
+ *
+ * This RNG is an implementation of the "xoroshoro-128+ 1.0" PRNG, based on the
+ * public-domain implementation given by David Blackman & Sebastiano Vigna at
+ * http://vigna.di.unimi.it/xorshift/xoroshiro128plus.c
+ *
+ * @param state The state structure to use/update.
+ */
+uint64_t rand(uint64_t state[2]);
+
+}
+
+/* ============================================================================
+  Softfloat library with fp32 and fp16 conversion functionality.
+============================================================================ */
+#if (ASTCENC_F16C == 0) && (ASTCENC_NEON == 0)
+	/* narrowing float->float conversions */
+	uint16_t float_to_sf16(float val);
+	float sf16_to_float(uint16_t val);
+#endif
+
+/*********************************
+  Vector library
+*********************************/
+#include "astcenc_vecmathlib.h"
+
+/*********************************
+  Declaration of line types
+*********************************/
+// parametric line, 2D: The line is given by line = a + b * t.
+
+struct line2
+{
+	vfloat4 a;
+	vfloat4 b;
+};
+
+// parametric line, 3D
+struct line3
+{
+	vfloat4 a;
+	vfloat4 b;
+};
+
+struct line4
+{
+	vfloat4 a;
+	vfloat4 b;
+};
+
+
+struct processed_line2
+{
+	vfloat4 amod;
+	vfloat4 bs;
+};
+
+struct processed_line3
+{
+	vfloat4 amod;
+	vfloat4 bs;
+};
+
+struct processed_line4
+{
+	vfloat4 amod;
+	vfloat4 bs;
+};
+
+#endif