#ifndef HVX_SIGMOID_H
#define HVX_SIGMOID_H
#include "hvx-base.h"
#include "hvx-inverse.h"
#define FAST_SIGMOID_LOG2F (0x3fb8aa3b)
#define FAST_SIGMOID_C1 (0x3d009076)
#define FAST_SIGMOID_C2 (0x3e8d74bd)
#define FAST_SIGMOID_C3 (0x3f000000)
static inline HVX_Vector hvx_vec_fast_sigmoid_f32(HVX_Vector v) {
v = Q6_Vqf32_vmpy_VsfVsf(v, Q6_V_vsplat_R(FAST_SIGMOID_LOG2F));
v = Q6_Vqf32_vmpy_VsfVsf(Q6_Vsf_equals_Vqf32(v), Q6_V_vsplat_R(FAST_SIGMOID_C3));
HVX_Vector in_int = hvx_vec_truncate_f32(Q6_Vsf_equals_Vqf32(v));
HVX_Vector x = Q6_Vqf32_vsub_Vqf32Vsf(v, Q6_Vsf_equals_Vw(in_int));
HVX_Vector xx = Q6_Vqf32_vmpy_Vqf32Vqf32(x, x);
HVX_Vector v1 = Q6_Vqf32_vmpy_VsfVsf(Q6_Vsf_equals_Vqf32(xx), Q6_V_vsplat_R(FAST_SIGMOID_C2));
v1 = Q6_Vqf32_vadd_Vqf32Vsf(v1, Q6_V_vsplat_R(FAST_SIGMOID_LOG2F));
HVX_Vector v2 = Q6_Vqf32_vmpy_VsfVsf(Q6_Vsf_equals_Vqf32(x), Q6_V_vsplat_R(FAST_SIGMOID_C1));
v2 = Q6_Vqf32_vmpy_Vqf32Vqf32(v2, xx);
v2 = Q6_Vqf32_vadd_Vqf32Vqf32(v2, x);
HVX_Vector v3 = Q6_Vsf_equals_Vqf32(Q6_Vqf32_vadd_Vqf32Vqf32(v2, v1));
HVX_Vector v3_exponent = Q6_Vw_vasl_VwR(v3, 1);
v3_exponent = Q6_Vuw_vlsr_VuwR(v3_exponent, 24);
v3_exponent = Q6_Vw_vadd_VwVw(in_int, v3_exponent);
v3 = Q6_Vw_vaslacc_VwVwR(v3, in_int, 24);
HVX_Vector v4 = Q6_Vsf_equals_Vqf32(Q6_Vqf32_vsub_Vqf32Vqf32(v2, v1));
HVX_Vector v5 = Q6_Vsf_equals_Vqf32(Q6_Vqf32_vsub_VsfVsf(v3, v4));
HVX_Vector res = hvx_vec_inverse_f32(v5);
res = Q6_Vqf32_vmpy_VsfVsf(v3, res);
return Q6_Vsf_equals_Vqf32(res);
}
static inline HVX_Vector hvx_vec_fast_sigmoid_f32_guard(HVX_Vector v,
HVX_Vector one,
HVX_Vector max_exp,
HVX_Vector min_exp) {
const HVX_VectorPred pred_max = Q6_Q_vcmp_gt_VsfVsf(max_exp, v);
const HVX_VectorPred pred_min = Q6_Q_vcmp_gt_VsfVsf(v, min_exp);
HVX_Vector out = hvx_vec_fast_sigmoid_f32(v);
out = Q6_V_vmux_QVV(pred_max, out, one);
return Q6_V_vmux_QVV(pred_min, out, Q6_V_vzero());
}
static inline HVX_Vector hvx_vec_tanh_f32(HVX_Vector x) {
HVX_Vector two = hvx_vec_splat_f32(2.0f);
HVX_Vector one = hvx_vec_splat_f32(1.0f);
HVX_Vector x2 = Q6_Vqf32_vmpy_VsfVsf(x, two);
HVX_Vector max_exp = hvx_vec_splat_f32(87.f);
HVX_Vector min_exp = hvx_vec_splat_f32(-87.f);
HVX_Vector sig2x = hvx_vec_fast_sigmoid_f32_guard(Q6_Vsf_equals_Vqf32(x2), one, max_exp, min_exp);
HVX_Vector res = Q6_Vqf32_vmpy_VsfVsf(sig2x, two);
res = Q6_Vqf32_vsub_Vqf32Vsf(res, one);
return Q6_Vsf_equals_Vqf32(res);
