mirror of
https://github.com/cc65/cc65.git
synced 2024-10-31 20:06:11 +00:00
412 lines
13 KiB
Plaintext
412 lines
13 KiB
Plaintext
<!doctype linuxdoc system>
|
|
|
|
<article>
|
|
<title>Commodore 128-specific information for cc65
|
|
<author><url url="mailto:uz@cc65.org" name="Ullrich von Bassewitz">,<newline>
|
|
<url url="mailto:polluks@sdf.lonestar.org" name="Stefan A. Haubenthal">
|
|
|
|
<abstract>
|
|
An overview over the C128 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 C128 runtime system as it comes with the
|
|
cc65 C compiler. It describes the memory layout, C128-specific header files,
|
|
available drivers, and any pitfalls specific to that platform.
|
|
|
|
Please note that C128-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.
|
|
|
|
|
|
<sect>Binary format<p>
|
|
|
|
The standard binary output format generated by the linker for the C128 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 I/O area and the
|
|
kernal ROM enabled. Note that this is a non standard memory layout, and that
|
|
there is no "memory configuration index" for this layout. This means that
|
|
special care has to be taken when changing the configuration, or calling any
|
|
code that does this. The memory configuration register at $FF00 should
|
|
be saved and restored instead of relying on the memory configuration index
|
|
stored in the zero page.
|
|
|
|
The setup gives a usable memory range of $1C00 - $BFFF. Having
|
|
just the kernal ROM mapped in means, that kernal entry points may be called
|
|
directly, but using the BASIC ROM is not possible without additional code.
|
|
|
|
Special locations:
|
|
|
|
<descrip>
|
|
<tag/Text screen/
|
|
The text screen is located at $400 (as in the standard setup).
|
|
|
|
<tag/Stack/
|
|
The C runtime stack is located at $BFFF, 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 C128-specific code may use the <tt/c128.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/c128.h/ and declares several functions
|
|
common to all CBM platforms.
|
|
|
|
|
|
<sect1>C128-specific functions<p>
|
|
|
|
The functions listed below are special for the C128. See the <url
|
|
url="funcref.html" name="function reference"> for declaration and usage.
|
|
|
|
<itemize>
|
|
<item>videomode
|
|
<item>c64mode
|
|
</itemize>
|
|
|
|
|
|
<sect1>C128-specific accelerator functions<p>
|
|
|
|
The functions listed below are accelerator functions for the C128. See the <url
|
|
url="funcref.html" name="function reference"> for declaration and usage.
|
|
|
|
<itemize>
|
|
<item>detect_c128
|
|
<item>detect_scpu
|
|
<item>get_c128_speed
|
|
<item>get_scpu_speed
|
|
<item>set_c128_speed
|
|
<item>set_scpu_speed
|
|
</itemize>
|
|
|
|
|
|
<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/c128.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/VIC/</tag>
|
|
The <tt/VIC/ structure allows access to the VIC II (the graphics
|
|
controller). See the <tt/_vic2.h/ header file located in the include
|
|
directory for the declaration of the structure.
|
|
|
|
<tag><tt/SID/</tag>
|
|
The <tt/SID/ structure allows access to the SID (the sound interface
|
|
device). See the <tt/_sid.h/ header file located in the include directory
|
|
for the declaration of the structure.
|
|
|
|
<tag><tt/VDC/</tag>
|
|
The <tt/VDC/ structure allows access to the VDC (the video display
|
|
controller). See the <tt/_vdc.h/ header file located in the include
|
|
directory for the declaration of the structure.
|
|
|
|
<tag><tt/CIA1, CIA2/</tag>
|
|
Access to the two CIA (complex interface adapter) chips is available via
|
|
the <tt/CIA1/ and <tt/CIA2/ variables. The structure behind these variables
|
|
is explained in <tt/_6526.h/.
|
|
|
|
<tag><tt/COLOR_RAM/</tag>
|
|
A character array that mirrors the color RAM of the C128 at $D800.
