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346
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1
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2
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3 def rotate_right(v, n):
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4 """ bit-wise Rotate right n times """
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5 mask = (2**n) - 1
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6 mask_bits = v & mask
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7 return (v >> n) | (mask_bits << (32 - n))
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8
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9 def rotate_left(v, n):
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10 assert n >= 0
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11 assert n < 32
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12 return rotate_right(v, 32 - n)
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13
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365
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14 def encode_imm32(v):
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15 """ Bundle 32 bit value into 4 bits rotation and 8 bits value
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16 """
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17 for i in range(0, 16):
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18 v2 = rotate_left(v, i*2)
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19 if (v2 & 0xFFFFFF00) == 0:
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20 rotation = i
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21 val = v2 & 0xFF
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22 x = (rotation << 8) | val
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23 return x
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24 raise Exception("Invalid value {}".format(v))
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346
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25
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