| @c Copyright (C) 1991, 92, 93, 94, 95, 96, 1997 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. |
| |
| @cindex @samp{-l} option, M680x0 |
| 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 |
| 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 |
| 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} |
| 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} |
| 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{-m68000} and related options |
| @cindex architecture options, M680x0 |
| @cindex M680x0 architecture options |
| @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 |
| 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 |
| |
| @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. |
| @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 |
| Pseudo-Op |BYTE WORD LONG LONG non-PC relative |
| +------------------------------------------------- |
| jbsr |bsrs bsr bsrl jsr jsr |
| jra |bras bra bral jmp jmp |
| * jXX |bXXs bXX bXXl bNXs;jmpl bNXs;jmp |
| * dbXX |dbXX dbXX dbXX; bra; jmpl |
| * fjXX |fbXXw fbXXw fbXXl fbNXw;jmp |
| |
| XX: condition |
| NX: negative of condition XX |
| |
| @end smallexample |
| @center @code{*}---see full description below |
| |
| @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. |
| |
| @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 |
| |
| For the cases of non-PC relative displacements and long displacements on |
| the 68000 or 68010, @code{@value{AS}} issues a longer code fragment in terms of |
| @var{NX}, the opposite condition to @var{XX}. For example, for the |
| non-PC relative case: |
| @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 |
| |
| Other than for word and byte displacements, when the source reads |
| @samp{db@var{XX} foo}, @code{@value{AS}} emits |
| @smallexample |
| db@var{XX} oo1 |
| bra oo2 |
| oo1:jmpl 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 |
| |
| For branch targets that are not PC relative, @code{@value{AS}} emits |
| @smallexample |
| fb@var{NX} oof |
| jmp foo |
| oof: |
| @end smallexample |
| when it encounters @samp{fj@var{XX} foo}. |
| |
| @end table |
| |
| @node M68K-Chars |
| @subsection Special Characters |
| |
| @cindex special characters, M680x0 |
| @cindex M680x0 immediate character |
| @cindex immediate character, M680x0 |
| @cindex M680x0 line comment character |
| @cindex line comment character, M680x0 |
| @cindex comments, M680x0 |
| The immediate character is @samp{#} for Sun compatibility. The |
| line-comment character is @samp{|} (unless the @samp{--bitwise-or} |
| option is used). If a @samp{#} appears at the beginning of a line, it |
| is treated as a comment unless it looks like @samp{# line file}, in |
| which case it is treated normally. |
| |