<!doctype linuxdoc system>
<article>
-
-<title>Commodore 64 specific information for cc65
-<author>Ullrich von Bassewitz, <htmlurl url="mailto:uz@cc65.org" name="uz@cc65.org">
-<date>2003-09-23
+<title>Commodore 64-specific information for cc65
+<author><url url="mailto:uz@cc65.org" name="Ullrich von Bassewitz"><newline>
+<url url="mailto:greg.king5@verizon.net" name="Greg King">
<abstract>
An overview over the C64 runtime system as it is implemented for the cc65 C
<sect>Overview<p>
This file contains an overview of the C64 runtime system as it comes with the
-cc65 C compiler. It describes the memory layout, C64 specific header files,
+cc65 C compiler. It describes the memory layout, C64-specific header files,
available drivers, and any pitfalls specific to that platform.
-Please note that C64 specific functions are just mentioned here, they are
-described in detail in the separate <htmlurl url="funcref.html" name="function
+Please note that C64-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 C64 target
-is a machine language program with a one line BASIC stub. 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.
+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>
</descrip><p>
+<sect>Linker configurations<p>
+
+The ld65 linker comes with a default config file for the Commodore 64,
+which is used via <tt/-t c64/. The
+c64 package comes with additional secondary linker config files, which are
+used via <tt/-t c64 -C <configfile>/.
+
+
+<sect1>default config file (<tt/c64.cfg/)<p>
+
+The default configuration is tailored to C programs. It supplies the load
+address and a small BASIC stub that starts the compiled program using a SYS
+command.
+
+
+<sect1><tt/c64-asm.cfg/<p>
+
+This configuration is made for assembler programmers who don't need a special
+setup. The default start address is $801. It can be changed with the
+linker command line option <tt/--start-addr/. All standard segments with the
+exception of <tt/zeropage/ are written to the output file and a two byte load
+address is prepended.
+
+To use this config file, assemble with <tt/-t c64/ and link with <tt/-C
+c64-asm.cfg/. The former will make sure that correct character translation is
+in effect, while the latter supplies the actual config. When using <tt/cl65/,
+use both command line options.
+
+Sample command line for <tt/cl65/:
-<sect>Platform specific header files<p>
+<tscreen><verb>
+cl65 -o file.prg -t c64 -C c64-asm.cfg source.s
+</verb></tscreen>
+
+To generate code that loads to $C000:
+
+<tscreen><verb>
+cl65 -o file.prg --start-addr $C000 -t c64 -C c64-asm.cfg source.s
+</verb></tscreen>
+
+It is also possible to add a small BASIC header to the program, that uses SYS
+to jump to the program entry point (which is the start of the code segment).
+The advantage is that the program can be started using RUN.
+
+To generate a program with a BASIC SYS header, use
-Programs containing C64 specific code may use the <tt/c64.h/ or <tt/cbm.h/
+<tscreen><verb>
+cl65 -o file.prg -u __EXEHDR__ -t c64 -C c64-asm.cfg source.s
+</verb></tscreen>
+
+Please note that in this case a changed start address doesn't make sense,
+since the program must be loaded to the BASIC start address.
+
+<sect>Extras<p>
+
+<sect1>80 Columns conio driver<p>
+
+The C64 package comes with an alternative software driven 80 columns
+module <tt/c64-soft80.o/ which uses the memory under I/O between $D000
+and $FF3F.
+
+In memory constrained situations the memory from $400 to $7FF
+can be made available to a program by calling <tt/_heapadd ((void *) 0x0400, 0x0400);/
+at the beginning of <tt/main()/. Doing so is beneficial even if the program
+doesn't use the the heap explicitly because loading a driver uses the heap implicitly.
+
+Using <tt/c64-soft80.o/ is as simple as placing it on the linker command
+line like this:
+
+<tscreen><verb>
+cl65 -t c64 myprog.c c64-soft80.o
+</verb></tscreen>
+
+Note that the soft80 conio driver is incompatible with the
+<tt/c64-ram.emd (c64_ram_emd)/ extended memory driver and the
+ <tt/c64-hi.tgi (c64_hi_tgi)/ graphics driver.
+
+<sect2>80 Columns conio driver (monochrome)<p>
+
+In an (even more) memory constrained situation, a size optimized version of the
+software driven 80 columns module may be used, which only supports one common
+text color for the whole screen.
+
+<tscreen><verb>
+cl65 -t c64 myprog.c c64-soft80mono.o
+</verb></tscreen>
+
+<sect>Platform-specific header files<p>
+
+Programs containing C64-specific code may use the <tt/c64.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/c64.h/ and declares several functions
common to all CBM platforms.
-<sect1>C64
specific functions<p>
+<sect1>C64
-specific functions<p>
-The functions listed below are special for the C64. See the <htmlurl
+The functions listed below are special for the C64. See the <url
url="funcref.html" name="function reference"> for declaration and usage.
<itemize>
</itemize>
-<sect1>CBM specific functions<p>
+<sect1>C64-specific accelerator functions<p>
+
+The functions listed below are accelerator functions for the C64. See the <url
+url="funcref.html" name="function reference"> for declaration and usage.
