Chapter 42.
Xtensa Dependent Features
This chapter covers features of the gnu assembler that are specific to the Xtensa architecture. For
details about the Xtensa instruction set, please consult the [Xtensa Instruction Set Architecture (ISA)
Reference Manual].
42.1. Command Line Options
The Xtensa version of the gnu assembler supports these special options:
 density |  no density
Enable or disable use of the Xtensa code density option (16 bit instructions). Section 42.3.1
Using Density Instructions. If the processor is configured with the density option, this is enabled
by default; otherwise, it is always disabled.
 relax |  no relax
Enable or disable relaxation of instructions with immediate operands that are outside the le 
gal range for the instructions. Section 42.4 Xtensa Relaxation. The default is
 relax
and this
default should almost always be used. If relaxation is disabled with
 no relax
, instruction
operands that are out of range will cause errors. Note: In the current implementation, these op 
tions also control whether assembler optimizations are performed, making these options equiva 
lent to
 generics
and
 no generics
.
 generics |  no generics
Enable or disable all assembler transformations of Xtensa instructions, including both relax 
ation and optimization. The default is
 generics
;
 no generics
should only be used in the
rare cases when the instructions must be exactly as specified in the assembly source. As with
 no relax
, using
 no generics
causes out of range instruction operands to be errors.
 text section literals |  no text section literals
Control the treatment of literal pools. The default is
 no text section literals
, which
places literals in a separate section in the output file. This allows the literal pool to be placed
in a data RAM/ROM, and it also allows the linker to combine literal pools from separate object
files to remove redundant literals and improve code size. With
 text section literals
, the
literals are interspersed in the text section in order to keep them as close as possible to their
references. This may be necessary for large assembly files.
 target align |  no target align
Enable or disable automatic alignment to reduce branch penalties at some expense in code size.
Section 42.3.2 Automatic Instruction Alignment. This optimization is enabled by default. Note
that the assembler will always align instructions like
LOOP
that have fixed alignment require 
ments.
 longcalls |  no longcalls
Enable or disable transformation of call instructions to allow calls across a greater range of
addresses. Section 42.4.2 Function Call Relaxation. This option should be used when call targets
can potentially be out of range, but it degrades both code size and performance. The default is
 no longcalls
.






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