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simde-f16.h
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simde-f16.h
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/* SPDX-License-Identifier: MIT
*
* 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.
*
* Copyright:
* 2021 Evan Nemerson <[email protected]>
* 2023 Ju-Hung Li <[email protected]> (Copyright owned by NTHU pllab)
*/
#include "hedley.h"
#include "simde-common.h"
#include "simde-detect-clang.h"
#if !defined(SIMDE_FLOAT16_H)
#define SIMDE_FLOAT16_H
HEDLEY_DIAGNOSTIC_PUSH
SIMDE_DISABLE_UNWANTED_DIAGNOSTICS
SIMDE_BEGIN_DECLS_
/* Portable version which should work on pretty much any compiler.
* Obviously you can't rely on compiler support for things like
* conversion to/from 32-bit floats, so make sure you always use the
* functions and macros in this file!
*
* The portable implementations are (heavily) based on CC0 code by
* Fabian Giesen: <https://gist.github.com/rygorous/2156668> (see also
* <https://fgiesen.wordpress.com/2012/03/28/half-to-float-done-quic/>).
* I have basically just modified it to get rid of some UB (lots of
* aliasing, right shifting a negative value), use fixed-width types,
* and work in C. */
#define SIMDE_FLOAT16_API_PORTABLE 1
/* _Float16, per C standard (TS 18661-3;
* <http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1945.pdf>). */
#define SIMDE_FLOAT16_API_FLOAT16 2
/* clang >= 6.0 supports __fp16 as an interchange format on all
* targets, but only allows you to use them for arguments and return
* values on targets which have defined an ABI. We get around the
* restriction by wrapping the __fp16 in a struct, but we can't do
* that on Arm since it would break compatibility with the NEON F16
* functions. */
#define SIMDE_FLOAT16_API_FP16_NO_ABI 3
/* This is basically __fp16 as specified by Arm, where arguments and
* return values are raw __fp16 values not structs. */
#define SIMDE_FLOAT16_API_FP16 4
/* Choosing an implementation. This is a bit rough, but I don't have
* any ideas on how to improve it. If you do, patches are definitely
* welcome. */
#if !defined(SIMDE_FLOAT16_API)
#if defined(__ARM_FP16_FORMAT_IEEE) && (defined(SIMDE_ARM_NEON_FP16) || defined(__ARM_FP16_ARGS))
#define SIMDE_FLOAT16_API SIMDE_FLOAT16_API_FP16
#elif !defined(__EMSCRIPTEN__) && !(defined(__clang__) && defined(SIMDE_ARCH_POWER)) && \
!(defined(HEDLEY_MSVC_VERSION) && defined(__clang__)) && \
!(defined(SIMDE_ARCH_MIPS) && defined(__clang__)) && \
!(defined(SIMDE_ARCH_ZARCH) && defined(__clang__)) && \
!(defined(SIMDE_ARCH_LOONGARCH) && defined(__clang__)) && \
!(defined(__clang__) && defined(SIMDE_ARCH_RISCV64)) && ( \
defined(SIMDE_X86_AVX512FP16_NATIVE) || \
(defined(SIMDE_ARCH_X86_SSE2) && HEDLEY_GCC_VERSION_CHECK(12,0,0)) || \
(defined(SIMDE_ARCH_AARCH64) && HEDLEY_GCC_VERSION_CHECK(7,0,0) && !defined(__cplusplus)) || \
(defined(SIMDE_ARCH_AARCH64) && HEDLEY_GCC_VERSION_CHECK(13,0,0)) || \
((defined(SIMDE_ARCH_X86_SSE2) || defined(SIMDE_ARCH_AMD64)) && SIMDE_DETECT_CLANG_VERSION_CHECK(15,0,0)) || \
(!(defined(SIMDE_ARCH_X86) || defined(SIMDE_ARCH_AMD64)) && SIMDE_DETECT_CLANG_VERSION_CHECK(6,0,0))) || \
