<!doctype linuxdoc system>
<article>
-
<title>Apple ][ specific information for cc65
-<author>Oliver Schmidt, <htmlurl url="mailto:ol.sc@web.de" name="ol.sc@web.de">
-<date>2009-10-07
+<author><url url="mailto:ol.sc@web.de" name="Oliver Schmidt">
<abstract>
An overview over the Apple ][ runtime system as it is
pitfalls specific to that platform.
Please note that Apple ][ specific functions are just mentioned
-here, they are described in detail in the separate <htmlurl url="funcref.html"
+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 file format generated by the linker for the
-Apple ][ target is a binary program with a 4 byte DOS 3.3 header
-containing the load address and load length. The default load address is
-$803.
-
-<bf/AppleCommander 1.3.5/ or later (available at <url
-url="http://applecommander.sourceforge.net/">) includes the option <tt/-cc65/
-that allows to put binary files with a DOS 3.3 header onto disk images
-containing DOS 3.3 as well as ProDOS 8.
+Apple ][ target is an <url name="AppleSingle"
+url="http://kaiser-edv.de/documents/AppleSingle_AppleDouble.pdf"> file.
+The default load address is $803.
-For ProDOS 8 system programs the load address is fixed to $2000 so there
-is no need for a header. Thus the linker configuration
-<htmlurl url="apple2-4.html#ss4.3" name="apple2-system.cfg"> for those programs
-omits the DOS 3.3 header. The right AppleCommander option to put system files
-without a header on a ProDOS 8 disk image is <tt/-p/.
+<bf/AppleCommander 1.4.0/ or later (available at <url
+url="https://applecommander.github.io/">) includes the option <tt/-as/ that
+allows to put AppleSingle files onto disk images containing DOS 3.3 as well
+as ProDOS 8.
<sect>Memory layout<p>
Enabling the Language Card allows to use it as additional memory for cc65
generated code. However code is never automatically placed there. Rather code
needs to be explicitly placed in the Language Card either per file by compiling
-with <tt/--code-name HIGHCODE/ or per function by enclosing in <tt/#pragma
-code-name (push, "HIGHCODE")/ and <tt/#pragma code-name (pop)/. In either case the
-cc65 runtime system takes care of actually moving the code into the Language
-Card.
+with <tt/--code-name LC/ or per function by enclosing in <tt/#pragma code-name
+(push, "LC")/ and <tt/#pragma code-name (pop)/. In either case the cc65 runtime
+system takes care of actually moving the code into the Language Card.
The amount of memory available in the Language Card for generated code depends
-on the chosen <htmlurl url="apple2-4.html" name="linker configuration">.
+on the <ref id="link-configs" name="linker configuration"> parameters. There are
+several usefull settings:
+
+<descrip>
+
+ <tag>LC address: $D400, LC size: $C00</tag>
+ For plain vanilla ProDOS 8 which doesn't actually use the Language Card bank 2
+ memory from $D400 to $DFFF. This is the default setting.
+
+ <tag>LC address: $D000, LC size: $1000</tag>
+ For ProDOS 8 together with the function <tt/rebootafterexit()/. If a program
+ doesn't quit to the ProDOS 8 dispatcher but rather reboots the machine after
+ exit then a plain vanilla ProDOS 8 doesn't make use of the Language Card bank
+ 2 at all.
+
+ <tag>LC address: $D000, LC size: $3000</tag>
+ For plain vanilla DOS 3.3 which doesn't make use of the Language Card at all.
+
+</descrip><p>
-<sect>Linker configurations<p>
+<sect>Linker configurations<label id="link-configs"><p>
-The ld65 linker comes with a builtin config file for the Apple ][,
-which is used via <tt/-t apple2/ (and displayed via <tt/--dump-config apple2/).
+The ld65 linker comes with a default config file for the Apple ][,
+which is used via <tt/-t apple2/.
The apple2 package comes with additional secondary linker config files, which
-are used via <tt/-C <configfile>/.
+are used via <tt/-t apple2 -C <configfile>/.