+
+<itemize>
+<item>detect_c128
+<item>detect_c64dtv
+<item>detect_c65
+<item>detect_chameleon
+<item>detect_scpu
+<item>detect_turbomaster
+<item>get_c128_speed
+<item>get_c64dtv_speed
+<item>get_c65_speed
+<item>get_chameleon_speed
+<item>get_scpu_speed
+<item>get_turbomaster_speed
+<item>set_c128_speed
+<item>set_c64dtv_speed
+<item>set_c65_speed
+<item>set_chameleon_speed
+<item>set_scpu_speed
+<item>set_turbomaster_speed
+</itemize>
+
+
+<sect1>CBM-specific functions<p>
Some functions are available for all (or at least most) of the Commodore
-machines. See the <htmlurl url="funcref.html" name="function reference"> for
+machines. See the <url url="funcref.html" name="function reference"> for
declaration and usage.
<itemize>
<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
for the declaration of the structure.
<tag><tt/CIA1, CIA2/</tag>
- Access to the two CIA (complex interface adapater) chips is available via
+ 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/_cia.h/.
+ is explained in <tt/_6526.h/.
<tag><tt/COLOR_RAM/</tag>
A character array that mirrors the color RAM of the C64 at $D800.
<sect>Loadable drivers<p>
+The names in the parentheses denote the symbols to be used for static linking of the drivers.
+
+
+<label id="graphics-drivers">
<sect1>Graphics drivers<p>
<em>Note:</em> All available graphics drivers for the TGI interface will use
-the space below the I/O area and kernal ROM, so you can have hires graphics in
-the standard setup without any memory loss or need for a changed
-configuration.
+the space below the I/O area and Kernal ROM; so, you can have hires graphics in
+the standard setup without any memory loss or need for a changed configuration.
+
+You can use a mouse driver at the same time that you use a TGI driver. But, if
+you want to see the default mouse pointer on the graphics screen, then you
+explicitly must link a special object file into your program. It will put the
+arrow into the "high RAM" area where the bitmaps are put. Its name is
+"<tt/c64-tgimousedata.o/". Example:
+
+<tscreen><verb>
+cl65 -t c64 -o program-file main-code.c subroutines.s c64-tgimousedata.o
+</verb></tscreen>
<descrip>
- <tag><tt/c64-hi.tgi/</tag>
+ <tag><tt/c64-hi.tgi (c64_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 choosen out of a
+ adjustable palette (that means that the two colors can be chosen out of a
palette of the 16 C64 colors).
</descrip><p>
+Note that the graphics drivers are incompatible with the
+<tt/c64-ram.emd (c64_ram_emd)/ extended memory driver and the
+ <tt/c64-soft80.o/ software 80-columns conio driver.
+
<sect1>Extended memory drivers<p>
<descrip>
- <tag><tt/c64-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/c64-65816.emd (c64_65816_emd)/</tag>
+ Extended memory driver for 65816 (eg SCPU) based extra RAM.
+ Written and contributed by Marco van den Heuvel.
+
+ <tag><tt/c64-c256k.emd (c64_c256k_emd)/</tag>
+ A driver for the C64 256K memory expansion. This driver offers 768 pages of
+ 256 bytes each. Written and contributed by Marco van den Heuvel.
+
+ <tag><tt/c64-dqbb.emd (c64_dqbb_emd)/</tag>
+ A driver for the Double Quick Brown Box cartridge. This driver offers
+ 64 pages of 256 bytes each. Written and contributed by Marco van den Heuvel.
+
+ <tag><tt/c64-georam.emd (c64_georam_emd)/</tag>
+ A driver for the Berkeley Softworks GeoRam cartridge. The driver will
+ determine the available RAM from the connected cartridge. It supports 64KB
+ up to 2048KB of RAM.
- <tag><tt/c64-ram.emd/</tag>
- A driver for the hidden RAM below the I/O area and kernal ROM. Supports 48
+ <tag><tt/c64-isepic.emd (c64_isepic_emd)/</tag>
+ A driver for the ISEPIC cartridge. This driver offers just 8 pages of 256
+ bytes each. Written and contributed by Marco van den Heuvel.
+
+ <tag><tt/c64-ram.emd (c64_ram_emd)/</tag>
+ A driver for the hidden RAM below the I/O area and kernal ROM. Supports 47
256 byte pages. Please note that this driver is incompatible with any of the
- graphics drivers!
+ graphics drivers, or the soft80 conio driver!
+
+ <tag><tt/c64-ramcart.emd (c64_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/c64-ramcart.emd/</tag>
- A driver for the RamCart 64/128. Will test the hardware for the available
- RAM.
+ <tag><tt/c64-reu.emd (c64_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/c64-reu.emd/</tag>
- A driver for the CBM REUs. The driver will determine from the connected REU
- if it supports 128KB of RAM or more. In the latter case, 256KB are assumed,
- but since there are no range checks, the application can use more memory if
- it has better knowledge about the hardware than the driver.
