GDB Stub: Initial commit

CMakeLists.txt

@@ -121,6 +121,7 @@ option(DINPUT       "DirectInput"
 option(CPPTHREADS   "C++11 threads"                                                 ON)
 option(NEW_DYNAREC  "Use the PCem v15 (\"new\") dynamic recompiler"                 OFF)
 option(MINITRACE    "Enable Chrome tracing using the modified minitrace library"    OFF)
+option(GDBSTUB      "Enable GDB stub server for debugging"                          ON)
 option(DEV_BRANCH   "Development branch"                                            OFF)
 if(NOT WIN32)
 option(QT           "QT GUI"                                                        ON)

src/86box.c

@@ -93,6 +93,7 @@
 #include <86box/ui.h>
 #include <86box/plat.h>
 #include <86box/version.h>
+#include <86box/gdbstub.h>
 
 
 /* Stuff that used to be globally declared in plat.h but is now extern there
@@ -736,6 +737,8 @@ usage:
 	if (lang_init)
 		lang_id = lang_init;
 
+	gdbstub_init();
+
 	/* All good! */
 	return(1);
 }
@@ -1171,6 +1174,8 @@ pc_close(thread_t *ptr)
 	mo_close();
 
 	scsi_disk_close();
+
+	gdbstub_close();
 }
 
 

src/CMakeLists.txt

@@ -23,6 +23,11 @@ if(CPPTHREADS)
     target_sources(86Box PRIVATE thread.cpp)
 endif()
 
+if(GDBSTUB)
+    add_compile_definitions(USE_GDBSTUB)
+    target_sources(86Box PRIVATE gdbstub.c)
+endif()
+
 if(NEW_DYNAREC)
     add_compile_definitions(USE_NEW_DYNAREC)
 endif()

src/cpu/386.c

@@ -22,6 +22,7 @@
 #include <86box/fdd.h>
 #include <86box/fdc.h>
 #include <86box/machine.h>
+#include <86box/gdbstub.h>
 #include "386_common.h"
 #ifdef USE_NEW_DYNAREC
 #include "codegen.h"
@@ -256,6 +257,11 @@ exec386(int cycs)
 
 		if (TIMER_VAL_LESS_THAN_VAL(timer_target, (uint32_t) tsc))
 			timer_process_inline();
+
+#ifdef USE_GDBSTUB
+		if (gdbstub_singlestep)
+			return;
+#endif
 	}
     }
 }

src/cpu/808x.c

@@ -34,6 +34,7 @@
 #include <86box/pic.h>
 #include <86box/ppi.h>
 #include <86box/timer.h>
+#include <86box/gdbstub.h>
 
 /* Is the CPU 8088 or 8086. */
 int is8086 = 0;
@@ -2832,5 +2833,10 @@ execx86(int cycs)
 
 		cpu_alu_op = 0;
 	}
+
+#ifdef USE_GDBSTUB
+		if (gdbstub_singlestep)
+			return;
+#endif
     }
 }

src/include/86box/gdbstub.h

@@ -0,0 +1,38 @@
+/*
+ * 86Box	A hypervisor and IBM PC system emulator that specializes in
+ *		running old operating systems and software designed for IBM
+ *		PC systems and compatibles from 1981 through fairly recent
+ *		system designs based on the PCI bus.
+ *
+ *		This file is part of the 86Box distribution.
+ *
+ *		Definitions for the GDB stub server.
+ *
+ *
+ *
+ * Authors:	RichardG, <richardg867@gmail.com>
+ *
+ *		Copyright 2022 RichardG.
+ */
+#ifndef EMU_GDBSTUB_H
+# define EMU_GDBSTUB_H
+
+#ifdef USE_GDBSTUB
+
+extern int gdbstub_singlestep;
+
+extern void gdbstub_pause(int *p);
+extern void gdbstub_init();
+extern void gdbstub_close();
+
+#else
+
+#define gdbstub_singlestep 0
+
+#define gdbstub_pause(p)
+#define gdbstub_init()
+#define gdbstub_close()
+
+#endif
+
+#endif

src/qt/qt_platform.cpp

@@ -92,6 +92,7 @@ extern "C" {
 
 #include "../cpu/cpu.h"
 #include <86box/plat.h>
+#include <86box/gdbstub.h>
 
 volatile int cpu_thread_run = 1;
 int mouse_capture = 0;
@@ -314,6 +315,8 @@ plat_pause(int p)
     static wchar_t oldtitle[512];
     wchar_t title[512], paused_msg[64];
 
+    gdbstub_pause(&p);
+
     if (p == dopause) {
 #ifdef Q_OS_WINDOWS
         if (source_hwnd)

src/unix/unix.c

@@ -32,6 +32,7 @@
 #include <86box/timer.h>
 #include <86box/nvr.h>
 #include <86box/ui.h>
+#include <86box/gdbstub.h>
 
 static int	first_use = 1;
 static uint64_t	StartingTime;
@@ -719,6 +720,8 @@ plat_pause(int p)
     static wchar_t oldtitle[512];
     wchar_t title[512];
 
+    gdbstub_pause(&p);
+
     if ((p == 0) && (time_sync & TIME_SYNC_ENABLED))
 	nvr_time_sync();
 

src/win/win_ui.c

@@ -44,6 +44,7 @@
 #include <86box/win.h>
 #include <86box/version.h>
 #include <86box/discord.h>
+#include <86box/gdbstub.h>
 
 #ifdef MTR_ENABLED
 #include <minitrace/minitrace.h>
@@ -1496,6 +1497,8 @@ plat_pause(int p)
     static wchar_t oldtitle[512];
     wchar_t title[512];
 
+    gdbstub_pause(&p);
+
     /* If un-pausing, as the renderer if that's OK. */
     if (p == 0)
 	p = get_vidpause();