lldb/examples/customization/bin-utils/binutils.py

   1 "Collection of tools for displaying bit representation of numbers."""
   2
   3 from __future__ import print_function
   4
   5 def binary(n, width=None):
   6     """
   7     Return a list of (0|1)'s for the binary representation of n where n >= 0.
   8     If you specify a width, it must be > 0, otherwise it is ignored.  The list
   9     could be padded with 0 bits if width is specified.
  10     """
  11     l = []
  12     if width and width <= 0:
  13         width = None
  14     while n > 0:
  15         l.append(1 if n & 1 else 0)
  16         n = n >> 1
  17
  18     if width:
  19         for i in range(width - len(l)):
  20             l.append(0)
  21
  22     l.reverse()
  23     return l
  24
  25
  26 def twos_complement(n, width):
  27     """
  28     Return a list of (0|1)'s for the binary representation of a width-bit two's
  29     complement numeral system of an integer n which may be negative.
  30     """
  31     val = 2**(width - 1)
  32     if n >= 0:
  33         if n > (val - 1):
  34             return None
  35         # It is safe to represent n with width-bits.
  36         return binary(n, width)
  37
  38     if n < 0:
  39         if abs(n) > val:
  40             return None
  41         # It is safe to represent n (a negative int) with width-bits.
  42         return binary(val * 2 - abs(n))
  43
  44 # print binary(0xABCD)
  45 # [1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 1]
  46 # print binary(0x1F, 8)
  47 # [0, 0, 0, 1, 1, 1, 1, 1]
  48 # print twos_complement(-5, 4)
  49 # [1, 0, 1, 1]
  50 # print twos_complement(7, 4)
  51 # [0, 1, 1, 1]
  52 # print binary(7)
  53 # [1, 1, 1]
  54 # print twos_complement(-5, 64)
  55 # [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1]
  56
  57
  58 def positions(width):
  59     """Helper function returning a list describing the bit positions.
  60     Bit positions greater than 99 are truncated to 2 digits, for example,
  61     100 -> 00 and 127 -> 27."""
  62     return ['{0:2}'.format(i)[-2:] for i in reversed(range(width))]
  63
  64
  65 def utob(debugger, command_line, result, dict):
  66     """Convert the unsigned integer to print its binary representation.
  67     args[0] (mandatory) is the unsigned integer to be converted
  68     args[1] (optional) is the bit width of the binary representation
  69     args[2] (optional) if specified, turns on verbose printing"""
  70     args = command_line.split()
  71     try:
  72         n = int(args[0], 0)
  73         width = None
  74         if len(args) > 1:
  75             width = int(args[1], 0)
  76             if width < 0:
  77                 width = 0
  78     except:
  79         print(utob.__doc__)
  80         return
  81
  82     if len(args) > 2:
  83         verbose = True
  84     else:
  85         verbose = False
  86
  87     bits = binary(n, width)
  88     if not bits:
  89         print("insufficient width value: %d" % width)
  90         return
  91     if verbose and width > 0:
  92         pos = positions(width)
  93         print(' ' + ' '.join(pos))
  94     print(' %s' % str(bits))
  95
  96
  97 def itob(debugger, command_line, result, dict):
  98     """Convert the integer to print its two's complement representation.
  99     args[0] (mandatory) is the integer to be converted
 100     args[1] (mandatory) is the bit width of the two's complement representation
 101     args[2] (optional) if specified, turns on verbose printing"""
 102     args = command_line.split()
 103     try:
 104         n = int(args[0], 0)
 105         width = int(args[1], 0)
 106         if width < 0:
 107             width = 0
 108     except:
 109         print(itob.__doc__)
 110         return
 111
 112     if len(args) > 2:
 113         verbose = True
 114     else:
 115         verbose = False
 116
 117     bits = twos_complement(n, width)
 118     if not bits:
 119         print("insufficient width value: %d" % width)
 120         return
 121     if verbose and width > 0:
 122         pos = positions(width)
 123         print(' ' + ' '.join(pos))
 124     print(' %s' % str(bits))