emBLOD is Marcus Jansson's second-stage boot loader for AVR32UC3A
parts as used in the EVK1100 and Mizar32 boards, designed to allow
firmware images larger than the on-chip flash memory by loading the
eLua binary from SD card into SDRAM and executing it there.
The source for the emBLOD loader is here https://github.com/cmp1084/emBLOD
When compilation option bootloader=emblod is given to scons, a special
version is compiled that
- locates the program at the start of SDRAM
- doesn't initialize the system clocks and SDRAM controller, as these
are already set up by emBLOD.
If the bootloader= option is not given, eLua is compiled exactly as before.
The changes I've made to Marcus' originally posted patches are to put
DATA and BSS in internal static RAM, the same as before, since in the
best case (memcpy) the SDRAM is three times slower than access to
static RAM
http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&t=80657
This also has an impact on code speed: the interpreter runs 9 times
slower in external SDRAM than it does in internal flash.
Tested and working on Mizar32
- Added direct access to interrupt flags; an interrupt doesn't have to trigger a handler anymore, its flag(s) can be checked instead (platform_cpu_get_interrupt_flag).
- Added experimental C interrupt handlers support (NOT TESTED). It can be compiled and used separately from the Lua interrupt support implementation. Hint: src/elua_int.c, elua_int_set_c_handler and elua_int_get_c_handler, also BUILD_C_INT_HANDLERS (as opposed to BUILD_LUA_INT_HANDLERS).
- Added tmr.set_match_int function that sets a match interrupt on a timer (one-shot or cyclic). Also works on virtual timers. In fact, it currently works only on virtual timers, as none of the platforms have support for this operation with hardware timers.
-Added more interrupt support functions in the CPU module.
All of the above were implemented and tested on the ELUA-PUC board, and nothing else. As a side effect, THIS COMMIT BRAKES THE STR912 PORT! The port will be modified to take advantage of the new interrupt structure soon; until then, please don't update it.
- automatically searches for compatible toolchain (and checks that it at least runs)
- running "scons -h" now shows descriptions of command line options and enumerates valid values
- caches last specifically requested configuration
More to come...
- enable file creation, reading, writing on mbed for the built-in filesystem
- implementation currently lacks support for directory listings, this will be
added when mbed implementation details are available.
Note: this should work with other ARM arm ports that are connected to a JTAG
debugger that implements semihosting, though I have not tested it.
- FAT changed to support the new opendir/readdir/closedir mechanism, and to use lseek directly instead of ioctl (also fixed a bug in FAT's lseek that always returned 0 instead of file position).
- ET-STM32 console moved to UART2@19200bps (to allow RFS to run on UART0). If UART0 is needee for console, remember to disable RFS.
- freed 700+ bytes of RAM by changing the devman implementation to keep pointers instead of actual DM_DEVICE structures
- other minor code changes and fixes
SCons decider for main build and luarpc have been switched to MD5-timestamp,
which will prevent scons from re-digesting files it has cached unless
timestamp has changed (should shave a little off of build times, but be safe).
Some of the PNG screenshots that didn't get crunched before the 0.7 release
have been run through optipng, advpng and pngout to wring out as many bytes as
possible without losing data/quality.
- added some more documentation (not yet done)
- alternate uarts can be selected (boot mode defaults to console uarts)
- renamed "remote" references to "rpc" (may as well keep the original name)
- switch default error handler to luaL_error (presumably wasn't available for
old 4.x LuaRPC)
- tweaks to exception handling to make things more consistent (hopefully)
Added another "romfs" parameter to SConstruct. It can take one of 3 values:
- "verbatim" (default): copy all the files from the eLua romfs/ directory to the binary image (exactly what happened until now)
- "compress": use LuaSrcDiet (http://luaforge.net/projects/luasrcdiet, now included in the eLua distribution) to "compress" the source code by using different tricks (shorter identifiers, removing comments and EOLS, and so on). The output is still a compilable Lua file (although in most case it looks completely different from the original) which is copied in the eLua binary image instead of the original Lua file. The compression obtained by using this method seems to be very good in practice, thus it will save flash when needed.
- "compile": use the eLua cross compiler (that must be built first by running 'scons -f cross-lua.py') to precompile the Lua files to bytecode, and write the bytecode to the image instead of the source file. This way, one can save both time (the scripts don't need to be compiled anymore) and RAM (for the same reason, especially since the Lua parser uses the stack a lot, which can lead to very nasty and hard to diagnose stack overflow bugs). It will be even more useful in the future, when (hopefully) more and more Lua bytecode data structures will be available directly from Flash (without having to copy them RAM as it happens now). It might also decrease the romfs memory footprint, but then again, it might not; it pretty much depends on the Lua programs included in the romfs.
debugging.
Might be nice to have a generalized form of something like this to help in
pointing in the right direction when one doesn't have a JTAG debugger.
any platform. No need to specify it in the file_list table.
- minor comments added to SConstruct
- LM3S platform specific modules commented
- Minor comments in Pong
- Debugging prints removed from Tetrives