}
#define hvx_sigmoid_loop_body(dst_type, src_type, vec_store) \
do { \
dst_type * restrict vdst = (dst_type *) dst; \
src_type * restrict vsrc = (src_type *) src; \
\
const HVX_Vector one = hvx_vec_splat_f32(1.f); \
const HVX_Vector max_exp = hvx_vec_splat_f32(87.f); \
const HVX_Vector min_exp = hvx_vec_splat_f32(-87.f); \
\
const uint32_t epv = 128 / sizeof(float); \
const uint32_t nvec = n / epv; \
const uint32_t nloe = n % epv; \
\
uint32_t i = 0; \
\
_Pragma("unroll(4)") \
for (; i < nvec; i++) { \
vdst[i] = hvx_vec_fast_sigmoid_f32_guard(vsrc[i], one, max_exp, min_exp); \
} \
if (nloe) { \
HVX_Vector tmp = hvx_vec_fast_sigmoid_f32_guard(vsrc[i], one, max_exp, min_exp); \
vec_store((void *) &vdst[i], nloe * sizeof(float), tmp); \
} \
} while(0)
#define hvx_tanh_loop_body(dst_type, src_type, vec_store) \
do { \
dst_type * restrict vdst = (dst_type *) dst; \
src_type * restrict vsrc = (src_type *) src; \
\
const uint32_t epv = 128 / sizeof(float); \
const uint32_t nvec = n / epv; \
const uint32_t nloe = n % epv; \
\
uint32_t i = 0; \
\
_Pragma("unroll(4)") \
for (; i < nvec; i++) { \
vdst[i] = hvx_vec_tanh_f32(vsrc[i]); \
} \
if (nloe) { \
HVX_Vector tmp = hvx_vec_tanh_f32(vsrc[i]); \
vec_store((void *) &vdst[i], nloe * sizeof(float), tmp); \
} \
} while(0)
static inline void hvx_sigmoid_f32_aa(uint8_t * restrict dst, const uint8_t * restrict src, uint32_t n) {
assert((unsigned long) dst % 128 == 0);
assert((unsigned long) src % 128 == 0);
hvx_sigmoid_loop_body(HVX_Vector, HVX_Vector, hvx_vec_store_a);
}
static inline void hvx_sigmoid_f32_au(uint8_t * restrict dst, const uint8_t * restrict src, uint32_t n) {
assert((unsigned long) dst % 128 == 0);
hvx_sigmoid_loop_body(HVX_Vector, HVX_UVector, hvx_vec_store_a);
}
static inline void hvx_sigmoid_f32_ua(uint8_t * restrict dst, const uint8_t * restrict src, uint32_t n) {
assert((unsigned long) src % 128 == 0);
hvx_sigmoid_loop_body(HVX_UVector, HVX_Vector, hvx_vec_store_u);
}
static inline void hvx_sigmoid_f32_uu(uint8_t * restrict dst, const uint8_t * restrict src, uint32_t n) {
hvx_sigmoid_loop_body(HVX_UVector, HVX_UVector, hvx_vec_store_u);
}
static inline void hvx_tanh_f32_aa(uint8_t * restrict dst, const uint8_t * restrict src, uint32_t n) {
assert((unsigned long) dst % 128 == 0);
assert((unsigned long) src % 128 == 0);
hvx_tanh_loop_body(HVX_Vector, HVX_Vector, hvx_vec_store_a);
}
#endif