-<sect1>
builtin config file<p>
+<sect1>
default config file (<tt/apple2.cfg/)<label id="apple-def-cfg"><p>
-Default configuration optimized for a binary program running on ProDOS 8 with
-BASIC.SYSTEM. A plain vanilla ProDOS 8 doesn't actually use the Language Card
-bank 2 memory from $D400 to $DFFF.
+Default configuration for a binary program.
+
+Parameters:
<descrip>
- <tag><tt/RAM:/ Main memory area</tag>
- From $803 to $95FF (35.5 KB)
+ <tag><tt/STARTADDRESS:/ Program start address</tag>
+ Default: $803. Use <tt/-S <addr>/ to set a different start address.
- <tag><tt/LC:/ Language Card memory area</tag>
- From $D400 to $DFFF (3 KB)
+ <tag><tt/__EXEHDR__:/ AppleSingle executable file header</tag>
+ Default: Yes. Use <tt/-D __EXEHDR__=0/ to omit the AppleSingle header.
- <tag><tt/STARTADDRESS:/ Program start address</tag>
- Variable (default: $803)
+ <tag><tt/__STACKSIZE__:/ C runtime stack size</tag>
+ Default: $800. Use <tt/-D __STACKSIZE__=<size>/ to set a different
+ stack size.
- <tag><tt/HEADER:/ Binary file header</tag>
- DOS 3.3 header (address and length)
+ <tag><tt/__HIMEM__:/ Highest usable memory address presumed at link time</tag>
+ Default: $9600. Use <tt/-D __HIMEM__=<addr>/ to set a different
+ highest usable address.
+
+ <tag><tt/__LCADDR__:/ Address of code in the Language Card</tag>
+ Default: $D400. Use <tt/-D __LCADDR__=<addr>/ to set a different
+ code address.
+
+ <tag><tt/__LCSIZE__:/ Size of code in the Language Card</tag>
+ Default: $C00. Use <tt/-D __LCSIZE__=<size>/ to set a different
+ code size.
</descrip><p>
-<sect1><tt/apple2-dos33.cfg/<p>
+<sect1><tt/apple2-system.cfg/<label id="apple-sys-cfg"><p>
+
+Configuration for a system program running on ProDOS 8 and using the memory from
+$2000 to $BEFF.
-Configuration optimized for a binary program running on DOS 3.3. A plain
-vanilla DOS 3.3 doesn't make use of the Language Card at all.
+Parameters:
<descrip>
- <tag><tt/RAM:/ Main memory area</tag>
- From $803 to $95FF (35.5 KB)
+ <tag><tt/__EXEHDR__:/ AppleSingle executable file header</tag>
+ Default: Yes. Use <tt/-D __EXEHDR__=0/ to omit the AppleSingle header.
- <tag><tt/LC:/ Language Card memory area</tag>
- From $D000 to $FFFF (12 KB)
+ <tag><tt/__STACKSIZE__:/ C runtime stack size</tag>
+ Default: $800. Use <tt/-D __STACKSIZE__=<size>/ to set a different
+ stack size.
- <tag><tt/STARTADDRESS:/ Program start address</tag>
- Variable (default: $803)
+ <tag><tt/__LCADDR__:/ Address of code in the Language Card</tag>
+ Default: $D400. Use <tt/-D __LCADDR__=<addr>/ to set a different
+ code address.
- <tag><tt/HEADER:/ Binary file header</tag>
- DOS 3.3 header (address and length)
+ <tag><tt/__LCSIZE__:/ Size of code in the Language Card</tag>
+ Default: $C00. Use <tt/-D __LCSIZE__=<size>/ to set a different
+ code size.
</descrip><p>
-<sect1><tt/apple2-system.cfg/<p>
+<sect1><tt/apple2-hgr.cfg/<p>
+
+Configuration for a program including a hires page. See <tt>testcode/lib/apple/hgrtest.c</tt>
+for an example of such a program.
-Configuration for a system program running on ProDOS 8.
+Parameters:
<descrip>
- <tag><tt/RAM:/ Main memory area</tag>
- From $2000 to $BEFF (39.75 KB)
+ <tag><tt/STARTADDRESS:/ Program start address</tag>
+ Default: $803. Use <tt/-S <addr>/ to set a different start address.
