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what does unimp a0 a1 mean? #14
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On Fri, Nov 23, 2018 at 12:02 AM D.pz ***@***.***> wrote:
What does asm volatile ("unimp" : : "r"(a0), "r"(a1)); mean? It sinces
there is no unimp in riscv specs.
unimp is an unimplemented instruction, guaranteed to cause an illegal
instruction trap. It is encoded as all ones.
Jim
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@jim-wilson that is clear, thanks a lot for your reply |
@decentsheep are you seeing a bug around here? The code you listed is horrible but usually works. |
@palmer-dabbelt no bug yet, I am just reading the source code |
Is there a reason mtvec is used to write the PAYLOAD_DEST and then a trap (unimp) is used to jump to this address for each hart? Instead of just jumping to it like from ZSBL -> FSBL?? |
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I am reading fsbl/main.c, and I see some code at line 404-424:
What does
asm volatile ("unimp" : : "r"(a0), "r"(a1));
mean? It sinces there is no unimp in riscv specs.The text was updated successfully, but these errors were encountered: