This commit introduces a large architectural change. Unlike previous
models of the fx-9860G series, the G-III models have a new user RAM
address different from 8801c000. The purpose of this change is to
dynamically load GMAPPED functions to this address by querying the TLB,
and call them through a function pointer whose address is determined
when loading.
Because of the overhead of using a function pointer in both assembly and
C code, changes have been made to avoid GMAPPED functions altogether.
Current, only cpu_setVBR() and gint_inth_callback() are left, the second
being used specifically to enable TLB misses when needed.
* Add a .gint.mappedrel section for the function pointers holding
addresses to GMAPPED functions; add function pointers for
cpu_setVBR() and gint_inth_callback()
* Move rram to address 0 instead of the hardcoded 0x8801c000
* Load GMAPPED functions at their linked address + the physical address
user RAM is mapped, to and compute their function pointers
* Remove the GMAPPED macro since no user function needs it anymore
* Add section flags "ax" (code) or "aw" (data) to every custom .section
in assembler code, as they default to unpredictable values that can
cause the section to be marked NOLOAD by the linker
* Update the main kernel, TMU, ETMU and RTC interrupt handlers to use
the new indirect calling method
This is made possible by new MMU functions giving direct access to the
physical area behind any virtualized page.
* Add an mmu_translate() function to query the TLB
* Add an mmu_uram() function to access user RAM from P1
The exception catching mechanism has been modified to avoid the use of
GMAPPED functions altogether.
* Set SR.BL=0 and SR.IMASK=15 before calling exception catchers
* Move gint_exc_skip() to normal text ROM
* Also fix registers not being popped off the stack before a panic
The timer drivers have also been modified to avoid GMAPPED functions.
* Invoke timer_stop() through gint_inth_callback() and move it to ROM
* Move and expand the ETMU driver to span 3 blocks at 0xd00 (ETMU4)
* Remove the timer_clear() function by inlining it into the ETMU handler
(TCR is provided within the storage block of each timer)
* Also split src/timer/inth.s into src/timer/inth-{tmu,etmu}.s
Additionally, VBR addresses are now determined at runtime to further
reduce hardcoded memory layout addresses in the linker script.
* Determine fx-9860G VBR addresses dynamically from mmu_uram()
* Determine fx-CG 50 VBR addresses dynamically from mmu_uram()
* Remove linker symbols for VBR addresses
Comments and documentation have been updated throughout the code to
reflect the changes.
This new mechanism allows an add-in to be restarted after exiting by
just never exiting in the first place, calling gint_osmenu() instead.
This makes sure that we can relaunch the add-in immediately, which is
normally possible through an option in the OS though no OS-independent
method of setting it is currently known.
Because this is gint_osmenu(), known pitfalls apply. On all platforms,
it is necessary to prepare the first frame before leaving. On fx-CG 50,
the inevitable display border is also there.
I have recenty discovered that the so-called "rram" section used by gint
to store its VBR space and a couple memory structures gets overwritten
when returning to the main menu. It is thus necessary to get rid of it
and store that data somewhere else.
My current lead is to have it at the start of the static RAM by querying
its address in the TLB. However, the static RAM is very small on SH3
(8k) so the VBR must be made more compact.
This change elaborates the event code translation scheme used on SH3 to
emulate SH4 event codes. It is now used to translate the event codes to
a gint-specific VBR layout that leaves no gaps and thus reduces the size
of the VBR space. The gint_inthandler() method has to be modified for
every new SH3 interrupt to maintain this scheme.
* Removed .pretext sections since the TLB is now entirely dynamic; left
only .text.entry for the start symbol.
* Reworked the main files of src/core to move the INTC to its own driver
and let the kernel handle only VBR space and CPU (now: VBR & CPUOPM).
* Moved src/core/gint.c to src/core/kernel.c and centralized all driver
loops that save or restore context for more robustness. This leaves
the callbacks of cpu_setVBR() (formerly gint_setvbr()) pretty short.
* Coalesced gint_switch_out() and gint_switch_in() into a single
function callback for cpu_setVBR().
* Added an abstraction of interrupt signals as an enumerated value so
that drivers no longer hardcode the IPR and IMR numbers and bits,
sometimes even with isSH3() due to differences in the SH7705.
* Changed the interrupt blocking method in cpu_setVBR() from SR.BL=1 to
SR.IMASK=15 so that TLB misses are still handled. This removes the
need for callback functions to be GMAPPED.
* Moved gint_osmenu() and its utilities to a new file src/core/osmenu.c.
* 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.
This is an obvious requirement for the interrupt routine, which was
forgotten and only surfaced when I used a timer callback started with
multiplications in an innocent add-in. r0..r7 are saved automatically,
which leaves pr, gbr, mach et macl susceptible to corruption by the
interrupt handler.
t6k11: use the gint array for variant detection
r61524: use true triple buffering by default
display: define DWIDTH and DHEIGHT
display: add C_RGB(r,g,b) (0 ≤ r,g,b ≤ 31) [fxcg50]
* Now uses topti instead of fxlib for text (including MMU failure)
* Fit .pretext into 4k for everything before MMU succeeds
* A short version of sprintf() for dynamic messages
* Support a driver function, status(), to allow early driver debug
* Expose more useful platform information in <gint/mpu.h>
* Expose the first of a few CASIOWIN syscalls
Lephe
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