/
misc.jl
258 lines (236 loc) · 7.21 KB
/
misc.jl
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
"""
pow(x, y)
Exponentiation operator, returns `x` raised to the power `y`.
"""
@inline function pow(x::V, y::V) where {V<:FloatType}
T = eltype(x)
yi = unsafe_trunc(fpinttype(T), y)
yisint = yi == y
yisodd = isodd(yi) & yisint
absx = abs(x)
logkx = logk(absx)
logkxy = dmul(logkx, y)
@static if VERSION ≥ v"1.6"
result = exp_hilo(
logkxy.hi,
logkxy.lo,
Val(ℯ),
VectorizationBase.has_feature(Val(:x86_64_avx512f)),
)
else
result = expk(logkxy)
end
result = ifelse(isnan(result), V(Inf), result)
result = ifelse(x > 0, result, ifelse(~yisint, V(NaN), ifelse(yisodd, -result, result)))
efx = flipsign(abs(x) - one(x), y)
# result = ifelse(y == V(Inf), ifelse(efx < 0, V(0.0), ifelse(efx == 0, V(1.0), V(Inf))), result)
result =
ifelse(isinf(y), ifelse(efx < 0, V(0.0), ifelse(efx == 0, V(1.0), V(Inf))), result)
result = ifelse(
isinf(x) | (x == 0),
ifelse(yisodd, _sign(x), V(1.0)) * ifelse(ifelse(x == 0, -y, y) < 0, V(0.0), V(Inf)),
result,
)
result = ifelse(isnan(x) | isnan(y), V(NaN), result)
result = ifelse((y == 0) | (x == 1), V(1.0), result)
return result
end
@inline pow_fast(x, y) = exp2(y * log2_fast(x))
@static if VERSION ≥ v"1.6"
@inline exp_hilo(
x::Union{Float32,AbstractSIMD{<:Any,Float32}},
xlo::Union{Float32,AbstractSIMD{<:Any,Float32}},
::Val{B},
_,
) where {B} = expk(Double(x, xlo))
const J_TABLE_BASE = Ref(Base.Math.J_TABLE)
@inline base_exp_table_pointer() = VectorizationBase.stridedpointer(
Base.unsafe_convert(Ptr{UInt64}, pointer_from_objref(J_TABLE_BASE)),
VectorizationBase.LayoutPointers.StrideIndex{1,(1,),1}(
(StaticInt{8}(),),
(StaticInt{0}(),),
),
)
@inline function exp_hilo(
x::Union{Float64,AbstractSIMD{<:Any,Float64}},
xlo::Union{Float64,AbstractSIMD{<:Any,Float64}},
::Val{B},
::False,
) where {B}
N_float = muladd(
x,
VectorizationBase.LogBo256INV(Val{B}(), Float64),
VectorizationBase.MAGIC_ROUND_CONST(Float64),
)
N = VectorizationBase.target_trunc(reinterpret(UInt64, N_float))
N_float = N_float - VectorizationBase.MAGIC_ROUND_CONST(Float64)
r = VectorizationBase.fast_fma(
N_float,
VectorizationBase.LogBo256U(Val{B}(), Float64),
x,
fma_fast(),
)
r = VectorizationBase.fast_fma(
N_float,
VectorizationBase.LogBo256L(Val{B}(), Float64),
r,
fma_fast(),
)
# @show (N & 0x000000ff) % Int
j = vload(base_exp_table_pointer(), (N & 0x000000ff,))
jU = reinterpret(Float64, Base.Math.JU_CONST | (j & Base.Math.JU_MASK))
jL = reinterpret(Float64, Base.Math.JL_CONST | (j >> 8))
k = N >>> 0x00000008
very_small = muladd(jU, VectorizationBase.expm1b_kernel(Val{B}(), r), jL)
small_part = muladd(jU, xlo, very_small) + jU
# small_part = reinterpret(UInt64, vfmadd(js, expm1b_kernel(Val{B}(), r), js))
# return reinterpret(Float64, small_part), r, k, N_float, js
twopk = (k % UInt64) << 0x0000000000000034
res = reinterpret(Float64, twopk + reinterpret(UInt64, small_part))
return res
end
@inline function exp_hilo(
x::Union{Float64,AbstractSIMD{<:Any,Float64}},
xlo::Union{Float64,AbstractSIMD{<:Any,Float64}},
::Val{B},
::True,
) where {B}
N_float = muladd(
x,
VectorizationBase.LogBo256INV(Val{B}(), Float64),
VectorizationBase.MAGIC_ROUND_CONST(Float64),
)
N = VectorizationBase.target_trunc(reinterpret(UInt64, N_float))
N_float = N_float - VectorizationBase.MAGIC_ROUND_CONST(Float64)
r = fma(N_float, VectorizationBase.LogBo256U(Val{B}(), Float64), x)
