Added pseudo-hires support

5 files changed, 231 insertions, 26 deletions

diff --git a/source/framebuffer.c b/source/framebuffer.c
index 4a4b03d..ef66235 100644
--- a/source/framebuffer.c
+++ b/source/framebuffer.c
@@ -259,7 +259,7 @@ void FB_Blit(sImage *img, int x, int y)
 {
     if (img->width==WIDTH && img->height==HEIGHT)
     {
-	dmaCopy(img->data8,buff,SCREEN_WIDTH*SCREEN_HEIGHT*2);
+	dmaCopy(img->image.data8,buff,SCREEN_WIDTH*SCREEN_HEIGHT*2);
     }
     else
     {
@@ -267,7 +267,7 @@ void FB_Blit(sImage *img, int x, int y)
 
 	for(f=0;f<img->height;f++)
 	{
-	    dmaCopy(img->data16+(f*img->width),
+	    dmaCopy(img->image.data16+(f*img->width),
 		    buff+x+(y+f)*WIDTH,img->width*2);
 	}
     }
diff --git a/source/keyboard.c b/source/keyboard.c
index eb50310..cb6a932 100644
--- a/source/keyboard.c
+++ b/source/keyboard.c
@@ -270,7 +270,7 @@ void SK_DisplayKeyboard(uint16 *vram)
 
     loadPCX(keyb_bin,&img);
     image8to16(&img);
-    dmaCopy(img.data8,vram,SCREEN_WIDTH*SCREEN_HEIGHT*2);
+    dmaCopy(img.image.data8,vram,SCREEN_WIDTH*SCREEN_HEIGHT*2);
 }
 
 
diff --git a/source/main.c b/source/main.c
index 29f4448..aed05f5 100644
--- a/source/main.c
+++ b/source/main.c
@@ -93,6 +93,7 @@ static void Splash(void)
     int y;
     int res=FALSE;
 
+    ZX81SuspendDisplay();
     ZX81DisplayString("10 print '%the zx81 is ace%'\n20 goto 10");
 
     FB_Clear();
@@ -159,6 +160,8 @@ static void Splash(void)
     {
 	swiWaitForVBlank();
     }
+
+    ZX81ResumeDisplay();
 }
 
 
@@ -173,6 +176,8 @@ static void MapJoypad(void)
 
     SK_DisplayKeyboard(BG_GFX_SUB);
 
+    ZX81SuspendDisplay();
+
     ZX81DisplayString("press the joypad button you want\n"
 		      "to define and then the ZX81 key\n"
 		      "you want to use.\n\n"
@@ -217,6 +222,8 @@ static void MapJoypad(void)
 
 	swiWaitForVBlank();
     }
+
+    ZX81ResumeDisplay();
 }
 
 
@@ -228,26 +235,34 @@ int main(int argc, char *argv[])
 
     powerON(POWER_ALL_2D);
 
-    /* Set up main text screen and load the ROM character data
+    /* Set up main screen for ZX81 and load the ROM character data
     */
-    videoSetMode(MODE_0_2D | DISPLAY_BG0_ACTIVE);
+    videoSetMode(MODE_3_2D | DISPLAY_BG0_ACTIVE | DISPLAY_BG3_ACTIVE);
 
-    vramSetBankA(VRAM_A_MAIN_BG_0x6000000);
-    vramSetBankB(VRAM_B_MAIN_BG_0x6020000);
+    vramSetBankA(VRAM_A_MAIN_BG_0x06000000);
+    vramSetBankB(VRAM_B_MAIN_BG_0x06020000);
 
-    BG0_CR = BG_COLOR_256|BG_MAP_BASE(0)|BG_TILE_BASE(1);
+    BG0_CR = BG_COLOR_256 | BG_MAP_BASE(0) | BG_TILE_BASE(1) | BG_PRIORITY(0);
     BG0_X0 = 0;
     BG0_Y0 = 0;
 
     BG_PALETTE[0] = RGB15(31,31,31);
     BG_PALETTE[1] = RGB15(0,0,0);
 
+    BG3_CR = BG_BMP16_256x256 | BG_BMP_BASE(2) | BG_PRIORITY(1);
+    BG3_XDX = 0x100;
+    BG3_XDY = 0;
+    BG3_YDX = 0;
+    BG3_YDY = 0x100;
+    BG3_CX = 0;
+    BG3_CY = 0;
+
     dmaCopy(rom_font_bin,(void *)BG_TILE_RAM(1),rom_font_bin_size);
 
     /* Set up the sub-screen for rotation (basically for use as a framebuffer)
     */
     videoSetModeSub(MODE_5_2D | DISPLAY_BG2_ACTIVE);
-    vramSetBankC(VRAM_C_SUB_BG_0x6200000);
+    vramSetBankC(VRAM_C_SUB_BG_0x06200000);
 
