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.
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.
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.
The driver kernels all require IRQ handling even if the actual drivers don't make use of it. So in order to successfully link a NES program using the joystick and/or TGI driver there has to be at least a "dummy" IRQ backend.
Up to now static drivers were created via co65 from dynamic drivers. However there was an issue with that approach:
The dynamic drivers are "o65 simple files" which obligates that they start with the 'code' segment. However dynamic drivers need to start with the module header - which is written to. For dynamic drivers this isn't more than a conceptual issue because they are always contain a 'data' segment and may therefore only be loaded into writable memory.
However when dynamic drivers are converted to static drivers using co65 then that issue becomes a real problem as then the 'code' segment may end up in non-writable memory - and thus writing to the module header fails.
Instead of changing the way dynamic drivers work I opted to rather make static driver creation totally independent from dynamic drivers. This allows to place the module header in the 'data' segment (see 'module.mac').
This change was suppsed to fix the issue that the former JUMPTABLE is merked as 'ro' while it is actually written to in several scenarios. When drivers are converted using co65 and then compiled into ROMs the JUMPTABLE isn't copied to RAM and therefore the write operations in question fail.
However unfortunately I didn't succeed in changing that :-( Just setting the former JUMPTABLE to 'rw' broke the drivers. So I placed the DATA segment directly after the former JUMPTABLE segment. This made the drivers converted with co65 work again - obviously after changing libsrc/Makefile:235 from '--code-label' to '--data-label'. But the actual dynamic drivers still didn't work as the former JUMPTABLE wasn't placed as the beginning of the loaded file anymore. That effect could be changed by exchanging src/ld65/o65.c:1391 with src/ld65/o65.c:1394 but doing so broke the drivers again :-((
Building the clean target in src or libsrc should only delete stuff created by the make in those directories. Having both separated allows the Travis CI build to replace the native binaries with cross built binaries while keeping everything else.
- No complex shell logic.
- "Source file shadowing" for all targets via vpath.
- Dependency handling.
- True incremental build.
- Don't write into source directories.
- Easy cleanup by just removing 'wrk'.
- No complex shell logic.
- "Source file shadowing" for all targets via vpath.
- Dependency handling.
- True incremental build.
- Don't write into source directories.
- Easy cleanup by just removing 'wrk'.
in the distribution.
Added --forget-inc-paths to the command line of the assembler in the
Makefiles, because the assembler does now have builtin paths and will find
include files from an installation first.
Hopefully fixed any problems that arose from the two changes.
git-svn-id: svn://svn.cc65.org/cc65/trunk@4223 b7a2c559-68d2-44c3-8de9-860c34a00d81
main() is encountered. Define this symbol in the startup code. This will
automatically force linking of the startup code which can then reside inside
the standard library as any other object file.
git-svn-id: svn://svn.cc65.org/cc65/trunk@3988 b7a2c559-68d2-44c3-8de9-860c34a00d81
