mirror of
https://sourceware.org/git/binutils-gdb.git
synced 2024-12-27 04:52:05 +08:00
a2c5833233
The result of running etc/update-copyright.py --this-year, fixing all the files whose mode is changed by the script, plus a build with --enable-maintainer-mode --enable-cgen-maint=yes, then checking out */po/*.pot which we don't update frequently. The copy of cgen was with commit d1dd5fcc38ead reverted as that commit breaks building of bfp opcodes files.
637 lines
22 KiB
Plaintext
637 lines
22 KiB
Plaintext
@c Copyright (C) 1991-2022 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 M68K-Dependent
|
|
@chapter M680x0 Dependent Features
|
|
@end ifset
|
|
@ifclear GENERIC
|
|
@node Machine Dependencies
|
|
@chapter M680x0 Dependent Features
|
|
@end ifclear
|
|
|
|
@cindex M680x0 support
|
|
@menu
|
|
* M68K-Opts:: M680x0 Options
|
|
* M68K-Syntax:: Syntax
|
|
* M68K-Moto-Syntax:: Motorola Syntax
|
|
* M68K-Float:: Floating Point
|
|
* M68K-Directives:: 680x0 Machine Directives
|
|
* M68K-opcodes:: Opcodes
|
|
@end menu
|
|
|
|
@node M68K-Opts
|
|
@section M680x0 Options
|
|
|
|
@cindex options, M680x0
|
|
@cindex M680x0 options
|
|
The Motorola 680x0 version of @code{@value{AS}} has a few machine
|
|
dependent options:
|
|
|
|
@table @samp
|
|
|
|
@cindex @samp{-march=} command-line option, M680x0
|
|
@item -march=@var{architecture}
|
|
This option specifies a target architecture. The following
|
|
architectures are recognized:
|
|
@code{68000},
|
|
@code{68010},
|
|
@code{68020},
|
|
@code{68030},
|
|
@code{68040},
|
|
@code{68060},
|
|
@code{cpu32},
|
|
@code{isaa},
|
|
@code{isaaplus},
|
|
@code{isab},
|
|
@code{isac} and
|
|
@code{cfv4e}.
|
|
|
|
|
|
@cindex @samp{-mcpu=} command-line option, M680x0
|
|
@item -mcpu=@var{cpu}
|
|
This option specifies a target cpu. When used in conjunction with the
|
|
@option{-march} option, the cpu must be within the specified
|
|
architecture. Also, the generic features of the architecture are used
|
|
for instruction generation, rather than those of the specific chip.
|
|
|
|
@cindex @samp{-m[no-]68851} command-line option, M680x0
|
|
@cindex @samp{-m[no-]68881} command-line option, M680x0
|
|
@cindex @samp{-m[no-]div} command-line option, M680x0
|
|
@cindex @samp{-m[no-]usp} command-line option, M680x0
|
|
@cindex @samp{-m[no-]float} command-line option, M680x0
|
|
@cindex @samp{-m[no-]mac} command-line option, M680x0
|
|
@cindex @samp{-m[no-]emac} command-line option, M680x0
|
|
@item -m[no-]68851
|
|
@itemx -m[no-]68881
|
|
@itemx -m[no-]div
|
|
@itemx -m[no-]usp
|
|
@itemx -m[no-]float
|
|
@itemx -m[no-]mac
|
|
@itemx -m[no-]emac
|
|
|
|
Enable or disable various architecture specific features. If a chip
|
|
or architecture by default supports an option (for instance
|
|
@option{-march=isaaplus} includes the @option{-mdiv} option),
|
|
explicitly disabling the option will override the default.
|
|
|
|
@cindex @samp{-l} option, M680x0
|
|
@item -l
|
|
You can use the @samp{-l} option to shorten the size of references to undefined
|
|
symbols. If you do not use the @samp{-l} option, references to undefined
|
|
symbols are wide enough for a full @code{long} (32 bits). (Since
|
|
@code{@value{AS}} cannot know where these symbols end up, @code{@value{AS}} can
|
|
only allocate space for the linker to fill in later. Since @code{@value{AS}}
|
|
does not know how far away these symbols are, it allocates as much space as it
|
|
can.) If you use this option, the references are only one word wide (16 bits).
