I'm trying to learn NASM assembly (Linux, AT & T syntax), but I get the code given below through the "Hello world" syscall and walk well, but it does not print anything . Any clue why?
.text .globl main main: movl $ 4,% ex movl $ 1,% ebx movl string1,% ecx movl $ 20,% edx int $ 0x80 .data string 1: string "Hello World" UPDATE : I found this. I need to include a $ symbol in front of "string 1", so any clarification of what happens when the line becomes "movl $ string1,% ecx" whenever it is not included?
The syscall you are using is expected in ecx An indicator for This adds the $ - the value of string to value in ecx . If you leave $ , then you are entering the first word in string1 on ecx - numeric value equivalent to hell is the ASCII string (which should be your case) on a small-endian machine, this means that you are entering 0x6c6c6568 in ecx . It is not that this value is a valid indicator for any type of string, so syscall does not print anything. It can be easily crashed or may be due to some other kind of crazy behavior.
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