defined(SIMDE_ARCH_RISCV_ZVFH)
/* We haven't found a better way to detect this. It seems like defining
* __STDC_WANT_IEC_60559_TYPES_EXT__, then including float.h, then
* checking for defined(FLT16_MAX) should work, but both gcc and
* clang will define the constants even if _Float16 is not
* supported. Ideas welcome. */
#define SIMDE_FLOAT16_API SIMDE_FLOAT16_API_FLOAT16
#elif defined(__FLT16_MIN__) && \
(defined(__clang__) && \
(!defined(SIMDE_ARCH_AARCH64) || SIMDE_DETECT_CLANG_VERSION_CHECK(7,0,0)) \
&& !defined(SIMDE_ARCH_RISCV64) && !defined(SIMDE_ARCH_LOONGARCH))
#define SIMDE_FLOAT16_API SIMDE_FLOAT16_API_FP16_NO_ABI
#else
#define SIMDE_FLOAT16_API SIMDE_FLOAT16_API_PORTABLE
#endif
#endif
#if SIMDE_FLOAT16_API == SIMDE_FLOAT16_API_FLOAT16
typedef _Float16 simde_float16;
#define SIMDE_FLOAT16_IS_SCALAR 1
#if !defined(__cplusplus)
#define SIMDE_FLOAT16_C(value) value##f16
#else
#define SIMDE_FLOAT16_C(value) HEDLEY_STATIC_CAST(_Float16, (value))
#endif
#elif SIMDE_FLOAT16_API == SIMDE_FLOAT16_API_FP16_NO_ABI
typedef struct { __fp16 value; } simde_float16;
#if defined(SIMDE_STATEMENT_EXPR_) && !defined(SIMDE_TESTS_H)
#define SIMDE_FLOAT16_C(value) (__extension__({ ((simde_float16) { HEDLEY_DIAGNOSTIC_PUSH SIMDE_DIAGNOSTIC_DISABLE_C99_EXTENSIONS_ HEDLEY_STATIC_CAST(__fp16, (value)) }); HEDLEY_DIAGNOSTIC_POP }))
#else
#define SIMDE_FLOAT16_C(value) ((simde_float16) { HEDLEY_STATIC_CAST(__fp16, (value)) })
#define SIMDE_FLOAT16_IS_SCALAR 1
#endif
#elif SIMDE_FLOAT16_API == SIMDE_FLOAT16_API_FP16
typedef __fp16 simde_float16;
#define SIMDE_FLOAT16_IS_SCALAR 1
#define SIMDE_FLOAT16_C(value) HEDLEY_STATIC_CAST(__fp16, (value))
#elif SIMDE_FLOAT16_API == SIMDE_FLOAT16_API_PORTABLE
typedef struct { uint16_t value; } simde_float16;
#else
#error No 16-bit floating point API.
#endif
#if \
defined(SIMDE_VECTOR_OPS) && \
(SIMDE_FLOAT16_API != SIMDE_FLOAT16_API_PORTABLE) && \
(SIMDE_FLOAT16_API != SIMDE_FLOAT16_API_FP16_NO_ABI)
#define SIMDE_FLOAT16_VECTOR
#endif
/* Reinterpret -- you *generally* shouldn't need these, they're really
* intended for internal use. However, on x86 half-precision floats
* get stuffed into a __m128i/__m256i, so it may be useful. */
SIMDE_DEFINE_CONVERSION_FUNCTION_(simde_float16_as_uint16, uint16_t, simde_float16)
SIMDE_DEFINE_CONVERSION_FUNCTION_(simde_uint16_as_float16, simde_float16, uint16_t)
#if SIMDE_FLOAT16_API == SIMDE_FLOAT16_API_PORTABLE
#define SIMDE_NANHF simde_uint16_as_float16(0x7E00) // a quiet Not-a-Number
#define SIMDE_INFINITYHF simde_uint16_as_float16(0x7C00)
#define SIMDE_NINFINITYHF simde_uint16_as_float16(0xFC00)
#else
#if SIMDE_FLOAT16_API == SIMDE_FLOAT16_API_FP16_NO_ABI
#if SIMDE_MATH_BUILTIN_LIBM(nanf16)
#define SIMDE_NANHF SIMDE_FLOAT16_C(__builtin_nanf16(""))
#elif defined(SIMDE_MATH_NAN)
#define SIMDE_NANHF SIMDE_FLOAT16_C(SIMDE_MATH_NAN)
#endif
#if SIMDE_MATH_BUILTIN_LIBM(inf16)
#define SIMDE_INFINITYHF SIMDE_FLOAT16_C(__builtin_inf16())
#define SIMDE_NINFINITYHF SIMDE_FLOAT16_C(-__builtin_inf16())
#else
#define SIMDE_INFINITYHF SIMDE_FLOAT16_C(SIMDE_MATH_INFINITY)