     SUB_BG2_CR = BG_BMP16_256x256;
     SUB_BG2_XDX = 0x100;
@@ -282,7 +297,7 @@ int main(int argc, char *argv[])
 	GUI_Alert(TRUE,"Failed to initialise\nthe Z80 CPU emulation!");
     }
 
-    ZX81Init((uint16*)SCREEN_BASE_BLOCK(0), z80);
+    ZX81Init((uint16*)BG_MAP_RAM(0), (uint16*)BG_BMP_RAM(2), z80);
 
     Splash();
 
diff --git a/source/tapes.c b/source/tapes.c
index bc5ac8b..8f141f9 100644
--- a/source/tapes.c
+++ b/source/tapes.c
@@ -232,6 +232,8 @@ void SelectTape(void)
 
     InitTapes();
 
+    ZX81SuspendDisplay();
+
     while(!done)
     {
 	uint32 key=0;
@@ -272,5 +274,7 @@ void SelectTape(void)
 	    done=TRUE;
 	}
     }
+
+    ZX81ResumeDisplay();
 }
 
diff --git a/source/zx81.c b/source/zx81.c
index d6edaa0..9a053b5 100644
--- a/source/zx81.c
+++ b/source/zx81.c
@@ -69,9 +69,15 @@ static Z80Val		FRAME_TSTATES=FAST_TSTATES;
 
 /* The ZX81 screen and memory
 */
+static void		(*DrawScreen)(Z80 *z80);
+
 static int		waitkey=FALSE;
 static int		started=FALSE;
 
+static int		hires=FALSE;
+static int		hires_dfile;
+static int		last_I;
+
 #define	SCR_W		256
 #define	SCR_H		192
 #define	TXT_W		32
@@ -95,7 +101,8 @@ static int		tape_len;
 
 /* GFX vars
 */
-static uint16		*screen;
+static uint16		*txt_screen;
+static uint16		*bmp_screen;
 
 /* The keyboard
 */
@@ -330,7 +337,89 @@ static void LoadExternalTape(FILE *tape, Z80 *z80)
 }
 
 
-static void DrawScreen(Z80 *z80)
+static void ClearBitmap(void)
+{
+    uint16 *s;
+    uint16 p;
+    int f;
+
+    s = bmp_screen;
+    p = 0x8000|RGB15(31,31,31);
+
+    for(f=0;f<SCREEN_WIDTH*SCREEN_HEIGHT;f++)
+    {
+    	*s++=p;
+    }
+}
+
+
+static void ClearText(void)
+{
+    uint16 *s;
+    int f;
+
+    s = txt_screen;
+
+    for(f=0;f<TXT_W*TXT_H;f++)
+    {
+    	*s++=0;
+    }
+}
+
+
+static void DrawScreen_HIRES(Z80 *z80)
+{
+    uint16 *bmp;
+    Z80Byte *scr;
+    int x,y;
+    int table;
+
+    scr = mem + hires_dfile;
+    bmp = bmp_screen;
+    table = z80->I << 8;
+
+    /* scr is increment in both loops so that it can skip of the end-of-line
+       character
+    */
+    for(y=0; y<192; y++)
+    {
+    	for(x=0; x<32; x++)
+	{
+	    int c;
+	    int v;
+	    int b;
+
+	    c = *scr;
+
+	    v = mem[table + (c&0x3f)*8];
+
+	    if (c & 0x80)
+	    {
+	    	v ^= 0xff;
+	    }
+
+	    for(b=0;b<8;b++)
+	    {
+	    	if (v & 0x80)
+		{
+		    *bmp++ = 0x8000;
+		}
+		else
+		{
+		    *bmp++ = 0xffff;
+		}
+
+		v=v<<1;
+	    }
+
+	    scr++;
+	}
+
+	scr++;
+    }
+}
+
+static void DrawScreen_TEXT(Z80 *z80)
 {
     Z80Byte *scr=mem+WORD(DFILE);
     int x,y;
@@ -349,11 +438,11 @@ static void DrawScreen(Z80 *z80)
 
 	    if (ch&0x80)
 	    {
-	    	screen[x+y*32]=(ch&0x3f)|0x40;
+	    	txt_screen[x+y*32]=(ch&0x3f)|0x40;
 	    }
 	    else
 	    {
-	    	screen[x+y*32]=(ch&0x3f);
+	    	txt_screen[x+y*32]=(ch&0x3f);
 	    }
 
 	    x++;
@@ -369,7 +458,7 @@ static void DrawSnow(Z80 *z80)
     uint16 *s;
     int f;
 
-    s = screen;
+    s = txt_screen;
 
     for(f=0;f<TXT_W*TXT_H;f++)
     {
@@ -378,6 +467,56 @@ static void DrawSnow(Z80 *z80)
 }
 
