linux - Understanding input and output in ASM -
can please me understand happening here? new assembly language , have written simple code follows: (i developing on linux)
what want accept integer user , display user has entered.
.section .data number: .long 0 .section .text .globl _start _start: movl $3, %eax #read system call movl $0, %ebx #file descriptor (stdin) movl $number, %ecx #the address data read into. movl $4, %edx #number of bytes read int $0x80 #the entered number stored in %ebx. can viewed using "echo $? " movl number , %ebx movl $1, %eax int $0x80 but not getting expected result. instead getting ascii codes character inputting.
for ex:
input - 2 output - 50 input - 1 output - 49 input - output - 97 .... , on? what wrong? changes should make have desired result? basic concept missed understanding.
input done in system's native codepage. if want convert numeral's ascii code corresponding number need 2 things first:
bounds check it. value must between '0' , '9' inclusive, otherwise wasn't numeral.
subtract '0'. way '0' becomes 0, '5' becomes 5, etc.
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