blob: f1aa48fa26db182b2735c1d8712307a84cffb90d [file] [log] [blame]
 "Collection of tools for displaying bit representation of numbers.""" from __future__ import print_function def binary(n, width=None): """ Return a list of (0|1)'s for the binary representation of n where n >= 0. If you specify a width, it must be > 0, otherwise it is ignored. The list could be padded with 0 bits if width is specified. """ l = [] if width and width <= 0: width = None while n > 0: l.append(1 if n & 1 else 0) n = n >> 1 if width: for i in range(width - len(l)): l.append(0) l.reverse() return l def twos_complement(n, width): """ Return a list of (0|1)'s for the binary representation of a width-bit two's complement numeral system of an integer n which may be negative. """ val = 2**(width - 1) if n >= 0: if n > (val - 1): return None # It is safe to represent n with width-bits. return binary(n, width) if n < 0: if abs(n) > val: return None # It is safe to represent n (a negative int) with width-bits. return binary(val * 2 - abs(n)) # print binary(0xABCD) # [1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 1] # print binary(0x1F, 8) # [0, 0, 0, 1, 1, 1, 1, 1] # print twos_complement(-5, 4) # [1, 0, 1, 1] # print twos_complement(7, 4) # [0, 1, 1, 1] # print binary(7) # [1, 1, 1] # print twos_complement(-5, 64) # [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] def positions(width): """Helper function returning a list describing the bit positions. Bit positions greater than 99 are truncated to 2 digits, for example, 100 -> 00 and 127 -> 27.""" return ['{0:2}'.format(i)[-2:] for i in reversed(range(width))] def utob(debugger, command_line, result, dict): """Convert the unsigned integer to print its binary representation. args[0] (mandatory) is the unsigned integer to be converted args[1] (optional) is the bit width of the binary representation args[2] (optional) if specified, turns on verbose printing""" args = command_line.split() try: n = int(args[0], 0) width = None if len(args) > 1: width = int(args[1], 0) if width < 0: width = 0 except: print(utob.__doc__) return if len(args) > 2: verbose = True else: verbose = False bits = binary(n, width) if not bits: print("insufficient width value: %d" % width) return if verbose and width > 0: pos = positions(width) print(' ' + ' '.join(pos)) print(' %s' % str(bits)) def itob(debugger, command_line, result, dict): """Convert the integer to print its two's complement representation. args[0] (mandatory) is the integer to be converted args[1] (mandatory) is the bit width of the two's complement representation args[2] (optional) if specified, turns on verbose printing""" args = command_line.split() try: n = int(args[0], 0) width = int(args[1], 0) if width < 0: width = 0 except: print(itob.__doc__) return if len(args) > 2: verbose = True else: verbose = False bits = twos_complement(n, width) if not bits: print("insufficient width value: %d" % width) return if verbose and width > 0: pos = positions(width) print(' ' + ' '.join(pos)) print(' %s' % str(bits))