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This chapter describes the Motorola syntax module, mostly used for the
M68k and ColdFire families of CPUs, which is available with the extension
mot.
This module is written in 2002-2024 by Frank Wille and is covered by the vasm copyright without modifications.
This syntax module provides the following additional options:
Enables natural alignment for data (e.g. dc, ds) and
offset directives (rs, so, fo).
Makes all 35 macro arguments available. Default are 9 arguments (\1
to \9). More arguments can be accessed through \a to
\z, which may conflict with escape characters or named arguments,
therefore they are not enabled by default.
Sets the two-byte code used for alignment padding with cnop in
code sections. Defaults to 0x4e71 on M68k.
Devpac-compatibility mode. Only directives known to Devpac are recognized.
__RS, __SO and __FO as
0, which otherwise are undefined until first referenced.
NOP instructions when aligning code
(see ‘-cnop=’).
Allow dots (.) within all identifiers.
Local symbols are prefixed by '_' instead of '.'. For
Devpac compatibility, which offers a similar option.
Disables local symbols to be recognized by their prefix (usually
'.'). This allows global symbols to be defined with it.
The '$' suffix for local symbols still works.
PhxAss-compatibility mode. Only directives known to PhxAss are recognized.
_PHXASS_ with value 2 (to differentiate
from the real PhxAss with value 1).
Allow whitespace characters in the operand field. Otherwise a whitespace would start the comment field there.
Warn about all lines, which have comments in the operand field, introduced
by a whitespace character. For example in: dc.w 1 + 2.
Labels must either start at the first column of a line or have to be
terminated by a colon (:). In the first case the mnemonic
has to be separated from the label by whitespace (not required in any case,
e.g. with the = directive). A double colon (::)
automatically makes the label externally visible (refer to directive
xdef).
Local labels are either prefixed by ’.’ or suffixed by ’$’.
For the rest, any alphanumeric character including ’_’ is allowed.
Local labels are valid between two global label definitions.
Otherwise dots (.) are not allowed within a label by default, unless
the option ‘-ldots’ or ‘-devpac’ was specified. Even then,
labels ending on .b, .w or .l can’t be defined.
It is possible to refer to any local symbol in the source by preceding its
name with the name of the last previously defined global symbol:
global_name\local_name. This is for PhxAss compatibility only,
and is no recommended style. Does not work in a macro, as it conflicts
with macro arguments.
Make sure that you don’t define a label on the same line as a directive for conditional assembly (if, else, endif)! This is not supported and leads to undefined behaviour.
Qualifiers are appended to the mnemonic,
separated by a dot (if the CPU-module supports qualifiers). The
operands are separated from the mnemonic by whitespace. Multiple
operands are separated by comma (,).
In this syntax module, the operand field must not contain any whitespace characters, as long as the option ‘-spaces’ was not specified.
Comments can be introduced everywhere by the characters ; or *.
The rest of the line will be ignored. Also everything following the operand
field, separated by a whitespace, will be regarded as comment (unless
‘-spaces’ was given). Be careful with *, which is either
recognized as the "current pc symbol" or as a multiplication operation
in any operand expression
Example:
mylabel inst.q op1,op2,op3 ;comment
In expressions, numbers starting with $ are hexadecimal (e.g.
$fb2c). % introduces binary numbers (e.g. %1100101).
Numbers starting with @ are assumed to be octal numbers, e.g.
@237. All numbers starting with a digit are decimal, e.g.
1239.
The following directives are supported by this syntax module (provided the CPU- and output-module support them):
<symbol> = <expression> Equivalent to <symbol> equ <expression>.
<symbol> =.s <expression> Equivalent to <symbol> fequ.s <expression>. PhxAss compatibility.
<symbol> =.d <expression> Equivalent to <symbol> fequ.d <expression>. PhxAss compatibility.
<symbol> =.x <expression> Equivalent to <symbol> fequ.x <expression>. PhxAss compatibility.
