Re: how to add read/write data breakpoint?

Posted on 2021-04-30, 06:37

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by llm

in DOSBox Development

in DOSBox Development

my third patchagainst current svn 4450 what works so far: read detection seems to work now - the breakpoint is getting activate on the next instruction but that is ok for now problems: i can't distinguish between dos program and debugger memory reads debug.cpp/AnalyzeInstruction and others also …

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Re: how to add read/write data breakpoint?

Posted on 2021-04-29, 13:00

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by llm

in DOSBox Development

in DOSBox Development

Alt-pause starts the debugger. I don't use debug.com very often. It's a convenient way to break at the start of a program. didn't know that watching the debugging flag does not work because its get set to false as soon as i hit F5 and reanabled when reaching another code bp case KEY_F(5): // Run …

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Re: how to add read/write data breakpoint?

Posted on 2021-04-29, 12:46

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by llm

in DOSBox Development

in DOSBox Development

Qbix wrote on 2021-04-29, 12:38: debug.com active shouldn't matter. that means, i must run the debug command - but its not needed to check for these vars to dectect if the debugger is present and i think its the static bool debugging flag in debug.cpp (that gets set by DEBUG_Enable)

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Re: how to add read/write data breakpoint?

Posted on 2021-04-29, 12:34

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by llm

in DOSBox Development

in DOSBox Development

Are you calling DEBUG_EnableDebugger somewhere when you encounter the memory location that you want to stop execution (will probably be after the read though) i thought that gets already set when i start "debug readb.com" currently its unclear to me: 1. how to detect if the debug command is running …

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is there a official github mirror?

Posted on 2021-04-29, 08:43

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by llm

in DOSBox Development

in DOSBox Development

there are several svn2github based dosbox mirrors on github but they all seem to be very outdated anything official available? (beside dosbox-X, dosbox-staging,...?)

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Re: how to add read/write data breakpoint?

Posted on 2021-04-29, 07:52

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by llm

in DOSBox Development

in DOSBox Development

it seems that my finding code is ok but my understanding of when/how breakpoints get activated is wrong

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Re: how to add read/write data breakpoint?

Posted on 2021-04-27, 08:07

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by llm

in DOSBox Development

in DOSBox Development

jmarsh wrote on 2021-04-26, 17:48: Edit the project configuration and add "SDL_VIDEODRIVER=windib" to the environment settings for running the debug build. Otherwise the directx backend is used by default and it uses global system locks that trigger the UI blocking you mentioned. thank you! any tip …

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Re: how to add read/write data breakpoint?

Posted on 2021-04-26, 08:47

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by llm

in DOSBox Development

in DOSBox Development

btw: i've got massive problems under VS2019 to debug the debugger itself - the dosbox or windows at whole is blocking very hard, mouse is invisble, etc. any tips to handle that?

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Re: how to add read/write data breakpoint?

Posted on 2021-04-24, 08:02

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by llm

in DOSBox Development

in DOSBox Development

just to be clear: i know that tracking memory reads can be very very very ... slow and that it will work only for core=normal

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Re: how to add read/write data breakpoint?

Posted on 2021-04-22, 15:30

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by llm

in DOSBox Development

in DOSBox Development

my second patch to svn 4448 added brakepoint at the hello world string with "BPMR 1dd:108 1" but it seems that my read-checks do not reach the string bytes - do i still miss some read functions? core=normal

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Re: how to add read/write data breakpoint?

Posted on 2021-04-22, 09:52

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by llm

in DOSBox Development

in DOSBox Development

i think i've found a way to get a host ptr from the location in my Find-Routine - but is that always the correct way or do i need to work with the get_tlb_read stuff like in the mem_readX_inline functions? CBreakpoint* CBreakpoint::FindMemReadBreakpoint(Bit8u const* const addr, Bit32u range) { std:: …

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Re: DOSBox debugger

Posted on 2021-04-22, 07:17

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by llm

in DOSBox Development

in DOSBox Development

Akuma wrote on 2020-06-03, 08:16: I would like to set a breakpoint on memory reads . That's the only thing I really miss. i try to implement that feature: how to add read/write data breakpoint? maybe you can have a look and help with the idea/implementation

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Re: how to add read/write data breakpoint?

Posted on 2021-04-22, 07:00

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by llm

in DOSBox Development

in DOSBox Development

seeking for help: attached is a WIP/Compilable but not working patch based on svn 4447 that shows my ideas how to hopefully cleanly add a memory read breakpoint feature to heavy-debug mode there is a new function DEBUG_CheckMemReadBreakpoint that gets called from (nearly) every memory reading …

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Re: how to add read/write data breakpoint?

Posted on 2021-04-20, 14:42

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by llm

in DOSBox Development

in DOSBox Development

and i think it will be only available for normal core mode

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Re: how to add read/write data breakpoint?

Posted on 2021-04-19, 14:37

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by llm

in DOSBox Development

in DOSBox Development

what i think so far what is needed dosbox\include\mem.h extend the host_reads like this (also for word,dword and WORDS_BIGENDIAN/C_UNALIGNED_MEMORY) static INLINE Bit8u host_readb( HostPt off ) { #ifdef C_HEAVY_DEBUG // check for mem-read-bp in range and activate bp if hit #endif return off[0]; } i …

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how to add read/write data breakpoint?

Posted on 2021-04-17, 06:46

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by llm

in DOSBox Development

in DOSBox Development

years ago i've added a feature for break point on memory read(write) ranges, slow and only available in heavy-debug mode something likes these commands BSMR seg:ofs range // detect reads BSMW seg:ofs range // detect writes BSRMW seg:ofs range // detect reads and writes but i've accidentally deleted …

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Re: Using debug.exe and experimenting with x86 instructions in DOSBox

Posted on 2020-02-14, 15:08

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by llm

in DOSBox General

in DOSBox General

A question: how does the CPU handle far calls in realmode? When e.g. an .exe file contains say "call far abdc:1234" does that mean the program will literally jump to that exact spot or is that what relocation items are for? every loading segment related data/code (jumps,call,offset,etc.) are …

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Re: Using debug.exe and experimenting with x86 instructions in DOSBox

Posted on 2020-02-14, 12:15

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by llm

in DOSBox General

in DOSBox General

Does the DOSBox debugger allow you to feed it a few instructions and execute them? no but as stated you can use a Visual Studio Debugger + simple x86 C/C++ Project for that (if VStudio is around) int main() { __asm { mov al, 2 mov dx,0xD007 add dx, al } return 0; } but maybe debug.exe fits already …

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Re: Using debug.exe and experimenting with x86 instructions in DOSBox

Posted on 2020-02-14, 05:14

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by llm

in DOSBox General

in DOSBox General

Looking for a way to quickly test the effect of x86 instructions 1. you can use visual studio with x86 inline assembler - works as long as segmented memory access or io ports access is not relevant to you, all 8/16/32bit opcodes still working 2. use Turbo/Borland C/C++ in Dosbox with Inline- …

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Re: Ways to dump memory to a file->

Posted on 2020-02-09, 18:58

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by llm

in DOSBox General

in DOSBox General

@Peter Swinkels reverse engineering is one of the stronges topics in software development - its very complicated and time consuming - you can spend month only on Alley Cats analysis (btw: someone does that already: https://github.com/gabonator/Work-in-progress/tree/master/DosGames/AlleyCat) 1. …

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