|
|
|
|
</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>
|
|
|
|
The default drivers, <tt/tgi_stddrv (tgi_static_stddrv)/, point to <tt/c128-vdc.tgi (c128_vdc_tgi)/.
|
|
|
|
Note: The graphics drivers for the VDC are incompatible with the extended
|
|
memory drivers using the VDC memory!
|
|
|
|
<descrip>
|
|
|
|
<tag><tt/c128-hi.tgi (c128_hi_tgi)/</tag>
|
|
This driver features a resolution of 320×200 with two colors and an
|
|
adjustable palette (that means that the two colors can be chosen out of a
|
|
palette of the 16 VIC colors). Unlike BASIC 7.0, this driver puts its
|
|
graphics data into the RAM behind the ROMs.
|
|
|
|
<tag><tt/c128-vdc.tgi (c128_vdc_tgi)/</tag>
|
|
This driver was written by Maciej Witkowiak. It uses the 80-column display,
|
|
and features a resolution of 640×200 with two colors and an adjustable
|
|
palette (that means that the two colors can be chosen out of the 16 VDC
|
|
colors).
|
|
|
|
<tag><tt/c128-vdc2.tgi (c128_vdc2_tgi)/</tag>
|
|
This driver was written by Maciej Witkowiak. This driver uses the 80-column
|
|
display, and features a resolution of 640×480 with two colors and an
|
|
adjustable palette (that means that the two colors can be chosen out of the
|
|
16 VDC colors). The driver requires 64KB VDC RAM.
|
|
|
|
</descrip><p>
|
|
|
|
Note: The colors are translated from the definitions in the headers to correct
|
|
VDC values; so, please use definitions or VIC color numbers only. Colors
|
|
<tt/GRAY3/ and <tt/BROWN/ are missing on the VDC; and, are translated to the
|
|
two colors missing from the VIC palette.
|
|
|
|
|
|
<sect1>Extended memory drivers<p>
|
|
|
|
<descrip>
|
|
|
|
<tag><tt/c128-efnram.emd (c128_efnram_emd)/</tag>
|
|
Extended memory driver for the C128 External Function RAM.
|
|
Written and contributed by Marco van den Heuvel.
|
|
|
|
<tag><tt/c128-georam.emd (c128_georam_emd)/</tag>
|
|
A driver for the GeoRam cartridge. The driver will always assume 2048 pages
|
|
of 256 bytes each. There are no checks, so if your program knows better,
|
|
just go ahead.
|
|
|
|
<tag><tt/c128-ifnram.emd (c128_ifnram_emd)/</tag>
|
|
Extended memory driver for the C128 Internal Function RAM.
|
|
Written and contributed by Marco van den Heuvel.
|
|
|
|
<tag><tt/c128-ram.emd (c128_ram_emd)/</tag>
|
|
An extended memory driver for the RAM in page 1. The common memory area is
|
|
excluded, so this driver supports 251 pages of 256 bytes each.
|
|
|
|
<tag><tt/c128-ram2.emd (c128_ram2_emd)/</tag>
|
|
An extended memory driver for the RAM in pages 1-3. The common memory area
|
|
is excluded, so this driver supports up to 731 pages of 256 bytes each. The
|
|
driver can be used as a full replacement for <tt/c128-ram.emd/, because RAM
|
|
in pages 2+3 is autodetected, but it's larger and there are not many
|
|
machines with RAM in banks 2+3, so it has been made a separate driver. The
|
|
additional code was contributed by Marco van den Heuvel.
|
|
|
|
<tag><tt/c128-ramcart.emd (c128_ramcart_emd)/</tag>
|
|
A driver for the RamCart 64/128 written and contributed by Maciej Witkowiak.
|
|
Will test the hardware for the available RAM.
|
|
|
|
<tag><tt/c128-reu.emd (c128_reu_emd)/</tag>
|
|
A driver for the CBM REUs. The driver will test the connected REU to find
|
|
out how much RAM is present.
