problem with printchar

i have this code
.globl mulai
mulai:
movl $4,%eax
movl $1,%ebx
movl $'a',%ecx
movl $1,%edx

   int   $0x80
   xorl  %eax,%eax
   movl  $1,%eax
   xorl  %ebx,%ebx
   int   $0x80

then i compile with
as program1.s -o program1.o
ld program1.o -o program1

by this code i want print one char but there is no output. can anybody help me why..?

Wow, is that valid?
Anyway, %ecx should not be the value of 'a'
but rather a pointer to a buffer.

ITYM 'incl %eax'.

Yes...
Because in ecx should be address (pointer) to char. Kernel silently ignores bad address so there is no output. You can use strace utility to watch whats going on

$strace ./program1

execve("./program1", ["./program1"], [/* 30 vars */]) = 0 write(1, ptrace: un: Input/output error
0x61, 1) = -1 EFAULT (Bad
addreexit(0) = ?

uh... the solution: you have to declare somewhere in memory a byte where you will store that char.

This is not "as" syntax but hope you will get an idea

mov ecx,my_char
mov [ecx],'a' ;you can cachnge it "on-line"

.....

DATASEG
my_char DB 'b'

Happy assembling,

Regards

Rudolf