|
|
This may be useful if you want the object file to be as small as possible, and
|
|
you know that the relevant symbols are always less than 17 bits away.
|
|
|
|
@cindex @samp{--register-prefix-optional} option, M680x0
|
|
@item --register-prefix-optional
|
|
For some configurations, especially those where the compiler normally
|
|
does not prepend an underscore to the names of user variables, the
|
|
assembler requires a @samp{%} before any use of a register name. This
|
|
is intended to let the assembler distinguish between C variables and
|
|
functions named @samp{a0} through @samp{a7}, and so on. The @samp{%} is
|
|
always accepted, but is not required for certain configurations, notably
|
|
@samp{sun3}. The @samp{--register-prefix-optional} option may be used
|
|
to permit omitting the @samp{%} even for configurations for which it is
|
|
normally required. If this is done, it will generally be impossible to
|
|
refer to C variables and functions with the same names as register
|
|
names.
|
|
|
|
@cindex @samp{--bitwise-or} option, M680x0
|
|
@item --bitwise-or
|
|
Normally the character @samp{|} is treated as a comment character, which
|
|
means that it can not be used in expressions. The @samp{--bitwise-or}
|
|
option turns @samp{|} into a normal character. In this mode, you must
|
|
either use C style comments, or start comments with a @samp{#} character
|
|
at the beginning of a line.
|
|
|
|
@cindex @samp{--base-size-default-16}
|
|
@cindex @samp{--base-size-default-32}
|
|
@item --base-size-default-16 --base-size-default-32
|
|
If you use an addressing mode with a base register without specifying
|
|
the size, @code{@value{AS}} will normally use the full 32 bit value.
|
|
For example, the addressing mode @samp{%a0@@(%d0)} is equivalent to
|
|
@samp{%a0@@(%d0:l)}. You may use the @samp{--base-size-default-16}
|
|
option to tell @code{@value{AS}} to default to using the 16 bit value.
|
|
In this case, @samp{%a0@@(%d0)} is equivalent to @samp{%a0@@(%d0:w)}.
|
|
You may use the @samp{--base-size-default-32} option to restore the
|
|
default behaviour.
|
|
|
|
@cindex @samp{--disp-size-default-16}
|
|
@cindex @samp{--disp-size-default-32}
|
|
@item --disp-size-default-16 --disp-size-default-32
|
|
If you use an addressing mode with a displacement, and the value of the
|
|
displacement is not known, @code{@value{AS}} will normally assume that
|
|
the value is 32 bits. For example, if the symbol @samp{disp} has not
|
|
been defined, @code{@value{AS}} will assemble the addressing mode
|
|
@samp{%a0@@(disp,%d0)} as though @samp{disp} is a 32 bit value. You may
|
|
use the @samp{--disp-size-default-16} option to tell @code{@value{AS}}
|
|
to instead assume that the displacement is 16 bits. In this case,
|
|
@code{@value{AS}} will assemble @samp{%a0@@(disp,%d0)} as though
|
|
@samp{disp} is a 16 bit value. You may use the
|
|
@samp{--disp-size-default-32} option to restore the default behaviour.
|
|
|
|
@cindex @samp{--pcrel}
|
|
@item --pcrel
|
|
Always keep branches PC-relative. In the M680x0 architecture all branches
|
|
are defined as PC-relative. However, on some processors they are limited
|
|
to word displacements maximum. When @code{@value{AS}} needs a long branch
|
|
that is not available, it normally emits an absolute jump instead. This
|
|
option disables this substitution. When this option is given and no long
|
|
branches are available, only word branches will be emitted. An error
|
|
message will be generated if a word branch cannot reach its target. This
|
|
option has no effect on 68020 and other processors that have long branches.
|
|
@pxref{M68K-Branch,,Branch Improvement}.