 
+static void FindHiresDFILE(void)
+{
+    /* Somewhat based on the code from xz81, an X-based ZX81 emulator,
+       (C) 1994 Ian Collier.  Search the ZX81's RAM until we find what looks
+       like a hi-res display file.
+
+       Bizarrely the original code used 'f' for a loop counter too...  Another
+       poor soul forever damaged by the ZX81's keyword entry system...
+    */
+    int f;
+
+    for(f=0x8000-(33*192); f>0x4000 ; f--)
+    {
+	int v;
+
+	v = mem[f+32];
+
+	if (v&0x40)
+	{
+	    int ok = TRUE;
+	    int n;
+
+	    for(n=0;n<192 && ok;n++)
+	    {
+	    	if (mem[f+33*n]&0x40)
+		{
+		    ok = FALSE;
+		}
+
+		if (mem[f+32+33*n] != v)
+		{
+		    ok = FALSE;
+		}
+	    }
+
+	    if (ok)
+	    {
+	    	hires_dfile = f;
+		return;
+	    }
+	}
+    }
+
+    /* All else fails, put the hires dfile at 0x4000 -- at least it should be
+       obvious that the hires won't work for whatever is being run.
+    */
+    hires_dfile = 0x4000;
+}
+
+
 /* Perform ZX81 housekeeping functions like updating FRAMES and updating LASTK
 */
 static void ZX81HouseKeeping(Z80 *z80)
@@ -464,9 +603,33 @@ static int CheckTimers(Z80 *z80, Z80Val val)
 {
     if (val>=FRAME_TSTATES)
     {
+    	/* Check for hi-res modes
+	*/
+	if (z80->I && z80->I != last_I)
+	{
+	    last_I = z80->I;
+
+	    if (z80->I == 0x1e)
+	    {
+	    	hires = FALSE;
+		DrawScreen = DrawScreen_TEXT;
+		ClearBitmap();
+	    }
+	    else
+	    {
+	    	hires = TRUE;
+		DrawScreen = DrawScreen_HIRES;
+		ClearText();
+		FindHiresDFILE();
+	    }
+	}
+
 	Z80ResetCycles(z80,val-FRAME_TSTATES);
 
-	if (started && ((mem[CDFLAG] & 0x80) || waitkey))
+	/* Kludge warning - We assume that a hires display will not be in
+	   FAST mode! 
+	*/
+	if (started && ((mem[CDFLAG] & 0x80) || waitkey || hires))
 	{
 	    DrawScreen(z80);
 	    FRAME_TSTATES=SLOW_TSTATES;
@@ -582,11 +745,19 @@ static int EDCallback(Z80 *z80, Z80Val data)
 
 /* ---------------------------------------- EXPORTED INTERFACES
 */
-void ZX81Init(uint16 *vram, Z80 *z80)
+void ZX81Init(uint16 *text_vram, uint16* bitmap_vram, Z80 *z80)
 {
     Z80Word f;
 
-    screen = vram;
+    txt_screen = text_vram;
+    bmp_screen = bitmap_vram;
+
+    hires = FALSE;
+    hires_dfile = 0;
+    last_I = 0x1e;
+    DrawScreen = DrawScreen_TEXT;
+
+    ClearBitmap();
 
     /* Load the ROM
     */
@@ -602,7 +773,6 @@ void ZX81Init(uint16 *vram, Z80 *z80)
     */
     memcpy(mem+ROMLEN,mem,ROMLEN);
 
-
     /* Memory size (16K)
     */
     RAMBOT=0x4000;
@@ -701,6 +871,7 @@ Z80Byte ZX81ReadPort(Z80 *z80, Z80Word port)
 	    break;
 
 	default:
+	    b = 0xff;	/* Idle bus */
 	    break;
     }
 
@@ -732,6 +903,13 @@ void ZX81Reset(Z80 *z80)
     Z80ResetCycles(z80,0);
 
     started=FALSE;
+
+    hires = FALSE;
+    hires_dfile = 0;
+    last_I = 0x1e;
+    DrawScreen = DrawScreen_TEXT;
+
+    ClearBitmap();
 }
 
 
@@ -748,20 +926,28 @@ void ZX81SetTape(const Z80Byte *image, int len)
 }
 
 
+void ZX81SuspendDisplay(void)
+{
+    ClearBitmap();
+    ClearText();
+}
+
+
+void ZX81ResumeDisplay(void)
+{
+    ClearText();
+}
+
+
 void ZX81DisplayString(const char *p)
 {
     uint16 *s;
     uint16 inv=0;
     int f;
 
-    s = screen;
-
-    for(f=0;f<TXT_W*TXT_H;f++)
-    {
-    	*s++=0;
-    }
+    ClearText();
 
-    s = screen;
+    s = txt_screen;
     f = 0;
 
     while(*p)