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Chapter 23. Intel 80960 Dependent Features

This option does not affect the Compare and Jump instructions; the code emitted for them is

always adjusted when necessary (depending on displacement size), regardless of whether you

use

 no relax

.

23.2. Floating Point

as

generates ieee floating point numbers for the directives

.float

,

.double

,

.extended

, and

.single

.

23.3. i960 Machine Directives

.bss symbol, length, align

Reserve

length

bytes in the bss section for a local

symbol

, aligned to the power of two speci 

fied by

align

.

length

and

align

must be positive absolute expressions. This directive differs

from

.lcomm

only in that it permits you to specify an alignment. Section 8.52

.lcomm symbol,

length

.

.extended flonums

.extended

expects zero or more flonums, separated by commas; for each flonum,

.extended

emits an ieee extended format (80 bit) floating point number.

.leafproc call lab, bal lab

You can use the

.leafproc

directive in conjunction with the optimized

callj

instruction to en 

able faster calls of leaf procedures. If a procedure is known to call no other procedures, you may

define an entry point that skips procedure prolog code (and that does not depend on system 

supplied saved context), and declare it as the

bal lab

using

.leafproc

. If the procedure

also has an entry point that goes through the normal prolog, you can specify that entry point

as

call lab

.

A

.leafproc

declaration is meant for use in conjunction with the optimized call instruction

callj

; the directive records the data needed later to choose between converting the

callj

into

a

bal

or a

call

.

call lab

is optional; if only one argument is present, or if the two arguments are identical, the

single argument is assumed to be the

bal

entry point.

.sysproc name, index

The

.sysproc

directive defines a name for a system procedure. After you define it using

.sysproc

, you can use

name

to refer to the system procedure identified by

index

when calling

procedures with the optimized call instruction

callj

.

Both arguments are required;

index

must be between 0 and 31 (inclusive).

23.4. i960 Opcodes

All Intel 960 machine instructions are supported; Section 23.1 i960 Command line Options for a

discussion of selecting the instruction subset for a particular 960 architecture.