|
|
|
|
@cindex @samp{-m68000} and related options
|
|
@cindex architecture options, M680x0
|
|
@cindex M680x0 architecture options
|
|
@item -m68000
|
|
@code{@value{AS}} can assemble code for several different members of the
|
|
Motorola 680x0 family. The default depends upon how @code{@value{AS}}
|
|
was configured when it was built; normally, the default is to assemble
|
|
code for the 68020 microprocessor. The following options may be used to
|
|
change the default. These options control which instructions and
|
|
addressing modes are permitted. The members of the 680x0 family are
|
|
very similar. For detailed information about the differences, see the
|
|
Motorola manuals.
|
|
|
|
@table @samp
|
|
@item -m68000
|
|
@itemx -m68ec000
|
|
@itemx -m68hc000
|
|
@itemx -m68hc001
|
|
@itemx -m68008
|
|
@itemx -m68302
|
|
@itemx -m68306
|
|
@itemx -m68307
|
|
@itemx -m68322
|
|
@itemx -m68356
|
|
Assemble for the 68000. @samp{-m68008}, @samp{-m68302}, and so on are synonyms
|
|
for @samp{-m68000}, since the chips are the same from the point of view
|
|
of the assembler.
|
|
|
|
@item -m68010
|
|
Assemble for the 68010.
|
|
|
|
@item -m68020
|
|
@itemx -m68ec020
|
|
Assemble for the 68020. This is normally the default.
|
|
|
|
@item -m68030
|
|
@itemx -m68ec030
|
|
Assemble for the 68030.
|
|
|
|
@item -m68040
|
|
@itemx -m68ec040
|
|
Assemble for the 68040.
|
|
|
|
@item -m68060
|
|
@itemx -m68ec060
|
|
Assemble for the 68060.
|
|
|
|
@item -mcpu32
|
|
@itemx -m68330
|
|
@itemx -m68331
|
|
@itemx -m68332
|
|
@itemx -m68333
|
|
@itemx -m68334
|
|
@itemx -m68336
|
|
@itemx -m68340
|
|
@itemx -m68341
|
|
@itemx -m68349
|
|
@itemx -m68360
|
|
Assemble for the CPU32 family of chips.
|
|
|
|
@item -m5200
|
|
@itemx -m5202
|
|
@itemx -m5204
|
|
@itemx -m5206
|
|
@itemx -m5206e
|
|
@itemx -m521x
|
|
@itemx -m5249
|
|
@itemx -m528x
|
|
@itemx -m5307
|
|
@itemx -m5407
|
|
@itemx -m547x
|
|
@itemx -m548x
|
|
@itemx -mcfv4
|
|
@itemx -mcfv4e
|
|
Assemble for the ColdFire family of chips.
|
|
|
|
@item -m68881
|
|
@itemx -m68882
|
|
Assemble 68881 floating point instructions. This is the default for the
|
|
68020, 68030, and the CPU32. The 68040 and 68060 always support
|
|
floating point instructions.
|
|
|
|
@item -mno-68881
|
|
Do not assemble 68881 floating point instructions. This is the default
|
|
for 68000 and the 68010. The 68040 and 68060 always support floating
|
|
point instructions, even if this option is used.
|
|
|
|
@item -m68851
|
|
Assemble 68851 MMU instructions. This is the default for the 68020,
|
|
68030, and 68060. The 68040 accepts a somewhat different set of MMU
|
|
instructions; @samp{-m68851} and @samp{-m68040} should not be used
|
|
together.
|
|
|
|
@item -mno-68851
|
|
Do not assemble 68851 MMU instructions. This is the default for the
|
|
68000, 68010, and the CPU32. The 68040 accepts a somewhat different set
|
|
of MMU instructions.
|
|
@end table
|
|
@end table
|
|
|
|
@node M68K-Syntax
|
|
@section Syntax
|
|
|
|
@cindex @sc{mit}
|
|
This syntax for the Motorola 680x0 was developed at @sc{mit}.
|
|
|
|
@cindex M680x0 syntax
|
|
@cindex syntax, M680x0
|
|
@cindex M680x0 size modifiers
|
|
@cindex size modifiers, M680x0
|
|
The 680x0 version of @code{@value{AS}} uses instructions names and
|
|
syntax compatible with the Sun assembler. Intervening periods are
|
|
ignored; for example, @samp{movl} is equivalent to @samp{mov.l}.
