Added memory menu and some devel changes

12 files changed, 1089 insertions, 132 deletions

diff --git a/src/Makefile b/src/Makefile
index 9486c2b..ba51a7e 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -18,7 +18,7 @@
 # 
 # -------------------------------------------------------------------------
 # 
-# $Id: Makefile,v 1.4 2003-12-19 19:31:57 ianc Exp $
+# $Id: Makefile,v 1.5 2003-12-22 00:01:31 ianc Exp $
 # 
 
 
@@ -37,6 +37,7 @@ SOURCE	=	main.c		\
 		config.c	\
 		gfx.c		\
 		gui.c		\
+		memmenu.c	\
 		exit.c
 
 OBJECTS	=	main.o		\
@@ -44,6 +45,7 @@ OBJECTS	=	main.o		\
 		config.o	\
 		gfx.o		\
 		gui.o		\
+		memmenu.o	\
 		exit.o
 
 EMMA	=	emma
@@ -72,94 +74,3 @@ depend:
 	cd z80; make depend ; cd ..
 
 # DO NOT DELETE THIS LINE -- make depend depends on it
-
-main.o: /usr/include/stdlib.h /usr/include/sys/cdefs.h
-main.o: /usr/include/sys/_types.h /usr/include/machine/_types.h
-main.o: /usr/include/stdio.h /usr/local/include/SDL/SDL.h
-main.o: /usr/local/include/SDL/SDL_main.h /usr/local/include/SDL/SDL_types.h
-main.o: /usr/local/include/SDL/SDL_getenv.h
-main.o: /usr/local/include/SDL/SDL_error.h
-main.o: /usr/local/include/SDL/begin_code.h
-main.o: /usr/local/include/SDL/close_code.h
-main.o: /usr/local/include/SDL/SDL_rwops.h /usr/local/include/SDL/SDL_timer.h
-main.o: /usr/local/include/SDL/SDL_audio.h
-main.o: /usr/local/include/SDL/SDL_byteorder.h
-main.o: /usr/local/include/SDL/SDL_cdrom.h
-main.o: /usr/local/include/SDL/SDL_joystick.h
-main.o: /usr/local/include/SDL/SDL_events.h
-main.o: /usr/local/include/SDL/SDL_active.h
-main.o: /usr/local/include/SDL/SDL_keyboard.h
-main.o: /usr/local/include/SDL/SDL_keysym.h
-main.o: /usr/local/include/SDL/SDL_mouse.h /usr/local/include/SDL/SDL_video.h
-main.o: /usr/local/include/SDL/SDL_mutex.h /usr/local/include/SDL/SDL_quit.h
-main.o: /usr/local/include/SDL/SDL_version.h z80/z80.h zx81.h gfx.h gui.h
-main.o: config.h exit.h
-zx81.o: /usr/include/stdlib.h /usr/include/sys/cdefs.h
-zx81.o: /usr/include/sys/_types.h /usr/include/machine/_types.h
-zx81.o: /usr/include/stdio.h /usr/include/string.h /usr/include/strings.h
-zx81.o: zx81.h z80/z80.h config.h exit.h
-config.o: /usr/include/stdlib.h /usr/include/sys/cdefs.h
-config.o: /usr/include/sys/_types.h /usr/include/machine/_types.h
-config.o: /usr/include/stdio.h /usr/include/string.h /usr/include/strings.h
-config.o: exit.h config.h
-gfx.o: /usr/include/stdlib.h /usr/include/sys/cdefs.h
-gfx.o: /usr/include/sys/_types.h /usr/include/machine/_types.h
-gfx.o: /usr/include/stdio.h /usr/include/string.h /usr/include/strings.h
-gfx.o: /usr/include/stdarg.h gfx.h /usr/local/include/SDL/SDL.h
-gfx.o: /usr/local/include/SDL/SDL_main.h /usr/local/include/SDL/SDL_types.h
-gfx.o: /usr/local/include/SDL/SDL_getenv.h /usr/local/include/SDL/SDL_error.h
-gfx.o: /usr/local/include/SDL/begin_code.h
-gfx.o: /usr/local/include/SDL/close_code.h /usr/local/include/SDL/SDL_rwops.h
-gfx.o: /usr/local/include/SDL/SDL_timer.h /usr/local/include/SDL/SDL_audio.h
-gfx.o: /usr/local/include/SDL/SDL_byteorder.h
-gfx.o: /usr/local/include/SDL/SDL_cdrom.h
-gfx.o: /usr/local/include/SDL/SDL_joystick.h
-gfx.o: /usr/local/include/SDL/SDL_events.h
-gfx.o: /usr/local/include/SDL/SDL_active.h
-gfx.o: /usr/local/include/SDL/SDL_keyboard.h
-gfx.o: /usr/local/include/SDL/SDL_keysym.h /usr/local/include/SDL/SDL_mouse.h
-gfx.o: /usr/local/include/SDL/SDL_video.h /usr/local/include/SDL/SDL_mutex.h
-gfx.o: /usr/local/include/SDL/SDL_quit.h /usr/local/include/SDL/SDL_version.h
-gfx.o: exit.h config.h font.h
-gui.o: /usr/include/stdlib.h /usr/include/sys/cdefs.h
-gui.o: /usr/include/sys/_types.h /usr/include/machine/_types.h
-gui.o: /usr/include/stdio.h /usr/include/string.h /usr/include/strings.h
-gui.o: /usr/include/stdarg.h gui.h /usr/local/include/SDL/SDL.h
-gui.o: /usr/local/include/SDL/SDL_main.h /usr/local/include/SDL/SDL_types.h
-gui.o: /usr/local/include/SDL/SDL_getenv.h /usr/local/include/SDL/SDL_error.h
-gui.o: /usr/local/include/SDL/begin_code.h
-gui.o: /usr/local/include/SDL/close_code.h /usr/local/include/SDL/SDL_rwops.h
-gui.o: /usr/local/include/SDL/SDL_timer.h /usr/local/include/SDL/SDL_audio.h
-gui.o: /usr/local/include/SDL/SDL_byteorder.h
-gui.o: /usr/local/include/SDL/SDL_cdrom.h
-gui.o: /usr/local/include/SDL/SDL_joystick.h
-gui.o: /usr/local/include/SDL/SDL_events.h
-gui.o: /usr/local/include/SDL/SDL_active.h
-gui.o: /usr/local/include/SDL/SDL_keyboard.h
-gui.o: /usr/local/include/SDL/SDL_keysym.h /usr/local/include/SDL/SDL_mouse.h
-gui.o: /usr/local/include/SDL/SDL_video.h /usr/local/include/SDL/SDL_mutex.h
-gui.o: /usr/local/include/SDL/SDL_quit.h /usr/local/include/SDL/SDL_version.h
-gui.o: gfx.h exit.h
-exit.o: /usr/include/stdlib.h /usr/include/sys/cdefs.h
-exit.o: /usr/include/sys/_types.h /usr/include/machine/_types.h
-exit.o: /usr/include/stdarg.h exit.h /usr/local/include/SDL/SDL.h
-exit.o: /usr/local/include/SDL/SDL_main.h /usr/local/include/SDL/SDL_types.h
-exit.o: /usr/local/include/SDL/SDL_getenv.h
-exit.o: /usr/local/include/SDL/SDL_error.h
-exit.o: /usr/local/include/SDL/begin_code.h
-exit.o: /usr/local/include/SDL/close_code.h
-exit.o: /usr/local/include/SDL/SDL_rwops.h /usr/include/stdio.h
-exit.o: /usr/local/include/SDL/SDL_timer.h /usr/local/include/SDL/SDL_audio.h
-exit.o: /usr/local/include/SDL/SDL_byteorder.h
-exit.o: /usr/local/include/SDL/SDL_cdrom.h
-exit.o: /usr/local/include/SDL/SDL_joystick.h
-exit.o: /usr/local/include/SDL/SDL_events.h
-exit.o: /usr/local/include/SDL/SDL_active.h
-exit.o: /usr/local/include/SDL/SDL_keyboard.h
-exit.o: /usr/local/include/SDL/SDL_keysym.h
-exit.o: /usr/local/include/SDL/SDL_mouse.h /usr/local/include/SDL/SDL_video.h
-exit.o: /usr/local/include/SDL/SDL_mutex.h /usr/local/include/SDL/SDL_quit.h
-exit.o: /usr/local/include/SDL/SDL_version.h
-emma.o: /usr/include/stdlib.h /usr/include/sys/cdefs.h
-emma.o: /usr/include/sys/_types.h /usr/include/machine/_types.h
-emma.o: /usr/include/stdio.h z80/z80.h
diff --git a/src/config.c b/src/config.c
index 3fdb00a..0614c64 100644
--- a/src/config.c
+++ b/src/config.c
@@ -50,6 +50,7 @@ static int	fullscreen=FALSE;
 static int	memsize=16;
 static int	frames=50;
 static int	scale=1;
+static int	trace=0;
 