#define SIMDE_NINFINITYHF SIMDE_FLOAT16_C(-SIMDE_MATH_INFINITY)
#endif
#else
#if SIMDE_MATH_BUILTIN_LIBM(nanf16)
#define SIMDE_NANHF __builtin_nanf16("")
#elif defined(SIMDE_MATH_NAN)
#define SIMDE_NANHF SIMDE_MATH_NAN
#endif
#if SIMDE_MATH_BUILTIN_LIBM(inf16)
#define SIMDE_INFINITYHF __builtin_inf16()
#define SIMDE_NINFINITYHF -(__builtin_inf16())
#else
#define SIMDE_INFINITYHF HEDLEY_STATIC_CAST(simde_float16, SIMDE_MATH_INFINITY)
#define SIMDE_NINFINITYHF HEDLEY_STATIC_CAST(simde_float16, -SIMDE_MATH_INFINITY)
#endif
#endif
#endif
/* Conversion -- convert between single-precision and half-precision
* floats. */
static HEDLEY_ALWAYS_INLINE HEDLEY_CONST
simde_float16
simde_float16_from_float32 (simde_float32 value) {
simde_float16 res;
#if \
(SIMDE_FLOAT16_API == SIMDE_FLOAT16_API_FLOAT16) || \
(SIMDE_FLOAT16_API == SIMDE_FLOAT16_API_FP16)
res = HEDLEY_STATIC_CAST(simde_float16, value);
#elif (SIMDE_FLOAT16_API == SIMDE_FLOAT16_API_FP16_NO_ABI)
res.value = HEDLEY_STATIC_CAST(__fp16, value);
#else
/* This code is CC0, based heavily on code by Fabian Giesen. */
uint32_t f32u = simde_float32_as_uint32(value);
static const uint32_t f32u_infty = UINT32_C(255) << 23;
static const uint32_t f16u_max = (UINT32_C(127) + UINT32_C(16)) << 23;
static const uint32_t denorm_magic =
((UINT32_C(127) - UINT32_C(15)) + (UINT32_C(23) - UINT32_C(10)) + UINT32_C(1)) << 23;
uint16_t f16u;
uint32_t sign = f32u & (UINT32_C(1) << 31);
f32u ^= sign;
/* NOTE all the integer compares in this function cast the operands
* to signed values to help compilers vectorize to SSE2, which lacks
* unsigned comparison instructions. This is fine since all
* operands are below 0x80000000 (we clear the sign bit). */
if (f32u > f16u_max) { /* result is Inf or NaN (all exponent bits set) */
f16u = (f32u > f32u_infty) ? UINT32_C(0x7e00) : UINT32_C(0x7c00); /* NaN->qNaN and Inf->Inf */
} else { /* (De)normalized number or zero */
if (f32u < (UINT32_C(113) << 23)) { /* resulting FP16 is subnormal or zero */
/* use a magic value to align our 10 mantissa bits at the bottom of
* the float. as long as FP addition is round-to-nearest-even this
* just works. */
f32u = simde_float32_as_uint32(simde_uint32_as_float32(f32u) + simde_uint32_as_float32(denorm_magic));
/* and one integer subtract of the bias later, we have our final float! */
f16u = HEDLEY_STATIC_CAST(uint16_t, f32u - denorm_magic);
} else {
uint32_t mant_odd = (f32u >> 13) & 1;
/* update exponent, rounding bias part 1 */
f32u += (HEDLEY_STATIC_CAST(uint32_t, 15 - 127) << 23) + UINT32_C(0xfff);
/* rounding bias part 2 */
f32u += mant_odd;
/* take the bits! */
f16u = HEDLEY_STATIC_CAST(uint16_t, f32u >> 13);
}
}
f16u |= sign >> 16;
res = simde_uint16_as_float16(f16u);
#endif
return res;
}
static HEDLEY_ALWAYS_INLINE HEDLEY_CONST
simde_float32
simde_float16_to_float32 (simde_float16 value) {
simde_float32 res;
#if defined(SIMDE_FLOAT16_FLOAT16) || defined(SIMDE_FLOAT16_FP16)
res = HEDLEY_STATIC_CAST(simde_float32, value);
#else
/* This code is CC0, based heavily on code by Fabian Giesen. */
uint16_t half = simde_float16_as_uint16(value);
