[Pgubook-readers] Why pushling %ebx

[Pupeno]

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Hello,
I'm reading "Programming from the ground up" and I've found something I can't 
understand.
On page 71 of the letter-sized version of the book: Chapter 6: Reading and 
Writting Simple Records, in the reading function (called read_record) it 
pushes %ebx without having put anything on it first, in fact, the only 
operations before that are for initializing the stack frame, and latter, 
before un-initializing the stack frame, it pops %ebx. It seems like %ebx has 
a value that needs saving, but this is a function, whatever value that needed 
saving that was in a register should have been saved before calling the 
function, am I wrong ? Well, then, can anybody explain it ?
Thanks.
- -- 
Pupeno: address@hidden - http://pupeno.com
Reading Science Fiction ? http://sfreaders.com.ar
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