+
+ <tag><tt/__EXEHDR__:/ AppleSingle executable file header</tag>
+ Default: Yes. Use <tt/-D __EXEHDR__=0/ to omit the AppleSingle header.
- <tag><tt/LC:/ Language Card memory area</tag>
- From $D400 to $DFFF (3 KB)
+ <tag><tt/__STACKSIZE__:/ C runtime stack size</tag>
+ Default: $800. Use <tt/-D __STACKSIZE__=<size>/ to set a different
+ stack size.
- <tag><tt/STARTADDRESS:/ Program start address</tag>
- Fixed ($2000)
+ <tag><tt/__HIMEM__:/ Highest usable memory address presumed at link time</tag>
+ Default: $9600. Use <tt/-D __HIMEM__=<addr>/ to set a different
+ highest usable address.
+
+ <tag><tt/__LCADDR__:/ Address of code in the Language Card</tag>
+ Default: $D400. Use <tt/-D __LCADDR__=<addr>/ to set a different
+ code address.
- <tag><tt/HEADER:/ Binary file header</tag>
- None
+ <tag><tt/__LCSIZE__:/ Size of code in the Language Card</tag>
+ Default: $C00. Use <tt/-D __LCSIZE__=<size>/ to set a different
+ code size.
</descrip><p>
-<sect1><tt/apple2-
loader.cfg/<p>
+<sect1><tt/apple2-
overlay.cfg/<p>
-Configuration optimized for a binary program running on ProDOS 8 without
-BASIC.SYSTEM. Intended to be used with <bf/LOADER.SYSTEM - an
-Apple ][ ProDOS 8 loader for cc65 programs/, which is available
-in the cc65 User Contributions section.
+Configuration for an overlay program with up to nine overlays. The overlay files
+don't include the AppleSingle header. See <tt>samples/overlaydemo.c</tt> for more
+information on overlays.
-A program loaded by LOADER.SYSTEM works like a ProDOS 8 system program but
-isn't tied to the start address $2000. Thus with the default start
-address $800 the main memory area is increased by 6 KB.
+Parameters:
<descrip>
- <tag><tt/RAM:/ Main memory area</tag>
- From $800 to $BEFF (45.75 KB)
+ <tag><tt/STARTADDRESS:/ Program start address</tag>
+ Default: $803. Use <tt/-S <addr>/ to set a different start address.
- <tag><tt/LC:/ Language Card memory area</tag>
- From $D400 to $DFFF (3 KB)
+ <tag><tt/__EXEHDR__:/ AppleSingle executable file header</tag>
+ Default: Yes. Use <tt/-D __EXEHDR__=0/ to omit the AppleSingle header.
- <tag><tt/STARTADDRESS:/ Program start address</tag>
- Variable (default: $800)
+ <tag><tt/__STACKSIZE__:/ C runtime stack size</tag>
+ Default: $800. Use <tt/-D __STACKSIZE__=<size>/ to set a different
+ stack size.
- <tag><tt/HEADER:/ Binary file header</tag>
- DOS 3.3 header (address and length)
+ <tag><tt/__HIMEM__:/ Highest usable memory address presumed at link time</tag>
+ Default: $9600. Use <tt/-D __HIMEM__=<addr>/ to set a different
+ highest usable address.
-</descrip><p>
+ <tag><tt/__LCADDR__:/ Address of code in the Language Card</tag>
+ Default: $D400. Use <tt/-D __LCADDR__=<addr>/ to set a different
+ code address.
+ <tag><tt/__LCSIZE__:/ Size of code in the Language Card</tag>
+ Default: $C00. Use <tt/-D __LCSIZE__=<size>/ to set a different
+ code size.
-<sect1><tt/apple2-reboot.cfg/<p>
+ <tag><tt/__OVERLAYSIZE__:/ Size of code in the overlays</tag>
+ Default: $1000. Use <tt/-D __OVERLAYSIZE__=<size>/ to set a different
+ code size.