 static const struct
 {
@@ -63,6 +64,7 @@ static const struct
 		{"memsize",	&memsize,	TRUE},
 		{"frames",	&frames,	TRUE},
 		{"scale",	&scale,		TRUE},
+		{"trace",	&trace,		TRUE},
 		{NULL,		NULL,		FALSE}
 	    };
 
@@ -151,7 +153,8 @@ int IConfig(IConfigVar v)
 		    &fullscreen,
 		    &memsize,
 		    &frames,
-		    &scale
+		    &scale,
+		    &trace
 		};
 
     return *vars[v];
diff --git a/src/config.h b/src/config.h
index d937cb6..4613db3 100644
--- a/src/config.h
+++ b/src/config.h
@@ -35,7 +35,8 @@ typedef enum
     CONF_FULLSCREEN,
     CONF_MEMSIZE,
     CONF_FRAMES_PER_SEC,
-    CONF_SCALE
+    CONF_SCALE,
+    CONF_TRACE
 } IConfigVar;
 
 
diff --git a/src/gfx.c b/src/gfx.c
index 57be20c..e7cecb8 100644
--- a/src/gfx.c
+++ b/src/gfx.c
@@ -225,6 +225,16 @@ void GFXEndFrame(int delay)
 }
 
 
+void GFXKeyRepeat(int repeat)
+{
+    if (repeat)
+    	SDL_EnableKeyRepeat(SDL_DEFAULT_REPEAT_DELAY,
+			    SDL_DEFAULT_REPEAT_INTERVAL);
+    else
+    	SDL_EnableKeyRepeat(0,0);
+}
+
+
 SDL_Event *GFXGetKey(void)
 {
     static SDL_Event e;
@@ -246,7 +256,7 @@ SDL_Event *GFXWaitKey(void)
     do
     {
     	SDL_WaitEvent(&e);
-    } while (e.type!=SDL_KEYUP);
+    } while (e.type!=SDL_KEYDOWN);
 
     return &e;
 }
@@ -342,4 +352,44 @@ void GFXPrint(int x, int y, Uint32 col, const char *format, ...)
 }
 
