Although the primary target OS for the Apple II for sure isn't DOS 3.3 but ProDOS 8 the Apple II binary files contained a DOS 3.3 4-byte header. Recently I was made aware of the AppleSingle file format. That format is a much better way to transport Apple II meta data from the cc65 toolchain to the ProDOS 8 file system. Therefore I asked AppleCommander to support the AppleSingle file format. Now that there's an AppleCommander BETA with AppleSingle support it's the right time for this change.
I bumped version to 2.17 because of this from the perspective of Apple II users of course incompatible change.
* The 16-bit comparison code actually didn't compare the high byte.
* This implementation supports only the 1541, 1571, and 1581; but, it didn't exclude the other drive types that GEOS supports.
* Two error code numbers were swapped.
* A 1571 converter didn't catch sector numbers that are too high.
* A 1581 converter didn't catch sector numbers that are too high.
All but one TGI drivers didn't use IRQs. Especially when the TGI driver kernel was the only .interruptor this meant quite some unnecessary overhead because it pulled in the whole IRQ infrastructure.
The one driver using IRQs (the graphics driver for the 160x102x16 mode on the Lynx) now uses a library reference to set up a JMP to its IRQ handler.
All but one joystick drivers didn't use IRQs. Espsecially when the joystick driver kernel was the only .interruptor this meant quite some unnecessary overhead because it pulled in the whole IRQ infrastructure.
I was told that the one driver using IRQs (the DXS/HIT-4 Player joystick driver for the C64) can be reworked to not do it. Until this is done that driver is defunct.
The Apple II linker configs don't define symbols for the STARTP segment anymore. There refer to the load/start address in the same way the executable file header does.
This function is used by many other CONIO functions, and the user program not
necessarily uses 'cgetc'. Having "setcursor" in a different object file saves
space in this case and also allows the user program to override it (e.g. when
not using GRAPHICS 0 mode).
As discussed in https://github.com/cc65/cc65/pull/452 after my premature merge the two functions in question don't work as expected.
Additionally I adjusted several style deviations in the pull request in question.
Please note that this change is absolutely untested!
Apart from the recent driver interface change:
- vic20-stdjoy.s was "slightly broken" because it didn't clear x on return from joy_read.
- vic20-ptvjoy.s was "heavily broken" because it returned a totally different set of bits of the first joystick.
The change is inspired by the code of the standard joystick driver. It is however absolutely untested.
Note: Sites like http://raster.atariportal.cz/english.htm state that there needs to be a delay when reading joysticks via the MultiJoy adapter. There's no such delay in the driver. But I don't dare to decide to add it.
So far the joy_masks array allowed several joystick drivers for a single target to each have different joy_read return values. However this meant that every call to joy_read implied an additional joy_masks lookup to post-process the return value.
Given that almost all targets only come with a single joystick driver this seems an inappropriate overhead. Therefore now the target header files contain constants matching the return value of the joy_read of the joystick driver(s) on that target.
If there indeed are several joystick drivers for a single target they must agree on a common return value for joy_read. In some cases this was alredy the case as there's a "natural" return value for joy_read. However a few joystick drivers need to be adjusted. This may cause some overhead inside the driver. But that is for sure smaller than the overhead introduced by the joy_masks lookup before.
!!! ToDo !!!
The following three joystick drivers become broken with this commit and need to be adjusted:
- atrmj8.s
- c64-numpad.s
- vic20-stdjoy.s
Some of the files in "libsrc/*/extra/" include other library files. But, the "lib/*.o" files weren't rebuilt when those other files changed.
The new dependency rules must be "bootstrapped". You must force a rebuild of all of the extra library object files (it will create the dependency files). Use these commands:
rm lib/*.o
make lib
This change includes some cleanups, removal of mainargs.s (game console
programs never have arguments), and a workaround for a problem I'm seeing.
The problem is that sometimes (in fact, more often than not) the clrscr()
call in testcode/lib/joy-test.c writes some garbage chars on the screen (most
often a "P"). Could be my hardware (I haven't seen it on MAME), but to
me the root cause is still unknown.