|
|
|
|
In the following table @var{apc} stands for any of the address registers
|
|
(@samp{%a0} through @samp{%a7}), the program counter (@samp{%pc}), the
|
|
zero-address relative to the program counter (@samp{%zpc}), a suppressed
|
|
address register (@samp{%za0} through @samp{%za7}), or it may be omitted
|
|
entirely. The use of @var{size} means one of @samp{w} or @samp{l}, and
|
|
it may be omitted, along with the leading colon, unless a scale is also
|
|
specified. The use of @var{scale} means one of @samp{1}, @samp{2},
|
|
@samp{4}, or @samp{8}, and it may always be omitted along with the
|
|
leading colon.
|
|
|
|
@cindex M680x0 addressing modes
|
|
@cindex addressing modes, M680x0
|
|
The following addressing modes are understood:
|
|
@table @dfn
|
|
@item Immediate
|
|
@samp{#@var{number}}
|
|
|
|
@item Data Register
|
|
@samp{%d0} through @samp{%d7}
|
|
|
|
@item Address Register
|
|
@samp{%a0} through @samp{%a7}@*
|
|
@samp{%a7} is also known as @samp{%sp}, i.e., the Stack Pointer. @code{%a6}
|
|
is also known as @samp{%fp}, the Frame Pointer.
|
|
|
|
@item Address Register Indirect
|
|
@samp{%a0@@} through @samp{%a7@@}
|
|
|
|
@item Address Register Postincrement
|
|
@samp{%a0@@+} through @samp{%a7@@+}
|
|
|
|
@item Address Register Predecrement
|
|
@samp{%a0@@-} through @samp{%a7@@-}
|
|
|
|
@item Indirect Plus Offset
|
|
@samp{@var{apc}@@(@var{number})}
|
|
|
|
@item Index
|
|
@samp{@var{apc}@@(@var{number},@var{register}:@var{size}:@var{scale})}
|
|
|
|
The @var{number} may be omitted.
|
|
|
|
@item Postindex
|
|
@samp{@var{apc}@@(@var{number})@@(@var{onumber},@var{register}:@var{size}:@var{scale})}
|
|
|
|
The @var{onumber} or the @var{register}, but not both, may be omitted.
|
|
|
|
@item Preindex
|
|
@samp{@var{apc}@@(@var{number},@var{register}:@var{size}:@var{scale})@@(@var{onumber})}
|
|
|
|
The @var{number} may be omitted. Omitting the @var{register} produces
|
|
the Postindex addressing mode.
|
|
|
|
@item Absolute
|
|
@samp{@var{symbol}}, or @samp{@var{digits}}, optionally followed by
|
|
@samp{:b}, @samp{:w}, or @samp{:l}.
|
|
@end table
|
|
|
|
@node M68K-Moto-Syntax
|
|
@section Motorola Syntax
|
|
|
|
@cindex Motorola syntax for the 680x0
|
|
@cindex alternate syntax for the 680x0
|
|
|
|
The standard Motorola syntax for this chip differs from the syntax
|
|
already discussed (@pxref{M68K-Syntax,,Syntax}). @code{@value{AS}} can
|
|
accept Motorola syntax for operands, even if @sc{mit} syntax is used for
|
|
other operands in the same instruction. The two kinds of syntax are
|
|
fully compatible.
|
|
|
|
In the following table @var{apc} stands for any of the address registers
|
|
(@samp{%a0} through @samp{%a7}), the program counter (@samp{%pc}), the
|
|
zero-address relative to the program counter (@samp{%zpc}), or a
|
|
suppressed address register (@samp{%za0} through @samp{%za7}). The use
|
|
of @var{size} means one of @samp{w} or @samp{l}, and it may always be
|
|
omitted along with the leading dot. The use of @var{scale} means one of
|
|
@samp{1}, @samp{2}, @samp{4}, or @samp{8}, and it may always be omitted
|
|
along with the leading asterisk.
|
|
|
|
The following additional addressing modes are understood:
|
|
|
|
@table @dfn
|
|
@item Address Register Indirect
|
|
@samp{(%a0)} through @samp{(%a7)}@*
|
|
@samp{%a7} is also known as @samp{%sp}, i.e., the Stack Pointer. @code{%a6}
|
|
is also known as @samp{%fp}, the Frame Pointer.