 
+void GFXPrintPaper(int x, int y, Uint32 col, Uint32 paper,
+		   const char *format, ...)
+{
+    char buff[257];
+    va_list va;
+    char *p;
+    int sx,sy;
+
+    va_start(va,format);
+    vsprintf(buff,format,va);
+    va_end(va);
+
+    p=buff;
+
+    LOCK;
+
+    while(*p)
+    {
+	for(sy=0;sy<8;sy++)
+	{
+	    if (y+sy<SCR_H && x<SCR_W)
+	    {
+		for(sx=0;sx<8;sx++)
+		{
+		    if (font[(int)*p][sx+sy*8] && x+sx<SCR_W)
+			putpixel(x+sx,y+sy,col);
+		    else
+			putpixel(x+sx,y+sy,paper);
+		}
+	    }
+	}
+
+	p++;
+	x+=8;
+    }
+
+    UNLOCK;
+}
+
+
 /* END OF FILE */
diff --git a/src/gfx.h b/src/gfx.h
index 93eef60..14394d8 100644
--- a/src/gfx.h
+++ b/src/gfx.h
@@ -77,6 +77,11 @@ void		GFXStartFrame(void);
 void		GFXEndFrame(int delay);
 
 
+/* Set key repeat
+*/
+void		GFXKeyRepeat(int repeat);
+
+
 /* Suck out keyboard events.  Returns NULL if no more keyboard events
 */
 SDL_Event	*GFXGetKey(void);
@@ -125,6 +130,13 @@ void		GFXVLine(int x, int y1, int y2, Uint32 col);
 void		GFXPrint(int x, int y, Uint32 col, const char *format, ...);
 
 
+/* As above, but draws text using the supplied background colour, rather
+   than transparently.
+*/
+void		GFXPrintPaper(int x, int y, Uint32 col, Uint32 paper,
+			      const char *format, ...);
+
+
 #endif
 
 
diff --git a/src/gui.c b/src/gui.c
index bda46d3..19b39dc 100644
--- a/src/gui.c
+++ b/src/gui.c
@@ -29,6 +29,7 @@ static const char ident[]="$Id$";
 #include <stdio.h>
 #include <string.h>
 #include <stdarg.h>
+#include <ctype.h>
 
 #include "gui.h"
 #include "gfx.h"
@@ -79,7 +80,7 @@ static void Centre(const char *p, int y, int r, int g, int b)
 */
 void GUIMessage(const char *title, const char *format,...)
 {
-    char buff[257];
+    char buff[1025];
     va_list va;
     char *p;
     int no;
@@ -119,6 +120,13 @@ void GUIMessage(const char *title, const char *format,...)
 
     width=(width*8)+16;
     height=(no+3)*10;
+
+    if (width>(SCR_W-10))
+    	width=SCR_W-10;
+
+    if (height>(SCR_H-10))
+    	height=SCR_H-10;
+
     y=(SCR_H-height)/2;
     x=(SCR_W-width)/2;
 
@@ -146,4 +154,57 @@ void GUIMessage(const char *title, const char *format,...)
 }
 
 
+const char *GUIInputString(const char *prompt, const char *orig)
+{
+    static const int y_pos=SCR_H-8;
+    static char buff[41];
+    size_t len;
+    int done=FALSE;
+    SDL_Event *e;
+
+    buff[0]=0;
+    strncat(buff,orig,40);
+    len=strlen(buff);
+
+    while(!done)
+    {
+    	GFXRect(0,y_pos,SCR_W,8,GFXRGB(0,0,0),TRUE);
+	GFXPrint(0,y_pos,GFXRGB(255,255,255),"%s %s%c",prompt,buff,FONT_CURSOR);
+	GFXEndFrame(FALSE);
+
+	e=GFXWaitKey();
+
+	switch(e->key.keysym.sym)
+	{
+	    case SDLK_RETURN:
+	    case SDLK_KP_ENTER:
+	    	done=TRUE;
+		break;
+
+	    case SDLK_ESCAPE:
+		buff[0]=0;
+		len=0;
+	    	break;
+
+	    case SDLK_BACKSPACE:
+	    case SDLK_DELETE:
+	    	if (len)
+		    buff[--len]=0;
+
+		break;
+
+	    default:
+	    	if (len<40 && isprint(e->key.keysym.sym))
+		{
+		    buff[len++]=(char)e->key.keysym.sym;
+		    buff[len]=0;
+		}
+		break;
+	}
+    }
+
+    return buff;
+}
+
+
 /* END OF FILE */
diff --git a/src/gui.h b/src/gui.h
index 02a5db5..4f03394 100644
--- a/src/gui.h
+++ b/src/gui.h
@@ -33,10 +33,15 @@
 /* ---------------------------------------- INTERFACES
 */
 
-/* Display a simple message box.  A message of longer than 256 bytes causes
+/* Display a simple message box.  A message of longer than 1024 bytes causes
    undefined behaviour.  Newlines cause a line break.
 */
-void	GUIMessage(const char *title, const char *format,...);
+void		GUIMessage(const char *title, const char *format,...);
+
+
+/* Enter a string, max 40 characters
+*/
+const char	*GUIInputString(const char *prompt, const char *orig);
 
 
 #endif
diff --git a/src/main.c b/src/main.c
index d4bb65d..8841f6e 100644
--- a/src/main.c
+++ b/src/main.c
@@ -32,6 +32,7 @@ static const char id[]="$Id$";
 #include "zx81.h"
 #include "gfx.h"
 #include "gui.h"
+#include "memmenu.h"
 #include "config.h"
 #include "exit.h"
 
@@ -63,10 +64,13 @@ static Uint32	grey;
 int main(int argc, char *argv[])
 {
     Z80 *z80;
+    SDL_Event *e;
+    int quit;
+    int trace;
 
     ConfigRead();
 
-    ZX81Init();
+    trace=IConfig(CONF_TRACE);
 
     z80=Z80Init(ZX81WriteMem,
     		ZX81ReadMem,
@@ -77,44 +81,58 @@ int main(int argc, char *argv[])
 
     GFXInit();
 
+    ZX81Init(z80);
+
     white=GFXRGB(255,255,255);
     grey=GFXRGB(128,128,128);
     black=GFXRGB(0,0,0);
 
