Write an assembly language program, Assembly Language

You are to write an assembly language program called subfaq.s that computes the generalized subfactorial function of nonnegative integer inputs i0 and n. The generalized subfactorial function is defined by the following recursion.

gs(0) = 1
inc(0) = i0

gs(n) = n gs(n-1) - inc(n-1)
inc(n) = -inc(n-1)

The generalized subfactorial function is closely related to the factorial function:
Factorial(n) can be written n! and is equal to gs(n) when i0 = 0.
Subfactorial(n) can be written !n and is equal to gs(n) when i0 = 1.

The values of both factorial and subfactorial get large very rapidly as n increases, so your program should return a 64-bit number representing gs(n) mod 264. In other words, just let your 64-bit register overflow. Try to make your code as short and efficient as possible. I recommend not using recursion, but rather writing a loop that starts from 0 and increments up to n. Write your assembly code from scratch rather than writing C and compiling to assembly. It takes only 10 to 20 instructions, and this will be your only assignment to write code in assembly. Don't miss out on the experience. You may copy your procedure entry and exit code from the textbook or the gcc compiler output without citing the source. Try to get your assembly code for subfac.s to occupy at most 50 bytes (30 is possible). To see your machine code, use
gcc64 -c subfaq.s

to produce object file subfaq.o , then use
objdump64 -d subfaq.o .

The following C program (called run_subfaq.c ) can be used to test your subfaq function. Do not include it with your submission; I already have it.

lli subfaq(int n, lli i0);

int main(int argc, char* argv[])
int i = 1, n;
lli i0, ans;
if(argc < 3) {printf("Usage: gs i0 n1 n2 n3 ... (list of non-negative integers)"); return -1;}
sscanf(argv[i++], "%lld", &i0);
while (i < argc) {
sscanf(argv[i], "%d", &n);
if(n < 0) printf("%d out of range\n", n);
else {
ans = subfaq(n, i0);
printf("gs(%d, %lld) = %lld\n", n, i0, ans);

The compile command to test your programs will look like this:
gcc64 -Wall -std=gnu99 -o gs run_subfaq.c subfaq.s .
Here are two sample outputs to use in testing your programs.
C:>gs 0 0 1 2 3 4 5 6 13
gs(0, 0) = 1
gs(1, 0) = 1
gs(2, 0) = 2
gs(3, 0) = 6
gs(4, 0) = 24
gs(5, 0) = 120
gs(6, 0) = 720
gs(20, 0) = 2432902008176640000
gs(21, 0) = -4249290049419214848
C:>gs 1 0 1 2 3 4 5 6 13
gs(0, 1) = 1
gs(1, 1) = 0
gs(2, 1) = 1
gs(3, 1) = 2
gs(4, 1) = 9
gs(5, 1) = 44
gs(6, 1) = 265
gs(20, 1) = 895014631192902121
gs(21, 1) = 348563181341392924

(The outputs for n = 21 have overflowed the 64-bit word size.)

Posted Date: 4/3/2013 2:04:13 AM | Location : United States

Related Discussions:- Write an assembly language program, Assignment Help, Ask Question on Write an assembly language program, Get Answer, Expert's Help, Write an assembly language program Discussions

Write discussion on Write an assembly language program
Your posts are moderated
Related Questions
take an integer and its base and the base in which you want to convert the number from user and perform conversion.

Machine Coding the Programs So far we have describe five programs which were  written  for hand coding  by a programmer. In this, we will now have a deep look at how these prog


Program: Write a program to perform addition of a series of 8-bit numbers. The series have 100 (numbers). Solution : In the first program, we have been implemented the add

Zero flag: The next line compares the value in register. A with the value 1. If they are equivalent, the Zero flag is set (to 1). The next line then jumps to start: only if th

) What is the difference between re-locatable program and re-locatable data?

Example : Write a program to move the contents of the memory location 0500H to BX and also to register CX. Add immediate byte 05H to the data residing in memory location, whose ad

Hand shaking : Handshaking, or 2-way handshaking, is 1 type of strobe operation. It typically involves 2 handshaking lines: an output line to denote when the board is ready an

Write an assembly language program to perform a rot13 1 conversion on characters in a text file.  The program should read charatcers from the input file, perform the rot13 convers

Interrupt System Based on Multiple 8259As A multiple 8259A interrupt system is diagrammed in given figure in this figure data bus drivers are not indicated, but they could be i