mirror of
https://github.com/michaelcmartin/Ophis.git
synced 2024-06-27 10:29:31 +00:00
595 lines
9.7 KiB
HTML
595 lines
9.7 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
|
<HTML
|
|
><HEAD
|
|
><TITLE
|
|
>Assembler directives</TITLE
|
|
><META
|
|
NAME="GENERATOR"
|
|
CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK
|
|
REL="HOME"
|
|
TITLE="Programming with Ophis"
|
|
HREF="book1.html"><LINK
|
|
REL="UP"
|
|
TITLE="Ophis Command Reference"
|
|
HREF="a505.html"><LINK
|
|
REL="PREVIOUS"
|
|
TITLE="Macros"
|
|
HREF="x692.html"></HEAD
|
|
><BODY
|
|
CLASS="SECTION"
|
|
BGCOLOR="#FFFFFF"
|
|
TEXT="#000000"
|
|
LINK="#0000FF"
|
|
VLINK="#840084"
|
|
ALINK="#0000FF"
|
|
><DIV
|
|
CLASS="NAVHEADER"
|
|
><TABLE
|
|
SUMMARY="Header navigation table"
|
|
WIDTH="100%"
|
|
BORDER="0"
|
|
CELLPADDING="0"
|
|
CELLSPACING="0"
|
|
><TR
|
|
><TH
|
|
COLSPAN="3"
|
|
ALIGN="center"
|
|
>Programming with Ophis</TH
|
|
></TR
|
|
><TR
|
|
><TD
|
|
WIDTH="10%"
|
|
ALIGN="left"
|
|
VALIGN="bottom"
|
|
><A
|
|
HREF="x692.html"
|
|
ACCESSKEY="P"
|
|
><<< Previous</A
|
|
></TD
|
|
><TD
|
|
WIDTH="80%"
|
|
ALIGN="center"
|
|
VALIGN="bottom"
|
|
>Ophis Command Reference</TD
|
|
><TD
|
|
WIDTH="10%"
|
|
ALIGN="right"
|
|
VALIGN="bottom"
|
|
> </TD
|
|
></TR
|
|
></TABLE
|
|
><HR
|
|
ALIGN="LEFT"
|
|
WIDTH="100%"></DIV
|
|
><DIV
|
|
CLASS="SECTION"
|
|
><H1
|
|
CLASS="SECTION"
|
|
><A
|
|
NAME="AEN732"
|
|
>Assembler directives</A
|
|
></H1
|
|
><P
|
|
> Assembler directives are all instructions to the assembler
|
|
that are not actual instructions. Ophis's set of directives
|
|
follow.
|
|
</P
|
|
><P
|
|
></P
|
|
><UL
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.advance</TT
|
|
> <I
|
|
CLASS="EMPHASIS"
|
|
>address</I
|
|
>:
|
|
Forces the program counter to
|
|
be <I
|
|
CLASS="EMPHASIS"
|
|
>address</I
|
|
>. Unlike
|
|
the <TT
|
|
CLASS="LITERAL"
|
|
>.org</TT
|
|
>
|
|
directive, <TT
|
|
CLASS="LITERAL"
|
|
>.advance</TT
|
|
> outputs zeroes until the
|
|
program counter reaches a specified address. Attempting
|
|
to <TT
|
|
CLASS="LITERAL"
|
|
>.advance</TT
|
|
> to a point behind the current
|
|
program counter is an assemble-time error.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.alias</TT
|
|
> <I
|
|
CLASS="EMPHASIS"
|
|
>label</I
|
|
> <I
|
|
CLASS="EMPHASIS"
|
|
>value</I
|
|
>: The
|
|
.alias directive assigns an arbitrary value to a label. This
|
|
value may be an arbitrary argument, but cannot reference any
|
|
label that has not already been defined (this prevents
|
|
recursive label dependencies).</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.byte</TT
|
|
> <I
|
|
CLASS="EMPHASIS"
|
|
>arg</I
|
|
> [ , <I
|
|
CLASS="EMPHASIS"
|
|
>arg</I
|
|
>, ... ]:
|
|
Specifies a series of arguments, which are evaluated, and
|
|
strings, which are included as raw ASCII data. The final
|
|
results of these arguments must be one byte in size. Seperate
|
|
constants are seperated by comments.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.checkpc</TT
|
|
> <I
|
|
CLASS="EMPHASIS"
|
|
>address</I
|
|
>: Ensures that the
|
|
program counter is less than or equal to the address
|
|
specified, and emits an assemble-time error if it is not.
|
|
<I
|
|
CLASS="EMPHASIS"
|
|
>This produces no code in the final binary - it is there to
|
|
ensure that linking a large amount of data together does not
|
|
overstep memory boundaries.</I
|
|
></P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.data</TT
|
|
> <I
|
|
CLASS="EMPHASIS"
|
|
>[label]</I
|
|
>: Sets the segment to
|
|
the segment name specified and disallows output. If no label
|
|
is given, switches to the default data segment.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.incbin</TT
|
|
> <I
|
|
CLASS="EMPHASIS"
|
|
>filename</I
|
|
>: Inserts the
|
|
contents of the file specified as binary data. Use it to
|
|
include graphics information, precompiled code, or other
|
|
non-assembler data.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.include</TT
|
|
> <I
|
|
CLASS="EMPHASIS"
|
|
>filename</I
|
|
>: Includes the
|
|
entirety of the file specified at that point in the program.
