Initial working version. Still todo : Tapes, Sound

5 files changed, 386 insertions, 422 deletions

diff --git a/source/config.c b/source/config.c
index 3abc1ab..8198290 100644
--- a/source/config.c
+++ b/source/config.c
@@ -40,7 +40,6 @@ const char *conf_filename = "SPEC48.CFG";
 const char *conf_entry[DSSPEC_NUM_CONFIG_ITEMS]=
 {
     "sticky_shift",
-    "allow_tape_save",
     "load_default_snapshot"
 };
 
@@ -50,7 +49,6 @@ const char *conf_entry[DSSPEC_NUM_CONFIG_ITEMS]=
 int	DSSPEC_Config[DSSPEC_NUM_CONFIG_ITEMS]=
 {
     TRUE,
-    FALSE,
     FALSE
 };
 
@@ -128,9 +126,6 @@ const char *ConfigDesc(DSSPEC_ConfigItem item)
 	case DSSPEC_LOAD_DEFAULT_SNAPSHOT:
 	    return "LOAD DEFAULT SNAPSHOT";
 
-	case DSSPEC_ALLOW_TAPE_SAVE:
-	    return "ALLOW TAPE SAVING";
-
     	default:
 	    return "UNKNOWN";
     }
diff --git a/source/gui.c b/source/gui.c
index 1d14fa3..604f910 100644
--- a/source/gui.c
+++ b/source/gui.c
@@ -850,7 +850,7 @@ int GUI_InputName(const char *prompt, const char *ext, char name[], int maxlen)
 
         FB_Print(&upper, "PRESS ENTER TO ACCEPT", 0, 32, 
                                 COL_BLACK, COL_TRANSPARENT);
-        FB_Print(&upper, "PRESS PERIOD TO BACKSPACE", 0, 40, 
+        FB_Print(&upper, "PRESS SYMBOL SHIFT TO BACKSPACE", 0, 40, 
                                 COL_BLACK, COL_TRANSPARENT);
         FB_Print(&upper, "PRESS SPACE/BREAK TO CANCEL", 0, 48, 
                                 COL_BLACK, COL_TRANSPARENT);
@@ -869,7 +869,7 @@ int GUI_InputName(const char *prompt, const char *ext, char name[], int maxlen)
 
 		switch(ev.key)
 		{
-		    case SK_PERIOD:
+		    case SK_SYMBOL:
 		    	if (l)
 			{
 			    name[--l] = 0;
diff --git a/source/main.c b/source/main.c
index 83dd070..f096f9a 100644
--- a/source/main.c
+++ b/source/main.c
@@ -60,7 +60,7 @@
 */
 static const char *main_menu[]=
 	{
-	    "Reset SPEC",
+	    "Reset Spectrum",
 	    "Select Tape",
 	    "Configure",
 	    "Map Joypad to Keys",
@@ -122,7 +122,6 @@ static void Splash(void)
     Framebuffer upper;
     Framebuffer lower;
 
-    SPECEnableFileSystem(TRUE);
     SNAP_Enable(TRUE);
 
     while(!(hidKeysDown() & KEY_A))
@@ -135,9 +134,9 @@ static void Splash(void)
         FB_Blit(&upper, IMG_SPLASH, 0, scr_y);
 
         FB_Print(&upper, "10 REM VERSION \001" DSSPEC_VERSION "\001\n"
-                         "20 PRINT \"\001THE SPEC IS ACE\001\"\n"
+                         "20 PRINT \"\001THE SPECTRUM IS ACE\001\"\n"
                          "30 GOTO 20", 
-                 0, 230, COL_WHITE, COL_TRANSPARENT);
+                 0, 230, COL_BLACK, COL_TRANSPARENT);
 
         FB_printf(&lower, scr_x, 8, COL_WHITE, COL_TRANSPARENT,
                   "%-42.42s",scroller);
@@ -191,9 +190,9 @@ static void MapJoypad(void)
         FB_Clear(&upper, COL_WHITE);
 