The configuration file and runtime (crt0.s) provided for the default NES
ROM layout (2x16k PRG, 8k CHR) incorrectly added interrupts (IRQ1, IRQ2,
TIMERIRQ) which are not supported by the NES hardware. For example, see
the NESdev wiki, which makes no reference to these interrupts.
https://wiki.nesdev.com/w/index.php/CPU_memory_map
The VECTORS region was also incorrectly set to 0xFFF6, which would have
left the 0xFFF4 normally unspecified. This did not result in any error,
however, since cc65 simply placed ROMV directly after ROM0 regardless of
start address.
(This layout may be due to a copy-and-paste from the PC-Engine
configuration, whose interrupt registers start at 0xFFF6, begins with
the three interrupts listed above, followed by NMI and START, and does
not end with a final IRQ interrupt.)
Despite the absence of any actual error, since START is still placed at
0xFFFC, this patch removes the nonexistent interrupts and also correctly
aligns the ROM0 and ROMV regions. It also has the (admittedly very
minor) benefit of freeing up 6 additional bytes for ROM0.
Stefan Dorndorf, author of XDOS, pointed out that retrieving the
default device by looking at an undocumented memory location won't
work in future XDOS versions.
He also showed a way to get the default device in a compatible
manner.
This change implements his method and adds a version check (XDOS
versions below 2.4 don't support this -- for them the behaviour
will be the same as, for example, AtariDOS: no notion of a default
drive).
For quite some time I deliberately didn't add cursor support to the Apple II CONIO imöplementation. I consider it inappropriate to increase the size of cgetc() unduly for a rather seldom used feature.
There's no hardware cursor on the Apple II so displaying a cursor during keyboard input means reading the character stored at the cursor location, writing the cursor character, reading the keyboard and finally writing back the character read initially.
The naive approach is to reuse the part of cputc() that determines the memory location of the character at the cursor position in order to read the character stored there. However that means to add at least one additional JSR / RTS pair to cputc() adding 4 bytes and 12 cycles :-( Apart from that this approach means still a "too" large cgetc().
The approach implemented instead is to include all functionality required by cgetc() into cputc() - which is to read the current character before writing a new one. This may seem surprising at first glance but an LDA(),Y / TAX sequence adds only 3 bytes and 7 cycles so it cheaper than the JSR / RTS pair and allows to brings down the code increase in cgetc() down to a reasonable value.
However so far the internal cputc() code in question saved the X register. Now it uses the X register to return the old character present before writing the new character for cgetc(). This requires some rather small adjustments in other functions using that internal cputc() code.
The final part of exec() called 'excexit' and only then restored the
stack pointer to its value at program entry. 'excexit' does all
cleanup (the same as '_exit()'), which means that on the atarixl
target the ROM is banked in again. On big programs the 'SP_save'
variable might reside at a high memory address which is no longer
accessible after the ROM has been banked in.
The change just moves the restoration of the stack pointer before
the call to 'excexit'.
Another change lets exec.s compile if UCASE_FILENAME is not defined.
And some other small cleanups, also in open.s.
- Adds new ENOEXEC error code, also used by Apple2 targets.
- Maximum command line length is 40, incl. program name. This is
an XDOS restriction.
- testcode/lib/tinyshell.c has been extended to be able to run
programs.
* libsrc/atari/ucase_fn.s: Fix handling if input parameter 'tmp2' is 0.
* libsrc/atari/open.s: Set 'tmp2' parameter for 'ucase_fn' if DEFAULT_DEVICE
is not defined.
About all CONIO functions offering a <...>xy variant call
popa
_gotoxy
By providing an internal gotoxy variant that starts with a popa all those CONIO function can be shortened by 3 bytes. As soon as program calls more than one CONIO function this means an overall code size reduction.
- use this function instead of directly looking at _dos_type in the included
targetutil and test programs
- fixes/improvements to the Atari runtime library regarding the recently
changed _dos_type values
- libsrc/atari/targetutil/w2cas.c: exit if no filename was entered
- add documentation for the new function
The Vic20 does not have kernal table entries for the following functions.
