Package envi :: Module bits

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Module bits

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A file full of bit twidling helpers

Functions

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unsigned(value, size)
Make a value unsigned based on it's size.

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signed(value, size)
Make a value signed based on it's size.

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is_signed(value, size)

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sign_extend(value, cursize, newsize)
Take a value and extend it's size filling in the space with the value of the high order bit.

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is_parity(val)

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is_parity_byte(bval)
An "optimized" parity checker that looks up the index.

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lsb(value)

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msb(value, size)

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is_signed_overflow(value, size)

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is_unsigned_carry(value, size)

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is_aux_carry(src, dst)

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parsebytes(bytes, offset, size, sign=False, bigend=False)
Mostly for pulling immediates out of strings...

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slowparsebytes(bytes, offset, size, sign=False, bigend=False)

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buildbytes(value, size, bigend=False)

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byteswap(value, size)

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intwidth(val)

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hex(value, size=None)

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binrepr(intval, bitwidth=None)
Return a string of one's and zero's for the given value.

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binary(binstr)
Decode a binary string of 1/0's into a python number

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binbytes(binstr)
Decode a binary string of 1/0's into a python binary string.

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parsebits(bytes, offset, bitoff, bitsize)
Parse bitsize bits from the bit offset bitoff beginning at offset bytes.

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Variables

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MAX_WORD = 8

u_maxes = [0, 255, 65535, 16777215, 4294967295, 1099511627775,...

sign_bits = [0, 128, 32768, 8388608, 2147483648, 549755813888,...

s_maxes = [0, 127, 32767, 8388607, 2147483647, 549755813887, 1...

b_masks = [0, 1, 3, 7, 15, 31, 63, 127, 255, 511, 1023, 2047, ...

parity_table = [True, False, False, True, False, True, True, F...

le_fmt_chars = (None, 'B', '<H', None, '<L', None, None, None,...

be_fmt_chars = (None, 'B', '>H', None, '>L', None, None, None,...

hex_fmt = {1: '0x%.2x', 2: '0x%.4x', 4: '0x%.8x', 8: '0x%.16x'}

__package__ = 'envi'

i = 255

Function Details

[hide private]

parsebits(bytes, offset, bitoff, bitsize)

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Parse bitsize bits from the bit offset bitoff beginning at offset bytes.

Example:

Variables Details

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u_maxes

Value:

[0,
 255,
 65535,
 16777215,
 4294967295,
 1099511627775,
 281474976710655,
 72057594037927935,
...

sign_bits

Value:

[0,
 128,
 32768,
 8388608,
 2147483648,
 549755813888,
 140737488355328,
 36028797018963968,
...

s_maxes

Value:

[0,
 127,
 32767,
 8388607,
 2147483647,
 549755813887,
 140737488355327,
 36028797018963967,
...

b_masks

Value:

[0,
 1,
 3,
 7,
 15,
 31,
 63,
 127,
...

parity_table

Value:

[True,
 False,
 False,
 True,
 False,
 True,
 True,
 False,
...

le_fmt_chars

Value:

(None, 'B', '<H', None, '<L', None, None, None, '<Q')

be_fmt_chars

Value:

(None, 'B', '>H', None, '>L', None, None, None, '>Q')