         FB_Print(&upper, "Press the joypad button you want\n"
-                         "to define and then the SPEC key\n"
-                         "you want to use.\n\n"
-		         "Press CONFIG to finish.",
+                         "to define and then the Spectrum key\n"
+                         "you want to use for that button.\n\n"
+		         "Press MENU to finish.",
                          0, upper.height - 40, COL_BLACK,COL_TRANSPARENT);
 
         if (pad != NUM_SOFT_KEYS)
@@ -263,6 +262,7 @@ int main(int argc, char *argv[])
     SK_DisplayKeyboard();
 
     SK_SetSticky(SK_SHIFT,DSSPEC_Config[DSSPEC_STICKY_SHIFT]);
+    SK_SetSticky(SK_SYMBOL,DSSPEC_Config[DSSPEC_STICKY_SHIFT]);
 
     if (DSSPEC_Config[DSSPEC_LOAD_DEFAULT_SNAPSHOT])
     {
@@ -279,9 +279,9 @@ int main(int argc, char *argv[])
 
         SK_DisplayKeyboard();
 
-    	Z80Exec(z80);
+        SPECStartFrame(&upper);
 
-        SPECRenderDisplay(&upper, z80);
+    	Z80Exec(z80);
 
         FB_EndFrame();
 
diff --git a/source/snap.c b/source/snap.c
new file mode 100644
index 0000000..1ddb6b9
--- /dev/null
+++ b/source/snap.c
@@ -0,0 +1,150 @@
+/*
+
+   3dsspec - Nintendo 3DS Sinclair Spectrum 48K emulator.
+
+   Copyright (C) 2021  Ian Cowburn
+   
+   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.
+  
+   $Id: snap.c 4 2006-09-15 00:30:18Z ianc $
+
+*/
+#include "snap.h"
+
+/* ---------------------------------------- MACROS
+*/
+#ifndef TRUE
+#define TRUE 1
+#endif
+
+#ifndef FALSE
+#define FALSE 0
+#endif
+
+#define ROMLEN 0x4000
+
+
+/* ---------------------------------------- PRIVATE DATA
+*/
+static Z80Byte	*tap_file;
+static int	tap_len;
+static int	tap_ptr;
+
+
+/* ---------------------------------------- PRIVATE FUNCTIONS
+*/
+static Z80Byte GetByte(void)
+{
+    Z80Byte ret=0;
+
+    if (tap_len)
+    {
+	ret=tap_file[tap_ptr];
+	tap_ptr=(tap_ptr+1)%tap_len;
+    }
+
+    return ret;
+}
+
+
+static Z80Word GetLSBWord(void)
+{
+    int c1,c2;
+
+    c1=GetByte();
+    c2=GetByte();
+
+    return c1+(c2<<8);
+}
+
+
+/* ---------------------------------------- INTERFACES
+*/
+void TAPSetTape(Z80Byte *tape, int len)
+{
+    tap_file = tape;
+    tap_len = len;
+    tap_ptr = 0;
+}
+
+
+int TAPLoad(Z80Byte id, Z80Word *addr, Z80Word *len, SNAP_Poke poke)
+{
+    Z80Word blen;
+    Z80Byte type,b,csum,tape_csum;
+
+    if (!tap_file)
+    {
+    	return FALSE;
+    }
+
+    b=0;
+
+    blen=GetLSBWord();
+    type=GetByte();
+    csum=id;
+
+    /* Have we found the requested block?
+    */
+    if (id==type)
+    {
+    	/* Knock of block type
+	*/
+	blen--;
+
+	while(blen && *len)
+	{
+	    b=GetByte();
+	    csum^=b;
+
+	    poke(*addr,b);
+
+	    (*addr)++;
+	    (*len)--;
+	    blen--;
+	}
+
+	/* Get the checksum
+	*/
+	if (blen)
+	{
+	    tape_csum=GetByte();
+	    blen--;
+	}
+	else
+	    tape_csum=b;
+
+	/* In case we've been request less bytes than the block size
+	*/
+	while(blen--)
+	    GetByte();
+
+	/* Check the checksum
+	*/
+	return csum==tape_csum;
+    }
+    else
+    {
+    	/* If it's the wrong type, skip it
+	*/
+	while(blen--)
+	    GetByte();
+
+	return FALSE;
+    }
+}
+
+
+/* END OF FILE */
diff --git a/source/spec.c b/source/spec.c
index e5932da..5fa5060 100644
--- a/source/spec.c
+++ b/source/spec.c
@@ -30,6 +30,7 @@
 #include "spec.h"
 #include "gui.h"
 #include "framebuffer.h"
+#include "snap.h"
 