-Configuration optimized for a binary program running on ProDOS 8 without
-BASIC.SYSTEM. Intended to be used with <bf/LOADER.SYSTEM - an
-Apple ][ ProDOS 8 loader for cc65 programs/ (see above) together
-with the function <tt/rebootafterexit()/.
+</descrip><p>
-If a ProDOS 8 system program doesn't quit to the ProDOS 8 dispatcher but rather
-reboots the machine after exit then a plain vanilla ProDOS 8 doesn't make use of
-the Language Card bank 2 at all.
-This setup makes nearly 50 KB available to a cc65 program - on a 64 KB machine!
+<sect1><tt/apple2-asm.cfg/<p>
-<descrip>
+Configuration for an assembler program that doesn't need a special setup.
- <tag><tt/RAM:/ Main memory area</tag>
- From $800 to $BEFF (45.75 KB)
+Parameters:
- <tag><tt/LC:/ Language Card memory area</tag>
- From $D000 to $DFFF (4 KB)
+<descrip>
<tag><tt/STARTADDRESS:/ Program start address</tag>
- Variable (default: $800)
+ Default: $803. Use <tt/-S <addr>/ to set a different start address.
- <tag><tt/HEADER:/ Binary file header</tag>
- DOS 3.3 header (address and length)
+ <tag><tt/__EXEHDR__:/ AppleSingle executable file header</tag>
+ Default: No. Use <tt/-u __EXEHDR__ apple2.lib/ to add the AppleSingle header.
</descrip><p>
The easiest (and for really large programs in fact the only) way to have a cc65
program use the memory from $800 to $2000 is to link it as binary
-(as opposed to system) program using the linker configuration
-<htmlurl url="apple2-4.html#ss4.4" name="apple2-loader.cfg"> with start address
-$800 and load it with <bf/LOADER.SYSTEM - an Apple ][
-ProDOS 8 loader for cc65 programs/. The program then works like a system program
-(i.e. quits to the ProDOS dispatcher).
+(as opposed to system) program using the default linker configuration
+<ref id="apple-def-cfg" name="apple2.cfg"> with <tt/__HIMEM__/ set to $BF00
+and load it with the LOADER.SYSTEM utility. The program then works like a system
+program (i.e. quits to the ProDOS dispatcher).
Using LOADER.SYSTEM is as simple as copying it to the ProDOS 8 directory of the
program to load under name <program>.SYSTEM as a system program. For
-example the program <tt/MYPROG/ is loaded by <tt/MYPROG.SYSTEM/.
+example the program <tt/MYPROG/ is loaded by <tt/MYPROG.SYSTEM/. The right
+AppleCommander option to put LOADER.SYSTEM on a ProDOS 8 disk image is <tt/-p/.
<sect1>Heap<p>
-If the cc65 program can be successully linked as system program using the linker
-configuration <htmlurl url="apple2-4.html#ss4.3" name="apple2-system.cfg"> but
+If the cc65 program can be successfully linked as system program using the linker
+configuration <ref id="apple-sys-cfg" name="apple2-system.cfg">, but
uses the heap either explicitly or implicitly (i.e. by loading a driver) then
the memory from $800 to $2000 can be added to the heap by calling
<tt/_heapadd ((void *) 0x0800, 0x1800);/ at the beginning of <tt/main()/.
in memory the primary benefit of <tt/apple2-iobuf-0800.o/ is a reduction in code
size - and thus program file size - of more than 1400 bytes.
-Using <tt/apple2-iobuf-0800.o/ is as simple as placing it on the linker command
+Using <tt/apple2-iobuf-0800.o/ is as simple as placing it on the linker command
line like this:
<tscreen><verb>
<sect1>Apple ][ specific functions<p>
The functions listed below are special for the Apple ][. See
-the <htmlurl url="funcref.html" name="function reference"> for declaration and
+the <url url="funcref.html" name="function reference"> for declaration and
usage.
<itemize>
+<item>_auxtype
<item>_dos_type
-<item>drivecount
-<item>drivelist
+<item>_filetype
<item>get_ostype
<item>rebootafterexit
-<item>rootdir
<item>ser_apple2_slot
<item>tgi_apple2_mix
</itemize>
<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>
<descrip>
- <tag><tt/a2.lo.tgi/</tag>
+ <tag><tt/a2.lo.tgi (a2_lo_tgi)/</tag>
This driver features a resolution of 40×48 with 16 colors.
