This means that if you want the shortest possible object code,
you have to enable optimization.
-Using the \c{-O} option, you can tell NASM to carry out different levels of optimization.
-The syntax is:
+Using the \c{-O} option, you can tell NASM to carry out different
+levels of optimization. The syntax is:
\b \c{-O0}: No optimization. All operands take their long forms,
- if a short form is not specified.
+ if a short form is not specified, except conditional jumps.
+ This is intended to match NASM 0.98 behavior.
\b \c{-O1}: Minimal optimization. As above, but immediate operands
which will fit in a signed byte are optimized,
- unless the long form is specified.
+ unless the long form is specified. Conditional jumps default
+ to the long form unless otherwise specified.
\b \c{-Ox} (where \c{x} is the actual letter \c{x}): Multipass optimization.
Minimize branch offsets and signed immediate bytes,
- overriding size specification unless the \c{strict} keyword
- has been used (see \k{strict}). For compatability with earlier
- releases, the letter \c{x} may also be any number greater than
- one. This number has no effect on the actual number of passes.
+ overriding size specification unless the \c{strict} keyword
+ has been used (see \k{strict}). For compatability with earlier
+ releases, the letter \c{x} may also be any number greater than
+ one. This number has no effect on the actual number of passes.
+
+The \c{-Ox} mode is recommended for most uses.
Note that this is a capital \c{O}, and is different from a small \c{o}, which
is used to specify the output file name. See \k{opt-o}.