<article>
-<title>enhanced Apple //e specific information for cc65
-<author>Ullrich von Bassewitz, <htmlurl url="mailto:uz@cc65.org" name="uz@cc65.org">
-<date>2003-12-16
+<title>Enhanced Apple //e specific information for cc65
+<author><url url="mailto:ol.sc@web.de" name="Oliver Schmidt">
+<date>2014-04-10
<abstract>
An overview over the enhanced Apple //e runtime system as it is
pitfalls specific to that platform.
Please note that enhanced Apple //e 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 output format generated by the linker for the
-enhanced Apple //e target is a machine language program with a 4 byte DOS
-3.3 header. The standard load address is $800.
+The standard binary file format generated by the linker for the
+enhanced Apple //e 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.
-The DOS header is in its own segment named <tt/EXEHDR/. If you don't want the
-header for some reason, you can change
-
-<verb>
- HEADER: start = $0000, size = $4, file = %O;
-</verb>
-
-to
-
-<verb>
- HEADER: start = $0000, size = $4, file = "";
-</verb>
-
-in the linker configuration to have the linker remove it.
-
-Please note that there is a "Apple ][ ProDOS 8 system program
-for loading binary programs" available in the cc65 User Contributions section.
-It adds all benefits of a ProDOS 8 system program to the standard binary
-program generated by the linker for the enhanced Apple //e target.
+<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.
+For ProDOS 8 system programs the load address is fixed to $2000 so there
+is no need for a header. Thus the linker configuration
+<ref id="apple-sys-cfg" name="apple2enh-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/.
<sect>Memory layout<p>
In the standard setup, cc65 generated programs use the memory from
-$800 to $95FF, so 35.5K of memory are available. ROM calls are
-possible without further precautions.
+$803 to $95FF, so 35.5 KB of RAM are available.
Special locations:
<descrip>
+
<tag/Stack/
The C runtime stack is located at HIMEM and grows downwards, regardless of
how your linker config file is setup.
<tag/Heap/
The C heap is located at the end of the program and grows towards the C
runtime stack.
+
+</descrip><p>
+
+While running <tt/main()/ the Language Card bank 2 is enabled for read access.
+However while running module constructors/destructors the Language Card is disabled.
+
+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.
+
+The amount of memory available in the Language Card for generated code depends
+on the chosen <ref id="link-configs" name="linker configuration">.
+
+
+
+<sect>Linker configurations<label id="link-configs"><p>
+
+The ld65 linker comes with a default config file for the enhanced Apple //e,
+which is used via <tt/-t apple2enh/.
+The apple2enh package comes with additional secondary linker config files, which
+are used via <tt/-t apple2enh -C <configfile>/.
+
+
+<sect1>default config file (<tt/apple2enh.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.
+
+<descrip>
+
+ <tag><tt/RAM:/ Main memory area</tag>
+ From $803 to $95FF (35.5 KB)
+
+ <tag><tt/LC:/ Language Card memory area</tag>
+ From $D400 to $DFFF (3 KB)
+
+ <tag><tt/STARTADDRESS:/ Program start address</tag>
+ Variable (default: $803)
+
+ <tag><tt/HEADER:/ Binary file header</tag>
+ DOS 3.3 header (address and length)
+
+</descrip><p>
+
+
+<sect1><tt/apple2enh-dos33.cfg/<p>
+
+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.
+
+<descrip>
+
+ <tag><tt/RAM:/ Main memory area</tag>
+ From $803 to $95FF (35.5 KB)
+
+ <tag><tt/LC:/ Language Card memory area</tag>
+ From $D000 to $FFFF (12 KB)
+
+ <tag><tt/STARTADDRESS:/ Program start address</tag>
+ Variable (default: $803)
+
+ <tag><tt/HEADER:/ Binary file header</tag>
+ DOS 3.3 header (address and length)
+
+</descrip><p>
+
+
+<sect1><tt/apple2enh-system.cfg/<label id="apple-sys-cfg"><p>
+
+Configuration for a system program running on ProDOS 8.
+
+<descrip>
+
+ <tag><tt/RAM:/ Main memory area</tag>
+ From $2000 to $BEFF (39.75 KB)
+
+ <tag><tt/LC:/ Language Card memory area</tag>
+ From $D400 to $DFFF (3 KB)
+
+ <tag><tt/STARTADDRESS:/ Program start address</tag>
+ Fixed ($2000)
+
+ <tag><tt/HEADER:/ Binary file header</tag>
+ None
+
+</descrip><p>
+
+
+<sect1><tt/apple2enh-loader.cfg/<label id="apple-load-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.
