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Unify NEON's pexp with generic implementation

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This commit is contained in:
Gael Guennebaud 2018-11-26 22:15:44 +01:00
parent 5c8406babc
commit 4a347a0054
2 changed files with 25 additions and 64 deletions
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64
Eigen/src/Core/arch/NEON/MathFunctions.h
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@ -21,69 +21,7 @@ namespace internal {
template<> EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS EIGEN_UNUSED
Packet4f pexp<Packet4f>(const Packet4f& _x)
{
Packet4f x = _x;
Packet4f tmp, fx;
_EIGEN_DECLARE_CONST_Packet4f(1 , 1.0f);
_EIGEN_DECLARE_CONST_Packet4f(half, 0.5f);
_EIGEN_DECLARE_CONST_Packet4i(0x7f, 0x7f);
_EIGEN_DECLARE_CONST_Packet4f(exp_hi, 88.3762626647950f);
_EIGEN_DECLARE_CONST_Packet4f(exp_lo, -88.3762626647949f);
_EIGEN_DECLARE_CONST_Packet4f(cephes_LOG2EF, 1.44269504088896341f);
_EIGEN_DECLARE_CONST_Packet4f(cephes_exp_C1, 0.693359375f);
_EIGEN_DECLARE_CONST_Packet4f(cephes_exp_C2, -2.12194440e-4f);
_EIGEN_DECLARE_CONST_Packet4f(cephes_exp_p0, 1.9875691500E-4f);
_EIGEN_DECLARE_CONST_Packet4f(cephes_exp_p1, 1.3981999507E-3f);
_EIGEN_DECLARE_CONST_Packet4f(cephes_exp_p2, 8.3334519073E-3f);
_EIGEN_DECLARE_CONST_Packet4f(cephes_exp_p3, 4.1665795894E-2f);
_EIGEN_DECLARE_CONST_Packet4f(cephes_exp_p4, 1.6666665459E-1f);
_EIGEN_DECLARE_CONST_Packet4f(cephes_exp_p5, 5.0000001201E-1f);
x = vminq_f32(x, p4f_exp_hi);
x = vmaxq_f32(x, p4f_exp_lo);
/* express exp(x) as exp(g + n*log(2)) */
fx = vmlaq_f32(p4f_half, x, p4f_cephes_LOG2EF);
/* perform a floorf */
tmp = vcvtq_f32_s32(vcvtq_s32_f32(fx));
/* if greater, substract 1 */
Packet4ui mask = vcgtq_f32(tmp, fx);
mask = vandq_u32(mask, vreinterpretq_u32_f32(p4f_1));
fx = vsubq_f32(tmp, vreinterpretq_f32_u32(mask));
tmp = vmulq_f32(fx, p4f_cephes_exp_C1);
Packet4f z = vmulq_f32(fx, p4f_cephes_exp_C2);
x = vsubq_f32(x, tmp);
x = vsubq_f32(x, z);
Packet4f y = vmulq_f32(p4f_cephes_exp_p0, x);
z = vmulq_f32(x, x);
y = vaddq_f32(y, p4f_cephes_exp_p1);
y = vmulq_f32(y, x);
y = vaddq_f32(y, p4f_cephes_exp_p2);
y = vmulq_f32(y, x);
y = vaddq_f32(y, p4f_cephes_exp_p3);
y = vmulq_f32(y, x);
y = vaddq_f32(y, p4f_cephes_exp_p4);
y = vmulq_f32(y, x);
y = vaddq_f32(y, p4f_cephes_exp_p5);
y = vmulq_f32(y, z);
y = vaddq_f32(y, x);
y = vaddq_f32(y, p4f_1);
/* build 2^n */
int32x4_t mm;
mm = vcvtq_s32_f32(fx);
mm = vaddq_s32(mm, p4i_0x7f);
mm = vshlq_n_s32(mm, 23);
Packet4f pow2n = vreinterpretq_f32_s32(mm);
y = vmulq_f32(y, pow2n);
return y;
return pexp_float(_x);
}
template<> EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS EIGEN_UNUSED

23
Eigen/src/Core/arch/NEON/PacketMath.h
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@ -109,6 +109,7 @@ template<> struct packet_traits<float> : default_packet_traits
HasHalfPacket=0, // Packet2f intrinsics not implemented yet
HasDiv = 1,
HasFloor = 1,
// FIXME check the Has*
HasSin = 0,
HasCos = 0,
@ -256,6 +257,18 @@ template<> EIGEN_STRONG_INLINE Packet4f pcmp_lt(const Packet4f& a, const Packet4
template<> EIGEN_STRONG_INLINE Packet4f pcmp_eq(const Packet4f& a, const Packet4f& b) { return vreinterpretq_f32_u32(vceqq_f32(a,b)); }
template<> EIGEN_STRONG_INLINE Packet4f pcmp_lt_or_nan(const Packet4f& a, const Packet4f& b) { return vreinterpretq_f32_u32(vmvnq_u32(vcgeq_f32(a,b))); }
template<> EIGEN_STRONG_INLINE Packet4f pfloor<Packet4f>(const Packet4f& a)
{
const Packet4f cst_1 = pset1<Packet4f>(1.0f);
/* perform a floorf */
Packet4f tmp = vcvtq_f32_s32(vcvtq_s32_f32(a));
/* if greater, substract 1 */
Packet4ui mask = vcgtq_f32(tmp, a);
mask = vandq_u32(mask, vreinterpretq_u32_f32(cst_1));
return vsubq_f32(tmp, vreinterpretq_f32_u32(mask));
}
// Logical Operations are not supported for float, so we have to reinterpret casts using NEON intrinsics
template<> EIGEN_STRONG_INLINE Packet4f pand<Packet4f>(const Packet4f& a, const Packet4f& b)
{
@ -379,6 +392,16 @@ template<> EIGEN_STRONG_INLINE Packet4f pfrexp<Packet4f>(const Packet4f& a, Pack
return pfrexp_float(a,exponent);
}
template<> EIGEN_STRONG_INLINE Packet4f pcast_and_shiftleft<Packet4f>(Packet4f v, int n)
{
Packet4i vi = vcvtq_s32_f32(v);
return vreinterpretq_f32_s32(vshlq_n_s32(vi, n));
}
template<> EIGEN_STRONG_INLINE Packet4f pldexp<Packet4f>(const Packet4f& a, const Packet4f& exponent) {
return pldexp_float(a,exponent);
}
template<> EIGEN_STRONG_INLINE float predux<Packet4f>(const Packet4f& a)
{
float32x2_t a_lo, a_hi, sum;