-    GFXClear(grey);
-    GFXPrint(1,1,black,"Quick SDL check");
-    GFXPrint(2,2,white,"Quick SDL check");
-    GFXRect(100,100,20,20,black,TRUE);
-    GFXRect(99,99,22,22,white,FALSE);
-
-    GFXRect(80,80,1,1,black,TRUE);
-    GFXRect(80,90,1,1,black,FALSE);
-
-    GFXRect(90,80,2,2,black,TRUE);
-    GFXRect(90,90,2,2,black,FALSE);
-
-    GFXRect(100,80,3,3,black,TRUE);
-    GFXRect(100,90,3,3,black,FALSE);
-
-    GFXHLine(0,319,0,white);
-    GFXVLine(0,1,199,black);
-
-    {
-    int f;
+    quit=FALSE;
 
-    for(f=0;f<10;f++)
+    while(!quit)
     {
-    	GFXPlot(rand()%320,rand()%200,white);
-	GFXEndFrame(FALSE);
-    }
+	Z80SingleStep(z80);
+
+	if (trace)
+	{
+	    DisplayState(z80);
+	    GFXEndFrame(FALSE);
+	}
+
+	while((e=GFXGetKey()))
+	{
+	    switch (e->key.keysym.sym)
+	    {
+	    	case SDLK_ESCAPE:
+		    if (e->key.state==SDL_RELEASED)
+			quit=TRUE;
+		    break;
+
+		case SDLK_F11:
+		    if (e->key.state==SDL_RELEASED)
+		    	MemoryMenu(z80);
+		    break;
+
+		case SDLK_F12:
+		    if (e->key.state==SDL_RELEASED)
+		    	trace=!trace;
+		    break;
+
+		default:
+		    ZX81KeyEvent(e);
+		    break;
+	    }
+	}
     }
 
-    GUIMessage("Test Message","Hello\nWorld\n%s",SConfig(CONF_TAPEDIR));
-
     SDL_Quit();
 
