Instructions
Objective
Write a Linux assignment on ARM program to create a calculator in x86-64 assembly.
Requirements and Specifications
Screenshots of output
Source Code
.intel_syntax noprefix
.text
.global _start
_start:
#initialize rax to zero
xor rax, rax
#point to start of commands
mov rbx, OFFSET [CALC_DATA_BEGIN]
loop1:
# if the command is zero
cmp BYTE PTR [rbx], 0
# if zero, exit
je done
# advance to command argument
add rbx, 8
# call function
call dummy
# repeat loop
jmp loop1
done:
# exit
mov rax, 60
mov rdi, 0
syscall
# dummy function that advances rbx by 8
dummy:
add rbx, 8
ret
.intel_syntax noprefix
.text
.global _start
_start:
#initialize rax to zero
xor rax, rax
# initialize sums to zero
mov QWORD PTR[SUM_NEGATIVE], rax
mov QWORD PTR[SUM_POSITIVE], rax
#point to start of commands
mov rbx, OFFSET [CALC_DATA_BEGIN]
loop1:
# load command
mov cl, BYTE PTR [rbx]
# advance to command argument
add rbx, 8
# if the command is zero
cmp cl, 0
# we are done
je done
# if the command is and
cmp cl, '&'
# do call function
je do_and
# if the command is or
cmp cl, '|'
# do call function
je do_or
# if the command is sum
cmp cl, 'S'
# do call function
je do_sum
# otherwise end
jmp done
do_and:
# call function
call AND_FUNCTION
# repeat loop
jmp loop1
do_or:
# call function
call OR_FUNCTION
# repeat loop
jmp loop1
do_sum:
# call function
call SUM_FUNCTION
# repeat loop
jmp loop1
done:
# exit
mov rax, 60
mov rdi, 0
syscall
.intel_syntax noprefix
.text
.global _start
_start:
#initialize rax to zero
xor rax, rax
# initialize sums to zero
mov QWORD PTR[SUM_NEGATIVE], rax
mov QWORD PTR[SUM_POSITIVE], rax
#point to start of commands
mov rbx, OFFSET [CALC_DATA_BEGIN]
loop1:
# load command
mov cl, BYTE PTR [rbx]
# advance to command argument
add rbx, 8
# if the command is zero
cmp cl, 0
# we are done
je done
# if the command is and
cmp cl, '&'
# do call function
je do_and
# if the command is or
cmp cl, '|'
# do call function
je do_or
# if the command is sum
cmp cl, 'S'
# do call function
je do_sum
# otherwise end
jmp done
do_and:
# call function
call AND_FUNCTION
# repeat loop
jmp loop1
do_or:
# call function
call OR_FUNCTION
# repeat loop
jmp loop1
do_sum:
# call function
call SUM_FUNCTION
# repeat loop
jmp loop1
done:
# print last value of rax, save it first in temp
mov QWORD PTR[temp], rax
# load value of stdout
mov rdi, 1
# load address to be printed
mov rsi, OFFSET [temp]
# print 8 bytes
mov rdx, 8
# load write syscall
mov rax, 1
# write on stdout
syscall
# print last value of SUM_POSITIVE
# load value of stdout
mov rdi, 1
# load address to be printed
mov rsi, OFFSET [SUM_POSITIVE]
# print 8 bytes
mov rdx, 8
# load write syscall
mov rax, 1
# write on stdout
syscall
# print last value of SUM_NEGATIVE
# load value of stdout
mov rdi, 1
# load address to be printed
mov rsi, OFFSET [SUM_NEGATIVE]
# print 8 bytes
mov rdx, 8
# load write syscall
mov rax, 1
# write on stdout
syscall
# print values between CALC_DATA_BEGIN and CALC_DATA_END
# load value of stdout
mov rdi, 1
# load address to be printed
mov rsi, OFFSET [CALC_DATA_BEGIN]
# calculate number of bytes to print
# load end address
mov rdx, OFFSET [CALC_DATA_END]
# subtract start address
sub rdx, rsi
# load write syscall
mov rax, 1
# write on stdout
syscall
# exit
mov rax, 60
mov rdi, 0
syscall
.data
# place to save temporary values
temp: .quad 0
.intel_syntax noprefix
.text
.global _start
_start:
#initialize rax to zero
xor rax, rax
# initialize sums to zero
mov QWORD PTR[SUM_NEGATIVE], rax
mov QWORD PTR[SUM_POSITIVE], rax
#point to start of commands
mov rbx, OFFSET [CALC_DATA_BEGIN]
loop1:
# load command
mov cl, BYTE PTR [rbx]
# advance to command argument
add rbx, 8
# if the command is zero
cmp cl, 0
# we are done
je done
# if the command is and
cmp cl, '&'
# do call function
je do_and
# if the command is or
cmp cl, '|'
# do call function
je do_or
# if the command is sum
cmp cl, 'S'
# do call function
je do_sum
# if the command is upper
cmp cl, 'U'
# do call function
je do_upper
# otherwise end
jmp done
do_and:
# call function
call AND_FUNCTION
# repeat loop
jmp loop1
do_or:
# call function
call OR_FUNCTION
# repeat loop
jmp loop1
do_sum:
# call function
call SUM_FUNCTION
# repeat loop
jmp loop1
do_upper:
# call function
call UPPER_FUNCTION
# repeat loop
jmp loop1
done:
# print last value of rax, save it first in temp
mov QWORD PTR[temp], rax
# load value of stdout
mov rdi, 1
# load address to be printed
mov rsi, OFFSET [temp]
# print 8 bytes
mov rdx, 8
# load write syscall
mov rax, 1
# write on stdout
syscall
# print last value of SUM_POSITIVE
# load value of stdout
mov rdi, 1
# load address to be printed
mov rsi, OFFSET [SUM_POSITIVE]
# print 8 bytes
mov rdx, 8
# load write syscall
mov rax, 1
# write on stdout
syscall
# print last value of SUM_NEGATIVE
# load value of stdout
mov rdi, 1
# load address to be printed
mov rsi, OFFSET [SUM_NEGATIVE]
# print 8 bytes
mov rdx, 8
# load write syscall
mov rax, 1
# write on stdout
syscall
# print values between CALC_DATA_BEGIN and CALC_DATA_END
# load value of stdout
mov rdi, 1
# load address to be printed
mov rsi, OFFSET [CALC_DATA_BEGIN]
# calculate number of bytes to print
# load end address
mov rdx, OFFSET [CALC_DATA_END]
# subtract start address
sub rdx, rsi
# load write syscall
mov rax, 1
# write on stdout
syscall
# exit
mov rax, 60
mov rdi, 0
syscall
.data
# place to save temporary values
temp: .quad 0