Assignment One - CS341 S2002
This assignment involves writing a bunch of snippets of assembly
language code. These are intended to give you practice with the basic
control and arithmetic instructions of the SPARC architecture, and
also with bit-twiddling. (20 points each, plus extra credit for the
You should include in what you hand in not only the raw code required,
but also code that sets up inputs for testing purposes. Grading will
include whether we like your tests - ie whether they cover boundary
- Design a way to represent, in a 16-bit word, an integer in the
range -16000 to 49000. This representation should allow these numbers
to be manipulated (added, subtracted, multiplied, check if a number is
negative, check if a number is zero) easily. (You don't need to worry
- Write code that assumes there is a 16-bit word representing an
integer between -16000 and 49000 as in problem 1, and that r1 holds
the address of that word. Fetch it from memory and manipulate it so
the number in question ends up in r2, represented as a standard 32-bit
2's complement integer.
- Assume that r1 contains the address of the start of a hunk of
memory, and r2 contains the address of the hunk's end, ie the address
of the last byte in the hunk. Write code that scans through 8-bit
numbers in the given hunk of memory. It should leave the sum of all
the 8-bit numbers, considered to be signed, in r3; their sum,
considering them unsigned, in r4; the number of bytes scanned in r5;
and the number of negative ones (thinking of them as signed) in r6.
- Write code that scans a chunk of 16-bit words starting at the
address in r1, with the number of elements in r2. Look for the
three-word sequence 1, 2, 3. If this sequence is found, leave the
address of the start of the sequence (ie of the word containing the
number 1) in r3. If it is not found, leave r3 holding zero.
- Implement memcpy(3), with the arguments dest, src, and n coming
from r1, r2, and r3, respectively. For extra credit make
your routine as fast as possible by minimizing the number of memory
accesses. In particular, this means not just loading and storing each
byte individually, but instead handling them in 32-bit hunks. But be
careful: dest and src are not necessarily word aligned, and n might
not be a multiple of 4.
When a unix person says "look at memcpy(3)" that means you can read
the documentation using "man 3 memcpy".
It is a good idea to first write pseudocode in pidgin C, and then
gradually translate it into assembly.
Chapter seven in MacCabe is a good source of ideas for problem 1.
The due date for this assignment is midnight Sat Feb 9, 2002.
To hand in your code, run
~bap/public_html/bin/hw-handin FILES OR DIRECTORIES
The script will recursively traverse directories, so be careful with
If you have a special note you wish to affix, use the -a
Please do not just email attachments to the instructors.