Hardware watchpoints don't fire since 0.8.0

[exelotl]

Hey, sorry for not reporting this earlier - in recent months I've found that hardware watchpoints don't function correctly (tested both on Windows and Linux). They previously used to work on 0.7.3, and must have broken some time between then and the release of 0.8.0.

Here's a minimal example using libtonc:

Example code

(can use this template to compile if you need)

#include <tonc.h>

int my_num = 0;

int main() {
	irq_init(NULL);
	irq_enable(II_VBLANK);
	while (1) {
		VBlankIntrWait();
		my_num = qran();   // Assign random value
	}
}

Debug scripts

Windows:

start "" /B "C:\Users\exelotl\path\to\mGBA.exe" -g mgba-watchpoints.elf
pause
C:\msys64\opt\devkitpro\devkitARM\bin\arm-none-eabi-gdb.exe mgba-watchpoints.elf -ex "target remote localhost:2345"

Linux:

mgba-qt -g mgba-watchpoints.elf &
sleep 2
/opt/devkitpro/devkitARM/bin/arm-none-eabi-gdb mgba-watchpoints.elf -ex "target remote localhost:2345"

GDB session - mGBA 0.7.3

✔️ behaves as expected

Reading symbols from mgba-watchpoints.elf...done.
Remote debugging using localhost:2345
0x08000190 in ClrLoop ()
(gdb) watch my_num
Hardware watchpoint 1: my_num
(gdb) c
Continuing.

Hardware watchpoint 1: my_num

Old value = 0
New value = 16537
main () at C:/msys64/home/exelotl/gba-tests/mgba-watchpoints/source/main.c:11
11                      VBlankIntrWait();
(gdb)

GDB session - mGBA 0.8.0 to 0.8.4

❌ watchpoint never fires

Reading symbols from mgba-watchpoints.elf...done.
Remote debugging using localhost:2345
0x08000190 in ClrLoop ()
(gdb) watch my_num
Hardware watchpoint 1: my_num
(gdb) c
Continuing.

[endrift]

Hm, gdb. I don't tend to use that as often so it's broken from time to time. I think I switched which type of watchpoint is set by default in 0.8.