mirror of
https://github.com/cc65/cc65.git
synced 2024-11-16 02:10:52 +00:00
274 lines
7.8 KiB
Plaintext
274 lines
7.8 KiB
Plaintext
<!doctype linuxdoc system>
|
|
|
|
<article>
|
|
<title>Commodore 16/116 specific information for cc65
|
|
<author><url url="mailto:uz@cc65.org" name="Ullrich von Bassewitz">
|
|
|
|
<abstract>
|
|
An overview over the C16 runtime system as it is implemented for the cc65 C
|
|
compiler.
|
|
</abstract>
|
|
|
|
<!-- Table of contents -->
|
|
<toc>
|
|
|
|
<!-- Begin the document -->
|
|
|
|
<sect>Overview<p>
|
|
|
|
This file contains an overview of the C16 runtime system as it comes with the
|
|
cc65 C compiler. It describes the memory layout, C16/116 specific header
|
|
files, available drivers, and any pitfalls specific to that platform.
|
|
|
|
Please note that C16 specific functions are just mentioned here, they are
|
|
described in detail in the separate <url url="funcref.html" name="function
|
|
reference">. Even functions marked as "platform dependent" may be available on
|
|
more than one platform. Please see the function reference for more
|
|
information.
|
|
|
|
Since the C16/C116 and the Commodore Plus/4 are almost identical (the former
|
|
don't have the 6551 ACIA and only 16KB of memory), the <url
|
|
url="plus4.html" name="Plus/4 documentation"> is also worth a look. The
|
|
difference between both cc65 targets is that the Plus/4 runtime uses banking
|
|
to support full 64K RAM, while the C16 does not use banking and supports up to
|
|
32K RAM. Because banking is not needed, most C16 programs will be somewhat
|
|
smaller than the same program compiled for the Plus/4. However, programs C16
|
|
will always run on the Plus/4, while the reverse is not necessarily true.
|
|
|
|
|
|
<sect>Binary format<p>
|
|
|
|
The standard binary output format generated by the linker for the C16/116
|
|
target is a machine language program with a one line BASIC stub which, calls
|
|
the machine language part via SYS. This means that a program can be loaded as
|
|
BASIC program and started with RUN. It is of course possible to change this
|
|
behaviour by using a modified startup file and linker config.
|
|
|
|
|
|
<sect>Memory layout<p>
|
|
|
|
cc65 generated programs with the default setup run with the kernal and basic
|
|
banked in. This gives a usable memory range of $1000 - $4000
|
|
(or $8000 if the machine is equipped with 32K RAM or more). Having the
|
|
kernal and basic ROMs banked in means, that ROM entry points may be called
|
|
directly from user code.
|
|
|
|
Special locations:
|
|
|
|
<descrip>
|
|
<tag/Text screen/
|
|
The text screen is located at $C00 (as in the standard setup).
|
|
|
|
<tag/Color RAM/
|
|
The color RAM is located at $800 (standard location).
|
|
|
|
<tag/Stack/
|
|
The C runtime stack is located at $3FFF ($7FFF in case of a
|
|
machine with 32K of memory or more) and growing downwards.
|
|
|
|
<tag/Heap/
|
|
The C heap is located at the end of the program and grows towards the C
|
|
runtime stack.
|
|
|
|
</descrip><p>
|
|
|
|
|
|
|
|
<sect>Platform specific header files<p>
|
|
|
|
Programs containing C16 specific code may use the <tt/c16.h/ or <tt/cbm.h/
|
|
header files. Using the later may be an option when writing code for more than
|
|
one CBM platform, since it includes <tt/c16.h/ and declares several functions
|
|
common to all CBM platforms.
|
|
|
|
Please note that most of the header file declarations from the <tt/c16.h/
|
|
header file are shared between the C16 and Plus/4 configurations. For this
|
|
reason, most of it is located in a common header file named <tt/cbm264.h/.
|
|
|
|
|
|
|
|
<sect1>C16/C116 specific functions<p>
|
|
|
|
There are currently no special C16/C116 functions.
|
|
|
|
|
|
<sect1>CBM specific functions<p>
|
|
|
|
Some functions are available for all (or at least most) of the Commodore
|
|
machines. See the <url url="funcref.html" name="function reference"> for
|
|
declaration and usage.
|
|
|
|
<itemize>
|
|
<item>cbm_close
|
|
<item>cbm_closedir
|
|
<item>cbm_k_setlfs
|
|
<item>cbm_k_setnam
|
|
<item>cbm_k_load
|
|
<item>cbm_k_save
|
|
<item>cbm_k_open
|
|
<item>cbm_k_close
|
|
<item>cbm_k_readst
|
|
<item>cbm_k_chkin
|
|
<item>cbm_k_ckout
|
|
<item>cbm_k_basin
|
|
<item>cbm_k_bsout
|
|
<item>cbm_k_clrch
|
|
<item>cbm_k_tksa
|
|
<item>cbm_k_second
|
|
<item>cbm_load
|
|
<item>cbm_open
|
|
<item>cbm_opendir
|
|
<item>cbm_read
|
|
<item>cbm_readdir
|
|
<item>cbm_save
|
|
<item>cbm_write
|
|
<item>get_tv
|
|
<item>waitvsync
|
|
</itemize>
|
|
|
|
|
|
<sect1>CBM specific CPU functions<p>
|
|
|
|
Some CPU related functions are available for some of the Commodore
|
|
machines. See the <url url="funcref.html" name="function reference"> for
|
|
declaration and usage.
