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Make more code aarch64 friendly

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Justine Tunney 2023-05-02 13:38:16 -07:00
parent ca2860947f
commit 2b73e72d59
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568 changed files with 2197 additions and 1061 deletions
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46
libc/tinymath/atanf_common.internal.h Normal file
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#ifndef COSMOPOLITAN_LIBC_TINYMATH_ATANF_COMMON_H_
#define COSMOPOLITAN_LIBC_TINYMATH_ATANF_COMMON_H_
#include "libc/tinymath/atanf_data.internal.h"
#include "libc/tinymath/estrin_wrap.internal.h"
#include "libc/tinymath/hornerf.internal.h"
#if !(__ASSEMBLER__ + __LINKER__ + 0)
COSMOPOLITAN_C_START_
// clang-format off
#if WANT_VMATH
#define FLT_T float32x4_t
#define P(i) v_f32 (__atanf_poly_data.poly[i])
#else
#define FLT_T float
#define P(i) __atanf_poly_data.poly[i]
#endif
/* Polynomial used in fast atanf(x) and atan2f(y,x) implementations
The order 7 polynomial P approximates (atan(sqrt(x))-sqrt(x))/x^(3/2). */
static inline FLT_T
eval_poly (FLT_T z, FLT_T az, FLT_T shift)
{
/* Use 2-level Estrin scheme for P(z^2) with deg(P)=7. However,
a standard implementation using z8 creates spurious underflow
in the very last fma (when z^8 is small enough).
Therefore, we split the last fma into a mul and and an fma.
Horner and single-level Estrin have higher errors that exceed
threshold. */
FLT_T z2 = z * z;
FLT_T z4 = z2 * z2;
/* Then assemble polynomial. */
FLT_T y = FMA (z4, z4 * ESTRIN_3_ (z2, z4, P, 4), ESTRIN_3 (z2, z4, P));
/* Finalize:
y = shift + z * P(z^2). */
return FMA (y, z2 * az, az) + shift;
}
COSMOPOLITAN_C_END_
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
#endif /* COSMOPOLITAN_LIBC_TINYMATH_ATANF_COMMON_H_ */