|
|
Use this to order your final sources.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.org</TT
|
|
> <I
|
|
CLASS="EMPHASIS"
|
|
>address</I
|
|
>: Sets the program
|
|
counter to the address specified. <I
|
|
CLASS="EMPHASIS"
|
|
>This does not emit any
|
|
code in and of itself, nor does it overwrite anything that
|
|
previously existed.</I
|
|
> If you wish to jump ahead in memory,
|
|
use <TT
|
|
CLASS="LITERAL"
|
|
>.advance</TT
|
|
>.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.require</TT
|
|
> <I
|
|
CLASS="EMPHASIS"
|
|
>filename</I
|
|
>: Includes the entirety
|
|
of the file specified at that point in the program. Unlike <TT
|
|
CLASS="LITERAL"
|
|
>.include</TT
|
|
>,
|
|
however, code included with <TT
|
|
CLASS="LITERAL"
|
|
>.require</TT
|
|
> will only be inserted once.
|
|
The <TT
|
|
CLASS="LITERAL"
|
|
>.require</TT
|
|
> directive is useful for ensuring that certain code libraries
|
|
are somewhere in the final binary. They are also very useful for guaranteeing that
|
|
macro libraries are available.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.space</TT
|
|
> <I
|
|
CLASS="EMPHASIS"
|
|
>label</I
|
|
> <I
|
|
CLASS="EMPHASIS"
|
|
>size</I
|
|
>: This
|
|
directive is used to organize global variables. It defines the
|
|
label specified to be at the current location of the program
|
|
counter, and then advances the program counter <I
|
|
CLASS="EMPHASIS"
|
|
>size</I
|
|
>
|
|
steps ahead. No actual code is produced. This is equivalent
|
|
to <TT
|
|
CLASS="LITERAL"
|
|
>label: .org ^+size</TT
|
|
>.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.text</TT
|
|
> <I
|
|
CLASS="EMPHASIS"
|
|
>[label]</I
|
|
>: Sets the segment to
|
|
the segment name specified and allows output. If no label is
|
|
given, switches to the default text segment.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.word</TT
|
|
> <I
|
|
CLASS="EMPHASIS"
|
|
>arg</I
|
|
> [ , <I
|
|
CLASS="EMPHASIS"
|
|
>arg</I
|
|
>, ... ]:
|
|
Like <TT
|
|
CLASS="LITERAL"
|
|
>.byte</TT
|
|
>, but values are all treated as two-byte
|
|
values and stored low-end first (as is the 6502's wont). Use
|
|
this to create jump tables (an unadorned label will evaluate
|
|
to that label's location) or otherwise store 16-bit
|
|
data.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.dword</TT
|
|
> <I
|
|
CLASS="EMPHASIS"
|
|
>arg</I
|
|
> [ , <I
|
|
CLASS="EMPHASIS"
|
|
>arg</I
|
|
>, ...]:
|
|
Like <TT
|
|
CLASS="LITERAL"
|
|
>.word</TT
|
|
>, but for 32-bit values.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.wordbe</TT
|
|
> <I
|
|
CLASS="EMPHASIS"
|
|
>arg</I
|
|
> [ , <I
|
|
CLASS="EMPHASIS"
|
|
>arg</I
|
|
>, ...]:
|
|
Like <TT
|
|
CLASS="LITERAL"
|
|
>.word</TT
|
|
>, but stores the value in a big-endian format (high byte first).</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.dwordbe</TT
|
|
> <I
|
|
CLASS="EMPHASIS"
|
|
>arg</I
|
|
> [ , <I
|
|
CLASS="EMPHASIS"
|
|
>arg</I
|
|
>, ...]:
|
|
Like <TT
|
|
CLASS="LITERAL"
|
|
>.dword</TT
|
|
>, but stores the value high byte first.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.scope</TT
|
|
>: Starts a new scope block. Labels
|
|
that begin with an underscore are only reachable from within
|
|
their innermost enclosing <TT
|
|
CLASS="LITERAL"
|
|
>.scope</TT
|
|
> statement.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.scend</TT
|
|
>: Ends a scope block. Makes the
|
|
temporary labels defined since the last <TT
|
|
CLASS="LITERAL"
|
|
>.scope</TT
|
|
>
|
|
statement unreachable, and permits them to be redefined in a
|
|
new scope.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.macro</TT
|
|
> <I
|
|
CLASS="EMPHASIS"
|
|
>name</I
|
|
>: Begins a macro
|
|
definition block. This is a scope block that can be inlined
|
|
at arbitrary points with <TT
|
|
CLASS="LITERAL"
|
|
>.invoke</TT
|
|
>. Arguments to the
|
|
macro will be bound to temporary labels with names like
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>_1</TT
|
|
>, <TT
|
|
CLASS="LITERAL"
|
|
>_2</TT
|
|
>, etc.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.macend</TT
|
|
>: Ends a macro definition
|
|
block.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.invoke</TT
|
|
> <I
|
|
CLASS="EMPHASIS"
|
|
>label</I
|
|
> [<I
|
|
CLASS="EMPHASIS"
|
|
>argument</I
|
|
> [,
|
|
<I
|
|
CLASS="EMPHASIS"
|
|
>argument</I
|
|
> ...]]: invokes (inlines) the specified
|
|
macro, binding the values of the arguments to the ones the
|
|
macro definition intends to read. A shorthand for <TT
|
|
CLASS="LITERAL"
|
|
>.invoke</TT
|
|
>
|
|
is the name of the macro to invoke, backquoted.</P
|
|
></LI
|
|
></UL
|
|
><P
|
|
> The following directives are deprecated, added for
|
|
compatibility with the old Perl
|
|
assembler <B
|
|
CLASS="COMMAND"
|
|
>P65</B
|
|
>. Use
|
|
the <TT
|
|
CLASS="LITERAL"
|
|
>-d</TT
|
|
> option to Ophis to enable
|
|
them.