const simde_float32 denorm_magic = simde_uint32_as_float32((UINT32_C(113) << 23));
const uint32_t shifted_exp = UINT32_C(0x7c00) << 13; /* exponent mask after shift */
uint32_t f32u;
f32u = (half & UINT32_C(0x7fff)) << 13; /* exponent/mantissa bits */
uint32_t exp = shifted_exp & f32u; /* just the exponent */
f32u += (UINT32_C(127) - UINT32_C(15)) << 23; /* exponent adjust */
/* handle exponent special cases */
if (exp == shifted_exp) /* Inf/NaN? */
f32u += (UINT32_C(128) - UINT32_C(16)) << 23; /* extra exp adjust */
else if (exp == 0) { /* Zero/Denormal? */
f32u += (1) << 23; /* extra exp adjust */
f32u = simde_float32_as_uint32(simde_uint32_as_float32(f32u) - denorm_magic); /* renormalize */
}
f32u |= (half & UINT32_C(0x8000)) << 16; /* sign bit */
res = simde_uint32_as_float32(f32u);
#endif
return res;
}
#ifdef SIMDE_FLOAT16_C
#define SIMDE_FLOAT16_VALUE(value) SIMDE_FLOAT16_C(value)
#else
#define SIMDE_FLOAT16_VALUE(value) simde_float16_from_float32(SIMDE_FLOAT32_C(value))
#endif
#if !defined(simde_isinfhf) && defined(simde_math_isinff)
#define simde_isinfhf(a) simde_math_isinff(simde_float16_to_float32(a))
#endif
#if !defined(simde_isnanhf) && defined(simde_math_isnanf)
#define simde_isnanhf(a) simde_math_isnanf(simde_float16_to_float32(a))
#endif
#if !defined(simde_isnormalhf) && defined(simde_math_isnormalf)
#define simde_isnormalhf(a) simde_math_isnormalf(simde_float16_to_float32(a))
#endif
#if !defined(simde_issubnormalhf) && defined(simde_math_issubnormalf)
#define simde_issubnormalhf(a) simde_math_issubnormalf(simde_float16_to_float32(a))
#endif
#define simde_fpclassifyhf(a) simde_math_fpclassifyf(simde_float16_to_float32(a))
static HEDLEY_INLINE
uint8_t
simde_fpclasshf(simde_float16 v, const int imm8) {
uint16_t bits = simde_float16_as_uint16(v);
uint8_t negative = (bits >> 15) & 1;
uint16_t const ExpMask = 0x7C00; // [14:10]
uint16_t const MantMask = 0x03FF; // [9:0]
uint8_t exponent_all_ones = ((bits & ExpMask) == ExpMask);
uint8_t exponent_all_zeros = ((bits & ExpMask) == 0);
uint8_t mantissa_all_zeros = ((bits & MantMask) == 0);
uint8_t zero = exponent_all_zeros & mantissa_all_zeros;
uint8_t signaling_bit = (bits >> 9) & 1;
uint8_t result = 0;
uint8_t snan = exponent_all_ones & (!mantissa_all_zeros) & (!signaling_bit);
uint8_t qnan = exponent_all_ones & (!mantissa_all_zeros) & signaling_bit;
uint8_t positive_zero = (!negative) & zero;
uint8_t negative_zero = negative & zero;
uint8_t positive_infinity = (!negative) & exponent_all_ones & mantissa_all_zeros;
uint8_t negative_infinity = negative & exponent_all_ones & mantissa_all_zeros;
uint8_t denormal = exponent_all_zeros & (!mantissa_all_zeros);
uint8_t finite_negative = negative & (!exponent_all_ones) & (!zero);
result = (((imm8 >> 0) & qnan) | \
((imm8 >> 1) & positive_zero) | \
((imm8 >> 2) & negative_zero) | \
((imm8 >> 3) & positive_infinity) | \
((imm8 >> 4) & negative_infinity) | \
((imm8 >> 5) & denormal) | \
((imm8 >> 6) & finite_negative) | \
((imm8 >> 7) & snan));
return result;
}
SIMDE_END_DECLS_
HEDLEY_DIAGNOSTIC_POP
#endif /* !defined(SIMDE_FLOAT16_H) */