 #include "stream.h"
 
@@ -45,63 +46,92 @@
 #define FALSE 0
 #endif
 
+#define HIBYTE(w)	((w)>>8)
+#define LOBYTE(w)	((w)&0xff)
+
 /* ---------------------------------------- STATICS
 */
 #define ROMLEN		0x4000
-#define ROM_SAVE	0x2fc
-#define ROM_LOAD	0x347
+#define ROM_SAVE	0x4c6
+#define ROM_LOAD	0x562
 
 #define ED_SAVE		0xf0
 #define ED_LOAD		0xf1
 
-#define SLOW_TSTATES	16000
-#define FAST_TSTATES	64000
-
-#define E_LINE		16404
-#define LASTK1		16421
-#define LASTK2		16422
-#define MARGIN		16424
-#define FRAMES		16436
-#define CDFLAG		16443
-
-#define NMI_PERIOD      208
+#define SCAN_CYCLES     224
 
-/* The SPEC screen and memory
+/* The 3DS screen
 */
-static int              fast_mode=FALSE;
-static int              nmigen=FALSE;
-static int              hsync=FALSE;
-static int              drawing_screen=FALSE;
-static int              ula_line_counter;
+#define GFX_W           400
+#define GFX_H           240
 
-static u16              black;
-static u16              white;
+/* The Spectrum screen and memory
+*/
+#define	SCR_W	        256
+#define	SCR_H	        192
+#define	TXT_W	        32
+#define	TXT_H	        24
+#define	SCRDATA	        0x4000
+#define	ATTR	        0x5800
 
-#define	SCR_W		256
-#define	SCR_H		192
-#define	TXT_W		32
-#define	TXT_H		24
+#define OFF_X           ((GFX_W-SCR_W)/2)
+#define OFF_Y           ((GFX_H-SCR_H)/2)
 
-static Z80Byte		mem[0x10000];
+#define	ATTR_AT(x,y)	mem[ATTR+(x)+((y)/8)*32]
 
-static u16              screen[SCR_W*SCR_H];
-static int              ula_ptr;
+Z80Byte			mem[0x10000];
 
-static Z80Word		RAMBOT=0;
-static Z80Word		RAMTOP=0;
+static int              border;
+static int              scanline;
 
-#define DFILE		0x400c
+#define	TOPL	64	/* Scanlines before 'first' line */
+#define	SCRL	SCR_H	/* Scanlines making up screen data */
+#define	BOTL	56	/* Scanlines after 'last' line */
 
-#define WORD(a)		(mem[a] | (Z80Word)mem[a+1]<<8)
+#define	TOTL	(TOPL+SCRL+BOTL)
 
