Assembly Language
Hashim-love1
Q.docx
Assembly Language
CS 245
20 Points
Name ____________________________________
Due: April 02, 2020
1. Each of these problems gives "before" conditions and an instruction. Give the indicated "after" state.
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Before |
Instruction executed |
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(a) |
ECX: 00 00 BF 7A |
mov ecx, -89 |
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(b) |
ECX: 00 00 BF 7A |
mov ecx, 984 |
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(c) |
EAX: 12 34 56 78 EDX: 9A BC DE F0 |
xchg ax, dx |
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(d) |
EAX: FF FF FF C8 |
add eax, 56 |
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ZF__ |
CF__ |
OF__ |
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(e) |
EDX: 00 00 02 E9 |
inc edx |
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ZF__ |
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(f) |
EBX: FF FF FF 3B |
neg ebx |
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ZF__ |
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(g) |
EAX: 01 23 45 67 ECX: 89 AB CD EF |
sub eax, ecx |
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ZF__ |
CF__ |
OF__ |
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(h) |
EAX: 00 CC 00 10 ECX: FF FF AF FD EDX: FF 03 FF 01 |
mul ecx |
EAX |
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EDX |
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CF,OF __ |
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EAX: 00 CC 00 0A EBX: 00 AA 00 0C EDX: FF 03 FF 01 |
imul eax,ebx |
EAX |
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EDX |
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(i) |
EAX: 00 CC 00 0A EBX: 00 AA 00 0C EDX: FF 03 FF 01 |
div ebx |
EAX |
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EDX |
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2. One way to calculate the harmonic mean of two numbers x and y is using the expression
Complete the following windows32 program to input two numbers and calculate and display their harmonic mean in dddd.dd format. Supply appropriate code in the boxed areas.
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.586
.MODEL FLAT
INCLUDE io.h ; header file for input/output
.STACK 4096
.DATA
x DWORD ?
y DWORD ?
prompt1 BYTE "First number", 0
prompt2 BYTE "Second number", 0
inArea BYTE 20 DUP (?)
mean BYTE 11 DUP (?), 0
meanLbl BYTE "Harmonic mean", 0
meanOut BYTE 4 DUP(?), '.', 2 DUP (?), 0
.CODE
_MainProc PROC
input prompt1, inArea, 20 ; read ASCII characters
atod inArea ; convert to integer
mov x, eax ; store in memory
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; repeat for second number |
3 (continued)
; calculate 100*(harmonic mean)in EAX
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dtoa mean, eax ; convert to ASCII characters
; copy digits, one at a time to meanOut (Complete the missing lines)
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mov al, mean+5 mov meanout, al mov al, mean+6 mov meanout+1, al mov al, mean+7 mov meanout+2, al
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; 1st digit
; 2nd digit
; 3rd digit
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; output label and mean |
mov eax, 0 ; exit with return code 0
ret
_MainProc ENDP
END ; end of source code
