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- ***********************
- The CS:APP Data Lab
- Directions to Students
- ***********************
-
- Your goal is to modify your copy of bits.c so that it passes all the
- tests in btest without violating any of the coding guidelines.
-
-
- *********
- 0. Files:
- *********
-
- Makefile - Makes btest, fshow, and ishow
- README - This file
- bits.c - The file you will be modifying and handing in
- bits.h - Header file
- btest.c - The main btest program
- btest.h - Used to build btest
- decl.c - Used to build btest
- tests.c - Used to build btest
- tests-header.c- Used to build btest
- dlc* - Rule checking compiler binary (data lab compiler)
- driver.pl* - Driver program that uses btest and dlc to autograde bits.c
- Driverhdrs.pm - Header file for optional "Beat the Prof" contest
- fshow.c - Utility for examining floating-point representations
- ishow.c - Utility for examining integer representations
-
- ***********************************************************
- 1. Modifying bits.c and checking it for compliance with dlc
- ***********************************************************
-
- IMPORTANT: Carefully read the instructions in the bits.c file before
- you start. These give the coding rules that you will need to follow if
- you want full credit.
-
- 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.
-
- Once you have a legal solution, you can test it for correctness using
- the ./btest program.
-
- *********************
- 2. Testing with btest
- *********************
-
- The Makefile in this directory compiles your version of bits.c with
- additional code to create a program (or test harness) named btest.
-
- To compile and run the btest program, type:
-
- unix> make btest
- unix> ./btest [optional cmd line args]
-
- You will need to recompile btest each time you change your bits.c
- program. When moving from one platform to another, you will want to
- get rid of the old version of btest and generate a new one. Use the
- commands:
-
- unix> make clean
- unix> make btest
-
- Btest tests your code for correctness by running millions of test
- cases on each function. It tests wide swaths around well known corner
- cases such as Tmin and zero for integer puzzles, and zero, inf, and
- the boundary between denormalized and normalized numbers for floating
- point puzzles. When btest detects an error in one of your functions,
- it prints out the test that failed, the incorrect result, and the
- expected result, and then terminates the testing for that function.
-
- Here are the command line options for btest:
-
- unix> ./btest -h
- Usage: ./btest [-hg] [-r <n>] [-f <name> [-1|-2|-3 <val>]*] [-T <time limit>]
- -1 <val> Specify first function argument
- -2 <val> Specify second function argument
- -3 <val> Specify third function argument
- -f <name> Test only the named function
- -g Format output for autograding with no error messages
- -h Print this message
- -r <n> Give uniform weight of n for all problems
- -T <lim> Set timeout limit to lim
-
- Examples:
-
- Test all functions for correctness and print out error messages:
- unix> ./btest
-
- Test all functions in a compact form with no error messages:
- unix> ./btest -g
-
- Test function foo for correctness:
- unix> ./btest -f foo
-
- Test function foo for correctness with specific arguments:
- unix> ./btest -f foo -1 27 -2 0xf
-
- Btest does not check your code for compliance with the coding
- guidelines. Use dlc to do that.
-
- *******************
- 3. 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)
-
-
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