If vectored interrupts are enabled (bits[1:0]
of mtvec/stvec == 1) then use the following
logic for trap entry address calculation:
pc = mtvec + cause * 4
In addition to adding support for vectored interrupts
this patch simplifies the interrupt delivery logic
by making sync/async cause decoding and encoding
steps distinct.
The cause code and the sign bit indicating sync/async
is split at the beginning of the function and fixed
cause is renamed to cause. The MSB setting for async
traps is delayed until setting mcause/scause to allow
redundant variables to be eliminated. Some variables
are renamed for conciseness and moved so that decls
are at the start of the block.
Backports commit acbbb94e5730c9808830938e869d243014e2923a from qemu
We can't allow the supervisor to control SEIP as this would allow the
supervisor to clear a pending external interrupt which will result in
lost a interrupt in the case a PLIC is attached. The SEIP bit must be
hardware controlled when a PLIC is attached.
This logic was previously hard-coded so SEIP was always masked even
if no PLIC was attached. This patch adds riscv_cpu_claim_interrupts
so that the PLIC can register control of SEIP. In the case of models
without a PLIC (spike), the SEIP bit remains software controlled.
This interface allows for hardware control of supervisor timer and
software interrupts by other interrupt controller models.
Backports commit e3e7039cc24ecf47d81c091e8bb04552d6564ad8 from qemu
Add a debugger field to CPURISCVState. Add riscv_csrrw_debug function
to set it. Disable mode checks when debugger field true.
Backports commit 753e3fe207db08ce0ef0405e8452c3397c9b9308 from qemu
This ports over the RISC-V architecture from Qemu. This is currently a
very barebones transition. No code hooking or any fancy stuff.
Currently, you can feed it instructions and query the CPU state itself.
This also allows choosing whether or not RISC-V 32-bit or RISC-V 64-bit
is desirable through Unicorn's interface as well.
Extremely basic examples of executing a single instruction have been
added to the samples directory to help demonstrate how to use the basic
functionality.
