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Use python bigfloat to calculate atan tables
[ieee754fpu.git]
/
src
/
ieee754
/
cordic
/
fpsin_cos.py
diff --git
a/src/ieee754/cordic/fpsin_cos.py
b/src/ieee754/cordic/fpsin_cos.py
index c61e6bf2648bfe530855e54fb8ae110e4eb7fb72..e75cbccc0cdc30e25975040cb6a20cbfd9acc64a 100644
(file)
--- a/
src/ieee754/cordic/fpsin_cos.py
+++ b/
src/ieee754/cordic/fpsin_cos.py
@@
-7,6
+7,8
@@
from nmigen.cli import rtlil
import math
from enum import Enum, unique
from ieee754.fpcommon.fpbase import FPNumBaseRecord, FPNumDecode
import math
from enum import Enum, unique
from ieee754.fpcommon.fpbase import FPNumBaseRecord, FPNumDecode
+import bigfloat as bf
+from bigfloat import BigFloat
@unique
@unique
@@
-25,8
+27,13
@@
class CordicROM(Elaboratable):
self.addr = Signal(range(iterations))
self.data = Signal(range(-M, M-1))
self.addr = Signal(range(iterations))
self.data = Signal(range(-M, M-1))
- angles = [int(round(M*math.atan(2**(-i))/(math.pi/2)))
- for i in range(self.iterations)]
+ angles = []
+ with bf.quadruple_precision:
+ for i in range(self.iterations):
+ x = bf.atan(BigFloat(2) ** BigFloat(-i))
+ x = x/(bf.const_pi()/2)
+ x = x * M
+ angles.append(int(round(x)))
self.mem = Memory(width=self.data.width,
depth=self.iterations,
self.mem = Memory(width=self.data.width,
depth=self.iterations,