Computer Systems - Tutorial 5
1. Write an 80x86 assembly language program that scans through a block of memory from DS:0000 to DS:A000 and counts the number of occurrences of numbers which are less than zero.
2. Assuming a system clock speed of 100Mhz, and an average instruction execution time of 3 machine cycles, write a program that provides a delay of approximately one second.
3. How would you modify the above program to create a delay of one minute?
4. Consider the following program.
PUSH BX
PUSH AX
MOV BX,0
NEXT: MOV AL,[BX]
MOV [ES:BX],AL
INC BX
CMP BX,0100h
JNE NEXT
POP AX
POP BX
END
What does this program do? Can you think of any ways in which you could make this program more efficient?
What is the speed up factor, if any, of your improvements?