<symbol> =.p <expression> Equivalent to <symbol> fequ.p <expression>. PhxAss compatibility.
align <bitcount> Insert as many zero bytes as required to reach an address where
<bitcount> low order bits are zero. For example align 2 would
make an alignment to the next 32-bit boundary.
assert <expression>[,<message>]Display an error with the optional <message> when the expression is false.
blk.b <exp>[,<fill>] Equivalent to dcb.b <exp>,<fill>.
blk.d <exp>[,<fill>] Equivalent to dcb.d <exp>,<fill>.
blk.l <exp>[,<fill>] Equivalent to dcb.l <exp>,<fill>.
blk.q <exp>[,<fill>] Equivalent to dcb.q <exp>,<fill>.
blk.s <exp>[,<fill>] Equivalent to dcb.s <exp>,<fill>.
blk.w <exp>[,<fill>] Equivalent to dcb.w <exp>,<fill>.
blk.x <exp>[,<fill>] Equivalent to dcb.x <exp>,<fill>.
bss Equivalent to section bss,bss.
bss_c Equivalent to section bss_c,bss,chip.
bss_f Equivalent to section bss_f,bss,fast.
cargs [#<offset>,]<symbol1>[.<size1>][,<symbol2>[.<size2>]]... Defines <symbol1> with the value of <offset>. Further symbols
on the line, separated by comma, will be assigned the <offset> plus
the size of the previous symbol. The size defaults to 2. Valid
optional size extensions are: .b, .w, .l,
where .l results in a size of 4, the others 2.
The <offset> argument defaults to the target’s address size
(4 for M68k) when omitted.
clrfo Reset stack-frame offset counter to zero. See fo directive.
clrso Reset structure offset counter to zero. See so directive.
cnop <offset>,<alignment>Insert as many padding bytes as required to reach an address which can be divided by <alignment>. Then add <offset> padding bytes. May fill the alignment- and padding-bytes with no-operation instructions for certain cpus. See option ‘-cnop’.
code Equivalent to section code,code.
code_c Equivalent to section code_c,code,chip.
code_f Equivalent to section code_f,code,fast.
comm <symbol>,<size>Create a common symbol with the given size. The alignment is always 32 bits.
comment Starting with the operand field everything is ignored and
seen as a comment.
There is only one exception, when the operand contains HEAD=.
Then the following expression is passed to the TOS output module
via the symbol ’ TOSFLAGS’, to define the Atari specific TOS
flags.
cseg Equivalent to section code,code.
data Equivalent to section data,data.
data_c Equivalent to section data_c,data,chip.
data_f Equivalent to section data_f,data,fast.
db <exp1>[,<exp2>,"<string1>",'<string2>'...] Equivalent to dc.b for ArgAsm, BAsm, HX68, Macro68, ProAsm, etc.
compatibility. Does not exist in PhxAss- or Devpac-compatiblity mode.
dc.b <exp1>[,<exp2>,"<string1>",'<string2>'...]Assign the integer or string constant operands into successive bytes of memory in the current section. Any combination of integer and character string constant operands is permitted.
dc.d <exp1>[,<exp2>...]Assign the values of the operands into successive 64-bit words of memory in the current section, using the IEEE double precision format when specifying them as floating point constants.
dc.l <exp1>[,<exp2>...]Assign the values of the operands into successive 32-bit words of memory in the current section.
dc.p <exp1>[,<exp2>...]Assign the values of the operands into successive 96-bit words of memory in the current section, using the Packed Decimal format when specifying them as floating point constants.
dc.q <exp1>[,<exp2>...]Assign the values of the operands into successive 64-bit words of memory in the current section.
dc.s <exp1>[,<exp2>...]Assign the values of the operands into successive 32-bit words of memory in the current section, using the IEEE single precision format when specifying them as floating point constants.
dc.w <exp1>[,<exp2>...]Assign the values of the operands into successive 16-bit words of memory in the current section.
dc.x <exp1>[,<exp2>...]Assign the values of the operands into successive 96-bit words of memory in the current section, using the IEEE extended precision format when specifying them as floating point constants.
dcb.b <exp>[,<fill>]Insert <exp> zero or <fill> bytes into the current section.
dcb.d <exp>[,<fill>]Insert <exp> zero or <fill> 64-bit words into the current section. <fill> may also be a floating point constant which is then written in IEEE double precision format.