     return EXIT_SUCCESS;
 }
 
 
+/* ---------------------------------------- PRIVATE FUNCTIONS
+*/
+
+
 /* END OF FILE */
diff --git a/src/memmenu.c b/src/memmenu.c
new file mode 100644
index 0000000..c2f5da7
--- /dev/null
+++ b/src/memmenu.c
@@ -0,0 +1,329 @@
+/*
+
+    ezx81 - X11 ZX81 emulator
+
+    Copyright (C) 2003  Ian Cowburn (ianc@noddybox.demon.co.uk)
+
+    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 the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+    -------------------------------------------------------------------------
+
+    Provides a common error exit point
+
+*/
+static const char ident[]="$Id$";
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "memmenu.h"
+#include "zx81.h"
+#include "gfx.h"
+#include "gui.h"
+
+#include <SDL.h>
+
+static const char ident_h[]=EZX81_MEMMENU_H;
+
+#ifndef TRUE
+#define TRUE 1
+#endif
+
+#ifndef FALSE
+#define FALSE 0
+#endif
+
+#define WHITE	GFXRGB(255,255,255)
+#define BLACK	GFXRGB(0,0,0)
+#define RED	GFXRGB(255,100,100)
+#define GREEN	GFXRGB(100,255,100)
+#define BLUE	GFXRGB(100,100,255)
+
+#define MENU
+
+
+/* ---------------------------------------- PRIVATE FUNCTIONS
+*/
+static void Centre(const char *p, int y, Uint32 col)
+{
+    GFXPrint((320-strlen(p)*8)/2,y,col,"%s",p);
+}
+
+
+static void DisplayMenu(void)
+{
+    static const char *menu[]=
+    {
+    	"1. Disassemble/Hex dump",
+    	"2. Return              ",
+	NULL
+    };
+
+    int f;
+
+    GFXClear(BLACK);
+
+    Centre("MEMORY MENU",0,WHITE);
+    Centre("Select an option",8,WHITE);
+
+    f=0;
+
+    while(menu[f])
+    {
+    	Centre(menu[f],20+f*10,WHITE);
+	f++;
+    }
+}
+
+
+static const char *FlagString(Z80Byte flag)
+{
+    static char s[]="76543210";
+    static char c[]="SZ5H3PNC";
+    int f;
+
+    for(f=0;f<8;f++)
+        if (flag&(1<<(7-f)))
+            s[f]=c[f];
+        else
+            s[f]='-';
+
+    return s;
+}
+
+
+static int EnterAddress(Z80Word *w)
+{
+    unsigned long ul;
+    const char *p;
+
+    p=GUIInputString("Address?","");
+
+    if (*p)
+    {
+	ul=strtoul(p,NULL,0);
+
+	if (ul>0xffff)
+	{
+	    GUIMessage("ERROR","Bad address");
+	}
+	else
+	{
+	    *w=(Z80Word)ul;
+	    return TRUE;
+	}
+    }
+
+    return FALSE;
+}
+
+
+static void DoDisassem(Z80 *z80, const Z80State *s)
+{
+    static int hexmode=FALSE;
+    Z80Word pc=s->PC;
+    int quit=FALSE;
+
+    while(!quit)
+    {
+	SDL_Event *e;
+	Z80Word curr;
+	Z80Word next;
+	int f;
+
+	GFXClear(BLACK);
+
+    	Centre("Press F1 for help",0,RED);
+
+	curr=pc;
+
+	for(f=0;f<21;f++)
+	{
+	    char s[80];
+	    char *p;
+	    int y;
+
+	    y=16+f*8;
+
+	    GFXPrint(0,y,GREEN,"%4.4x",curr);
+
+	    if (hexmode)
+	    {
+		int n;
+
+	    	for(n=0;n<8;n++)
+		{
+		    GFXPrint(40+n*24,y,WHITE,"%2.2x",
+		    		(int)ZX81ReadForDisassem(z80,curr));
+
+		    curr++;
+		}
+	    }
+	    else
+	    {
+		strcpy(s,Z80Disassemble(z80,&curr));
+
+		p=strtok(s,";");
+		GFXPrint(40,y,WHITE,"%s",p);
+	    }
+
+	    if (f==0)
+		next=curr;
+	}
+
+	GFXEndFrame(FALSE);
+
+	e=GFXWaitKey();
+
+	switch(e->key.keysym.sym)
+	{
+	    case SDLK_F1:
+		GUIMessage
+		    ("DISASSEMBLY HELP","%s",
+		       "ESC - Exit\n"
+		       "H - Switch between disassembly/hex\n"
+		       "Enter - Enter address to display\n"
+		       "Cursor Up - Prev op\n"
+		       "Cursor Down - Next op\n"
+		       "Page Up - Move back a page\n"
+		       "Page Down - Move forward a page\n"
+		       "Cursor Left - Move PC by -1024\n"
+		       "Cursor Right - Move PC by 1024");
+		break;
+
+	    case SDLK_ESCAPE:
+	    	quit=TRUE;
+		break;
+
+	    case SDLK_h:
+		hexmode=!hexmode;
+	    	break;
+
+	    case SDLK_RETURN:
+	    case SDLK_KP_ENTER:
+		EnterAddress(&pc);
+	    	break;
+
+	    case SDLK_UP:
+		if (hexmode)
+		    pc-=8;
+		else
+		    pc--;
+	    	break;
+
+	    case SDLK_DOWN:
+		pc=next;
+	    	break;
+
+	    case SDLK_PAGEUP:
+		if (hexmode)
+		    pc-=21*8;
+		else
+		    pc-=21;
+		break;
+
+	    case SDLK_PAGEDOWN:
+	    	pc=curr;
+		break;
+
+	    case SDLK_LEFT:
+	    	pc-=1024;
+		break;
+
+	    case SDLK_RIGHT:
+	    	pc+=1024;
+		break;
+
+	    default:
+	    	break;
+	}
+    }
+}
+
+
+/* ---------------------------------------- EXPORTED INTERFACES
+*/
+void MemoryMenu(Z80 *z80)
+{
+    SDL_Event *e;
+    int quit=FALSE;
+    Z80State s;
+
+    Z80GetState(z80,&s);
+
+    GFXKeyRepeat(TRUE);
+
+    while(!quit)
+    {
+	DisplayMenu();
+	DisplayState(z80);
+	GFXEndFrame(FALSE);
+
+	e=GFXWaitKey();
+
+	switch(e->key.keysym.sym)
+	{
+	    case SDLK_1:
+	    	DoDisassem(z80,&s);
+		break;
+
+	    case SDLK_ESCAPE:
+	    case SDLK_2:
+	    	quit=TRUE;
+		break;
+
+	    default:
+	    	break;
+	}
+    }
+
+    GFXKeyRepeat(FALSE);
+}
+
+
+void DisplayState(Z80 *z80)
+{
+    Z80State s;
+    int y;
+
+    Z80GetState(z80,&s);
+
+    y=136;
+
+    GFXPrintPaper(0,y,RED,BLACK,"PC=%4.4x  A=%2.2x     F=%s",
+                    s.PC,s.AF>>8,FlagString(s.AF&0xff));
+    y+=8;
+
+    GFXPrintPaper(0,y,RED,BLACK,"BC=%4.4x  DE=%4.4x  HL=%4.4x",s.BC,s.DE,s.HL);
+    y+=8;
+
+    GFXPrintPaper(0,y,RED,BLACK,"IX=%4.4x  IY=%4.4x  SP=%4.4x",s.IX,s.IY,s.SP);
+    y+=8;
+
+    GFXPrintPaper(0,y,RED,BLACK,"I=%2.2x     IM=%2.2x    R=%2.2x",s.I,s.IM,s.R);
+    y+=8;
+
+    GFXPrintPaper(0,y,RED,BLACK,"IFF1=%2.2x  IFF2=%2.2x",s.IFF1,s.IFF2);
+    y+=8;
+
+    y+=8;
+    GFXPrintPaper(0,y,RED,BLACK,"%s\n",ZX81Info(z80));
+    y+=8;
+}
+
+
+
+
+/* END OF FILE */
diff --git a/src/memmenu.h b/src/memmenu.h
new file mode 100644
index 0000000..bacbef9
--- /dev/null
+++ b/src/memmenu.h
@@ -0,0 +1,46 @@
+/*
+
+    ezx81 - X11 ZX81 emulator
+
+    Copyright (C) 2003  Ian Cowburn (ianc@noddybox.demon.co.uk)
+
+    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 the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+    -------------------------------------------------------------------------
+
+    Provides a menu driven interface for analysing memory
+
+*/
+
+#ifndef EZX81_MEMMENU_H
+#define EZX81_MEMMENU_H "$Id$"
+
+#include "z80.h"
+
+
+/* Memory menu
+*/
+void	MemoryMenu(Z80 *z80);
+
+
+/* Display the state of the ZX81 at the bottom of the screen
+*/
+void	DisplayState(Z80 *z80);
+
+
+#endif
+
+
+/* END OF FILE */
diff --git a/src/zx81.c b/src/zx81.c
index 9fa09f6..515cd07 100644
--- a/src/zx81.c
+++ b/src/zx81.c
@@ -29,11 +29,21 @@ static const char ident[]="$Id$";
 #include <stdio.h>
 #include <string.h>
 #include "zx81.h"
+#include "gfx.h"
+#include "gui.h"
 #include "config.h"
 #include "exit.h"
 
 static const char ident_h[]=EZX81ZX81H;
 