|
|
|
|
@item Address Register Postincrement
|
|
@samp{(%a0)+} through @samp{(%a7)+}
|
|
|
|
@item Address Register Predecrement
|
|
@samp{-(%a0)} through @samp{-(%a7)}
|
|
|
|
@item Indirect Plus Offset
|
|
@samp{@var{number}(@var{%a0})} through @samp{@var{number}(@var{%a7})},
|
|
or @samp{@var{number}(@var{%pc})}.
|
|
|
|
The @var{number} may also appear within the parentheses, as in
|
|
@samp{(@var{number},@var{%a0})}. When used with the @var{pc}, the
|
|
@var{number} may be omitted (with an address register, omitting the
|
|
@var{number} produces Address Register Indirect mode).
|
|
|
|
@item Index
|
|
@samp{@var{number}(@var{apc},@var{register}.@var{size}*@var{scale})}
|
|
|
|
The @var{number} may be omitted, or it may appear within the
|
|
parentheses. The @var{apc} may be omitted. The @var{register} and the
|
|
@var{apc} may appear in either order. If both @var{apc} and
|
|
@var{register} are address registers, and the @var{size} and @var{scale}
|
|
are omitted, then the first register is taken as the base register, and
|
|
the second as the index register.
|
|
|
|
@item Postindex
|
|
@samp{([@var{number},@var{apc}],@var{register}.@var{size}*@var{scale},@var{onumber})}
|
|
|
|
The @var{onumber}, or the @var{register}, or both, may be omitted.
|
|
Either the @var{number} or the @var{apc} may be omitted, but not both.
|
|
|
|
@item Preindex
|
|
@samp{([@var{number},@var{apc},@var{register}.@var{size}*@var{scale}],@var{onumber})}
|
|
|
|
The @var{number}, or the @var{apc}, or the @var{register}, or any two of
|
|
them, may be omitted. The @var{onumber} may be omitted. The
|
|
@var{register} and the @var{apc} may appear in either order. If both
|
|
@var{apc} and @var{register} are address registers, and the @var{size}
|
|
and @var{scale} are omitted, then the first register is taken as the
|
|
base register, and the second as the index register.
|
|
@end table
|
|
|
|
@node M68K-Float
|
|
@section Floating Point
|
|
|
|
@cindex floating point, M680x0
|
|
@cindex M680x0 floating point
|
|
Packed decimal (P) format floating literals are not supported.
|
|
Feel free to add the code!
|
|
|
|
The floating point formats generated by directives are these.
|
|
|
|
@table @code
|
|
@cindex @code{float} directive, M680x0
|
|
@item .float
|
|
@code{Single} precision floating point constants.
|
|
|
|
@cindex @code{double} directive, M680x0
|
|
@item .double
|
|
@code{Double} precision floating point constants.
|
|
|
|
@cindex @code{extend} directive M680x0
|
|
@cindex @code{ldouble} directive M680x0
|
|
@item .extend
|
|
@itemx .ldouble
|
|
@code{Extended} precision (@code{long double}) floating point constants.
|
|
@end table
|
|
|
|
@node M68K-Directives
|
|
@section 680x0 Machine Directives
|
|
|
|
@cindex M680x0 directives
|
|
@cindex directives, M680x0
|
|
In order to be compatible with the Sun assembler the 680x0 assembler
|
|
understands the following directives.
|
|
|
|
@table @code
|
|
@cindex @code{data1} directive, M680x0
|
|
@item .data1
|
|
This directive is identical to a @code{.data 1} directive.
|
|
|
|
@cindex @code{data2} directive, M680x0
|
|
@item .data2
|
|
This directive is identical to a @code{.data 2} directive.
|
|
|
|
@cindex @code{even} directive, M680x0
|
|
@item .even
|
|
This directive is a special case of the @code{.align} directive; it
|
|
aligns the output to an even byte boundary.
|
|
|
|
@cindex @code{skip} directive, M680x0
|
|
@item .skip
|
|
This directive is identical to a @code{.space} directive.