dcb.l <exp>[,<fill>]Insert <exp> zero or <fill> 32-bit words into the current section.
dcb.q <exp>[,<fill>]Insert <exp> zero or <fill> 64-bit words into the current section.
dcb.s <exp>[,<fill>]Insert <exp> zero or <fill> 32-bit words into the current section. <fill> may also be a floating point constant which is then written in IEEE single precision format.
dcb.w <exp>[,<fill>]Insert <exp> zero or <fill> 16-bit words into the current section.
dcb.x <exp>[,<fill>]Insert <exp> zero or <fill> 96-bit words into the current section. <fill> may also be a floating point constant which is then written in IEEE extended precision format.
dl <exp1>[,<exp2>...] Equivalent to dc.l for ArgAsm, BAsm, HX68, Macro68, ProAsm, etc.
compatibility. Does not exist in PhxAss- or Devpac-compatiblity mode.
dr.b <exp1>[,<exp2>...]Calculates <expN> - <current pc value> and stores it into successive bytes of memory in the current section.
dr.w <exp1>[,<exp2>...]Calculates <expN> - <current pc value> and stores it into successive 16-bit words of memory in the current section.
dr.l <exp1>[,<exp2>...]Calculates <expN> - <current pc value> and stores it into successive 32-bit words of memory in the current section.
ds.b <exp> Equivalent to dcb.b <exp>,0.
ds.d <exp> Equivalent to dcb.d <exp>,0.
ds.l <exp> Equivalent to dcb.l <exp>,0.
ds.q <exp> Equivalent to dcb.q <exp>,0.
ds.s <exp> Equivalent to dcb.s <exp>,0.
ds.w <exp> Equivalent to dcb.w <exp>,0.
ds.x <exp> Equivalent to dcb.x <exp>,0.
dseg Equivalent to section data,data.
dw <exp1>[,<exp2>...] Equivalent to dc.w for ArgAsm, BAsm, HX68, Macro68, ProAsm, etc.
compatibility. Does not exist in PhxAss- or Devpac-compatiblity mode.
dx.b <exp> Tries to allocate space in the DataBss portion of a code or
data section. Otherwise equivalent to dcb.b <exp>,0.
dx.d <exp> Tries to allocate space in the DataBss portion of a code or
data section. Otherwise equivalent to dcb.d <exp>,0.
dx.l <exp> Tries to allocate space in the DataBss portion of a code or
data section. Otherwise equivalent to dcb.l <exp>,0.
dx.q <exp> Tries to allocate space in the DataBss portion of a code or
data section. Otherwise equivalent to dcb.q <exp>,0.
dx.s <exp> Tries to allocate space in the DataBss portion of a code or
data section. Otherwise equivalent to dcb.s <exp>,0.
dx.w <exp> Tries to allocate space in the DataBss portion of a code or
data section. Otherwise equivalent to dcb.w <exp>,0.
dx.x <exp> Tries to allocate space in the DataBss portion of a code or
data section. Otherwise equivalent to dcb.x <exp>,0.
echo <"string"|exp>[,<"string"|exp>]...Prints one or more strings or expressions to stdout, terminated by a newline. Strings are identified by single- or double-quotes. In PhxAss-comapatibility mode only a single string can be printed.
einline End a block of isolated local labels, started by inline.
else Assemble the following lines if the previous if condition
was false.
elseif Same as else, for compatibility!
elif <exp> This is a real else-if directive! Not supported by Devpac.
It’s the same as else followed by if, but without the
need for a matching endif directive. Avoids nesting.
endAssembly will terminate with this line. The subsequent source text is ignored.
endifEnds a section of conditional assembly.
endmEnds a macro definition.
endrEnds a repetition block.
<symbol> equ <expression>Define a new program symbol with the name <symbol> and assign to it the value of <expression>. Defining <symbol> twice will cause an error.
<symbol> equ.s <expression> Equivalent to <symbol> fequ.s <expression>. PhxAss compatibility.
<symbol> equ.d <expression> Equivalent to <symbol> fequ.d <expression>. PhxAss compatibility.
