With this change we allocate stack space only for the registers we
actually store in the thread interrupt stack frame.
Furthermore, no function is called on with the interrupt context save
frame %sp so no full frame is needed here. ABI functions are called
later in the interrupt trap handler, but that is after the dedicated
interrupt stack has been installed.
This saves 96 bytes of stack space for each interrupted context.
Signed-off-by: Martin Åberg <martin.aberg@gaisler.com>
The input registers (i0..i7) are not modified by the interrupt trap
handler and are preserved by function calls. So we do not need to
store them in the interrupt stack frame.
This saves 48 bytes of stack space for each interrupted context,
and eliminates 4 double word stores and 4 double word loads.
Signed-off-by: Martin Åberg <martin.aberg@gaisler.com>
SPARC is an open and royalty free processor architecture.
This commit provides SPARC architecture support to Zephyr. It is
compatible with the SPARC V8 specification and the SPARC ABI and is
independent of processor implementation.
Functionality specific to SPRAC processor implementations should
go in soc/sparc. One example is the LEON3 SOC which is part of this
patch set.
The architecture port is fully SPARC ABI compatible, including trap
handlers and interrupt context.
Number of implemented register windows can be configured.
Some SPARC V8 processors borrow the CASA (compare-and-swap) atomic
instructions from SPARC V9. An option has been defined in the
architecture port to forward the corresponding code-generation option
to the compiler.
Stack size related config options have been defined in sparc/Kconfig
to match the SPARC ABI.
Co-authored-by: Nikolaus Huber <nikolaus.huber.melk@gmail.com>
Signed-off-by: Martin Åberg <martin.aberg@gaisler.com>
