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- In assignment 6,
How were the example files in ~tochna1/03b/assign6 generated?
- In assignment 6,
How do I handle the case where only a subset of the fields or a subset
of the opcodes are specified in the spec. file?
- In assignment 6,
How can I override the default setting of SPECFILE in the makefile?
- In assignment 5, operations on Big_int struct,
How can I verify that the reading of the input number succeeds?
- In assignment 5, operations on Big_int struct,
How can the main function detect a failure in bi_init() and
bi_mul(), as these 2 functions are subject to fail due to insuficient
memory?
- In assignment 5, operations on Big_int struct,
are there any constraints on BASE?
- In assignment 4, photo program, when I run under
windows, I get the error message below, and the program aborts.
ERROR: Read failed!
- In assignment 4, photo program, when I run the
program in interactive mode through Exceed, I get the error message
below, and the program aborts.
GLUT: Fatal Error in photo: OpenGL GLX extension not supported by display: class5-05.math.tau.ac.il:0.0
- In assignment 4, photo program, when using the
'cubic' method some of the calculated signatures differ from the
signatures provided with the examples, even though the image looks
nice to the naked eye, and the code seems correct. What shell I do?
- In assignment 4, photo program, the display of
the scaled-down image is skewed for some scale-down factors. Why and
how can I fix it?
- In assignment 4, photo program, what is the
exact width and height of the scaled down image?
- How can I compile and run the photo program on
windows?
- In assignment 3, wxercise hanoi, What is the
maximum number of disks?
- In assignment 2, exercise maxbin2eng, how should
the program dhandle large numbers?
- Is it allowed to use the pow() function from
the math library to solve the "cos" exercise of assignment 1?
- I generated an executable, say prog, in the current
directory, but I cannot run it. When I type its name, I get:
prog: command not found
- What am I supposed to do in exercise 1 of assignment 1
(d2u, u2d)?
All generated files (i.e., inst.h, inst.c, prog1.e, prog2.e, and
prog3.e) were generated based on spec1.t (spec.t is a soft link to
spec1.t)
spec2.t and spec3.t were not used at all, just provided as additional
examples for specification files.
prog1.e based on spec2.t looks like:
0x00002006
0x00003006
0x00004321
0x00000047
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prog1.e based on spec3.t looks like:
0x00100006
0x00180006
0x00201811
0x00000027
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Naturally, the choice of specification file has no effect on the output
files (assuming the spec files are legal).
- The spec. file must specify all 4 fields. Otherwise, you will get
compilation errors when compiling "asm" or "sim". This is acceptable.
Naturally, you may verify that they are specified already in "gen",
and exit with an error code, in case one or more is missing.
- Not all 6 opcodes must be specified. This deficiency has no effect
on "gen". "asm" and "sim", on the other hand, must be prepared to
handle all operations ("asm" must distinguish between "in", "out",
and all the rest, as they have different arguments). A good solution
is to embed the code that process a given operation within
#ifdef,#endif pair as follows:
#ifdef OPCODE_ADD
(process OPCODE_ADD)
#endif
#ifdef OPCODE_SUB
...
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You can overrdie the setting of the makefile variable SPECFILE in two
ways:
- Permanently - by setting the environment variable SPECFILE to
a new value
- Temporary - for a single makefile session:
make "SPECFILE=spec1.t" prog.e sim
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You can use the function
strtoul()
to read the input number.
You have 3 options; (1) print an error message and exit the program
immediately from these 2 functions. This is not recommended, as there
might be other things that need to be cleaned up. (2) introduce a global
variable, say bi_error. Set it when an error occurs, and test it from
main, or (3) change the return type to int, and make the functions return
a code indicating whether an error has occurred. It is common to return
0 for no error, and a negative number, say -1, for an error. The last
option implies a change to the header file, but this is the only change
allowed!
You may assume that BASE is never larger than 10!
Search for the fopen() statement, and add the letter 'b', for
binary, to the mode:
FILE * ppmfile = fopen (file_name, "rb");
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Apparantly, you need to run the program under Linux directly, and not
through Exceed! You should be able to run Linux directly on every machine
in the lab.
The calculation of the image signature is sensitive to acceptable
variations in the implementation of the 'cubic' method. If your
signatures match the provided ones, your code is probably correct.
Otherwise, it does not necessarily imply that it is not. This will
be taken in account when the code is checked.
I've added alternative correct signatures of images scaled down with the
'cubic' method for the examples under ~tochna1/03b/assign4/photo directory.
On some display systems, the width of the displayed image (the number
of pixels in every line) must be a product of 4. This is necessary to
guarantee that an entire line of pixels ends at a word (4 bytes)
boundary. This means that you may need to pad each line with a fixed
number of black pixels (with rgb value 0). The amount of pixels to pad
depends on the new width and could be either 0, 1, 2, or 3.
The padding has no effect on the signature of the image. It affects
its proper display only.
The width and height of the original image and the scaled down image are
integers. The width (resp. height) of the scaled-down image is the
integer part of the width (resp. height) divided by the scale factor,
where the scale factor is represented with a double, and the
division operation is carried out in double.
- Using GNU gcc through cygwin
- Verify that your cygwin installation supports opengl32 and glut32.
If you don't have
/usr/include/GL/{gl.h,glu.h,glut.h},
you need to download and install the openGl libraries of the cygwin
Graphics-component.
- Compile the photo program
gcc -Wall photo.c -lglut32 -lopengl32 -o photo
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- Run the program
- Using Visual Studio
- Download the glut headers and precompiled dll and lib from
glut, and
follow the installation procedure
- Compile the cp_photo
- Link
link -nologo cp_photo.obj -subsystem:console glut32.lib opengl32.lib -Out:cp_photo.exe
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- Run
You may assume that the mnumber of disks is not larger than 32.
You may assume that the number of bits in the binary format (the input), is
not greater than 32.
In principle it's allowed. When you use this function (or any other
function from the math library for that matter), your program must be
linked with the math library. Add the command line option -lm to
the compilation command to link with the math libarry.
In practice, using the pow() function is not very efficient,
because the i+1-th element in the sequence can be calculated
more efficiently based on the i-th element without the use of this
function.
In any case you may assume that the automatic checking program will add
-lm to the compilation command to link with the math libarry.
You are probably missing the current directory in your search path. The
current directory is indicated by '.'. You need to add it to your search
path. Under bash, type:
Under csh or tcsh type
Perhaps the terms DOS and UNIX got you confused. Instead call them format
D and format U. You are given a text file in format D. A text file in
format D consists of Ascii characters, where every character '\n' follows
the character '\r' to indicate the end of a line. You need to convert it
to a text file in format U. A text file in format U consists of Ascii
characters, where the end of line is indicated by a single character '\n'.
Maintained by
Efi Fogel.
Last modified: June 06 2003.
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