<symbol> equ.x <expression> Equivalent to <symbol> fequ.x <expression>. PhxAss compatibility.
<symbol> equ.p <expression> Equivalent to <symbol> fequ.p <expression>. PhxAss compatibility.
eremEnds an outcommented block. Assembly will continue.
even Aligns to an even address. Equivalent to cnop 0,2.
fail <message>Show an error message including the <message> string. Do not generate an output file.
<symbol> fequ.s <expression>Define a new program symbol with the name <symbol> and assign to it the floating point value of <expression>. Defining <symbol> twice will cause an error. The extension is for Devpac-compatibility, but will be ignored.
<symbol> fequ.d <expression> Equivalent to <symbol> fequ.s <expression>.
<symbol> fequ.x <expression> Equivalent to <symbol> fequ.s <expression>.
<symbol> fequ.p <expression> Equivalent to <symbol> fequ.s <expression>.
<label> fo.<size> <expression> Assigns the current value of the stack-frame offset counter to <label>.
Afterwards the counter is decremented by the instruction’s <size>
multiplied by <expression>. Any valid M68k size extension is allowed
for <size>: b, w, l, q, s, d, x, p.
The offset counter can also be referenced directly under the name
__FO.
idnt <name>Sets the file or module name in the generated object file to <name>, when the selected output module supports it. By default, the input filename passed on the command line is used.
if <expression>Conditionally assemble the following lines if <expression> is non-zero.
if1Just for compatibility. Not really supported, as vasm parses a source text only once. Always true.
if2Just for compatibility. Not really supported, as vasm parses a source text only once. Always false.
ifeq <expression>Conditionally assemble the following lines if <expression> is zero.
ifne <expression>Conditionally assemble the following lines if <expression> is non-zero.
ifgt <expression>Conditionally assemble the following lines if <expression> is greater than zero.
ifge <expression>Conditionally assemble the following lines if <expression> is greater than zero or equal.
iflt <expression>Conditionally assemble the following lines if <expression> is less than zero.
ifle <expression>Conditionally assemble the following lines if <expression> is less than zero or equal.
ifb <operand>Conditionally assemble the following lines when <operand> is completely blank, except for an optional comment.
ifnb <operand>Conditionally assemble the following lines when <operand> is non-blank.
ifc <string1>,<string2>Conditionally assemble the following lines if <string1> matches <string2>.
ifnc <string1>,<string2>Conditionally assemble the following lines if <string1> does not match <string2>.
ifd <symbol>Conditionally assemble the following lines if <symbol> is defined.
ifnd <symbol>Conditionally assemble the following lines if <symbol> is undefined.
ifmacrod <macro>Conditionally assemble the following line if <macro> is defined.
ifmacrond <macro>Conditionally assemble the following line if <macro> is undefined.
ifp1 Just for compatibility. Equivalent to if1.
iif <expression> <statement> Conditionally assemble the <statement> following <expression>.
IIF stands for Immediate IF.
If the value of <expression> is non-zero then <statement> is assembled.
No ENDC must be used in conjunction with this directive.
The <statement> cannot include a label, but a label may precede the
IIF directive. For example:
foo IIF bar equ 42
The foo label will be assigned with 42 if bar
evaluates to true, otherwise foo will be assigned with the
current program counter.
Assigning a value in the IIF <statement> using
the equal (=) operator, while the option ‘-spaces’
was given, cannot work, because the equal operator will be
evaluated as part of the expression.
I.e. foo IIF 1+1 = 42 works, but foo IIF 1 + 1 = 42,
when the option ‘-spaces’ was specified, won’t, as
= 42 is evaluated as part of the expression.
incbin <filename>[,<offset>[,<length>]]Inserts the binary contents of <filename> into the object code at this position. When <offset> is specified, then the given number of bytes will be skipped at the beginning of the file. The optional <length> argument specifies the maximum number of bytes to be read from that file.
incdir <path>Add another path to search for include files to the list of known paths. Paths defined with ‘-I’ on the command line are searched first.
include <filename>Include source text of <filename> at this position. When the file name specified has no absolute path, then search it in all defined paths in the order of occurrence, starting with the current work directory.
inline Local labels in the following block are isolated from previous
local labels and those after einline.
listThe following lines will appear in the listing file, if it was requested.
llen <len>Set the line length in a listing file to a maximum of <len> characters. Currently without any effect.
localSeparates two blocks of local labels. Which means, local labels from above this directive may be reused.
macro <name> Defines a macro which can be referenced by <name>. For compatibility,
the <name> may alternatively appear on the left side of
the macro directive, starting on the first column.
