Segmented or Flat model

I need clarification to a particular gnu assembly question. When i write a 
code:

.section .data
output:
   .int 1

.section .text
.globl _start
_start:
   movl $output, %ebx
   ....


here what type of memory model is used for movl statement(flat or 
segmented)?
Also how does movl knows which logical address to use? I mean how do 
variables
get their logical address?

Thanks.

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