;-----------------------------------------------------------------------------
; Functions which are not in the kernal jump table for VIC-20 but are for C64
CINT := $E518
IOINIT := $FDF9
RAMTAS := $FD8D
All other kernal entries are the same as the C64, however, without this change, the startup code fails.
Without this change the vic20.lib builds incorrectly.
_sys() is supposed to be (primarily) intended to call ROM routines. Leveraging the "file overlay" mechanism of the cc65 build system allows to provide a Apple II specific _sys() implementation that temporarily switches in the ROM.
Make the same changes to the Apple II that were done with 0ee9b2e446 to the C64.
Notes:
- The startup code deliberately doesn't make use of symbols defined for the LC segment as that segment is optional.
- The <...>-asm.cfg configs move the segment BSS to an own memory area BSS although this doesn't seem necessary. However the benefit is that the size of the memeory area MAIN is identical to the number of bytes loaded from disk into RAM. To keep this an invariant for all Apple II configs allows to simplify the EXEHDR to just refer to the symbols defined for MAIN.
The constructors are _NOT_ allowed anymore to access the BSS. Rather they must use the DATA segment or the INIT segment. The latter isn't cleared at any point so the constructors may use it to expose values to the main program. However they must make sure to always write the values as they are not pre-initialized.
The BSS segment and the ONCE segment share the same start address. So they need to be placed in two different memory areas.
So far BSS was placed in the MAIN memory area and ONCE was placed in an additional memory area. Both memory areas were written to the output file. They just "happened" to be loadable and runnable at a stretch.
Now ONCE is placed in the MAIN memory area and BSS is placed in an additional memory area. Only MAIN is written to the output file. It becomes more obvious that BSS is "just" defined to share memory with ONCE.
The name RAM doesn't make much sense in general for a memeory area because i.e. the zero page is for sure RAM but is not part of the memory area named RAM.
For disk based targets it makes sense to put the disk file more into focus and here MAIN means the main part of the file - in contrast to some header.
Only for ROM based targets the name RAM is kept as it makes sense to focus on the difference between RAM and ROM.
The way we want to use the INITBSS segment - and especially the fact that it won't have the type bss on all ROM based targets - means that the name INITBSS is misleading. After all INIT is the best name from my perspective as it serves several purposes and therefore needs a rather generic name.
Unfortunately this means that the current INIT segment needs to be renamed too. Looking for a short (ideally 4 letter) name I came up with ONCE as it contains all code (and data) accessed only once during initialization.
Conceptually the INITBSS segment is not initialized in any way. Therefore it makes sense to not load it from disk. However the INIT segment has to be loaded from disk and therefore moved to its run location above the INITBSS segment. The necessary move routine increases runtime RAM usage :-(
Therefore we now "unnecessarily" load the INITBSS segment from disk too meaning that the INIT segment is loaded at its run location. Therefore there's no need for the move routine anymore.
After all we trade disk space for (runtime) RAM space - an easy decision ;-)
Notes:
- The code allowing to re-run a program without re-load present so far could not have worked as far as I can see as it only avoided to re-run the move routine but still tried to re-run the code in the INIT segment that was clobbered by zeroing the BSS. Therefore I removed the code in question altogether. I'm personally not into this "dirty re-run" but if someone wants to add an actually working solution I won't block that.
- INITBSS is intentionally not just merged with the DATA segment as ROM-based targets can't reuse the INIT segment for the BSS and therefore have no reason to place the INIT segment above INITBSS.
- Because ROM-based targets don't copy INITBSS from the ROM (like it is done with the DATA segment) all users of INITBSS _MUST_NOT_ presume INITBSS to be initialized with zeros!
Kym Greenshields <kym.greenshields@gmail.com> has expressed interest
in contributing and maintaining support for the VTech CreatiVision system.
this resembles commit 8e6b8dd0af from oliver
A call to $FDA3 cannot be used because it re-enables the BASIC ROM. If a large program (such as Contiki's webbrowser80) has destructor code or data "behind" that ROM, then the program might crash when it tries to quit gracefully. Changing that code to set CIA2_PRA works well enough.