-/* Tape
+/* GFX vars
 */
-static int		enable_filesystem;
-static int		allow_save;
-static const Z80Byte	*tape_image;
-static int		tape_len;
+#define			FLASH	16	/* Frames per flash */
+
+static Framebuffer      *fb;
+
+static int		flash=0;
+static int		flashctr=0;
+
+#define 		NVAL	205	/* Normal RGB intensity */
+#define 		BVAL	255	/* Bright RGB intensity */
+
+static Z80Byte		*line[SCR_H];	/* Accelerators to screen data */
+
+#define NO_COLS 16
+
+static struct
+{
+    u16	        col;
+    int		r,g,b;
+} coltable[NO_COLS]=
+{
+    {0,     0x00,0x00,0x00},        /* BLACK */
+    {0,     0x00,0x00,NVAL},        /* BLUE */
+    {0,     NVAL,0x00,0x00},        /* RED */
+    {0,     NVAL,0x00,NVAL},        /* MAGENTA */
+    {0,     0x00,NVAL,0x00},        /* GREEN */
+    {0,     0x00,NVAL,NVAL},        /* CYAN */
+    {0,     NVAL,NVAL,0x00},        /* YELLOW */
+    {0,     NVAL,NVAL,NVAL},        /* WHITE */
+
+    {0,     0x00,0x00,0x00},        /* BLACK */
+    {0,     0x00,0x00,BVAL},        /* BLUE */
+    {0,     BVAL,0x00,0x00},        /* RED */
+    {0,     BVAL,0x00,BVAL},        /* MAGENTA */
+    {0,     0x00,BVAL,0x00},        /* GREEN */
+    {0,     0x00,BVAL,BVAL},        /* CYAN */
+    {0,     BVAL,BVAL,0x00},        /* YELLOW */
+    {0,     BVAL,BVAL,BVAL},        /* WHITE */
+
+};
 
-static char		last_dir[FILENAME_MAX] = "/";
 
 /* The keyboard
 */
@@ -126,29 +156,20 @@ static struct
 
 /* ---------------------------------------- PRIVATE FUNCTIONS
 */
-#define PEEKW(addr)		(mem[addr] | (Z80Word)mem[addr+1]<<8)
-
-#define POKEW(addr,val)         do					\
-                                {					\
-                                    Z80Word wa=addr;			\
-                                    Z80Word wv=val;			\
-                                    mem[wa]=wv;				\
-                                    mem[wa+1]=wv>>8;			\
-                                } while(0)
-
 static void RomPatch(void)
 {
     static const Z80Byte save[]=
     {
     	0xed, ED_SAVE,		/* (SAVE)		*/
-	0xc3, 0x07, 0x02,	/* JP $0207		*/
+	0xc9,                   /* RET		        */
 	0xff			/* End of patch		*/
     };
 
     static const Z80Byte load[]=
     {
+	0x08,			/* EX AF,AF'		*/
     	0xed, ED_LOAD,		/* (LOAD)		*/
-	0xc3, 0x07, 0x02,	/* JP $0207		*/
+	0xc9,                   /* RET		        */
 	0xff			/* End of patch		*/
     };
 
@@ -165,176 +186,108 @@ static void RomPatch(void)
     }
 }
 
-/* Open a tape file the passed address
-*/
-static FILE *OpenTapeFile(Z80Word addr, int *cancelled, const char *mode)
+
+static void DrawScanline(int y, int sline)
 {
-    static const char zx_chars[] = "\"#$:?()><=+-*/;,."
-				   "0123456789"
-				   "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
-    FILE *fp;
-    char full_fn[FILENAME_MAX] = DEFAULT_SNAPDIR;
-    char fn[FILENAME_MAX];
-    int f;
-    int done;
+    int aline;
+    int f,r;
+    int ink,paper,t;
+    Z80Byte *scr;
+    Z80Byte b;
+    Z80Byte att;
 
-    fp = NULL;
-    f = 0;
-    done = FALSE;
-    *cancelled = FALSE;
+    aline=sline-TOPL;
 
-    while(f<(FILENAME_MAX-3) && !done)
+    y = fb->height - y - 1;
+
+    for(f = 0; f < fb->width; f++)
     {
-    	int ch;
+        FB_ADDR(fb, f, y) = coltable[border].col;
+    }
 
-	ch = mem[addr++];
+    if (aline>=0 && aline<SCRL)
+    {
+	scr=line[aline];
 
-	if (ch&0x80)
+	for(f=0;f<TXT_W;f++)
 	{
-	    done = TRUE;
-	    ch &= 0x7f;
-	}
+	    att=ATTR_AT(f,aline);
 