+#ifndef TRUE
+#define TRUE 1
+#endif
+
+#ifndef FALSE
+#define FALSE 0
+#endif
+
 
 /* ---------------------------------------- STATICS
 */
@@ -41,6 +51,17 @@ static const int	ROMLEN=0x2000;
 static const int	ROM_SAVE=0x2fc;
 static const int	ROM_LOAD=0x347;
 
+/* No of cycles in each 64us HSYNC (hopefully)
+*/
+static const int	HSYNC_PERIOD=321;
+
+/* The ZX81 screen
+*/
+static const int	SCR_W=256;
+static const int	SCR_H=192;
+static const int	TXT_W=32;
+static const int	TXT_H=24;
+
 /* These assume a 320x200 screen
 */
 static const int	OFF_X=(320-256)/2;
@@ -52,30 +73,377 @@ static Z80Word		RAMBOT=0;
 static Z80Word		RAMTOP=0;
 static Z80Word		RAMLEN=0;
 
+/* Counter used when triggering the interrupts for the display
+*/
+static int		nmigen=FALSE;
+static int		hsync=FALSE;
+
+/* The ULA
+*/
+static struct
+{
+    int		x;
+    int		y;
+    int		c;
+    int		release;
+} ULA;
+
+/* GFX vars
+*/
+static Uint32		white;
+static Uint32		black;
+
+
+/* The keyboard
+*/
+static Z80Byte		matrix[8];
+
+typedef struct
+{
+    SDLKey	key;
+    int		m1,b1,m2,b2;
+} MatrixMap;
+
+#define KY1(m,b)		m,1<<b,-1,-1
+#define KY2(m1,b1,m2,b2)	m1,1<<b1,m2,1<<b2
+
+static const MatrixMap keymap[]=
+{
+    {SDLK_1,		KY1(3,0)},
+    {SDLK_2,		KY1(3,1)},
+    {SDLK_3,		KY1(3,2)},
+    {SDLK_4,		KY1(3,3)},
+    {SDLK_5,		KY1(3,4)},
+    {SDLK_6,		KY1(4,4)},
+    {SDLK_7,		KY1(4,3)},
+    {SDLK_8,		KY1(4,2)},
+    {SDLK_9,		KY1(4,1)},
+    {SDLK_0,		KY1(4,0)},
+
+    {SDLK_a,		KY1(1,0)},
+    {SDLK_b,		KY1(7,4)},
+    {SDLK_c,		KY1(0,3)},
+    {SDLK_d,		KY1(1,2)},
+    {SDLK_e,		KY1(2,2)},
+    {SDLK_f,		KY1(1,3)},
+    {SDLK_g,		KY1(1,4)},
+    {SDLK_h,		KY1(6,4)},
+    {SDLK_i,		KY1(5,2)},
+    {SDLK_j,		KY1(6,3)},
+    {SDLK_k,		KY1(6,2)},
+    {SDLK_l,		KY1(6,1)},
+    {SDLK_m,		KY1(7,2)},
+    {SDLK_n,		KY1(7,3)},
+    {SDLK_o,		KY1(5,1)},
+    {SDLK_p,		KY1(5,0)},
+    {SDLK_q,		KY1(2,0)},
+    {SDLK_r,		KY1(2,3)},
+    {SDLK_s,		KY1(1,1)},
+    {SDLK_t,		KY1(2,4)},
+    {SDLK_u,		KY1(5,3)},
+    {SDLK_v,		KY1(0,4)},
+    {SDLK_w,		KY1(2,1)},
+    {SDLK_x,		KY1(0,2)},
+    {SDLK_y,		KY1(5,4)},
+    {SDLK_z,		KY1(0,1)},
+
+    {SDLK_RETURN,	KY1(6,0)},
+    {SDLK_SPACE,	KY1(7,0)},
+
+    {SDLK_COMMA,	KY1(7,1)},	/* In the right place... */
+    {SDLK_PERIOD,	KY1(7,1)},	/* ...or the right key... */
+
+    {SDLK_BACKSPACE,	KY2(0,0,4,0)},
+    {SDLK_DELETE,	KY2(0,0,4,0)},
+    {SDLK_UP,		KY2(0,0,4,3)},
+    {SDLK_DOWN,		KY2(0,0,4,4)},
+    {SDLK_LEFT,		KY2(0,0,3,4)},
+    {SDLK_RIGHT,	KY2(0,0,4,2)},
+
+    {SDLK_RSHIFT,	KY1(0,0)},
+    {SDLK_LSHIFT,	KY1(0,0)},
+
+    {SDLK_UNKNOWN,	0,0,0,0},
+};
+
 