r = fma(N_float, VectorizationBase.LogBo256L(Val{B}(), Float64), r)
# @show (N & 0x000000ff) % Int
# @show N N & 0x000000ff
j = vload(base_exp_table_pointer(), (N & 0x000000ff,))
jU = reinterpret(Float64, Base.Math.JU_CONST | (j & Base.Math.JU_MASK))
jL = reinterpret(Float64, Base.Math.JL_CONST | (j >> 8))
# @show N & 0x000000ff j jU jL
# k = N >>> 0x00000008
# small_part = reinterpret(UInt64, vfmadd(js, expm1b_kernel(Val{B}(), r), js))
very_small = muladd(jU, VectorizationBase.expm1b_kernel(Val{B}(), r), jL)
small_part = muladd(jU, xlo, very_small) + jU
# small_part = vfmadd(js, expm1b_kernel(Val{B}(), r), js)
# return reinterpret(Float64, small_part), r, k, N_float, js
res = VectorizationBase.vscalef(small_part, 0.00390625 * N_float)
# twopk = (k % UInt64) << 0x0000000000000034
# res = reinterpret(Float64, twopk + small_part)
return res
end
end
@inline function cbrt_kernel(x::FloatType64)
c6 = -0.640245898480692909870982
c5 = 2.96155103020039511818595
c4 = -5.73353060922947843636166
c3 = 6.03990368989458747961407
c2 = -3.85841935510444988821632
c1 = 2.2307275302496609725722
evalpoly(x, (c1, c2, c3, c4, c5, c6))
end
@inline function cbrt_kernel(x::FloatType32)
c6 = -0.601564466953277587890625f0
c5 = 2.8208892345428466796875f0
c4 = -5.532182216644287109375f0
c3 = 5.898262500762939453125f0
c2 = -3.8095417022705078125f0
c1 = 2.2241256237030029296875f0
evalpoly(x, (c1, c2, c3, c4, c5, c6))
end
"""
Algorithm:
movsxd rax, edi
imul rax, rax, 1431655766
mov rcx, rax
shr rcx, 63
shr rax, 32
add eax, ecx
ret
"""
@inline function divby3(a32::AbstractSIMD{<:Any,T}) where {T}
c = 1431655766
a = a32 % Int64
rax = a * c
rcx = rax
rcx >>>= 63
rax >>>= 32
(rcx + rax) % T
end
@inline divby3(x::Int32) = x ÷ Int32(3)
@inline divby3(x::Int64) = ((x % Int32) ÷ Int32(3)) % Int64
"""
cbrt_fast(x)
Return `x^{1/3}`.
"""
@inline function cbrt_fast(d::V) where {V<:FloatType}
T = eltype(d)
e = absilogbk(d)
d = ldexp2k_nem1(d, e)
eplus6144 = e + 6145
edivby3 = divby3(eplus6144)
r = eplus6144 - edivby3 * 3
# r = (e + 6144) % 3
q = ifelse(r == 1, V(M2P13), V(1))
q = ifelse(r == 2, V(M2P23), q)
q = ldexp2k(q, edivby3 - 2048)
q = flipsign(q, d)
d = abs(d)
x = cbrt_kernel(d)
y = x * x
y = y * y
x = vfnmadd(vfmsub(d, y, x), T(1 / 3), x)
y = d * x * x
y = (y - T(2 / 3) * y * vfmsub(y, x, 1)) * q
end
"""
cbrt(x)
Return `x^{1/3}`. The prefix operator `∛` is equivalent to `cbrt`.
"""
function cbrt(d::V) where {V<:FloatType}
T = eltype(d)
e = absilogbk(d)
d = ldexp2k_nem1(d, e)
eplus6144 = e + 6145
edivby3 = divby3(eplus6144)
r = eplus6144 - edivby3 * 3
q2 = ifelse(r == 1, MD2P13(T), Double(V(1)))
q2 = ifelse(r == 2, MD2P23(T), q2)
q2 = flipsign(q2, d)
d = abs(d)
x = cbrt_kernel(d)
y = x * x
y = y * y
x = vfnmadd(vfmsub(d, y, x), T(1 / 3), x)
z = x
u = dsqu(x)
u = dsqu(u)
u = dmul(u, d)
u = dsub(u, x)
y = V(u)
y = T(-2 / 3) * y * z
v = dadd(dsqu(z), y)
v = dmul(v, d)
v = dmul(v, q2)
z = ldexp2k(V(v), edivby3 - 2048)
# @show z
# z = ifelse(isinf(d), flipsign(T(Inf), q2.hi), z)
z = ifelse(isfinite(d), z, d)
# z = ifelse(d == 0, flipsign(T(0), q2.hi), z)
z = ifelse(d == 0, zero(V), z)
return z
end
"""
hypot(x,y)
Compute the hypotenuse `\\sqrt{x^2+y^2}` avoiding overflow and underflow.
"""
@inline function hypot(x::T, y::T) where {T<:vIEEEFloat}
a = abs(x)
b = abs(y)
x = min(a, b)
y = max(a, b)
r = y / x
ifelse(x == 0, y, x * sqrt(muladd(r, r, one(T))))
end