-	if (ch>=11 && ch<=63)
-	{
-	    fn[f++] = zx_chars[ch-11];
-	}
-    }
+	    ink=(att&0x07);
+	    paper=(att&0x38)>>3;
 
-    if (fn[0] == '*')
-    {
-    	if (GUI_FileSelect(last_dir,fn,".P"))
-	{
-	    fp = fopen(fn, mode);
-	}
-	else
-	{
-	    *cancelled = TRUE;
-	}
+	    if (att&0x40)
+	    {
+		ink+=8;
+		paper+=8;
+	    }
 
-	SK_DisplayKeyboard();
-    }
-    else
-    {
-	fn[f++] = '.';
-	fn[f++] = 'P';
-	fn[f] = 0;
+	    if ((att&0x80)&&(flash))
+	    {
+		t=ink;
+		ink=paper;
+		paper=t;
+	    }
 
-	strcat(full_fn,fn);
+	    for(r=0,b=*scr++;r<8;r++)
+            {
+                if (b & 0x80)
+                {
+                    FB_ADDR(fb, f*8+r+OFF_X, y) = coltable[ink].col;
+                }
+                else
+                {
+                    FB_ADDR(fb, f*8+r+OFF_X, y) = coltable[paper].col;
+                }
 
-	if (!(fp = fopen(full_fn, mode)))
-	{
-	    fp = fopen(fn, mode);
+                b = b << 1;
+            }
 	}
     }
-
-    return fp;
-}
-
-
-static void LoadInternalTape(Z80 *z80)
-{
-    memcpy(mem+0x4009,tape_image,tape_len);
 }
 
 
-static void LoadExternalTape(FILE *tape, Z80 *z80)
+static int CheckTimers(Z80 *z80, Z80Val val)
 {
-    int c;
-    Z80Byte *a;
-
-    a=mem+0x4009;
+    int ret = TRUE;
 
-    while((c=getc(tape))!=EOF)
+    if (val > SCAN_CYCLES)
     {
-    	*a++=c;
-    }
-}
-
+        int y;
 
-static void SaveExternalTape(FILE *tape, Z80 *z80)
-{
-    int f;
-    int end;
+	Z80ResetCycles(z80, val-SCAN_CYCLES);
 
-    f = 0x4009;
-    end = WORD(E_LINE);
+	/* Increment scan line and check for frame flyback
+	*/
+	scanline++;
 
-    while(f <= end)
-    {
-    	fputc(mem[f++], tape);
-    }
-}
+	if (scanline==TOTL)
+	{
+	    scanline=0;
 
+	    flashctr++;
 
-static int CheckTimers(Z80 *z80, Z80Val val)
-{
-    static Z80Word last_PC;
-    static Z80Byte last_R;
-    int ret = TRUE;
+	    if (flashctr==FLASH)
+	    {
+	    	flash^=1;
+		flashctr=0;
+	    }
 
-    /* See if we're started or stopping executing the display file
-    */
-    if (z80->PC > 0x7fff)
-    {
-        if (last_PC < 0x8000)
-        {
-            drawing_screen = TRUE;
-            ula_ptr = 0;
-        }
-    }
+	    Z80Interrupt(z80,0xff);
 
-    if (z80->PC < 0x8000)
-    {
-        if (last_PC > 0x7fff && ula_ptr == SCR_W * SCR_H)
-        {
-            drawing_screen = FALSE;
-            ula_ptr = 0;
-            Z80ResetCycles(z80, val - SLOW_TSTATES);
             ret = FALSE;
-        }
-    }
+	}
 
-    last_PC = z80->PC;
+	/* Draw scanline
+	*/
+        y = scanline - TOPL + OFF_Y;
 
-    /* Check HSYNC generation
-    */
-    if (hsync && !nmigen)
-    {
-        if (last_R & 0x40 && !(z80->R & 0x40))
+        if (y >= 0 && y < fb->height)
         {
-            Z80Interrupt(z80, 0xff);
-            ula_line_counter = (ula_line_counter + 1) % 8;
+            DrawScanline(y, scanline);
         }
-    }
-
-    last_R = z80->R;
 