Then the operand field is ignored. The macro definition is terminated
by an endm directive. When calling a macro you may pass
up to 9 arguments, separated by comma. These arguments are
referenced within the macro context as \1 to \9.
Parameter \0 is set to the macro’s first qualifier
(mnemonic extension), when given.
In Devpac- and PhxAss-compatibility mode, or with option
‘-allmp’, up to 35 arguments are accepted,
where argument 10-35 can be referenced by \a to \z.
In case you have a macro argument which contains commas or spaces you
may enclose it between < and > characters. A >
character may still be included by writing >>, or when
embedded within a string. (Note that strings are ignored in Devpac
compatibility mode.)
Special macro parameters:
\@Insert a unique id, useful for defining labels. Every macro call gets its own unique id.
\@!Push the current unique id onto a global id stack, then insert it.
\@?Push the current unique id below the top element of the global id stack, then insert it.
\@@Pull the top element from the global id stack and insert it. The macro’s current unique id is not affected by this operation.
\# Insert the number of arguments that have been passed to this macro.
Equivalent to the contents of the symbol NARG.
\?n Insert the length of the n’th macro argument.
\. Insert the argument which is selected by the current value of the
CARG symbol (first argument, when CARG is 1).
\+ Works like \., but increments the value of CARG after
that.
\- Works like \., but decrements the value of CARG after
that.
\<symbolname> Inserts the current decimal value of the absolute
symbol symbolname.
\<$symbolname> Inserts the current hexadecimal value of the absolute
symbol symbolname, without leading $.
mexit Leave the current macro and continue with assembling the parent
context. Note that this directive also resets the level of conditional
assembly to a state before the macro was invoked; which means that
it also works as a ’break’ command on all new if directives.
msource on/off Enable or disable source level debugging within a macro context.
It can be used before one or more macro definitions.
When off, the debugger will show the invoking source text line
instead. Defaults to on. Also numeric expressions like
0 or 1 are allowed.
Note, that this directive currently only has a meaning when using
the ‘-linedebug’ option with the hunk-format output module
(‘-Fhunk’).
nolistThis line and the following lines will not be visible in a listing file.
nopageNever start a new page in the listing file. This implementation will only prevent emitting the formfeed code.
nref <symbol>[,<symbol>...] Flag <symbol> as externally defined, similar to xref,
but also indicate that references can be optimized to base-relative
addressing modes, when possible. This directive is only present
in PhxAss-compatibility mode.
odd Aligns to an odd address. Equivalent to cnop 1,2.
Bugs: Note that this is not a real odd directive, as it
wastes two bytes when the address is already odd.
offset [<expression>] Switches to a special offset-section, similar to a section
directive, although its contents is not included in the output.
Its labels may be referenced as absolute offset symbols.
Can be used to define structure offsets.
The optional <expression> gives the start offset for this section.
When missing, the last offset of the previous offset-section is used,
or 0.
<expression> must evaluate as a constant!
org <expression> Sets the base address for the subsequent code. Note that it is allowed
to embed such an absolute ORG block into a section. Return to
relocatable mode with any new section directive.
Although, in Devpac compatibility mode the previous section will
stay absolute.
output <name> Sets the output file name to <name> when no output name was
given on the command line. A special case for Devpac-compatibility
is when <name> starts with a '.' and an output name was
already given. Then the current output name gets <name>
appended as an extension. When an extension already exists,
then it is replaced.
pageStart a new page in the listing file (not implemented). Make sure to start a new page when the maximum page length is reached.
plen <len> Set the page length for a listing file to <len> lines.
