Project Assignment 1

CSC255 - Information Structures & Representations

Due: 5/2/2001

Your colleague has decided to build a computing device for a class project and has asked for your help. Your colleague has made some design decisions to reduce the work involved. One of these decisions limits the word size of the device to six bits.

You have been asked to help with the technical manual for this device. Your tasks include producing the following deliverables:

1. Integer appendix:
   • Two's complement and excess notation must be supported. In each case produce a table of bit patterns indicating the full range of decimal numbers that may be represented.
   • Provide worked examples in two's complement arithmetic for the following:
     • 5₁₀ + 10₁₀
     • 12₁₀ - 8₁₀
   • Double precision will be supported. Indicate the largest positive and negative numbers that may be represented.
   • Quadruple precision may be supported in a future release. Indicate the largest positive and negative numbers that may be represented.
2. Floating-Point appendix:
   • Double precision will be supported. You have both agreed that single precision floating-point would be of little value and have decided that double precision should allow one sign bit, six exponent bits (excess notation), and five mantissa bits. Provide a description of this floating-point scheme that includes examples to show the largest and smallest numbers that may be represented.
   • Outline a quadruple precision scheme that may be supported in a future release. Suggest a sensible partitioning of the twenty-four available bits. As above, provide examples to show the largest and smallest numbers that may be represented.
3. Character set appendix:
   • Devise a coding scheme to accommodate text. You have both agreed that it should be based on the ASCII coding scheme but since only six bits are available you will have to make compromises. Provide a table of bit patterns for the character set that will be supported.
     Note: You must support A-Z, a-z, 0-9.
   • Use the following sentences to illustrate your coding scheme:
     • Hello world
     • Where are you
     • 2 + 3 = 5
   • Provide instructions that will allow the user of the appendix to convert your character set to ASCII. Your instructions should include an example.
   • Discuss the limitations of your coding scheme and suggest how it could be improved (i.e. to accommodate a more complete set of characters).