-
+
The function <tt/tgi_apple2_mix()/ allows to activate 4 lines of text. The
function clears the corresponding area at the bottom of the screen.
- <tag><tt/a2.hi.tgi/</tag>
+ <tag><tt/a2.hi.tgi (a2_hi_tgi)/</tag>
This driver features a resolution of 280×192 with 8 colors and two
hires pages. Note that programs using this driver will have to be linked
- with <tt/--start-addr $4000/ to reserve the first hires page or with
- <tt/--start-addr $6000/ to reserve both hires pages.
+ with <tt/-S $4000/ to reserve the first hires page or with <tt/-S $6000/
+ to reserve both hires pages.
The function <tt/tgi_apple2_mix()/ allows to activate 4 lines of text. The
function doesn't clear the corresponding area at the bottom of the screen.
<descrip>
- <tag><tt/a2.auxmem.emd/</tag>
- Gives access to 47,5 KB RAM (190 pages of 256 bytes each) on an Extended
+ <tag><tt/a2.auxmem.emd (a2_auxmem_emd)/</tag>
+ Gives access to 47.5 KB RAM (190 pages of 256 bytes each) on an Extended
80-Column Text Card.
-
+
Note that this driver doesn't check for the actual existence of the memory
and that it doesn't check for ProDOS 8 RAM disk content!
<descrip>
- <tag><tt/a2.stdjoy.joy/</tag>
+ <tag><tt/a2.stdjoy.joy (a2_stdjoy_joy)/</tag>
Supports up to two standard analog joysticks connected to the game port of
the Apple ][.
<descrip>
- <tag><tt/a2.stdmou.mou/</tag>
+ <tag><tt/a2.stdmou.mou (a2_stdmou_mou)/</tag>
Driver for the AppleMouse II Card. Searches all Apple II slots
for an AppleMouse II Card compatible firmware. The default bounding
box is [0..279,0..191].
-
- Programs using this driver will have to be linked with <tt/--start-addr $4000/
+
+ Programs using this driver will have to be linked with <tt/-S $4000/
to reserve the first hires page if they are intended to run on an
Apple ][ (in contrast to an Apple //e) because the
AppleMouse II Card firmware writes to the hires page when initializing
<descrip>
- <tag><tt/a2.ssc.ser/</tag>
+ <tag><tt/a2.ssc.ser (a2_ssc_ser)/</tag>
Driver for the Apple II Super Serial Card. Supports up to 19200 baud,
hardware flow control (RTS/CTS) and interrupt driven receives. Note
that because of the peculiarities of the 6551 chip transmits are not
<descrip>
- <tag>Disk File I/O</tag>
+ <tag>Disk file I/O</tag>
There's no disk file I/O support. Any attempt to use it yields an error with
<tt/errno/ set to <tt/ENOSYS/. This implicitly means that loadable drivers
- are in general not functional as they depend on disk file I/O. However they
- may be converted to statically linked drivers using the co65 object-file
- converter.
+ are in general not functional as they depend on disk file I/O. Therefore the statically
+ linked drivers have to be used instead.
<tag/Interrupts/
There's no <tt/interruptor/ support. Any attempt to use it yields the message
'FAILED TO ALLOC INTERRUPT' on program startup. This implicitly means that
- <tt/a2.stdmou.mou/ and <tt/a2.ssc.ser/ are not functional as they depend on
- interrupts.
-
+ mouse and RS232 device drivers are not functional as they depend on interrupts.
+
</descrip><p>
+<sect1>D
irect console I/O<p>
-Although <htmlurl url="dio.html" name="DIO"> generally works with all ProDOS 8
-devices, the function <htmlurl url="dio-3.html" name="dio_query_sectcount()">
-simply always return 280 (which is only correct for a 140 KB disk).
+The Apple ][ has no color text mode. Therefore the functions
+<tt/textcolor()/, <tt/bgcolor()/ and <tt/bordercolor()/ have no effect.
