95 lines
1.5 KiB
Python
95 lines
1.5 KiB
Python
__all__ = [
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'sign_extend64',
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'sign_extend32',
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'sign_extend16',
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'sign_extend12',
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'sign_extend8',
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'zero_extend32',
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'zero_extend16',
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'zero_extend8',
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'zero_extend4',
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'zero_extend1',
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'signed_saturate48',
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'signed_saturate32',
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'register',
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'bit',
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]
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#
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# sign_extend
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#
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def sign_extend(x, b):
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m = 1 << (b - 1)
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x = x & ((1 << b) - 1)
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r = (x ^ m) - m
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return r
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def sign_extend64(x):
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return sign_extend(x, 64)
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def sign_extend32(x):
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return sign_extend(x, 32)
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def sign_extend16(x):
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return sign_extend(x, 16)
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def sign_extend12(x):
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return sign_extend(x, 12)
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def sign_extend8(x):
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return sign_extend(x, 8)
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#
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# zero_extend
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#
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def zero_extend(x, b):
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x = x & ((1 << b) - 1)
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return x
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def zero_extend32(x):
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return zero_extend(x, 32)
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def zero_extend16(x):
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return zero_extend(x, 16)
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def zero_extend8(x):
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return zero_extend(x, 8)
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def zero_extend4(x):
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return zero_extend(x, 4)
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def zero_extend1(x):
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return zero_extend(x, 1)
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#
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# signed_saturate
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#
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def signed_saturate(x, b):
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upper = (2 ** (b - 1)) - 1
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lower = -(2 ** (b - 1))
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if x > upper:
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return upper
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elif x < lower:
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return lower
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else:
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return x
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def signed_saturate48(x):
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return signed_saturate(x, 48)
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def signed_saturate32(x):
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return signed_saturate(x, 32)
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#
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# "convenience" functions
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#
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def register(x):
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return zero_extend(x, 32)
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def bit(x):
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return zero_extend(x, 1)
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