GDB stub (#1583)

* gdbstub beginnings

* gdbstub: finish gdb impl things, next up is integration with melonDS

* holy fuck the gdbstub works

* gdb breakpoints work, but there's a mysterious crash on continue

* fix memory corruption that sometimes happened, and make resetting the console thru gdb work

* remove some gdb debug printing

* fix things in gdbstub

* separate option for enabling gdbstub

* add mode-dependent CPU registers

* C++ize the GDBstub code

* add gdbstub config in emu settings dialog

* make sure gdb is disabled when jit is enabled

* Remove unnecessary compiler flags, mark ARMJIT assembly code as no-execute-stack

This hardens the binary a little bit against common exploitation methods

* add option to wait for debugger attach on startup

* only insert GNU stack notes on linux

* disable gdbstub enable checkbox when jit is enabled

* fix non-linux incompatibilities

* enable gdbstub by default

* fix issues with gdbstub settings disable stuff

* format stuff

* update gdb test code

* Fix segfault when calling StubCallbacks->GetCPU()

C++ overrides are hard. Please I'm just a lowly C programmer.

* fix packet size not being sent correctly

Thanks to @GlowingUmbreon on Github for troubleshooting this

* fix select(2) calls (i should read docs more properly)

* fix GDB command sequencing/parsing issue (hopefully)

* [GDB] implement no-ack mode

* fix sending ack on handshake

* get lldb to work

1 files changed, 7 insertions, 3 deletions

diff --git a/src/SPU.cpp b/src/SPU.cpp
index e83a0c7..3939aef 100644
--- a/src/SPU.cpp
+++ b/src/SPU.cpp
@@ -856,9 +856,13 @@ void Mix(u32 dummy)
 
     // OutputBufferFrame can never get full because it's
     // transfered to OutputBuffer at the end of the frame
-    OutputBackbuffer[OutputBackbufferWritePosition    ] = leftoutput >> 1;
-    OutputBackbuffer[OutputBackbufferWritePosition + 1] = rightoutput >> 1;
-    OutputBackbufferWritePosition += 2;
+    // FIXME: apparently this does happen!!!
+    if (OutputBackbufferWritePosition * 2 < OutputBufferSize - 1)
+    {
+        OutputBackbuffer[OutputBackbufferWritePosition    ] = leftoutput >> 1;
+        OutputBackbuffer[OutputBackbufferWritePosition + 1] = rightoutput >> 1;
+        OutputBackbufferWritePosition += 2;
+    }
 
     NDS::ScheduleEvent(NDS::Event_SPU, true, 1024, Mix, 0);
 }