|
|
|
|
@cindex @code{arch} directive, M680x0
|
|
@item .arch @var{name}
|
|
Select the target architecture and extension features. Valid values
|
|
for @var{name} are the same as for the @option{-march} command-line
|
|
option. This directive cannot be specified after
|
|
any instructions have been assembled. If it is given multiple times,
|
|
or in conjunction with the @option{-march} option, all uses must be for
|
|
the same architecture and extension set.
|
|
|
|
@cindex @code{cpu} directive, M680x0
|
|
@item .cpu @var{name}
|
|
Select the target cpu. Valid values
|
|
for @var{name} are the same as for the @option{-mcpu} command-line
|
|
option. This directive cannot be specified after
|
|
any instructions have been assembled. If it is given multiple times,
|
|
or in conjunction with the @option{-mopt} option, all uses must be for
|
|
the same cpu.
|
|
|
|
@end table
|
|
|
|
@need 2000
|
|
@node M68K-opcodes
|
|
@section Opcodes
|
|
|
|
@cindex M680x0 opcodes
|
|
@cindex opcodes, M680x0
|
|
@cindex instruction set, M680x0
|
|
@c doc@cygnus.com: I don't see any point in the following
|
|
@c paragraph. Bugs are bugs; how does saying this
|
|
@c help anyone?
|
|
@ignore
|
|
Danger: Several bugs have been found in the opcode table (and
|
|
fixed). More bugs may exist. Be careful when using obscure
|
|
instructions.
|
|
@end ignore
|
|
|
|
@menu
|
|
* M68K-Branch:: Branch Improvement
|
|
* M68K-Chars:: Special Characters
|
|
@end menu
|
|
|
|
@node M68K-Branch
|
|
@subsection Branch Improvement
|
|
|
|
@cindex pseudo-opcodes, M680x0
|
|
@cindex M680x0 pseudo-opcodes
|
|
@cindex branch improvement, M680x0
|
|
@cindex M680x0 branch improvement
|
|
Certain pseudo opcodes are permitted for branch instructions.
|
|
They expand to the shortest branch instruction that reach the
|
|
target. Generally these mnemonics are made by substituting @samp{j} for
|
|
@samp{b} at the start of a Motorola mnemonic.
|
|
|
|
The following table summarizes the pseudo-operations. A @code{*} flags
|
|
cases that are more fully described after the table:
|
|
|
|
@smallexample
|
|
Displacement
|
|
+------------------------------------------------------------
|
|
| 68020 68000/10, not PC-relative OK
|
|
Pseudo-Op |BYTE WORD LONG ABSOLUTE LONG JUMP **
|
|
+------------------------------------------------------------
|
|
jbsr |bsrs bsrw bsrl jsr
|
|
jra |bras braw bral jmp
|
|
* jXX |bXXs bXXw bXXl bNXs;jmp
|
|
* dbXX | N/A dbXXw dbXX;bras;bral dbXX;bras;jmp
|
|
fjXX | N/A fbXXw fbXXl N/A
|
|
|
|
XX: condition
|
|
NX: negative of condition XX
|
|
|
|
@end smallexample
|
|
@center @code{*}---see full description below
|
|
@center @code{**}---this expansion mode is disallowed by @samp{--pcrel}
|
|
|
|
@table @code
|
|
@item jbsr
|
|
@itemx jra
|
|
These are the simplest jump pseudo-operations; they always map to one
|
|
particular machine instruction, depending on the displacement to the
|
|
branch target. This instruction will be a byte or word branch is that
|
|
is sufficient. Otherwise, a long branch will be emitted if available.
|
|
If no long branches are available and the @samp{--pcrel} option is not
|
|
given, an absolute long jump will be emitted instead. If no long
|
|
branches are available, the @samp{--pcrel} option is given, and a word
|
|
branch cannot reach the target, an error message is generated.
|
|
|
|
In addition to standard branch operands, @code{@value{AS}} allows these
|
|
pseudo-operations to have all operands that are allowed for jsr and jmp,
|
|
substituting these instructions if the operand given is not valid for a
|
|
branch instruction.