|
|
|
|
<tag><tt/c128-vdc.emd (c128_vdc_emd)/</tag>
|
|
A driver for the VDC memory of the C128, written and contributed by Maciej
|
|
Witkowiak. Autodetects the amount of memory available (16 or 64K), and offers
|
|
64 or 256 pages of 256 bytes each. Note: This driver is incompatible with
|
|
any of the graphics drivers using the VDC!
|
|
|
|
</descrip><p>
|
|
|
|
|
|
<sect1>Joystick drivers<p>
|
|
|
|
The default drivers, <tt/joy_stddrv (joy_static_stddrv)/, point to <tt/c128-stdjoy.joy (c128_stdjoy_joy)/.
|
|
|
|
<descrip>
|
|
|
|
<tag><tt/c128-ptvjoy.joy (c128_ptvjoy_joy)/</tag>
|
|
Driver for the Protovision 4-player adapter originally written by Groepaz
|
|
for the C64, and converted for the C128 by Uz. See <url
|
|
url="http://www.protovision-online.de/hardw/4_player.php?language=en"
|
|
name="Protovision shop"> for prices and building instructions. Up to four
|
|
joysticks are supported.
|
|
|
|
<tag><tt/c128-stdjoy.joy (c128_stdjoy_joy)/</tag>
|
|
Supports up to two joysticks connected to the standard joysticks ports of
|
|
the C128.
|
|
|
|
</descrip><p>
|
|
|
|
|
|
|
|
<sect1>Mouse drivers<p>
|
|
|
|
The default drivers, <tt/mouse_stddrv (mouse_static_stddrv)/, point to <tt/c128-1351.mou (c128_1351_mou)/.
|
|
|
|
<descrip>
|
|
|
|
<tag><tt/c128-1351.mou (c128_1351_mou)/</tag>
|
|
Supports a standard mouse connected to port #0 of the C128.
|
|
|
|
<tag><tt/c128-inkwell.mou (c128_inkwell_mou)/</tag>
|
|
Supports the Inkwell Systems lightpens, connected to port #0 of the
|
|
C128. It can read both the one-button 170-C and the two-button 184-C pens.
|
|
(It can read other lightpens and light-guns that send their button signal to
|
|
the joystick left-button pin or the paddle Y [up/down] pin.) It works on
|
|
only the 40-column screen.
|
|
|
|
<tag><tt/c128-joy.mou (c128_joy_mou)/</tag>
|
|
Supports a mouse emulated by a standard joystick, e.g. 1350 mouse, in port
|
|
#1 of the C128.
|
|
|
|
<tag><tt/c128-pot.mou (c128_pot_mou)/</tag>
|
|
Supports a potentiometer device, e.g. Koala Pad, connected to port #1 of
|
|
the C128.
|
|
|
|
</descrip><p>
|
|
|
|
|
|
<sect1>RS232 device drivers<p>
|
|
|
|
<descrip>
|
|
|
|
<tag><tt/c128-swlink.ser (c128_swlink_ser)/</tag>
|
|
Driver for the SwiftLink cartridge. Supports up to 38400 BPS, hardware flow
|
|
control (RTS/CTS), and interrupt-driven receives. Note that, because of the
|
|
peculiarities of the 6551 chip, together with the use of the NMI, transmits
|
|
are not interrupt driven; and, the transceiver blocks if the receiver asserts
|
|
flow control because of a full buffer.
|
|
|
|
The driver uses the RS232 variables and buffers of the kernal (buffers at
|
|
$C00 and $D00).
|
|
|
|
</descrip><p>
|
|
|
|
|
|
|
|
<sect>Limitations<p>
|
|
|
|
|
|
<sect1>Realtime clock<p>
|
|
|
|
The realtime clock functions use the CIA1 TOD clock. As that clock only stores
|
|
the time but not the date, the date set by <tt/clock_settime()/ is simply stored
|
|
inside the C library for retrieval in the same program via <tt/clock_gettime()/.
|
|
|
|
|
|
|
|
<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 directly 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 C128 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>
|