+ <tag><tt/c64-vdc.emd (c64_vdc_emd)/</tag>
+ A driver for the VDC memory of the C128. Written and contributed by Maciej
+ Witkowiak. Can be used if the program is running in C64 mode of the C128.
+ Autodetects the amount of memory available (16 or 64K) and offers 64 or 256
+ pages of 256 bytes each.
- <tag><tt/c64-vdc.emd/</tag>
- A driver for the VDC memory of the C128. Can be used if the program is
- running in C64 mode of the C128. Autodetects the amount of memory available
- (16 or 64K) and offers 64 or 256 pages of 256 bytes each.
+ <tag><tt/dtv-himem.emd (dtv_himem_emd)/</tag>
+ A driver for the C64 D2TV (the second or PAL version). This driver offers
+ indeed 7680 pages of 256 bytes each.
</descrip><p>
<sect1>Joystick drivers<p>
+The default drivers, <tt/joy_stddrv (joy_static_stddrv)/, point to <tt/c64-stdjoy.joy (c64_stdjoy_joy)/.
+
<descrip>
- <tag><tt/c64-hitjoy.joy/</tag>
- Driver for the Digital Excess & Hitmen adapter. See
- <htmlurl url="http://www.digitalexcess.de/downloads/productions.php"
- name="http://www.digitalexcess.de/downloads/productions.php"> on
+ <tag><tt/c64-hitjoy.joy (c64_hitjoy_joy)/</tag>
+ Driver for the Digital Excess & Hitmen adapter contributed by Groepaz.
+ See <url url="http://www.digitalexcess.de/downloads/productions.php"> on
instructions how to build one. Up to four joysticks are supported.
- <tag><tt/c64-ptvjoy.joy/</tag>
- Driver for the Protovision 4-player adapter. See
- <htmlurl url="http://www.protovision-online.de/hardw/hardwstart.htm"
- name="http://www.protovision-online.de/hardw/hardwstart.htm"> for prices
- and building instructions. Up to four joysticks are supported.
+ <tag><tt/c64-ptvjoy.joy (c64_ptvjoy_joy)/</tag>
+ Driver for the Protovision 4-player adapter contributed by Groepaz. 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/c64-stdjoy.joy/</tag>
+ <tag><tt/c64-stdjoy.joy (c64_stdjoy_joy)/</tag>
Supports up to two standard joysticks connected to the joysticks port of
the C64.
-</descrip><p>
+ <tag><tt/c64-numpad.joy (c64_numpad_joy)/</tag>
+ Supports one joystick emulated by the numberpad of the C128 in C64 mode,
+ the firebutton is labeled &dquot;5&dquot; and ENTER.
+</descrip><p>
<sect1>Mouse drivers<p>
-Currently no drivers available (in fact, the API for loadable mouse drivers
-does not exist).
+You can use these drivers in text-mode or graphics-mode (TGI) programs. See
+the description of <ref id="graphics-drivers" name="the graphics drivers">.
+
+The default drivers, <tt/mouse_stddrv (mouse_static_stddrv)/, point to <tt/c64-1351.mou (c64_1351_mou)/.
+
+<descrip>
+
+ <tag><tt/c64-1351.mou (c64_1351_mou)/</tag>
+ Supports a standard mouse connected to port #0 of the C64.
+
+ <tag><tt/c64-inkwell.mou (c64_inkwell_mou)/</tag>
+ Supports the Inkwell Systems lightpens, connected to port #0 of the C64.
+ 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.)
+
+ <tag><tt/c64-joy.mou (c64_joy_mou)/</tag>
+ Supports a mouse emulated by a standard joystick, e.g. 1350 mouse, in port
+ #1 of the C64.
+
+ <tag><tt/c64-pot.mou (c64_pot_mou)/</tag>
+ Supports a potentiometer device, e.g. Koala Pad, connected to port #1 of
+ the C64.
+
+</descrip><p>
<sect1>RS232 device drivers<p>
<descrip>
- <tag><tt/c64-swlink.ser/</tag>
- Driver for the SwiftLink cartridge. Supports up to 38400 baud, 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
+ <tag><tt/c64-swlink.ser (c64_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.
</descrip><p>
<sect>Other hints<p>
+
+<sect1>Escape code<p>
+
+For an Esc, press CTRL and the <tt/[/ key.
+
+
<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 choosen:
+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", ARG 3,, ARG5, ...
+ RUN:REM ARG1 " ARG2 IS QUOTED" ARG3 "" ARG5
</verb></tscreen>
<enum>
-<item>Arguments are separated by commas.
-<item>There must be a comma after the first <tt/REM/.
-<item>Leading spaces are ignored; trailing spaces are included unless the
- argument was quoted.
-<item>The first argument passed to <tt/main/ is the program name.
+<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.
-<sect>Bugs/Feedback<p>
-If you have problems using the library, if you find any bugs, or if you're
-doing something interesting with it, I would be glad to hear from you. Feel
-free to contact me by email (<htmlurl url="mailto:uz@cc65.org"
-name="uz@cc65.org">).
+<sect1>Interrupts<p>
+
+The runtime for the C64 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">.
</enum>
</article>
-
-
-
projects / cc65 / blobdiff