-<sect1>
Direct console I/O<p>
+<sect1>
Random number generator<p>
-<descrip>
+The random number seed is generated from the time the program waits for user input.
+Therefore it is necessary to wait for at least one user keypress either via Standard
+I/O or via Direct console I/O before initializing the pseudo random number generator.
- <tag/Color/
- The Apple ][ has no color text mode. Therefore the functions
- <htmlurl url="funcref-205.html" name="textcolor()">,
- <htmlurl url="funcref-68.html" name="bgcolor()"> and
- <htmlurl url="funcref-69.html" name="bordercolor()"> have no effect.
- <tag/Cursor/
- The Apple ][ has no hardware cursor. Therefore the function
- <htmlurl url="funcref-88.html" name="cursor()"> has no effect.
+<sect1>Realtime clock<p>
-</descrip><p>
+There are several types of realtime clocks. It's not desirable to have specific code
+for all of them. As ProDOS 8 supports file timestamps, realtime clock owners usually
+use ProDOS 8 drivers for their realtime clock. Those drivers read the realtime clock
+and write the result to the date/time location in RAM ($BF90 to $BF93).
+ProDOS 8 reads the date/time from that RAM location. If there's no realtime clock the
+RAM location keeps containing zeros. ProDOS 8 uses those zeros as timestamps and the
+files show up in a directory as <tt/<NO DATE>/.
+
+There's no common interface to set realtime clocks so if a realtme clock <bf/IS/
+present there's just nothing to do. However, if there's <bf/NO/ realtime clock present,
+the user might very well be interested to "manually" set the RAM location in order to
+have timestamps. But he surely doesn't want to manually set the RAM location over and
+over again. Rather he wants to set it just once after booting ProDOS 8.
+
+From that perspective it makes most sense to not set both the date and the time but
+rather only set the date and have the time just stay zero. Then files show up in a
+directory as <tt/DD-MON-YY 0:00/.
+
+So <tt/clock_settime()/ checks if the current time equals 0:00. If it does <bf/NOT/
+then a realtime clock is supposed to be active and <tt/clock_settime()/ fails with
+<tt/ERANGE/. Otherwise <tt/clock_settime()/ sets the date - and completely ignores
+the time provided as parameter.
+
+<tt/clock_getres()/ too checks if the current time equals 0:00. If it does <bf/NOT/
+then a realtime clock is supposed to be active and <tt/clock_getres()/ returns a time
+resolution of one minute. Otherwise <tt/clock_getres()/ presumes that the only one
+who sets the RAM location is <tt/clock_settime()/ and therefore returns a time
+resolution of one day.
<sect1>Interrupts<p>
-The runtime for the Apple ][ uses routines marked as <tt/.CONDES/
-type <tt/interruptor/ for ProDOS 8 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 <htmlurl url="ca65.html"
-name="assembler manual">.
+The runtime for the Apple ][ uses routines marked as
+<tt/.INTERRUPTOR/ for ProDOS 8 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">.
<sect1>DIO<p>
-The function <htmlurl url="dio-1.html" name="dio_open()"> has the single parameter
-<tt/drive_id/ to identify the drive to be opened. Therefore an Apple II
-slot and drive pair is mapped to that <tt/drive_id/ according to the formula
+<descrip>
+
+ <tag/Drive ID/
+ The function <url url="dio.html#s1" name="dio_open()"> has the single
+ parameter <tt/device/ to identify the device to be opened. Therefore an
+ Apple II slot and drive pair is mapped to that <tt/device/ according
+ to the formula
+
+ <tscreen>
+ device = slot + (drive - 1) * 8
+ </tscreen>
+
+ so that for example slot 6 drive 2 is mapped to <tt/device/ 14.
-<verb>
- drive_id = slot * 16 + (drive - 1) * 128
-</verb>
+ <tag/Sector count/
+ The function <url url="dio.html#s3" name="dio_query_sectcount()"> returns
+ the correct sector count for all ProDOS 8 disks. However for any non-ProDOS 8
+ disk it simply always returns 280 (which is only correct for a 140 KB disk).
