diff --git a/include/QF/pr_debug.h b/include/QF/pr_debug.h
index 93f016385..322615b2a 100644
--- a/include/QF/pr_debug.h
+++ b/include/QF/pr_debug.h
@@ -32,7 +32,7 @@
 #ifndef __pr_debug_h
 #define __pr_debug_h
 
-typedef struct {
+typedef struct pr_auxfunction_s {
 	unsigned long function;		// function def this aux info is for
 	unsigned long source_line;	// first source line for this function
 	unsigned long line_info;	// index to first lineno entry
@@ -40,7 +40,7 @@ typedef struct {
 	unsigned long num_locals;	// number of local defs
 } pr_auxfunction_t;
 
-typedef struct {
+typedef struct pr_lineno_s {
 	union {
 		unsigned long func;		// (line==0) index of function aux info
 		unsigned long addr;		// (line!=0) dstatement_t address
@@ -50,7 +50,7 @@ typedef struct {
 
 #define PROG_DEBUG_VERSION 0x00001001	// MMmmmRRR 0.001.001 (hex)
 
-typedef struct {
+typedef struct pr_debug_header_s {
 	int				version;
 	unsigned short	crc;		// of the progs.dat this progs.sym file is for
 	unsigned short	you_tell_me_and_we_will_both_know;
diff --git a/include/QF/progs.h b/include/QF/progs.h
index 47d59735c..4078f2b24 100644
--- a/include/QF/progs.h
+++ b/include/QF/progs.h
@@ -32,6 +32,7 @@
 #include "QF/link.h"
 #include "QF/vfile.h"
 #include "QF/pr_comp.h"
+#include "QF/pr_debug.h"
 
 typedef union pr_type_u {
 	float	float_var;
@@ -71,6 +72,7 @@ void PR_PrintStatement (progs_t * pr, dstatement_t *s);
 void PR_ExecuteProgram (progs_t *pr, func_t fnum);
 void PR_LoadProgs (progs_t *pr, char *progsname);
 void PR_LoadStrings (progs_t *pr);
+void PR_LoadDebug (progs_t *pr);
 edict_t *PR_InitEdicts (progs_t *pr, int num_edicts);
 
 void PR_Profile_f (void);
@@ -153,13 +155,27 @@ char *PR_GlobalStringNoContents (progs_t *pr, int ofs);
 pr_type_t *GetEdictFieldValue(progs_t *pr, edict_t *ed, char *field);
 
 //
-// PR STrings stuff
+// PR Strings stuff
 //
 
 char *PR_GetString(progs_t *pr, int num);
 int PR_SetString(progs_t *pr, char *s);
 void PR_GarbageCollect (progs_t *pr);
 
+//
+// PR Debug stuff
+//
+
+void PR_Debug_Init (void);
+void PR_Debug_Init_Cvars (void);
+pr_auxfunction_t *PR_Get_Lineno_Func (progs_t *pr, pr_lineno_t *lineno);
+unsigned long PR_Get_Lineno_Addr (progs_t *pr, pr_lineno_t *lineno);
+unsigned long PR_Get_Lineno_Line (progs_t *pr, pr_lineno_t *lineno);
+pr_lineno_t *PR_Find_Lineno (progs_t *pr, unsigned long addr);
+const char *PR_Get_Source_File (progs_t *pr, pr_lineno_t *lineno);
+const char *PR_Get_Source_Line (progs_t *pr, unsigned long addr);
+
+extern struct cvar_s *pr_debug;
 
 //============================================================================
 
@@ -179,6 +195,7 @@ typedef struct strref_s {
 } strref_t;
 
 struct progs_s {
+	char			*progs_name;
 	dprograms_t		*progs;
 
 	struct hashtab_s *function_hash;
@@ -232,6 +249,13 @@ struct progs_s {
 	builtin_t		*builtins;
 	int				numbuiltins;
 
+	// debug info
+	char			*debugfile;
+	struct pr_debug_header_s *debug;
+	struct pr_auxfunction_s *auxfunctions;
+	struct pr_lineno_s *linenos;
+	ddef_t			*local_defs;
+
 	// required globals
 	struct {
 		float		*time;
diff --git a/libs/gamecode/Makefile.am b/libs/gamecode/Makefile.am
index 22395ce42..344077e4b 100644
--- a/libs/gamecode/Makefile.am
+++ b/libs/gamecode/Makefile.am
@@ -3,6 +3,6 @@ INCLUDES= -I$(top_srcdir)/include
 lib_LTLIBRARIES = libQFgamecode.la
 
 libQFgamecode_la_LDFLAGS = -version-info 1:0:0
-libQFgamecode_la_SOURCES = pr_edict.c pr_exec.c pr_opcode.c pr_strings.c
+libQFgamecode_la_SOURCES = pr_edict.c pr_debug.c pr_exec.c pr_opcode.c pr_strings.c
 