|
|
|
|
<itemize>
|
|
<item>fast
|
|
<item>slow
|
|
<item>isfast
|
|
</itemize>
|
|
|
|
<sect1>Hardware access<p>
|
|
|
|
The following pseudo variables declared in the <tt/c16.h/ header file do
|
|
allow access to hardware located in the address space. Some variables are
|
|
structures, accessing the struct fields will access the chip registers.
|
|
|
|
<descrip>
|
|
|
|
<tag><tt/TED/</tag>
|
|
The <tt/TED/ structure allows access to the TED chip. See the
|
|
<tt/_ted.h/ header file located in the include directory for the
|
|
declaration of the structure.
|
|
|
|
<tag><tt/COLOR_RAM/</tag>
|
|
A character array that mirrors the color RAM of the C16 at $0800.
|
|
|
|
</descrip><p>
|
|
|
|
|
|
|
|
<sect>Loadable drivers<p>
|
|
|
|
The names in the parentheses denote the symbols to be used for static linking of the drivers.
|
|
|
|
|
|
<sect1>Graphics drivers<p>
|
|
|
|
No graphics drivers are currently available for the C16/C116.
|
|
|
|
|
|
<sect1>Extended memory drivers<p>
|
|
|
|
<descrip>
|
|
|
|
<tag><tt/c16-ram.emd (c16_ram_emd)/</tag>
|
|
A driver for the hidden RAM below the BASIC and KERNAL ROMs. Supports 125
|
|
pages with 256 bytes each if the machine is equipped with 64K of memory
|
|
(a Plus/4 or a memory extended C16/116).
|
|
|
|
</descrip><p>
|
|
|
|
|
|
|
|
<sect1>Joystick drivers<p>
|
|
|
|
<descrip>
|
|
|
|
<tag><tt/c16-stdjoy.joy (c16_stdjoy_joy)/</tag>
|
|
Supports up to two joysticks connected to the standard joysticks port of
|
|
the Commodore 16/116.
|
|
|
|
</descrip><p>
|
|
|
|
|
|
|
|
<sect1>Mouse drivers<p>
|
|
|
|
No mouse drivers are currently available for the C16/C116.
|
|
|
|
|
|
<sect1>RS232 device drivers<p>
|
|
|
|
The Commodore 16 does not have a builtin ACIA and no RS232 extensions are
|
|
known. For this reason, there are no RS232 drivers available. Please note that
|
|
the standard Plus/4 driver will <em>not</em> run together with the C16
|
|
library, because the latter does not support interrupts needed by the driver.
|
|
|
|
|
|
<sect>Limitations<p>
|
|
|
|
|
|
|
|
<sect>Other hints<p>
|
|
|
|
<sect1>Passing arguments to the program<p>
|
|
|
|
Command line arguments can be passed to <tt/main()/. Since this is not
|
|
supported by BASIC, the following syntax was chosen:
|
|
|
|
<tscreen><verb>
|
|
RUN:REM ARG1 " ARG2 IS QUOTED" ARG3 "" ARG5
|
|
</verb></tscreen>
|
|
|
|
<enum>
|
|
<item>Arguments are separated by spaces.
|
|
<item>Arguments may be quoted.
|
|
<item>Leading and trailing spaces around an argument are ignored. Spaces within
|
|
a quoted argument are allowed.
|
|
<item>The first argument passed to <tt/main/ is the program name.
|
|
<item>A maximum number of 10 arguments (including the program name) are
|
|
supported.
|
|
</enum>
|
|
|
|
|
|
<sect1>Program return code<p>
|
|
|
|
The program return code (low byte) is passed back to BASIC by use of the
|
|
<tt/ST/ variable.
|
|
|
|
|
|
<sect1>Interrupts<p>
|
|
|
|
The runtime for the C16 uses routines marked as <tt/.INTERRUPTOR/ for
|
|
interrupt handlers. Such routines must be written as simple machine language
|
|
subroutines and will be called automatically by the interrupt handler code
|
|
when they are linked into a program. See the discussion of the <tt/.CONDES/
|
|
feature in the <url url="ca65.html" name="assembler manual">.
|
|
|
|
|
|
|
|
<sect>License<p>
|
|
|
|
This software is provided 'as-is', without any expressed or implied
|
|
warranty. In no event will the authors be held liable for any damages
|
|
arising from the use of this software.
|
|
|
|
Permission is granted to anyone to use this software for any purpose,
|
|
including commercial applications, and to alter it and redistribute it
|
|
freely, subject to the following restrictions:
|
|
|
|
<enum>
|
|
<item> The origin of this software must not be misrepresented; you must not
|
|
claim that you wrote the original software. If you use this software
|
|
in a product, an acknowledgment in the product documentation would be
|
|
appreciated but is not required.
|
|
<item> Altered source versions must be plainly marked as such, and must not
|
|
be misrepresented as being the original software.
|
|
<item> This notice may not be removed or altered from any source
|
|
distribution.
|
|
</enum>
|
|
|
|
</article>
|