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5442622d88
The following inline assembly in set_irq_level() turned out
to have incorrect constraints:
int newvalue = /* input parameter */;
int oldvalue;
asm volatile ("mrs %0, primask\n"
"msr primask, %1\n"
: "=r"(oldvalue) : "r"(newvalue));
leading to incorrect code generation for common cases like
disable_irq_save(), which compiles to:
mov r5, #1
mrs r5, primask
msr primask, r5
...which doesn't disable IRQs at all, since both of the
operands got assigned to the same register; the write of
'oldvalue' clobbers the 'newvalue' input before it's used.
Apparently GCC assumes that input operands are read before
output operands are written. One way to fix this is adding
the '&' constraint: "=&r"(oldvalue), but it's better to
break things down into separate, simpler asm statements
which GCC can figure out itself.
Also add compiler memory barriers where primask is modified
to ensure loads/stores aren't incorrectly moved outside of
critical sections.
While here, optimize disable_irq_save() a bit by using the
cpsid instruction, which avoids the extra "mov" and register
allocation needed by "msr primask".
Change-Id: Iac94a76db5bac399a1cf028da4241a0473259a46
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|---|---|---|
| android | ||
| apps | ||
| backdrops | ||
| bootloader | ||
| docs | ||
| firmware | ||
| fonts | ||
| gdb | ||
| icons | ||
| lib | ||
| manual | ||
| packaging | ||
| tools | ||
| uisimulator | ||
| utils | ||
| wps | ||
| .gitattributes | ||
| .gitignore | ||
| .gitreview | ||
__________ __ ___.
Open \______ \ ____ ____ | | _\_ |__ _______ ___
Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
\/ \/ \/ \/ \/
Build Your Own Rockbox
1. Clone 'rockbox' from git (or extract a downloaded archive).
$ git clone git://git.rockbox.org/rockbox
or
$ tar xJf rockbox.tar.xz
2. Create a build directory, preferably in the same directory as the firmware/
and apps/ directories. This is where all generated files will be written.
$ cd rockbox
$ mkdir build
$ cd build
3. Make sure you have mips/m68k/arm-elf-gcc and siblings in the PATH. Make sure
that you have 'perl' in your PATH too. Your gcc cross compiler needs to be
a particular version depending on what player you are compiling for. These
can be generated using the rockboxdev.sh script in the /tools/ folder of the
source.
$ which arm-elf-eabi-gcc
$ which perl
4. In your build directory, run the 'tools/configure' script and enter what
target you want to build for and if you want a debug version or not (and a
few more questions). It'll prompt you. The debug version is for making a
gdb version out of it. It is only useful if you run gdb towards your target
Archos.
$ ../tools/configure
5. *ploink*. Now you have got a Makefile generated for you.
6. Run 'make' and soon the necessary pieces from the firmware and the apps
directories have been compiled, linked and scrambled for you.
$ make
$ make zip
7. unzip the rockbox.zip on your music player, reboot it and
*smile*.
If you want to build for more than one target, just create several build
directories and create a setup for each target:
$ mkdir build-fuzeplus
$ cd build-fuzeplus
$ ../tools/configure
$ mkdir build-xduoox3
$ cd build-xduoox3
$ ../tools/configure
Questions anyone? Ask on the mailing list or on IRC. We'll be happy to help you!