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Exp 12

This document contains an assembly language program that calculates the factorial of a user-input number. It includes macros for system calls, procedures for converting ASCII to hexadecimal, and a recursive function for computing the factorial. The program also handles user input and displays the result in a formatted manner.

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Sadiya Sayed
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25 views3 pages

Exp 12

This document contains an assembly language program that calculates the factorial of a user-input number. It includes macros for system calls, procedures for converting ASCII to hexadecimal, and a recursive function for computing the factorial. The program also handles user input and displays the result in a formatted manner.

Uploaded by

Sadiya Sayed
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as TXT, PDF, TXT or read online on Scribd
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%macro scall 4;

common macro for input/output


mov rax, %1

mov
rdi,%2
mov
rsi,%3
mov
rdx,%4
syscall

%end macro

section
.data
num db
00h

msg db"Factorial is:"


msglen equ $-msg

msg1 db "*****Program to find factorial of a number*****",0AH db "Enter the


number:",
msg1len equ $-msg1

zerofact db "00000001"
zerofactlen equ $-zerofact

section .bss
dispnum resb 16
result resb 4
temp resb 3

section
.text
global
_start
_start:
scall 1,1,msg1,msg1len
scall 0,0,temp,3;
accept number from user
call convert;
convert number from ascii to hex mov
[num],dl

scall 1,1,msg.
mov al,[num];
store number in accumulator cmp al,01h
jbe endfact
mov rbx,0;
RMD mov bl,01h
call factr;
call factorial procedure call display

call exit endfact:


scall 1,1,zerofact,zerofactlen call exit

factr:
;recursive procedure cmp rax,01h
je recton1 push rax dec rax

call factr retcon:


pop rbx
mul ebx jmp endpr

retcon1; if rax=1 return pop rbx


jmp retcon endpr:
ret
display: ;procedure to convert hex to acci

mov
rsi,dispnum+15
mov rcx,0
;R
MD mov cl,16
cont:
mov rdx,0; RMD
mov rbx,0
;
RMD mov
bl,10h
div ebx
cmp
dl,09h
jbe
skip
add
dl,07h
skip:
add
dl,30h
mov
[rsi],dl
dec rsi
loop count

scall
1,1,dispnum,16

ret

convert: ;procedure to convery ascii to hex


mov rsi,temp
mov cl.02h
MOV rax,0 ;RMD
mov rdx,0
;

RMD countc:
rol
dl,04h
mov
al,[rsi]
cmp
al,39h
jbe
skipc
sub
al,07h
skipc:
sub
al,30 h
add
dl,al
inc rsi
dec cl knz cont ret

exit:
;exit system call

mov
rax,60
mov
rdi,0
syscall
ret

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