 /* ---------------------------------------- PRIVATE FUNCTIONS
 */
-void ULA_Video_Shifter(Z80 *z80, Z80Byte val)
+static void RomPatch(void)
+{
+    static const Z80Byte save[]=
+    {
+    	0xed, 0xf0,		/* ED F0 illegal op	*/
+	0xc3, 0x08, 0x02,	/* JP $0207		*/
+	0xff			/* End of patch		*/
+    };
+
+    static const Z80Byte load[]=
+    {
+    	0xed, 0xf1,		/* ED F0 illegal op	*/
+	0xc3, 0x08, 0x02,	/* JP $0207		*/
+	0xff			/* End of patch		*/
+    };
+
+    int f;
+
+    for(f=0;save[f]!=0xff;f++)
+    	mem[ROM_SAVE+f]=save[f];
+
+    for(f=0;load[f]!=0xff;f++)
+    	mem[ROM_LOAD+f]=load[f];
+}
+
+
+static char ToASCII(Z80Byte b)
+{
+    if (b==0)			/* SPACE */
+    	return ' ';
+    
+    if (b==22)			/* Dash (-) */
+    	return '-';
+
+    if (b>=28 && b<=37)		/* 0-9 */
+    	return '0'+b-28;
+
+    if (b>=38 && b<=63)		/* A-Z */
+    	return 'a'+b-38;
+
+    return 0;
+}
+
+
+static const char *ConvertFilename(Z80Word addr)
+{
+    static char buff[FILENAME_MAX];
+    char *p;
+
+    p=buff;
+    *p=0;
+
+    if (addr>0x8000)
+    	return buff;
+
+    do
+    {
+    	char c=ToASCII(mem[addr]&0x7f);
+
+	if (c)
+	    *p++=c;
+
+    } while(mem[addr++]<0x80);
+
+    *p=0;
+
+    return buff;
+}
+
+
+static void LoadTape(Z80State *state)
+{
+    const char *p=ConvertFilename(state->DE);
+    char path[FILENAME_MAX];
+    FILE *fp;
+    Z80Word addr;
+    int c;
+
+    if (strlen(p)==0)
+    {
+    	GUIMessage("ERROR","Can't load empty filename");
+	return;
+    }
+
+    strcpy(path,SConfig(CONF_TAPEDIR));
+    strcat(path,"/");
+    strcat(path,p);
+    strcat(path,".p");
+
+    if (!(fp=fopen(path,"rb")))
+    {
+    	GUIMessage("ERROR","Can't load file:\n%s",path);
+	return;
+    }
+
+    addr=0x4009;
+
+    while((c=getc(fp))!=EOF)
+    {
+	if (addr>=0x4000)
+	    mem[addr]=(Z80Byte)c;
+
+	addr++;
+    }
+
+    fclose(fp);
+}
+
+
+static void SaveTape(Z80State *state)
+{
+    const char *p=ConvertFilename(state->DE);
+    char path[FILENAME_MAX];
+    FILE *fp;
+    Z80Word start;
+    Z80Word end;
+
+    if (strlen(p)==0)
+    {
+    	GUIMessage("ERROR","Can't save empty filename");
+	return;
+    }
+
+    strcpy(path,SConfig(CONF_TAPEDIR));
+    strcat(path,"/");
+    strcat(path,p);
+    strcat(path,".p");
+
+    if (!(fp=fopen(path,"wb")))
+    {
+    	GUIMessage("ERROR","Can't write file:\n%s",path);
+	return;
+    }
+
+    start=0x4009;
+    end=(Z80Word)mem[0x4014]|(Z80Word)mem[0x4015]<<8;
+
+    while(start<=end)
+    	putc(mem[start++],fp);
+
+    fclose(fp);
+}
+
+
+static int EDCallback(Z80 *z80, Z80Val data)
 {
+    Z80State state;
+
+    Z80GetState(z80,&state);
+
+    switch((Z80Byte)data)
+    {
+    	case 0xf0:
+	    SaveTape(&state);
+	    break;
+
+    	case 0xf1:
+	    LoadTape(&state);
+	    break;
+
+	default:
+	    break;
+    }
+
+    return TRUE;
+}
+
+
+static void ULA_Video_Shifter(Z80 *z80, Z80Byte val)
+{
+    Z80State state;
+    Z80Word base;
+    int x,y;
+    int inv;
+    int b;
+
+    Z80GetState(z80,&state);
+
+    /* Extra check due to out dodgy ULA emulation
+    */
+    if (ULA.y>=0 && ULA.y<SCR_H)
+    {
+	Uint32 fg,bg;
+
+    	/* Position on screen corresponding to ULA
+	*/
+	x=OFF_X+ULA.x*8;
+	y=OFF_Y+ULA.y;
+
+	/* Get ULA invert state and clear to ULA 6-but code
+	*/
+	inv=val&0x80;
+	val&=0x3f;
+
+	base=((Z80Word)state.I<<8)|(val<<3)|ULA.c;
+
+	if (inv)
+	{
+	    fg=white;
+	    bg=black;
+	}
+	else
+	{
+	    fg=black;
+	    bg=white;
+	}
+
+	for(b=0;b<8;b++)
+	{
+	    if (mem[base]&(1<<(7-b)))
+	    	GFXPlot(x+b,y,fg);
+	    else
+	    	GFXPlot(x+b,y,bg);
+	}
+    }
+
+    ULA.x=(ULA.x+1)&0x1f;
+
+    if (ULA.x==0)
+    	Z80Interrupt(z80,0xff);
+}
+
+
+static int CheckTimers(Z80 *z80, Z80Val val)
+{
+    if (val>HSYNC_PERIOD)
+    {
+	Z80ResetCycles(z80,0);
+
+	if (nmigen)
+	{
+	    Z80NMI(z80,0xff);
+	}
+	else if (hsync)
+	{
+	    if (ULA.release)
+	    {
+	    	/* ULA.release=FALSE; */
+		ULA.c=(ULA.c+1)&7;
+		ULA.y++;
+		ULA.x=0;
+	    }
+	}
+    }
+
+    return TRUE;
 }
 
 
 /* ---------------------------------------- EXPORTED INTERFACES
 */
-void ZX81Init(void)
+void ZX81Init(Z80 *z80)
 {
     FILE *fp;
     Z80Word f;
 
     if (!(fp=fopen(SConfig(CONF_ROMFILE),"rb")))
-    	Exit("Failed to open ZX81 ROM - %s\n",SConfig(CONF_ROMFILE));
+    {
+	GUIMessage("ERROR","Failed to open ZX81 ROM\n%s",SConfig(CONF_ROMFILE));
+	Exit("");
+    }
 
     if (fread(mem,1,ROMLEN,fp)!=ROMLEN)
     {
     	fclose(fp);
-	Exit("ROM file must be %d bytes long\n",ROMLEN);
+	GUIMessage("ERROR","ROM file must be %d bytes long\n",ROMLEN);
+	Exit("");
     }
 