 LIBLIST = libQFgamecode.la @LIBRARY_SEARCH_PATH@
diff --git a/libs/gamecode/pr_debug.c b/libs/gamecode/pr_debug.c
new file mode 100644
index 000000000..1b4051bfe
--- /dev/null
+++ b/libs/gamecode/pr_debug.c
@@ -0,0 +1,312 @@
+/*
+	pr_debug.c
+
+	progs debugging
+
+	Copyright (C) 2001       Bill Currie <bill@tanwiha.org>
+
+	Author: Bill Currie <bill@tanwiha.org>
+	Date: 2001/7/13
+
+	This program is free software; you can redistribute it and/or
+	modify it under the terms of the GNU General Public License
+	as published by the Free Software Foundation; either version 2
+	of the License, or (at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+	See the GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with this program; if not, write to:
+
+		Free Software Foundation, Inc.
+		59 Temple Place - Suite 330
+		Boston, MA  02111-1307, USA
+
+	$Id$
+*/
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+#ifdef HAVE_STRING_H
+# include <string.h>
+#endif
+#ifdef HAVE_STRINGS_H
+# include <strings.h>
+#endif
+#include <stdlib.h>
+
+#include "QF/cvar.h"
+#include "QF/hash.h"
+#include "QF/pr_debug.h"
+#include "QF/progs.h"
+#include "QF/qendian.h"
+#include "QF/sys.h"
+#include "QF/vfs.h"
+#include "QF/zone.h"
+
+typedef struct {
+	char *text;
+	size_t len;
+} line_t;
+
+typedef struct {
+	char *name;
+	char *text;
+	line_t *lines;
+	int num_lines;
+} file_t;
+
+cvar_t      *pr_debug;
+static hashtab_t  *file_hash;
+
+file_t *
+PR_Load_Source_File (progs_t *pr, const char *fname)
+{
+	file_t *f = Hash_Find (file_hash, fname);
+	char *l;
+
+	if (f)
+		return f;
+	f = malloc (sizeof (file_t));
+	if (!f)
+		return 0;
+	f->text = COM_LoadFile (fname, 0);
+	if (!f->text) {
+		free (f);
+		return 0;
+	}
+	for (f->num_lines = 1, l = f->text; *l; l++)
+		if (*l == '\n')
+			f->num_lines++;
+	f->name = strdup (fname);
+	if (!f->name) {
+		free (f->text);
+		free (f);
+		return 0;
+	}
+	f->lines = malloc (f->num_lines * sizeof (line_t));
+	if (!f->lines) {
+		free (f->name);
+		free (f->text);
+		free (f);
+		return 0;
+	}
+	f->lines[0].text = f->text;
+	for (f->num_lines = 0, l = f->text; *l; l++) {
+		if (*l == '\n') {
+			f->lines[f->num_lines].len = l - f->lines[f->num_lines].text;
+			f->lines[++f->num_lines].text = l + 1;
+		}
+	}
+	f->lines[f->num_lines++].len = l - f->lines[f->num_lines].text;
+	Hash_Add (file_hash, f);
+	return f;
+}
+
+void
+PR_LoadDebug (progs_t *pr)
+{
+	pr_type_t  *str = PR_GetGlobalPointer (pr, ".debug_file");
+	int         start = Hunk_LowMark ();
+	int         i;
+	char       *path_end;
+	char       *sym_file;
+	char       *sym_path;
+
+	Hash_FlushTable (file_hash);
+	if (!str)
+		return;
+	pr->debugfile = PR_GetString (pr, str->string_var);
+	sym_file = COM_SkipPath (pr->debugfile);
+	path_end = COM_SkipPath (pr->progs_name);
+	sym_path = Hunk_TempAlloc (strlen (sym_file) + (path_end - pr->progs_name) + 1);
+	strncpy (sym_path, pr->progs_name, path_end - pr->progs_name);
+	strcpy (sym_path + (path_end - pr->progs_name), sym_file);
+	pr->debug = (pr_debug_header_t*)COM_LoadHunkFile (sym_path);
+	if (!pr->debug) {
+		Sys_Printf ("can't load %s for debug info\n", sym_path);
+		return;
+	}
+	pr->debug->version = LittleLong (pr->debug->version);
+	if (pr->debug->version != PROG_DEBUG_VERSION) {
+		Sys_Printf ("ignoring %s with unsupported version %x.%03x.%03x\n",
+					sym_path,
+					(pr->debug->version >> 24) & 0xff,
+					(pr->debug->version >> 12) & 0xfff,
+					pr->debug->version & 0xfff);
+		Hunk_FreeToLowMark (start);
+		pr->debug = 0;
+		pr->auxfunctions = 0;
+		pr->linenos = 0;
+		pr->local_defs = 0;
+		return;
+	}
+	pr->debug->crc = LittleShort (pr->debug->crc);
+	if (pr->debug->crc != pr->crc) {
+		Sys_Printf ("ignoring %s that doesn't match %s. (crcs: sys:%d dat:%d)",
+					sym_path,
+					pr->progs_name,
+					pr->debug->crc,
+					pr->crc);
+		Hunk_FreeToLowMark (start);
+		pr->debug = 0;
+		pr->auxfunctions = 0;
+		pr->linenos = 0;
+		pr->local_defs = 0;
+		return;
+	}
+	pr->debug->you_tell_me_and_we_will_both_know = LittleShort (pr->debug->you_tell_me_and_we_will_both_know);
+	pr->debug->auxfunctions = LittleLong (pr->debug->auxfunctions);
+	pr->debug->num_auxfunctions = LittleLong (pr->debug->num_auxfunctions);
+	pr->debug->linenos = LittleLong (pr->debug->linenos);