-    /* Check NMI generator
-    */
-    if (nmigen && val > NMI_PERIOD)
-    {
-        Z80NMI(z80);
-        Z80ResetCycles(z80, val - NMI_PERIOD);
-    }
-
-    /* We should only be able to execute FAST_TSTATES if we're not drawing the
-       screen.
-    */
-    if (val >= FAST_TSTATES)
-    {
-	Z80ResetCycles(z80,val-FAST_TSTATES);
-
-	if (mem[CDFLAG] & 0x80)
-	{
-	    fast_mode = FALSE;
-	}
-	else
-	{
-            fast_mode = TRUE;
-	}
-
-	ret = FALSE;
+	/* TODO: Process sound emulation */
     }
 
     return ret;
@@ -346,58 +299,23 @@ static int EDCallback(Z80 *z80, Z80Val data)
     switch((Z80Byte)data)
     {
     	case ED_SAVE:
-	    if (allow_save && z80->DE.w<0x8000)
-	    {
-		FILE *fp;
-		int cancel;
-
-		if ((fp=OpenTapeFile(z80->HL.w, &cancel, "wb")))
-		{
-		    SaveExternalTape(fp,z80);
-		    fclose(fp);
-		}
-	    }
+	    z80->AF.b[Z80_LO_WORD] &= ~eZ80_Carry;
 	    break;
 
     	case ED_LOAD:
-	    /* Try and load the external file if a name given.  Otherwise, we
-	       try the internal one.  Some of this is slightly dodgy -- it was
-	       never intended for the emulator to be doing any GUI related
-	       nonsense (like the alerts) but simply emulating.
-	    */
-	    if (enable_filesystem && z80->DE.w<0x8000)
+	    if (TAPLoad(z80->AF.b[Z80_HI_WORD],
+			&z80->IX.w,
+			&z80->DE.w,
+			SPECWriteSnap))
 	    {
-		FILE *fp;
-		int cancel;
-
-		if ((fp=OpenTapeFile(z80->DE.w, &cancel, "rb")))
-		{
-		    LoadExternalTape(fp,z80);
-		    fclose(fp);
-		}
-		else
-		{
-		    if (!cancel)
-		    {
-			GUI_Alert(FALSE,"Couldn't open tape");
-			SK_DisplayKeyboard();
-		    }
-		}
+		z80->AF.b[Z80_LO_WORD] |= eZ80_Carry;
+		z80->BC.w=0xb001;
 	    }
 	    else
 	    {
-		if (tape_image)
-		{
-		    LoadInternalTape(z80);
-		}
-		else
-		{
-		    GUI_Alert(FALSE,"No tape image selected");
-		    SK_DisplayKeyboard();
-		}
+		z80->AF.b[Z80_LO_WORD] &= ~eZ80_Carry;
+		z80->BC.w = 0xff01;
 	    }
-
-	    mem[CDFLAG]=0xc0;
 	    break;
 
 	default:
@@ -412,10 +330,14 @@ static int EDCallback(Z80 *z80, Z80Val data)
 */
 void SPECInit(Z80 *z80)
 {
-    Z80Word f;
+    int f;
 
-    black = FB_GetColour(COL_BLACK);
-    white = FB_GetColour(COL_WHITE);
+    for(f = 0; f < NO_COLS; f++)
+    {
+        coltable[f].col = RGB8_to_565(coltable[f].r,
+                                      coltable[f].g,
+                                      coltable[f].b);
+    }
 
     /* Load the ROM
     */
@@ -427,58 +349,13 @@ void SPECInit(Z80 *z80)
     Z80LodgeCallback(z80,eZ80_EDHook,EDCallback);
     Z80LodgeCallback(z80,eZ80_Instruction,CheckTimers);
 