|
|
|
|
@item j@var{XX}
|
|
Here, @samp{j@var{XX}} stands for an entire family of pseudo-operations,
|
|
where @var{XX} is a conditional branch or condition-code test. The full
|
|
list of pseudo-ops in this family is:
|
|
@smallexample
|
|
jhi jls jcc jcs jne jeq jvc
|
|
jvs jpl jmi jge jlt jgt jle
|
|
@end smallexample
|
|
|
|
Usually, each of these pseudo-operations expands to a single branch
|
|
instruction. However, if a word branch is not sufficient, no long branches
|
|
are available, and the @samp{--pcrel} option is not given, @code{@value{AS}}
|
|
issues a longer code fragment in terms of @var{NX}, the opposite condition
|
|
to @var{XX}. For example, under these conditions:
|
|
@smallexample
|
|
j@var{XX} foo
|
|
@end smallexample
|
|
gives
|
|
@smallexample
|
|
b@var{NX}s oof
|
|
jmp foo
|
|
oof:
|
|
@end smallexample
|
|
|
|
@item db@var{XX}
|
|
The full family of pseudo-operations covered here is
|
|
@smallexample
|
|
dbhi dbls dbcc dbcs dbne dbeq dbvc
|
|
dbvs dbpl dbmi dbge dblt dbgt dble
|
|
dbf dbra dbt
|
|
@end smallexample
|
|
|
|
Motorola @samp{db@var{XX}} instructions allow word displacements only. When
|
|
a word displacement is sufficient, each of these pseudo-operations expands
|
|
to the corresponding Motorola instruction. When a word displacement is not
|
|
sufficient and long branches are available, when the source reads
|
|
@samp{db@var{XX} foo}, @code{@value{AS}} emits
|
|
@smallexample
|
|
db@var{XX} oo1
|
|
bras oo2
|
|
oo1:bral foo
|
|
oo2:
|
|
@end smallexample
|
|
|
|
If, however, long branches are not available and the @samp{--pcrel} option is
|
|
not given, @code{@value{AS}} emits
|
|
@smallexample
|
|
db@var{XX} oo1
|
|
bras oo2
|
|
oo1:jmp foo
|
|
oo2:
|
|
@end smallexample
|
|
|
|
@item fj@var{XX}
|
|
This family includes
|
|
@smallexample
|
|
fjne fjeq fjge fjlt fjgt fjle fjf
|
|
fjt fjgl fjgle fjnge fjngl fjngle fjngt
|
|
fjnle fjnlt fjoge fjogl fjogt fjole fjolt
|
|
fjor fjseq fjsf fjsne fjst fjueq fjuge
|
|
fjugt fjule fjult fjun
|
|
@end smallexample
|
|
|
|
Each of these pseudo-operations always expands to a single Motorola
|
|
coprocessor branch instruction, word or long. All Motorola coprocessor
|
|
branch instructions allow both word and long displacements.
|
|
|
|
@end table
|
|
|
|
@node M68K-Chars
|
|
@subsection Special Characters
|
|
|
|
@cindex special characters, M680x0
|
|
|
|
@cindex M680x0 line comment character
|
|
@cindex line comment character, M680x0
|
|
@cindex comments, M680x0
|
|
Line comments are introduced by the @samp{|} character appearing
|
|
anywhere on a line, unless the @option{--bitwise-or} command-line option
|
|
has been specified.
|
|
|
|
An asterisk (@samp{*}) as the first character on a line marks the
|
|
start of a line comment as well.
|
|
|
|
@cindex M680x0 immediate character
|
|
@cindex immediate character, M680x0
|
|
|
|
A hash character (@samp{#}) as the first character on a line also
|
|
marks the start of a line comment, but in this case it could also be a
|
|
logical line number directive (@pxref{Comments}) or a preprocessor
|
|
control command (@pxref{Preprocessing}). If the hash character
|
|
appears elsewhere on a line it is used to introduce an immediate
|
|
value. (This is for compatibility with Sun's assembler).
|
|
|
|
@cindex M680x0 line separator
|
|
@cindex line separator, M680x0
|
|
|
|
Multiple statements on the same line can appear if they are separated
|
|
by the @samp{;} character.
|