+	pr->debug->num_linenos = LittleLong (pr->debug->num_linenos);
+	pr->debug->locals = LittleLong (pr->debug->locals);
+	pr->debug->num_locals = LittleLong (pr->debug->num_locals);
+
+	pr->auxfunctions = (pr_auxfunction_t*)((char*)pr->debug + pr->debug->auxfunctions);
+	pr->linenos = (pr_lineno_t*)((char*)pr->debug + pr->debug->linenos);
+	pr->local_defs = (ddef_t*)((char*)pr->debug + pr->debug->locals);
+
+	for (i = 0; i < pr->debug->num_auxfunctions; i++) {
+		pr->auxfunctions[i].function = LittleLong (pr->auxfunctions[i].function);
+		pr->auxfunctions[i].source_line = LittleLong (pr->auxfunctions[i].source_line);
+		pr->auxfunctions[i].line_info = LittleLong (pr->auxfunctions[i].line_info);
+		pr->auxfunctions[i].local_defs = LittleLong (pr->auxfunctions[i].local_defs);
+		pr->auxfunctions[i].num_locals = LittleLong (pr->auxfunctions[i].num_locals);
+	}
+	for (i = 0; i < pr->debug->num_linenos; i++) {
+		pr->linenos[i].fa.func = LittleLong (pr->linenos[i].fa.func);
+		pr->linenos[i].line = LittleLong (pr->linenos[i].line);
+	}
+	for (i = 0; i < pr->debug->num_locals; i++) {
+		pr->local_defs[i].type = LittleShort (pr->local_defs[i].type);
+		pr->local_defs[i].ofs = LittleShort (pr->local_defs[i].ofs);
+		pr->local_defs[i].s_name = LittleLong (pr->local_defs[i].s_name);
+	}
+}
+
+pr_auxfunction_t *
+PR_Get_Lineno_Func (progs_t *pr, pr_lineno_t *lineno)
+{
+	while (lineno > pr->linenos && lineno->line)
+		lineno--;
+	if (lineno->line)
+		return 0;
+	return &pr->auxfunctions[lineno->fa.func];
+}
+
+unsigned long
+PR_Get_Lineno_Addr (progs_t *pr, pr_lineno_t *lineno)
+{
+	pr_auxfunction_t *f;
+
+	if (lineno->line)
+		return lineno->fa.addr;
+	f = &pr->auxfunctions[lineno->fa.func];
+	return pr->pr_functions[f->function].first_statement;
+}
+
+unsigned long
+PR_Get_Lineno_Line (progs_t *pr, pr_lineno_t *lineno)
+{
+	pr_auxfunction_t *f;
+
+	if (lineno->line)
+		return lineno->line;
+	f = &pr->auxfunctions[lineno->fa.func];
+	return f->source_line;
+}
+
+pr_lineno_t *
+PR_Find_Lineno (progs_t *pr, unsigned long addr)
+{
+	pr_lineno_t *lineno = 0;
+	int i;
+
+	if (!pr->debug)
+		return 0;
+	if (!pr->debug->num_linenos)
+		return 0;
+	for (i = pr->debug->num_linenos - 1; i >= 0; i--) {
+		if (PR_Get_Lineno_Addr (pr, &pr->linenos[i]) <= addr) {
+			lineno = &pr->linenos[i];
+			break;
+		}
+	}
+	return lineno;
+}
+
+const char *
+PR_Get_Source_File (progs_t *pr, pr_lineno_t *lineno)
+{
+	pr_auxfunction_t *f;
+
+	f = PR_Get_Lineno_Func (pr, lineno);
+	return PR_GetString(pr, pr->pr_functions[f->function].s_file);
+}
+
+const char *
+PR_Get_Source_Line (progs_t *pr, unsigned long addr)
+{
+	pr_auxfunction_t *func;
+	const char *fname;
+	unsigned long line;
+	char       *str;
+	file_t     *file;
+
+	pr_lineno_t *lineno = PR_Find_Lineno (pr, addr);
+	if (!lineno || PR_Get_Lineno_Addr (pr, lineno) != addr)
+		return 0;
+	func = PR_Get_Lineno_Func (pr, lineno);
+	fname = PR_Get_Source_File (pr, lineno);
+	if (!func || !fname)
+		return 0;
+	line = PR_Get_Lineno_Line (pr, lineno);
+	line += func->source_line;
+
+	str = Hunk_TempAlloc (strlen (fname) + 12);
+	sprintf (str, "%s:%ld", fname, line);
+
+	file = PR_Load_Source_File (pr, fname);
+	if (!file || line > file->num_lines)
+		return str;
+
+	str = Hunk_TempAlloc (strlen (str) + file->lines[line - 1].len + 2);
+	sprintf (str, "%s:%ld:%.*s", fname, line,
+			 (int)file->lines[line - 1].len, file->lines[line - 1].text);
+	return str;
+}
+
+static const char *
+file_get_key (void *_f, void *unused)
+{
+	return ((file_t*)_f)->name;
+}
+
+static void
+file_free (void *_f, void *unused)
+{
+	file_t *f = (file_t*)_f;
+	free (f->lines);
+	free (f->text);
+	free (f->name);
+	free (f);
+}
+
+void
+PR_Debug_Init (void)
+{
+	file_hash = Hash_NewTable (1024, file_get_key, file_free, 0);
+}
+
+void
+PR_Debug_Init_Cvars (void)
+{
+	pr_debug = Cvar_Get ("pr_debug", "0", CVAR_NONE, NULL,
+						 "enable progs debugging");
+}
diff --git a/libs/gamecode/pr_edict.c b/libs/gamecode/pr_edict.c
index f0c862933..4277fc44b 100644
--- a/libs/gamecode/pr_edict.c
+++ b/libs/gamecode/pr_edict.c
@@ -1039,6 +1039,8 @@ PR_LoadProgs (progs_t * pr, char *progsname)
 		PR_Error (pr, "%s has unrecognised version number (%08x)",
 				  progsname, pr->progs->version);
 
