cse30-fa16-lab01-ChrisL-BrandonN: A C repository from ucsd-cse30-fall-2016

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# CSE30 Data Representation Lab
# README
# Copyright (c) 2002-2016, R. Bryant and D. O'Hallaron
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This lab tests the  student's understanding of bit
representations, two's complement arithmetic, and IEEE floating point.

System requirements: Raspbian OS with ARM GCC compiler (comes built-in) 
Can work on both emulation and hardware platforms.


*********
0. Files:
*********

Makefile        - Makes bits, fshow, and ishow
README          - This file
bits.c          - The C file you will be modifying and handing in
bits.h          - Header file for bits.c
test_bits.c     - Add your test cases for bits.c, a few tests provided 
bits_ARM.s      - The Assembly file you will be modifying and handing in
bits_ARM.h      - Header file for testing the Assembly code
test_bits_ARM.c - Add your test cases for bits_ARM.s 
dlc*            - Rule checking compiler binary (data lab compiler)
driver.pl*      - Driver program that uses dlc to autograde bits.c
fshow.c         - Utility for examining floating-point representations
ishow.c         - Utility for examining integer representations


************
1. Overview
************

In this lab, you will work on a C file, called bits.c, that consists
of 15 programming "puzzles".  Each puzzle is an empty
function body that must be completed so that it implements a specified
mathematical function, such as "absolute value". Students must solve
the non-floating point puzzles using only straight-line C code and a
restricted set of C arithmetic and logical operators. For the
floating-point puzzles they can use conditionals and arbitrary
operators. We have asked that you translate a subset of your non-floating point 
C functions to ARM assembly, however we are not imposing the same constraints
as we have on C code . The ARM assembly code should be straight-line (no loops)


Along with it, we have also supplied the a compiler called datalab 
compiler, or dlc that checks each function in bits.c for
compliance with the coding guidelines, checks for the  use of
less than the maximum number of operators, checks for straight-line code, 
and for using legal operators. You may use this with your C implementation


You must check for the correctness of your C and Assembly code by completing
and adding to the test cases provided in test_bits.c and test_bits_ARM.c


*******************
2. Helper Programs
*******************


We have included the ishow and fshow programs to help you decipher
integer and floating point representations respectively. Each takes a
single decimal or hex number as an argument. To build them type:

    unix> make

Example usages:

    unix> ./ishow 0x27
    Hex = 0x00000027,   Signed = 39,    Unsigned = 39

    unix> ./ishow 27
    Hex = 0x0000001b,   Signed = 27,    Unsigned = 27

    unix> ./fshow 0x15213243
    Floating point value 3.255334057e-26
    Bit Representation 0x15213243, sign = 0, exponent = 0x2a, fraction = 0x213243
    Normalized.  +1.2593463659 X 2^(-85)

    linux> ./fshow 15213243
    Floating point value 2.131829405e-38
    Bit Representation 0x00e822bb, sign = 0, exponent = 0x01, fraction = 0x6822bb
    Normalized.  +1.8135598898 X 2^(-126)


********************
3. Building the Lab
*******************

Step 1: Make necessary changes in bits.c

Step 2: Type the following in the current directory:
     unix> make clean
     unix> make 

The Makefile generates compiles the bits.c files & builds the dlc binary
(if necessary). Please ignore any warnings from btest.c at this stage.

Step 3: You can check correctness of your bits.c by writing debug prints in the main()
function and checking the answers.

Step 4: Last step is to check if you adhere to the guidelines. 

Use the dlc compiler (./dlc) to automatically check your version of
bits.c for compliance with the coding guidelines:

       unix> ./dlc bits.c

dlc returns silently if there are no problems with your code.
Otherwise it prints messages that flag any problems.  Running dlc with
the -e switch:

        unix> ./dlc -e bits.c

causes dlc to print counts of the number of operators used by each function.

******************
4. Grading the Lab
******************

You will need to submit all the files by pushing your code to your github repo
You also need to submit the files bits.c and bits_ARM.s via gradscope where it will be
autograded. The gradescope autograder only checks for logical correctness of
your bits.c and bits_ARM.s files. The dlc checker will be run on your code
after the submission deadline. Passing the tests of correctness for bits.c and
bits_ARM.c and dlc for ONLY bits.c will give you
full credit for the lab.
ucsd-cse30-fall-2016/cse30-fa16-lab01-ChrisL-BrandonN
