Disables spread spectrum by default so that the frequency estimations of
the CPG driver (notably used by the timer driver and libprof) are more
accurate.
The unload() function is not very relevant for drivers because hardware
state is managed by ctx_save() and ctx_restore() and software state is
managed by underlying drivers when there are dependencies.
For now, it's been replaced with a wait() function that allows drivers
to not be interrupted at any point. It is currently used by the DMA to
wait for ongoing transfers to finish before disabling interrupts (which
would prevent the transfer end from being detected) and switching in and
out of gint.
* Add the gint_switch() function which executes user-provided code from
the system (CASIOWIN) context.
* Added interrupt masks to the core context (should have been there long
ago).
* Added the gint_osmenu() function that switches out of gint to invoke
GetKeyWait() and inject KEY_CTRL_MENU to trigger the main menu. This
uses many CASIOWIN syscalls, but we don't care because gint is unloaded.
Trickery is used to catch the key following the return in the add-in
and/or display a new application frame before GetKeyWait() even finishes
after coming back. This is only available on fx9860g for now.
* Removed any public syscall definition to clear up interfaces.
* Patched the DMA interruption problem in a weird way on fxcg50, a
driver function will be used to do that properly eventually.
* Changed the driver model to save driver contexts in preallocated
spaces instead of on the stack for overall less risk.
* Enabled return-to-menu with the MENU key on fx9860g in getkey().
* Changed the keyboard driver to emit releases before presses, as a
return-to-menu acts as a press+release of different keys in a single
driver frame, which confuses getkey().
* Fixed a really stupid bug in memcpy() that made the function really
not work.
Improvements in the timer driver:
* Expose ETMU modules as SH7705_TMU and SH7305_TMU in <gint/mpu/tmu.h>.
* Remove the timer_t structures, using SH*_ETMU and SH*_TMU instead.
Only interrupt gate entries are left hardcoded.
* Discovered that not only every write to the TCNT or TCR of an ETMU
takes about 1/32k of a second (hinting at registers being powered by
the same clock as the timer), but every write occuring while a previous
write is pending is *lost*. This led to terrible bugs when switching
ETMU contexts too fast in gint_switch().
* Removed an internal timer_address() function.
* Overall simplified the handling of timers and the initialization step.
Since Memallox's newlib port is currently unstable, gint has to
provide some standard functions on its own. Instead of a single
<gint/std.h> header, this commit makes a gint/std directory containing
headers under standard names.