-    /* Mirror the ROM
-    */
-    memcpy(mem+ROMLEN,mem,ROMLEN);
-
-    /* Memory size (16K)
-    */
-    RAMBOT=0x4000;
-    RAMTOP=RAMBOT+0x4000;
-
-    for(f = RAMBOT; f <= RAMTOP; f++)
-    {
-    	mem[f] = 0;
-    }
-
-    for(f = 0; f < 8; f++)
-    {
-    	matrix[f] = 0x1f;
-    }
+    SPECReset(z80);
 }
 
 
-void SPECRenderDisplay(Framebuffer *fb, Z80 *z80)
+void SPECStartFrame(Framebuffer *framebuffer)
 {
-    if (fast_mode)
-    {
-        u16 x;
-        u16 y;
-
-        for(x = 0; x < fb->width; x++)
-        {
-            for(y = 0; y < fb->height; y++)
-            {
-                FB_ADDR(fb, x, y) = ((x+y) % 2) ? black : white;
-            }
-        }
-    }
-    else
-    {
-        int x;
-        int y;
-
-        FB_Clear(fb, COL_WHITE);
-
-        for(y = 0; y < SCR_H; y++)
-        {
-            for(x = 0; x < SCR_W; x++)
-            {
-                FB_ADDR(fb, 72 + x, fb->height - 24 - y) =
-                                            screen[x + y * SCR_W];
-            }
-        }
-    }
+    fb = framebuffer;
 }
 
 
@@ -497,75 +374,29 @@ void SPECHandleKey(SoftKey key, int is_pressed)
     }
     else
     {
-    	/* TODO: Joysticks?  Were there any common ones for the 81? */
+    	/* TODO: Joysticks?  */
     }
 }
 
 
 Z80Byte SPECReadMem(Z80 *z80, Z80Word addr)
 {
-    if (addr & 0x8000)
-    {
-        Z80Byte b;
-
-        b = mem[addr & 0x7fff];
-
-        /* If bit 6 of the byte is set it is sent to the CPU, otherwise it is
-           used to generate the video signal and zero sent to the CPU
-        */
-        if (b & 0x40)
-        {
-            screen[ula_ptr++] = white;
-            screen[ula_ptr++] = white;
-            screen[ula_ptr++] = white;
-            screen[ula_ptr++] = white;
-            screen[ula_ptr++] = white;
-            screen[ula_ptr++] = white;
-            screen[ula_ptr++] = white;
-            screen[ula_ptr++] = white;
-        }
-        else
-        {
-            Z80Word base;
-            int inv;
-            int f;
-
-            inv=b & 0x80;
-            b &= 0x3f;
-
-            base = ((Z80Word)z80->I<<8)|(b<<3)|ula_line_counter;
-
-            b = mem[base];
-
-            for(f = 0; f < 8; f++)
-            {
-                if (b & 0x80)
-                {
-                    screen[ula_ptr++] = rand(); // inv ? white : black;
-                }
-                else
-                {
-                    screen[ula_ptr++] = rand(); // inv ? black : white;
-                }
-
-                b = b << 1;
-            }
+    return mem[addr];
+}
 
-            b = 0;
-        }
 
-        return b;
-    }
-    else
+void SPECWriteMem(Z80 *z80, Z80Word addr, Z80Byte val)
+{
+    if (addr>=ROMLEN)
     {
-        return mem[addr];
+	mem[addr]=val;
     }
 }
 
 
-void SPECWriteMem(Z80 *z80, Z80Word addr, Z80Byte val)
+void SPECWriteSnap(Z80Word addr, Z80Byte val)
 {
-    if (addr>=RAMBOT && addr<=RAMTOP)
+    if (addr>=ROMLEN)
     {
 	mem[addr]=val;
     }
@@ -574,55 +405,39 @@ void SPECWriteMem(Z80 *z80, Z80Word addr, Z80Byte val)
 
 Z80Byte SPECReadPort(Z80 *z80, Z80Word port)
 {
-    Z80Byte b=0;
+    Z80Byte lo=port&0xff;
+    Z80Byte hi=port>>8;
+    Z80Byte b=0xff;
+    int f;
 
