def test_qround_non_default():
verif(drv(t=Fixp[11, 33], seq=[1, 2, 117]),
f=qround(name='dut', fract=21),
ref=qround(fract=21))
cosim('/dut', 'verilator', outdir='/tmp/qround')
sim()
def iir_df1dsos(din, *, a, b, gain, ogain):
# init temp
temp = din
# add cascades for all b coefficients
for i in range(len(b)):
# format every cascaded output as input
temp = temp | iir_1dsos(a=a[i], b=b[i], gain=gain[i]) | qround(
fract=din.dtype.fract) | saturate(t=din.dtype)
# add output gain and format as input
dout = (temp *
ogain) | qround(fract=din.dtype.fract) | saturate(t=din.dtype)
return dout
def test_qround_fixp(lang):
seq = [
-1.5 - 0.0625, -1.5, -0.5 - 0.0625, -0.5, 0.5 - 0.0625, 0.5,
1.5 - 0.0625, 1.5
]
verif(drv(t=Fixp[6, 10], seq=seq), f=qround(name='dut'), ref=qround)
cosim('/dut', 'verilator', lang=lang)
sim()
def fir_direct(din, *, b):
# init delayed input and output sum
x = din
y_sum = x * b[0]
# construct filter structure for all fir coefficients
for b_coef in b[1:]:
# add delay
x = x | dreg(init=0)
# summation
y_sum = y_sum + (x * b_coef)
# format sum as input
return y_sum | qround(fract=din.dtype.fract) | saturate(t=din.dtype)
def fir_transposed(din, *, b):
# init output sum
y_sum = din * b[0]
# construct filter structure for all fir coefficients
for b_coef in b[1:]:
# multiply input with b coefficient
mult_b_result = din * b_coef
# delay output sum
delayed_y_sum = y_sum | dreg(init=0)
# add to output sum
y_sum = mult_b_result + delayed_y_sum
# format sum as input
return y_sum | qround(fract=din.dtype.fract) | saturate(t=din.dtype)
def iir_1dsos(din, *, a, b, gain):
# add input gain and init delayed inputs
zu0 = din * gain
zu1 = zu0 | dreg(init=0)
zu2 = zu1 | dreg(init=0)
# perform b coefficient sum
a1 = (zu1 * b[1]) + (zu2 * b[2])
a2 = a1 + (zu0 * b[0])
# declare output interface and its type
y = Intf(a2.dtype)
# init delayed outputs
zy1 = y | decouple(init=0)
zy2 = zy1 | dreg(init=0)
# perform a coefficient sum
b1 = (zy2 * a[2]) + (zy1 * a[1])
# add both sums and set output
y |= (a2 - b1) | qround(fract=a2.dtype.fract) | saturate(t=a2.dtype)
return y
def iir_2tsos(din, *, a, b, gain):
# add input gain
x = din * gain
# declare output interface and its type
y = Intf(din.dtype)
# perform first tap multiplication and sum
z0 = ((x * b[2]) - (y * a[2]))
# delay first sum output
z0_delayed = z0 | dreg(init=0)
# perform second tap multiplication and sum
z1 = ((x * b[1]) + z0_delayed - (y * a[1]))
# delay second sum output
z1_delayed = z1 | decouple(init=0)
# perform final sum and set output
y |= ((x * b[0]) +
z1_delayed) | qround(fract=din.dtype.fract) | saturate(t=din.dtype)
return y
def format_fixp(din, *, t):
return din | qround(fract=t.fract) | saturate(t=t)
