Re: [hatari-devel] Hatari debugger questions

[Uwe Seimet <Uwe.Seimet@xxxxxxxxx>]

Hi Nicolas,

Thank you, I will try this as soon as I have time. I am always using the
latest Hatari development version, by the way.

Best regards

Uwe

> Le 26/02/2018 à 11:46, Nicolas Pomarède a écrit :
> 
> >> Further, when I change the pc value and then enter 's' my expectation is
> >> that the first command at the new pc location is executed. What happens
> >> instead is that the instruction at the previous (old) pc location is
> >> executed.
> >>
> >> Am I doing something wrong? What do I have to do in order to change the
> >> pc value and then to single-step starting at the new pc location?
> >>
> > 
> > I will write a small asm test code to check if I can reproduce this.
> > 
> 
> It seems to work for me. Consider this small example :
> 
>          moveq   #0,d0
>          moveq   #0,d1
>          moveq   #0,d2
> 
>          moveq   #1,d1
>          moveq   #2,d2
>          moveq   #3,d3
> 
>          nop
> 
> attached is the resulting .prg.
> 
> Now, run hatari and press alt+pause to enter debugger when gem desktop 
> appears for example.
> 
> Load the program at address $40000 for a quick test :
> 
> loadbin debug.prg $40000
> 
> set 2 breakpoints at $40022 and $40028 and set pc=$4001c :
> 
> a $40022
> a $40028
> r pc=$4001c
> 
> This is the code in RAM :
> 
> $0004001c : 7000                               moveq     #0,d0
> $0004001e : 7200                               moveq     #0,d1
> $00040020 : 7400                               moveq     #0,d2
> $00040022 : 7201                               moveq     #1,d1
> $00040024 : 7402                               moveq     #2,d2
> $00040026 : 7603                               moveq     #3,d3
> $00040028 : 4e71                               nop
> 
> Type 'r', you can see that d0/d1/d2/d3 have various non null values
> 
> Now type 'c', program will run from $4001e until breakpoint at $40022 -> 
> -> d0/d1/d2 are correctly set to '0'
> 
> Skip instr at $40022 by changing PC
>  > r pc=$40024
> 
> type 's' to continue and execute only 1 instruction and type 'r' after.
> 
>  > s
> 
> CPU=$40026, VBL=2862, FrameCycles=2480, HBL=4, LineCycles=432, DSP=N/A
> $00040026 : 7603                               moveq     #3,d3
>  > r
>    D0 00000000   D1 00000000   D2 00000002   D3 00000000
> 
> So, only D2 was changed (by instruction at PC=40024) and program goes 
> back to debugger correctly with PC=$40026.
> -> The 1st instruction at the new PC was correctly executed.
> 
> Can you try this ? I checked with 68000 cpu, do you use 68030 ?
> 
> This requires hatari 2.1, as 2.0 could have prefetch issue when changing PC.
> 
> 
> Nicolas
> 
> 
> 
> 
> 


> 
> 	moveq	#0,d0
> 	moveq	#0,d1
> 	moveq	#0,d2
> 
> 	moveq	#1,d1
> 	moveq	#2,d2
> 	moveq	#3,d3
> 
> 	nop
>