def approximate_reciprocal(divisor, k, f, theta):
"""
returns aproximation of 1/divisor
where type(divisor) = cint
"""
def twos_complement(x):
bits = x.bit_decompose(k)[::-1]
bit_array = Array(k, cint)
bit_array.assign(bits)
twos_result = MemValue(cint(0))
@for_range(k)
def block(i):
val = twos_result.read()
val <<= 1
val += 1 - bit_array[i]
twos_result.write(val)
return twos_result.read() + 1
bit_array = Array(k, cint)
bits = divisor.bit_decompose(k)[::-1]
bit_array.assign(bits)
cnt_leading_zeros = MemValue(regint(0))
flag = MemValue(regint(0))
cnt_leading_zeros = MemValue(regint(0))
normalized_divisor = MemValue(divisor)
@for_range(k)
def block(i):
flag.write(flag.read() | bit_array[i] == 1)
@if_(flag.read() == 0)
def block():
cnt_leading_zeros.write(cnt_leading_zeros.read() + 1)
normalized_divisor.write(normalized_divisor << 1)
q = MemValue(two_power(k))
e = MemValue(twos_complement(normalized_divisor.read()))
qr = q.read()
er = e.read()
for i in range(theta):
qr = qr + shift_two(qr * er, k)
er = shift_two(er * er, k)
q = qr
res = shift_two(q, (2 * k - 2 * f - cnt_leading_zeros))
return res
def approximate_reciprocal(divisor, k, f, theta):
"""
returns aproximation of 1/divisor
where type(divisor) = cint
"""
def twos_complement(x):
bits = x.bit_decompose(k)[::-1]
bit_array = Array(k, cint)
bit_array.assign(bits)
twos_result = MemValue(cint(0))
@for_range(k)
def block(i):
val = twos_result.read()
val <<= 1
val += 1 - bit_array[i]
twos_result.write(val)
return twos_result.read() + 1
bit_array = Array(k, cint)
bits = divisor.bit_decompose(k)[::-1]
bit_array.assign(bits)
cnt_leading_zeros = MemValue(regint(0))
flag = MemValue(regint(0))
cnt_leading_zeros = MemValue(regint(0))
normalized_divisor = MemValue(divisor)
@for_range(k)
def block(i):
flag.write(flag.read() | bit_array[i] == 1)
@if_(flag.read() == 0)
def block():
cnt_leading_zeros.write(cnt_leading_zeros.read() + 1)
normalized_divisor.write(normalized_divisor << 1)
q = MemValue(two_power(k))
e = MemValue(twos_complement(normalized_divisor.read()))
qr = q.read()
er = e.read()
for i in range(theta):
qr = qr + shift_two(qr * er, k)
er = shift_two(er * er, k)
q = qr
res = shift_two(q, (2*k - 2*f - cnt_leading_zeros))
return res
def int2FL_plain(a, gamma, l, kappa):
lam = gamma - 1
a_abs = 0
v = cint(0)
p = cint(0)
s = cint(0)
z = cint(0)
# extracts the sign and calculates the abs
s = cint(a < 0)
a_abs = a * (1 - 2 * s)
# isolates most significative bit
a_bits = a_abs.bit_decompose()
b = 0
b_c = 1
blen = 0
for a_i in range(len(a_bits) - 1, -1, -1): # enumerate(a_bits):
b = (a_bits[a_i]) * (b == 0) * ((b_c) / 2) + b
blen = (a_bits[a_i]) * (blen == 0) * ((a_i + 1)) + blen
b_c = b_c * 2
# obtains p
# blen= len(a_bits) - blen
v = a_abs * b # (2 ** (b))#scale a
p = - (lam - blen) # (len(a_bits)-blen))
# reduces v
v_l = MemValue(v)
z_l = MemValue(z)
if_then(a_abs > 0)
if (lam > l):
v_l.write(v_l.read() / (2 ** (gamma - l - 1)))
else:
v_l.write(v_l.read() * (2 ** l - lam))
else_then()
z_l.write(cint(1))
end_if()
# corrects output
# s is coming from the abs extraction
v = cint(v_l.read())
z = cint(z_l.read())
p = cint((p + lam - l) * (1 - z))
return v, p, z, s
def twos_complement(x):
bits = x.bit_decompose(k)[::-1]
bit_array = Array(k, cint)
bit_array.assign(bits)
twos_result = MemValue(cint(0))
@for_range(k)
def block(i):
val = twos_result.read()
val <<= 1
val += 1 - bit_array[i]
twos_result.write(val)
return twos_result.read() + 1
def twos_complement(x):
bits = x.bit_decompose(k)[::-1]
bit_array = Array(k, cint)
bit_array.assign(bits)
twos_result = MemValue(cint(0))
@for_range(k)
def block(i):
val = twos_result.read()
val <<= 1
val += 1 - bit_array[i]
twos_result.write(val)
return twos_result.read() + 1
