Setting up Flycast GDB - Revision history

Colton at 15:47, 12 October 2023

2023-10-12T15:47:49Z

← Older revision		Revision as of 15:47, 12 October 2023
Line 33:		Line 33:
	In the GDB shell run the following commands to configure the GDB session		In the GDB shell run the following commands to configure the GDB session
	set arch sh4		set arch sh4
	~~set endian big~~		set endian little

	~~</br></br>~~
	~~'''Note:''' If run in big endian mode, even and odd instructions will be swapped. This can be worked around by changing lines 37 & 38 in <code>code/debug/debug_agent.h</code> to:~~
	~~#define SWAP_32(a) (a)~~
	~~#define SWAP_16(a) (a)~~
	~~And then use <code>~~set endian little~~</code> and GDB will work as expected.~~
	~~</br></br></br>~~

	Start Flycast Emulation and then connect to running core		Start Flycast Emulation and then connect to running core

Colton at 21:23, 9 October 2023

2023-10-09T21:23:29Z

← Older revision		Revision as of 21:23, 9 October 2023
Line 34:		Line 34:
	set arch sh4		set arch sh4
	set endian big		set endian big

			</br></br>
			'''Note:''' If run in big endian mode, even and odd instructions will be swapped. This can be worked around by changing lines 37 & 38 in <code>code/debug/debug_agent.h</code> to:
			#define SWAP_32(a) (a)
			#define SWAP_16(a) (a)
			And then use <code>set endian little</code> and GDB will work as expected.
			</br></br></br>

	Start Flycast Emulation and then connect to running core		Start Flycast Emulation and then connect to running core

Colton: Created page with "=== Clone dev branch of Flycast === git clone https://github.com/flyinghead/flycast -b dev cd flycast git submodule update --init --recursive === Build with GDB Support === mkdir build cd build cmake -DCMAKE_BUILD_TYPE=Release -DENABLE_GDB_SERVER=ON .. make -j$(nproc) === Enable GDB in Config File === Briefly launch Flycast to make sure config file exists ./flycast Edit config file to enable GDB Path on Linux: ~/.config/flycast/emu.cfg Under "[config]" make..."

2023-10-07T12:47:05Z

Created page with "=== Clone dev branch of Flycast === git clone https://github.com/flyinghead/flycast -b dev cd flycast git submodule update --init --recursive === Build with GDB Support === mkdir build cd build cmake -DCMAKE_BUILD_TYPE=Release -DENABLE_GDB_SERVER=ON .. make -j$(nproc) === Enable GDB in Config File === Briefly launch Flycast to make sure config file exists ./flycast Edit config file to enable GDB Path on Linux: ~/.config/flycast/emu.cfg Under "[config]" make..."

New page

=== Clone dev branch of Flycast ===
git clone https://github.com/flyinghead/flycast -b dev
cd flycast
git submodule update --init --recursive

=== Build with GDB Support ===
mkdir build
cd build
cmake -DCMAKE_BUILD_TYPE=Release -DENABLE_GDB_SERVER=ON ..
make -j$(nproc)

=== Enable GDB in Config File ===
Briefly launch Flycast to make sure config file exists
./flycast

Edit config file to enable GDB

Path on Linux: ~/.config/flycast/emu.cfg

Under "[config]" make sure GDBEnabled is set to yes
[config]
...
Debug.GDBEnabled = yes
Debug.GDBPort = 3263
...

=== Start GDB Session ===
Start a gdb with SH4 support, I use gdb-multiarch from my package manager
gdb-multiarch

In the GDB shell run the following commands to configure the GDB session
set arch sh4
set endian big

Start Flycast Emulation and then connect to running core
target remote :3263
This will pause execution of the game upon connecting

From here you can set breakpoints, instruction step, and read/write memory using normal GDB commands
Handy reference: [https://darkdust.net/files/GDB%20Cheat%20Sheet.pdf GDB Cheat Sheet]

The following commands show a terminal interface of the registers and instructions:
layout asm on
layout regs on

Single Instruction Step
nexti
Pressing Enter with no command typed will just repeat the last command (good for stepping)