Re: [hatari-devel] Natfeats doc?

[Thorsten Otto <admin@xxxxxxxxxxx>]

On Mittwoch, 8. September 2021 17:39:00 CEST Eero Tamminen wrote:

> Or you inline the opcode.

 

That won't work (at least not by just specifying the opcode). The interface is designed to expect a normal function call, including the return address, and parameters starting at stack offset 4.

 

What you could do is something like:

 

move.l nf_debugger_id,-(a7)

clr.l -(a7)

dc.w 0x7301

addq.w #8,a7

 

But even then you would still have to step over the addq when returning.

 

Changed registers should normally not be a problem; the only register that is modified by the call is D0.

 

Another possibility would be to specify a new opcode for just this purpose, eg. 0x7302. Would be also another method of invoking the debugger, but tightly related to natfeats, and i think better than some XBIOS call, or catching access to some I/O address that should normally trigger a bus-error.