+    /* Patch the ROM
+    */
+    RomPatch();
+    Z80LodgeCallback(z80,Z80_EDHook,EDCallback);
+    Z80LodgeCallback(z80,Z80_Fetch,CheckTimers);
+
     /* Mirror the ROM
     */
     memcpy(mem+ROMLEN,mem,ROMLEN);
@@ -93,6 +461,48 @@ void ZX81Init(void)
 
     for(f=RAMBOT;f<=RAMTOP;f++)
     	mem[f]=0;
+
+    for(f=0;f<8;f++)
+    	matrix[f]=0x1f;
+
+    white=GFXRGB(230,230,230);
+    black=GFXRGB(0,0,0);
+
+    nmigen=FALSE;
+    hsync=FALSE;
+
+    GFXStartFrame();
+}
+
+
+void ZX81KeyEvent(SDL_Event *e)
+{
+    const MatrixMap *m;
+
+    m=keymap;
+
+    while(m->key!=SDLK_UNKNOWN)
+    {
+    	if (e->key.keysym.sym==m->key)
+	{
+	    if (e->key.state==SDL_PRESSED)
+	    {
+	    	matrix[m->m1]&=~m->b1;
+
+		if (m->m2!=-1)
+		    matrix[m->m2]&=~m->b2;
+	    }
+	    else
+	    {
+	    	matrix[m->m1]|=m->b1;
+
+		if (m->m2!=-1)
+		    matrix[m->m2]|=m->b2;
+	    }
+	}
+
+	m++;
+    }
 }
 
 
@@ -134,19 +544,109 @@ Z80Byte ZX81ReadMem(Z80 *z80, Z80Word addr)
 
 void ZX81WriteMem(Z80 *z80, Z80Word addr, Z80Byte val)
 {
+    addr=addr&0x7fff;
+
     if (addr>=RAMBOT && addr<=RAMTOP)
-	mem[addr&0x7fff]=val;
+	mem[addr]=val;
 }
 
 
 Z80Byte ZX81ReadPort(Z80 *z80, Z80Word port)
 {
-    return 0;
+    Z80Byte b=0;
+
+    printf("IN  %4.4x\n",port);
+
+    switch(port&0xff)
+    {
+    	case 0xfe:	/* ULA */
+	    /* Key matrix
+	    */
+	    switch(port&0xff00)
+	    {
+	    	case 0xfe00:
+		    b=matrix[0];
+		    break;
+	    	case 0xfd00:
+		    b=matrix[1];
+		    break;
+	    	case 0xfb00:
+		    b=matrix[2];
+		    break;
+	    	case 0xf700:
+		    b=matrix[3];
+		    break;
+	    	case 0xef00:
+		    b=matrix[4];
+		    break;
+	    	case 0xdf00:
+		    b=matrix[5];
+		    break;
+	    	case 0xbf00:
+		    b=matrix[6];
+		    break;
+	    	case 0x7f00:
+		    b=matrix[7];
+		    break;
+	    }
+
+	    /* Turn off HSYNC if NMI generator is OFF and redraw screen to
+	       match output ULA has since sent out.
+	    */
+	    if (!nmigen && hsync)
+	    {
+	    	hsync=FALSE;
+
+		GFXEndFrame(TRUE);
+		GFXClear(white);
+
+		ULA.x=0;
+		ULA.y=-1;
+		ULA.c=7;
+		ULA.release=FALSE;
+
+		GFXStartFrame();
+	    }
+	    else
+	    {
+	    	/* Reset and hold ULA counter
+		*/
+		ULA.c=0;
+		ULA.release=FALSE;
+	    }
+	    break;
+
+	default:
+	    break;
+    }
+
+    return b;
 }
 
 
 void ZX81WritePort(Z80 *z80, Z80Word port, Z80Byte val)
 {
+    printf("OUT %4.4x\n",port);
+
+    /* Any port write releases the ULA line counter
+    */
+    ULA.release=TRUE;
+
+    switch(port&0xff)
+    {
+    	case 0xfd:	/* NMI generator OFF */
+	    nmigen=FALSE;
+	    break;
+
+	case 0xfe:	/* NMI generator ON */
+	    nmigen=TRUE;
+	    break;
+
+	case 0xff:	/* HSYNC generator ON */
+	    hsync=TRUE;
+	    Z80ResetCycles(z80,0);
+	    break;
+    }
 }
 
 
@@ -156,4 +656,16 @@ Z80Byte ZX81ReadForDisassem(Z80 *z80, Z80Word addr)
 }
 
 
+const char *ZX81Info(Z80 *z80)
+{
+    static char buff[80];
+
+    sprintf(buff,"NMIGEN: %s  HSYNC: %s",
+		    nmigen ? "ON":"OFF",
+		    hsync ? "ON":"OFF");
+
+    return buff;
+}
+
+
 /* END OF FILE */
diff --git a/src/zx81.h b/src/zx81.h
index 7fa865d..037363f 100644
--- a/src/zx81.h
+++ b/src/zx81.h
@@ -28,11 +28,16 @@
 #define EZX81ZX81H "$Id$"
 
 #include "z80.h"
+#include "SDL.h"
 
 
 /* Initialise the ZX81
 */
-void	ZX81Init(void);
+void	ZX81Init(Z80 *z80);
+
+/* Handle keypresses
+*/
+void	ZX81KeyEvent(SDL_Event *e);
 
 /* Interfaces for the Z80
 */
@@ -42,6 +47,10 @@ Z80Byte	ZX81ReadPort(Z80 *z80, Z80Word port);
 void	ZX81WritePort(Z80 *z80, Z80Word port, Z80Byte val);
 Z80Byte	ZX81ReadForDisassem(Z80 *z80, Z80Word addr);
 
+/* Interfaces for memory menu
+*/
+const char	*ZX81Info(Z80 *z80);
+
 
 #endif