+ This condition is indicated by the <tt/_oserror/ value 82.
-so that for example slot 6 drive 2 is mapped to <tt/drive_id/ 224.
+</descrip><p>
+<sect1>Specifying file types for fopen<p>
-<sect>Bugs/Feedback<p>
+<descrip>
-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">).
+ <tag>Explanation of File Types</tag>
+
+ ProDOS associates a file type and an auxiliary type with each file.
+ These type specifications are separate from the file's name, unlike
+ Windows which uses the file name's suffix (a.k.a.
+ extension) to specify the file type. For example, <tt/.exe/,
+ <tt/.doc/, or <tt/.bat/.
+ The ProDOS low-level
+ Machine-Language Interface (MLI) functions for creating and opening
+ files require these types to be specified. And if they don't match
+ with the file being opened, the operation may fail.
+
+ In contrast, the ISO C function <tt/fopen()/ and the POSIX function
+ <tt/open()/ have no parameter to specify either a file type or an
+ auxiliary type. Therefore, some additional mechanism for specifying
+ the file types is needed.
+
+ <tag>Specifying the File Type and Auxiliary Type</tag>
+
+ There are two global variables provided that allow the file type
+ and auxiliary type to be specified before a call to <tt/fopen()/
+ or <tt/open()/. They are defined in <tt/apple2_filetype.h/:
+
+ <tscreen>
+ <verb>
+ extern unsigned char _filetype; /* Default: PRODOS_T_BIN */
+ extern unsigned int _auxtype; /* Default: 0 */
+ </verb>
+ </tscreen>
+
+ The header file <tt/apple2_filetype.h/ also defines many values
+ that can be used to set these variables. It is included in
+ <tt/apple2.h/, which is in turn included in <tt/apple2enh.h/.
+ So it isn't necessary to include it directly. Just
+ include one of <tt/apple2.h/ or <tt/apple2enh.h/.
+
+ <tag>Example</tag>
+
+ A text file cannot be created with just the
+ standard C functions because they default to the binary type
+ <tt/PRODOS_T_BIN/. The <tt/_filetype/ variable must be set to
+ <tt/PRODOS_T_TXT/ to create a text file.
+
+ For a text file,
+ <tt/_auxtype/ specifies the record length. A zero record
+ length text file is referred to as a sequential text file.
+ This is equivalent to text files on
+ other operating systems, except that the line terminator is a
+ carriage return instead of a line-feed (Linux/BSD/MacOS) or
+ carriage return, line-feed pair (Windows).
+
+ The "sequential" text file terminology is in contrast to a
+ "random-access" text file which would
+ have a fixed-length, non-zero record length, so that the
+ file position of any individual record can be calculated.
+
+ For this example, the
+ <tt/_auxtype/ does not need to be set because it defaults to
+ the desired value, which is zero. To be more explicit,
+ <tt/_auxtype/ can also be set to <tt/PRODOS_AUX_T_TXT_SEQ/
+ which is defined as zero.
+
+ <tscreen>
+ <verb>
+ #include <stdio.h>
+ #include <string.h>
+ #include <errno.h>
+ #include <apple2.h>
+
+ void main(void)
+ {
+ FILE *out;
+ char *name = "MY.FAVS";
+
+ /*-----------------------------*/
+
+ _filetype = PRODOS_T_TXT;
+ _auxtype = PRODOS_AUX_T_TXT_SEQ;
+
+ /*-----------------------------*/
+
+ if ((out = fopen(name, "w")) != NULL) {
+ fputs("Jorah Mormont\r", out);
+ fputs("Brienne of Tarth\r", out);
+ fputs("Daenerys Targaryen\r", out);
+ fputs("Sandor Clegane\r", out);
+ if (fclose(out) == EOF) {
+ fprintf(stderr, "fclose failed for %s: %s", name, strerror(errno));
+ }
+ }
+ else {
+ fprintf(stderr, "fopen failed for %s: %s", name, strerror(errno));
+ }
+ }
+ </verb>
+ </tscreen>
+</descrip><p>
<sect>License<p>
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.
+<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>
projects / cc65 / blobdiff