Chapter 11.

Alpha Dependent Features

11.1. Notes

The documentation here is primarily for the ELF object format.

as

also supports the ECOFF and

EVAX formats, but features specific to these formats are not yet documented.

11.2. Options

 mcpu

This option specifies the target processor. If an attempt is made to assemble an instruction which

will not execute on the target processor, the assembler may either expand the instruction as a

macro or issue an error message. This option is equivalent to the

.arch

directive.

The following processor names are recognized:

21064

,

21064a

,

21066

,

21068

,

21164

,

21164a

,

21164pc

,

21264

,

21264a

,

21264b

,

ev4

,

ev5

,

lca45

,

ev5

,

ev56

,

pca56

,

ev6

,

ev67

,

ev68

. The special name

all

may be used to allow the assembler to accept instructions

valid for any Alpha processor.

In order to support existing practice in OSF/1 with respect to

.arch

, and existing practice

within

MILO

(the Linux ARC bootloader), the numbered processor names (e.g. 21064) enable

the processor specific PALcode instructions, while the "electro vlasic" names (e.g.

ev4

) do not.

 mdebug

 no mdebug

Enables or disables the generation of

.mdebug

encapsulation for stabs directives and procedure

descriptors. The default is to automatically enable

.mdebug

when the first stabs directive is seen.

 relax

This option forces all relocations to be put into the object file, instead of saving space and re 

solving some relocations at assembly time. Note that this option does not propagate all symbol

arithmetic into the object file, because not all symbol arithmetic can be represented. However,

the option can still be useful in specific applications.

 g

This option is used when the compiler generates debug information. When

gcc

is using

mips tfile

to generate debug information for ECOFF, local labels must be passed through to

the object file. Otherwise this option has no effect.

 Gsize

A local common symbol larger than

size

is placed in

.bss

, while smaller symbols are placed

in

.sbss

.