+
+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.
+
+<descrip>
+
+ <tag><tt/RAM:/ Main memory area</tag>
+ From $800 to $BEFF (45.75 KB)
+
+ <tag><tt/LC:/ Language Card memory area</tag>
+ From $D400 to $DFFF (3 KB)
+
+ <tag><tt/STARTADDRESS:/ Program start address</tag>
+ Variable (default: $800)
+
+ <tag><tt/HEADER:/ Binary file header</tag>
+ DOS 3.3 header (address and length)
+
</descrip><p>
+<sect1><tt/apple2enh-reboot.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/ (see above) together
+with the function <tt/rebootafterexit()/.
+
+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!
+
+<descrip>
+
+ <tag><tt/RAM:/ Main memory area</tag>
+ From $800 to $BEFF (45.75 KB)
+
+ <tag><tt/LC:/ Language Card memory area</tag>
+ From $D000 to $DFFF (4 KB)
+
+ <tag><tt/STARTADDRESS:/ Program start address</tag>
+ Variable (default: $800)
+
+ <tag><tt/HEADER:/ Binary file header</tag>
+ DOS 3.3 header (address and length)
+
+</descrip><p>
+
+
+
+<sect>ProDOS 8 system programs<p>
+
+ProDOS 8 system programs are always loaded to the start address $2000.
+For cc65 programs this means that the 6 KB from $800 to $2000 are
+by default unused. There are however several options to make use of that memory
+range.
+
+
+<sect1>LOADER.SYSTEM<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
+<ref id="apple-load-cfg" name="apple2enh-loader.cfg"> with start address
+$803 and load it with the targetutil LOADER.SYSTEM. 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/.
+
+
+<sect1>Heap<p>
+
+If the cc65 program can be successfully linked as system program using the linker
+configuration <ref id="apple-sys-cfg" name="apple2enh-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()/.
+
+
+<sect1>ProDOS 8 I/O buffers<p>
+
+ProDOS 8 requires for every open file a page-aligned 1 KB I/O buffer. By default
+these buffers are allocated by the cc65 runtime system on the heap using
+<tt/posix_memalign()/. While this is generally the best solution it means quite
+some overhead for (especially rather small) cc65 programs which do open files
+but don't make use of the heap otherwise.
+
+The apple2enh package comes with the alternative ProDOS 8 I/O buffer allocation
+module <tt/apple2enh-iobuf-0800.o/ which uses the memory between $800 and
+the program start address for the 1 KB I/O buffers. For system programs (with
+start address $2000) this results in up to 6 I/O buffers and thus up to 6
+concurrently open files.
+
+While using <tt/_heapadd()/ as described in the section above together with the
+default I/O buffer allocation basically yields the same placement of I/O buffers
+in memory the primary benefit of <tt/apple2enh-iobuf-0800.o/ is a reduction in code
+size - and thus program file size - of more than 1400 bytes.
+
+Using <tt/apple2enh-iobuf-0800.o/ is as simple as placing it on the linker command
+line like this:
+
+<tscreen><verb>
+cl65 -t apple2enh -C apple2enh-system.cfg myprog.c apple2enh-iobuf-0800.o
+</verb></tscreen>
+
+
<sect>Platform specific header files<p>
<tt/apple2enh.h/ header file.
-<sect1>
enhanced Apple //e specific functions<p>
+<sect1>
Enhanced Apple //e specific functions<p>
The functions listed below are special for the enhanced Apple //e. 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>_textframe
-<item>_textframexy
+<item>_filetype
<item>get_ostype
+<item>rebootafterexit
+<item>ser_apple2_slot
+<item>textframe
+<item>textframexy
+<item>tgi_apple2_mix
+<item>videomode
</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/a2e.lo.tgi/</tag>
- This driver was written by Stefan Haubenthal. It features a resolution of
- 40×40 with 16 colors. At the bottom of the screen, 4 additional text
- lines are available.
+ <tag><tt/a2e.lo.tgi (a2e_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/a2e.hi.tgi (a2e_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.