+	pr->progs_name = progsname;	//XXX is this safe?
+
 	pr->pr_functions =
 		(dfunction_t *) ((byte *) pr->progs + pr->progs->ofs_functions);
 	pr->pr_strings = (char *) pr->progs + pr->progs->ofs_strings;
@@ -1129,6 +1131,8 @@ PR_LoadProgs (progs_t * pr, char *progsname)
 	// initialise the strings managment code
 	PR_LoadStrings (pr);
 
+	PR_LoadDebug (pr);
+
 	// LordHavoc: bounds check anything static
 	for (i = 0, st = pr->pr_statements; i < pr->progs->numstatements; i++, st++) {
 		switch (st->op) {
@@ -1280,12 +1284,14 @@ PR_Init_Cvars (void)
 				  "Server progs bounds checking");
 	pr_deadbeef = Cvar_Get ("pr_deadbeef", "0", CVAR_NONE, NULL,
 							"set to clear unallocated memory ot 0xdeadbeef");
+	PR_Debug_Init_Cvars ();
 }
 
 void
 PR_Init (void)
 {
 	PR_Opcode_Init ();
+	PR_Debug_Init ();
 }
 
 edict_t    *
diff --git a/libs/gamecode/pr_exec.c b/libs/gamecode/pr_exec.c
index f520b8fa1..0627bc93b 100644
--- a/libs/gamecode/pr_exec.c
+++ b/libs/gamecode/pr_exec.c
@@ -58,6 +58,12 @@ PR_PrintStatement (progs_t * pr, dstatement_t *s)
 	int         addr = s - pr->pr_statements;
 	opcode_t   *op;
 
+	if (pr_debug->int_val) {
+		const char *source_line = PR_Get_Source_Line (pr, addr);
+
+		if (source_line)
+			Con_Printf ("%s\n", source_line);
+	}
 	Con_Printf ("%-7d ", addr);
 	op = PR_Opcode (s->op);
 	if (op) {