Currently ignored.
printt <string>[,<string>...] Prints <string> to stdout. Every additional string into a new line.
Quotes are optional.
printv <expression>[,<expression>...] Evaluate <expression> and print it to stdout out in hexadecimal,
decimal, ASCII and binary format.
public <symbol>[,<symbol>...] Flag <symbol> as an external symbol, which means that
<symbol> is visible to all modules in the linking process.
It may be either defined or undefined.
popsection Restore the top section from the internal section-stack and
activate it. Also refer to pushsection.
pushsection Pushes the current section onto an internal stack, where it may be
restored from by the popsection directive.
rem The assembler will ignore everything from encountering the rem
directive until an erem directive was found.
rept <expression> Repeats the assembly of the block between rept and endr
<expression> number of times. <expression> should be
positive. Negative values are regarded like 0.
The internal symbol REPTN always holds the iteration counter
of the inner repeat loop, starting with 0. REPTN is -1 outside
of any repeat block.
rorg <expression>[,<fill>] Sets the program counter to an offset relative to the start
of the current section, as defined by <expression>.
The new program counter (section offset) must not be smaller than the
current one. Any space will be padded by the optional <fill>
value, or zero.
<label> rs.<size> <expression> Works like the so directive, with the only difference that
the offset symbol is named __RS.
rseven Align the structure offset counter (__RS) to an even count.
rsreset Equivalent to clrso, but the symbol manipulated is __RS.
rsset <expression> Sets the structure offset counter (__RS) to <expression>.
See rs directive.
section <name>[,<sec_type>][,<mem_type>] Starts a new section named <name> or reactivates an old one.
<sec_type> defines the section type and may be code,
text (same as code), data or bss.
If the selected output format does not support section names (like
"aout", "tos" or "xfile"), then a missing <sec_type>
argument makes vasm interpret the first argument, <name>,
as section type instead. Otherwise a missing <sec_type>
defaults to a code section with the given name.
The optional <mem_type> has currently only a meaning for
the hunk-format output module and defines a 32-bit
memory attribute which specifies where to load the section.
<mem_type> is either a numerical constant or one of the
keywords chip (for Chip-RAM) or fast (for Fast-RAM).
Optionally it is also possible to attach the suffix _C, _F
or _P to the <sec_type> argument for defining the memory
type.
<symbol> set <expression>Create a new symbol with the name <symbol> and assign the value of <expression>. If <symbol> is already assigned, it will contain a new value from now on.
setfo <expression> Sets the structure offset counter (__FO) to <expression>.
See fo directive.
setso <expression> Sets the structure offset counter (__SO) to <expression>.
See so directive.
showoffset [<text>] Print current section offset (or absolute address) to the console,
preceded by the optional <text> (may use quotes).
PhxAss compatibility. Do not use in new code.
<label> so.<size> <expression> Assigns the current value of the structure offset counter to
<label>.
Afterwards the counter is incremented by the instruction’s
<size> multiplied by <expression>.
Any valid M68k size extension is allowed for <size>:
b, w, l, q, s, d, x,
p.
The offset counter can also be referenced directly under the name
__SO.
spc <lines> Output <lines> number of blank lines in the listing file.
Currently without any effect.
text Equivalent to section code,code.
ttl <name>Devpac/PhxAss syntax. Set current page title for the listing file.
<name> ttlMotorola syntax. Set current page title for the listing file.
weak <symbol>[,<symbol>...] Flag <symbol> as a weak symbol, which means that <symbol>
is visible to all modules in the linking process, but may be replaced
by any global symbol with the same name.
When a weak symbol remains undefined its value defaults to 0.
xdef <symbol>[,<symbol>...] Flag <symbol> as a global symbol, which means that
<symbol> is visible to all modules in the linking process.
See also public.
xref <symbol>[,<symbol>...] Flag <symbol> as externally defined, which means it has to
be imported from another module into the linking process.
See also public.
Some known problems of this module at the moment:
odd directive wastes two bytes, when address is already odd.
echo, printt and printv do not work when the
source text doesn’t contain any real code.
This module has the following error messages:
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