-    switch(port&0xff)
+    switch(lo)
     {
-    	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;
-	    }
-
-	    /* Some code expects some of the top bits set...  Of course, whether
-	       or not this may be worse as other code doesn't expect the bits,
-	       we shall find out!
-	    */
-	    b |= 0x60;
+	case 0x1f:	/* Kempston joystick */
+	    break;
 
-            /* Reset ULA line counter
-            */
-            ula_line_counter = 0;
+	case 0x7f:	/* Fuller joystick */
+	    break;
 
+	case 0xfb:	/* ZX Printer */
 	    break;
 
-	default:
-	    b = 0xff;	/* Idle bus */
+	default:	/* ULA */
+	    if (!(lo&1))
+	    {
+		/* Key matrix
+		*/
+		b=0xff;
+
+		for(f=0;f<8;f++)
+		    if (!(hi&(1<<f)))
+			b&=matrix[f];
+
+		b|=0xa0;
+
+		/* TODO: Emulation of contention? */
+	    }
+	    else
+	    	b=0xff;
 	    break;
     }
 
@@ -632,20 +447,19 @@ Z80Byte SPECReadPort(Z80 *z80, Z80Word port)
 
 void SPECWritePort(Z80 *z80, Z80Word port, Z80Byte val)
 {
-    switch(port&0xff)
+    Z80Byte lo=port&0xff;
+
+    switch(lo)
     {
-    	case 0xfd:              /* NMI generator OFF */
-            nmigen = FALSE;
+	case 0xfe:	/* ULA */
+	    border = val & 0x07;
 	    break;
 
-	case 0xfe:              /* NMI generator ON */
-            nmigen = TRUE;
-            Z80ResetCycles(z80, 0);
+	case 0xfb:	/* ZX Printer */
 	    break;
 
-        case 0xff:              /* HSYNC generator ON */
-            hsync = TRUE;
-            break;
+	default:
+	    break;
     }
 }
 
@@ -653,6 +467,8 @@ void SPECWritePort(Z80 *z80, Z80Word port, Z80Byte val)
 void SPECReset(Z80 *z80)
 {
     int f;
+    int c;
+    int r;
 
     for(f=0;f<8;f++)
     	matrix[f]=0x1f;
@@ -660,27 +476,32 @@ void SPECReset(Z80 *z80)
     Z80Reset(z80);
     Z80ResetCycles(z80,0);
 
-    nmigen = FALSE;
-    hsync = FALSE;
-}
-
+    border = 0;
+    scanline = 0;
 
-void SPECEnableFileSystem(int enable)
-{
-    enable_filesystem=enable;
-}
+    /* Set up screen
+    */
+    c=0;
+    r=0;
+    for(f=0;f<SCRL;f++)
+    {
+    	line[f]=mem+SCRDATA+(c*8*TXT_W)+(r*TXT_W);
 
+	c++;
 
-void SPECSetTape(const Z80Byte *image, int len)
-{
-    tape_image=image;
-    tape_len=len;
+	if ((c%8)==0)
+	{
+	    if (++r==8)
+	    	r=0;
+	    else
+	    	c-=8;
+	}
+    }
 }
 
 
 void SPECReconfigure(void)
 {
-    allow_save = enable_filesystem && DSSPEC_Config[DSSPEC_ALLOW_TAPE_SAVE];
 }
 
 
@@ -698,8 +519,7 @@ void SPECSaveSnapshot(FILE *fp)
 	PUT_Byte(fp, matrix[f]);
     }
 
-    PUT_ULong(fp, RAMBOT);
-    PUT_ULong(fp, RAMTOP);
+    PUT_Byte(fp, border);
 }
 
 
@@ -717,8 +537,7 @@ void SPECLoadSnapshot(FILE *fp)
 	matrix[f] = GET_Byte(fp);
     }
 
-    RAMBOT = GET_ULong(fp);
-    RAMTOP = GET_ULong(fp);
+    border = GET_Byte(fp);
 }