[MLBEDSW-2845] Improve unit test coverage of fp_math
Improved unit test coverage of fp_math.py
Signed-off-by: Fredrik Svedberg <fredrik.svedberg@arm.com>
Change-Id: I883fd984a1bfa67102826a400380e41a363fc59d
diff --git a/ethosu/vela/fp_math.py b/ethosu/vela/fp_math.py
index eaeb84a..2515b77 100644
--- a/ethosu/vela/fp_math.py
+++ b/ethosu/vela/fp_math.py
@@ -21,29 +21,49 @@
# point implementation.
import numpy as np
+# Convert floating point to fixed point, default Q5.26
+def from_float(x, integer_bits=5):
+ i32info = np.iinfo(np.int32)
+ fractional_bits = i32info.bits - integer_bits - 1
+ return min(max(round(x * (1 << fractional_bits)), i32info.min), i32info.max)
+
+
+# Convert fixed point to floating point, default Q5.26
+def to_float(x, integer_bits=5):
+ fractional_bits = np.iinfo(np.int32).bits - integer_bits - 1
+ return x / (1 << fractional_bits)
+
def saturating_rounding_mul(a, b):
assert np.int32(a) == a
assert np.int32(b) == b
if a == b and a == np.iinfo(np.int32).min:
return np.int32(np.iinfo(np.int32).max)
- ab = np.int64(a) * np.int64(b)
- nudge = (1 << 30) if ab >= 0 else (1 - (1 << 30))
- result = np.int32(np.right_shift(ab + nudge, 31))
- if result < 0:
- result += 1
- return result
+ divider = 1 << 31
+ ab = a * b
+ if ab >= 0:
+ nudge = 1 << 30
+ return (ab + nudge) // divider
+ else:
+ nudge = 1 - (1 << 30)
+ ab_plus_nudge = ab + nudge
+ result = ab_plus_nudge // divider
+ # Python uses floor, the reference uses truncation
+ # so we need to compensate for that.
+ if result * divider < ab_plus_nudge:
+ result += 1
+ return result
def shift_left(a, offset):
assert np.int32(a) == a
assert offset >= 0
- a_info = np.iinfo(a)
+ i32_info = np.iinfo(np.int32)
shifted = a * (1 << offset)
- if shifted < a_info.min:
- return np.int32(a_info.min)
- elif shifted > a_info.max:
- return np.int32(a_info.max)
+ if shifted < i32_info.min:
+ return np.int32(i32_info.min)
+ elif shifted > i32_info.max:
+ return np.int32(i32_info.max)
else:
return np.int32(shifted)
@@ -62,7 +82,7 @@
return result
-def saturating_rounding_multiply_by_pot(exponent, x):
+def saturating_rounding_multiply_by_pot(x, exponent):
assert np.int32(x) == x
assert np.int32(exponent) == exponent
threshold = (1 << (np.iinfo(np.int32).bits - 1 - exponent)) - 1
@@ -79,7 +99,10 @@
assert np.int32(integer_bits_dst) == integer_bits_dst
assert np.int32(x) == x
exponent = integer_bits_src - integer_bits_dst
- result = saturating_rounding_multiply_by_pot(exponent, x)
+ if exponent < 0:
+ result = rounding_divide_by_pot(x, -exponent)
+ else:
+ result = saturating_rounding_multiply_by_pot(x, exponent)
return result