interp: Handle jumps in branch delay slots better #15952
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This matches tests from a PSP-2000. Seems to consistently run the instruction even if likely, which writes rd. If the likely branch is not taken, the jump in the delay slot is taken. However, it should cancel the rd write (not implemented here.)
hrydgard
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See hrydgard#15952 for more detail.
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Sep 18, 2022
(beql/bnel). Found in Brooktown High USA -ULUS10257: 0x088D2A44: [0x55E0FFE5] - bnel $t7, $zr, 0x088D29DC 0x088D2A48: [0x03E00008] - jr $ra
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This matches tests from a PSP-2000. Seems to consistently run the instruction even if likely, which writes rd. Interestingly, compare to the rules in #3175 (which are different)... in this case of beq/bne/beql/bnel + jalr/jr/j:
The link only when not likely is not implemented here (probably a real edge case, too.)
This is only the interpreter so far because I want to see if it helps #7223.
-[Unknown]