+
+ Note that the second hires page is only available if the text display is not in
+ 80 column mode. This can be asserted by calling <tt/videomode (VIDEOMODE_40COL);/
+ before installing the driver.
+
+ 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.
- <tag><tt/a2e.hi.tgi/</tag>
- This driver was written by Stefan Haubenthal. It features a resolution of
- 280×192 with 6 colors. Note that programs using this driver will have
- to be linked with <tt/--start-addr $4000/ to reserve the first hires page.
+ In memory constrained situations the memory from $803 to $1FFF
+ can be made available to a program by calling <tt/_heapadd ((void *) 0x0803, 0x17FD);/
+ at the beginning of <tt/main()/. Doing so is beneficial even if the program
+ doesn't use the the heap explicitly because loading the driver (and in fact
+ already opening the driver file) uses the heap implicitly.
</descrip><p>
<descrip>
- <tag><tt/a2e.lc.emd/</tag>
- Gives access to 12KB RAM (48 pages of 256 bytes each) on the
- Apple II Language Card. The driver was contributed by Stefan Haubenthal.
- Note that this driver is incompatible with any DOS using the Language
- Card memory!
+ <tag><tt/a2e.auxmem.emd (a2e_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><p>
<descrip>
- <tag><tt/a2e.stdjoy.joy/</tag>
+ <tag><tt/a2e.stdjoy.joy (a2e_stdjoy_joy)/</tag>
Supports up to two standard analog joysticks connected to the game port of
the enhanced Apple //e.
<descrip>
- <tag><tt/a2e.stdmou.mou/</tag>
+ <tag><tt/a2e.stdmou.mou (a2e_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].
<descrip>
- <tag><tt/a2e.ssc.ser/</tag>
+ <tag><tt/a2e.ssc.ser (a2e_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
interrupt driven, and the transceiver blocks if the receiver asserts
flow control because of a full buffer.
- The driver defaults to slot 2. Call <tt/ser_ioctl(0, <slot>)/ prior to
- <tt/ser_open/ in order to select a different slot. <tt/ser_ioctl/ succeeds
- for all Apple II slots, but <tt/ser_open/ fails with
+ The driver defaults to slot 2. Call <tt/ser_apple2_slot()/ prior to
+ <tt/ser_open()/ in order to select a different slot. <tt/ser_apple2_slot()/
+ succeeds for all Apple II slots, but <tt/ser_open()/ fails with
<tt/SER_ERR_NO_DEVICE/ if there's no SSC firmware found in the selected slot.
</descrip><p>
<sect>Limitations<p>
+<sect1>DOS 3.3<p>
+
+Although the standard binaries generated by the linker for the enhanced Apple //e
+generally run both on DOS 3.3 (with Applesoft BASIC) and on ProDOS 8 (with
+BASIC.SYSTEM) there are some limitations for DOS 3.3:
+
+<descrip>
+
+ <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. 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/a2e.stdmou.mou/ and <tt/a2e.ssc.ser/ are not functional as they depend on
+ interrupts.
+
+</descrip><p>
+
+
+<sect1>Direct console I/O<p>
+
+<descrip>
+
+ <tag/Color/
+ The enhanced Apple //e has no color text mode. Therefore the functions
+ textcolor(), bgcolor() and bordercolor() have no effect.
+
+ <tag/Cursor/
+ The enhanced Apple //e has no hardware cursor. Therefore the function
+ cursor() has no effect.
+
+</descrip><p>
+
+
<sect>Other hints<p>
supported by BASIC, the following syntax was chosen:
<tscreen><verb>
-]CALL2048:REM ARG1 " ARG2 IS QUOTED" ARG3 "" ARG5
+]CALL2051:REM ARG1 " ARG2 IS QUOTED" ARG3 "" ARG5
</verb></tscreen>
<enum>
<sect1>Interrupts<p>
-The runtime for the enhanced Apple //e uses routines marked as <tt/.CONDES/
-type 2 for ProDOS 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 enhanced Apple //e 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>
+
+<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/drive_id/ according
+ to the formula
-<sect>Bugs/Feedback<p>
+ <tscreen>
+ device = slot + (drive - 1) * 8
+ </tscreen>
-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">).
+ so that for example slot 6 drive 2 is mapped to <tt/device/ 14.
+
+ <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.
+
+</descrip><p>
<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
+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,
projects / cc65 / blobdiff