|
|
</P
|
|
><P
|
|
></P
|
|
><UL
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.ascii</TT
|
|
>: Equivalent to <TT
|
|
CLASS="LITERAL"
|
|
>.byte</TT
|
|
>,
|
|
which didn't used to be able to handle strings.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.code</TT
|
|
>: Equivalent to <TT
|
|
CLASS="LITERAL"
|
|
>.text</TT
|
|
>.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.segment</TT
|
|
>: Equivalent to <TT
|
|
CLASS="LITERAL"
|
|
>.text</TT
|
|
>,
|
|
from when there was no distinction between <TT
|
|
CLASS="LITERAL"
|
|
>.text</TT
|
|
> and
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>.data</TT
|
|
> segments.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.address</TT
|
|
>: Equivalent to
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>.word</TT
|
|
>.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>.link</TT
|
|
> <I
|
|
CLASS="EMPHASIS"
|
|
>filename address</I
|
|
>: Assembles
|
|
the file specified as if it began at the address specified.
|
|
This is generally for use in <SPAN
|
|
CLASS="QUOTE"
|
|
>"top-level"</SPAN
|
|
> files, where there
|
|
is not necessarily a one-to-one correspondence between file
|
|
position and memory position. This is equivalent to an
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>.org</TT
|
|
> directive followed by an <TT
|
|
CLASS="LITERAL"
|
|
>.include</TT
|
|
>.
|
|
With the introduction of the <TT
|
|
CLASS="LITERAL"
|
|
>.org</TT
|
|
> directive this one is
|
|
less useful (and in most cases, any <TT
|
|
CLASS="LITERAL"
|
|
>.org</TT
|
|
> statement
|
|
you use will actually be at the top of the <TT
|
|
CLASS="LITERAL"
|
|
>.include</TT
|
|
>d
|
|
file).</P
|
|
></LI
|
|
></UL
|
|
></DIV
|
|
><DIV
|
|
CLASS="NAVFOOTER"
|
|
><HR
|
|
ALIGN="LEFT"
|
|
WIDTH="100%"><TABLE
|
|
SUMMARY="Footer navigation table"
|
|
WIDTH="100%"
|
|
BORDER="0"
|
|
CELLPADDING="0"
|
|
CELLSPACING="0"
|
|
><TR
|
|
><TD
|
|
WIDTH="33%"
|
|
ALIGN="left"
|
|
VALIGN="top"
|
|
><A
|
|
HREF="x692.html"
|
|
ACCESSKEY="P"
|
|
><<< Previous</A
|
|
></TD
|
|
><TD
|
|
WIDTH="34%"
|
|
ALIGN="center"
|
|
VALIGN="top"
|
|
><A
|
|
HREF="book1.html"
|
|
ACCESSKEY="H"
|
|
>Home</A
|
|
></TD
|
|
><TD
|
|
WIDTH="33%"
|
|
ALIGN="right"
|
|
VALIGN="top"
|
|
> </TD
|
|
></TR
|
|
><TR
|
|
><TD
|
|
WIDTH="33%"
|
|
ALIGN="left"
|
|
VALIGN="top"
|
|
>Macros</TD
|
|
><TD
|
|
WIDTH="34%"
|
|
ALIGN="center"
|
|
VALIGN="top"
|
|
><A
|
|
HREF="a505.html"
|
|
ACCESSKEY="U"
|
|
>Up</A
|
|
></TD
|
|
><TD
|
|
WIDTH="33%"
|
|
ALIGN="right"
|
|
VALIGN="top"
|
|
> </TD
|
|
></TR
|
|
></TABLE
|
|
></DIV
|
|
></BODY
|
|
></HTML
|
|
> |