Re: [hatari-devel] Wrong bus error stack frame with 68000 and JSR

[Christian Zietz <czietz@xxxxxxx>]

Christian Zietz schrieb:

> I can't say if I will be able do more testing before next weekend,
> either. Sorry.

I can, however, add that the behavior that I observed is documented in 
the 68000UM and should therefore apply to all addressing modes:

"The value saved for the program counter is advanced 2–10 bytes beyond 
the address of the first word of the instruction that made the reference 
causing the bus error. If the bus error occurred during the fetch of the 
next instruction, the saved program counter has a value in the vicinity 
of the current instruction, even if the current instruction is a branch, 
a jump, or a return instruction."

I.e., for branches, jumps and returns, the stacked PC is "near" the PC 
of the branch/jump/return instruction, and not the target of this 
instruction. Sadly, the exact offset is not documented, and probably 
depends on instruction and addressing mode.

Regards
Christian
--
Christian Zietz  -  CHZ-Soft  -  czietz@xxxxxxx
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