@c Copyright (C) 1996, 1998 Free Software Foundation, Inc.
@c This is part of the GAS manual.
@c For copying conditions, see the file as.texinfo.

@ifset GENERIC
@page
@node ARM-Dependent
@chapter ARM Dependent Features
@end ifset

@ifclear GENERIC
@node Machine Dependencies
@chapter ARM Dependent Features
@end ifclear

@cindex ARM support
@cindex Thumb support
@menu
* ARM Options::              Options
* ARM Syntax::               Syntax
* ARM Floating Point::       Floating Point
* ARM Directives::           ARM Machine Directives
* ARM Opcodes::              Opcodes
@end menu

@node ARM Options
@section Options
@cindex ARM options (none)
@cindex options for ARM (none)
@table @code
@cindex @code{-marm} command line option, ARM
@item -marm @var{[2|250|3|6|60|600|610|620|7|7m|7d|7dm|7di|7dmi|70|700|700i|710|710c|7100|7500|7500fe|7tdmi|8|strongarm|strongarm110]}
This option specifies the target processor.  The assembler will issue an
error message if an attempt is made to assemble an instruction which
will not execute on the target processor.
@cindex @code{-marmv} command line option, ARM
@item -marmv @var{[2|2a|3|3m|4|4t]}
This option specifies the target architecture.  The assembler will issue
an error message if an attempt is made to assemble an instruction which
will not execute on the target architecture.
@cindex @code{-mthumb} command line option, ARM
@item -mthumb
This option specifies that only Thumb instructions should be assembled.
@cindex @code{-mall} command line option, ARM
@item -mall
This option specifies that any Arm or Thumb instruction should be assembled.
@cindex @code{-mfpa} command line option, ARM
@item -mfpa @var{[10|11]}
This option specifies the floating point architecture in use on the
target processor. 
@cindex @code{-mfpe-old} command line option, ARM
@item -mfpe-old
Do not allow the assemble of floating point multiple instructions.
@cindex @code{-mno-fpu} command line option, ARM
@item -mno-fpu
Do not allow the assembly of any floating point instructions.
@cindex @code{-mthumb-interwork} command line option, ARM
@item -mthumb-interwork
This option specifies that the output generated by the assembler should
be marked as supporting interworking.
@cindex @code{-mapcs} command line option, ARM
@item -mapcs @var{[26|32]}
This option specifies that the output generated by the assembler should
be marked as supporting the indicated version of the Arm Procedure.
Calling Standard.
@cindex @code{-EB} command line option, ARM
@item -EB
This option specifies that the output generated by the assembler should
be marked as being encoded for a big-endian processor.
@cindex @code{-EL} command line option, ARM
@item -EL
This option specifies that the output generated by the assembler should
be marked as being encoded for a little-endian processor.
@end table


@node ARM Syntax
@section Syntax
@menu
* ARM-Chars::                Special Characters
* ARM-Regs::                 Register Names
@end menu

@node ARM-Chars
@subsection Special Characters

@cindex line comment character, ARM
@cindex ARM line comment character
@samp{;} is the line comment character.

@cindex identifiers, ARM
@cindex ARM identifiers
*TODO* Explain about /data modifier on symbols.

@node ARM-Regs
@subsection Register Names

@cindex ARM register names
@cindex register names, ARM
*TODO* Explain about ARM register naming, and the predefined names.

@node ARM Floating Point
@section Floating Point

@cindex floating point, ARM (@sc{ieee})
@cindex ARM floating point (@sc{ieee})
The ARM family uses @sc{ieee} floating-point numbers.



@node ARM Directives
@section ARM Machine Directives

@cindex machine directives, ARM
@cindex ARM machine directives
@table @code

@cindex @code{req} directive, ARM
@item @var{name} .req @var{register name}
This creates an alias for @var{register name} called @var{name}.  For
example:

@smallexample
        foo .req r0
@end smallexample

@cindex @code{code} directive, ARM
@item .code @var{[16|32]}
This directive selects the instruction set being generated. The value 16
selects Thumb, with the value 32 selecting ARM.

@cindex @code{thumb} directive, ARM
@item .thumb
This performs the same action as @var{.code 16}.

@cindex @code{arm} directive, ARM
@item .arm
This performs the same action as @var{.code 32}.

@cindex @code{force_thumb} directive, ARM
@item .force_thumb
This directive forces the selection of Thumb instructions, even if the
target processor does not support those instructions

@cindex @code{thumb_func} directive, ARM
@item .thumb_func
This directive specifies that the following symbol is the name of a
Thumb encoded function.  This information is necessary in order to allow
the assembler and linker to generate correct code for interworking
between Arm and Thumb instructions and should be used even if
interworking is not going to be performed.

@cindex @code{.ltorg} directive, ARM
@item .ltorg
This directive causes the current contents of the literal pool to be
dumped into the current section (which is assumed to be the .text
section) at the current location (aligned to a word boundary).

@cindex @code{.pool} directive, ARM
@item .pool
This is a synonym for .ltorg.

@end table

@node ARM Opcodes
@section Opcodes

@cindex ARM opcodes
@cindex opcodes for ARM
@code{@value{AS}} implements all the standard ARM opcodes.

*TODO* Document the pseudo-ops (adr, nop)

For information on the ARM or Thumb instruction sets, see @cite{ARM
Software Development Toolkit Reference Manual}, Advanced RISC Machines
Ltd.

