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-rw-r--r--arm9/source/zx81.c828
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diff --git a/arm9/source/zx81.c b/arm9/source/zx81.c
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+++ b/arm9/source/zx81.c
@@ -0,0 +1,828 @@
+/*
+ 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 the emulation for the ZX81
+
+*/
+static const char ident[]="$Id$";
+
+#if 0
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include "zx81.h"
+#include "gfx.h"
+#include "gui.h"
+#include "config.h"
+#include "util.h"
+#include "exit.h"
+
+static const char ident_h[]=EZX81_ZX81H;
+
+#ifndef TRUE
+#define TRUE 1
+#endif
+
+#ifndef FALSE
+#define FALSE 0
+#endif
+
+
+/* ---------------------------------------- STATICS
+*/
+#define ROMLEN 0x2000
+#define ROM_SAVE 0x2fc
+#define ROM_LOAD 0x347
+
+#define ED_SAVE 0xf0
+#define ED_LOAD 0xf1
+#define ED_WAITKEY 0xf2
+#define ED_ENDWAITKEY 0xf3
+#define ED_PAUSE 0xf4
+
+#define SLOW_TSTATES 16000
+#define FAST_TSTATES 64000
+
+#define LASTK1 16421
+#define LASTK2 16422
+#define MARGIN 16424
+#define FRAMES 16436
+#define CDFLAG 16443
+
+static Z80Val FRAME_TSTATES=FAST_TSTATES;
+
+/* The ZX81 screen and memory
+*/
+static int waitkey=FALSE;
+static int started=FALSE;
+
+#define SCR_W 256
+#define SCR_H 192
+#define TXT_W 32
+#define TXT_H 24
+
+#define OFF_X (GFX_WIDTH-SCR_W)/2
+#define OFF_Y (GFX_HEIGHT-SCR_H)/2
+
+static Z80Byte mem[0x10000];
+
+static Z80Word RAMBOT=0;
+static Z80Word RAMTOP=0;
+static Z80Word RAMLEN=0;
+
+#define DFILE 0x400c
+
+#define WORD(a) (mem[a] | (Z80Word)mem[a+1]<<8)
+
+/* 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
+*/
+#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 */
+ 0xff /* End of patch */
+ };
+
+ static const Z80Byte load[]=
+ {
+ 0xed, ED_LOAD, /* (LOAD) */
+ 0xc3, 0x07, 0x02, /* JP $0207 */
+ 0xff /* End of patch */
+ };
+
+ static const Z80Byte fast_hack[]=
+ {
+ 0xed, ED_WAITKEY, /* (START KEY WAIT) */
+ 0xcb,0x46, /* L: bit 0,(hl) */
+ 0x28,0xfc, /* jr z,L */
+ 0xed, ED_ENDWAITKEY, /* (END KEY WAIT) */
+ 0x00, /* nop */
+ 0xff /* End of patch */
+ };
+
+ static const Z80Byte kbd_hack[]=
+ {
+ 0x2a,0x25,0x40, /* ld hl,(LASTK) */
+ 0xc9, /* ret */
+ 0xff /* End of patch */
+ };
+
+ static const Z80Byte pause_hack[]=
+ {
+ 0xed, ED_PAUSE, /* (PAUSE) */
+ 0x00, /* nop */
+ 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];
+ }
+
+ for(f=0;fast_hack[f]!=0xff;f++)
+ {
+ mem[0x4ca+f]=fast_hack[f];
+ }
+
+ for(f=0;kbd_hack[f]!=0xff;f++)
+ {
+ mem[0x2bb+f]=kbd_hack[f];
+ }
+
+ for(f=0;pause_hack[f]!=0xff;f++)
+ {
+ mem[0xf3a+f]=pause_hack[f];
+ }
+
+ /* Trust me, we have a ZX81... Honestly.
+ */
+ mem[0x21c]=0x00;
+ mem[0x21d]=0x00;
+
+ /* Remove HALTs as we don't do interrupts
+ */
+ mem[0x0079]=0;
+ mem[0x02ec]=0;
+}
+
+static char ToASCII(Z80Byte b)
+{
+ if (b==0) /* SPACE */
+ return ' ';
+
+ if (b==22) /* Dash (-) */
+ return '-';
+
+ if (b==27) /* Period (.) */
+ 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(Z80 *z80)
+{
+ const char *p=ConvertFilename(z80->DE.w);
+ char path[FILENAME_MAX];
+ FILE *fp;
+
+ if (strlen(p)==0)
+ {
+ GUIMessage(eMessageBox,"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(eMessageBox,"ERROR","Can't load file:\n%s",path);
+ return;
+ }
+
+ fread(mem+0x4009,1,0x4000,fp);
+ fclose(fp);
+}
+
+
+static void SaveTape(Z80 *z80)
+{
+ const char *p=ConvertFilename(z80->DE.w);
+ char path[FILENAME_MAX];
+ FILE *fp;
+ Z80Word start;
+ Z80Word end;
+
+ if (strlen(p)==0)
+ {
+ GUIMessage(eMessageBox,"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(eMessageBox,"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 void PrintZX81Char(int x,int y,int code,int base)
+{
+ int cx,cy;
+ Uint32 fg,bg;
+
+ x*=8;
+ y*=8;
+
+ if (code&0x80)
+ {
+ fg=white;
+ bg=black;
+ code-=0x80;
+ }
+ else
+ {
+ fg=black;
+ bg=white;
+ }
+
+ base=base<<8;
+ base+=code*8;
+
+ for(cy=0;cy<8;cy++)
+ {
+ for(cx=0;cx<8;cx++)
+ {
+ if (mem[base]&(1<<(7-cx)))
+ GFXFastPlot(OFF_X+x+cx,OFF_Y+y+cy,fg);
+ else
+ GFXFastPlot(OFF_X+x+cx,OFF_Y+y+cy,bg);
+ }
+
+ base++;
+ }
+}
+
+
+static void DrawScreen(Z80 *z80)
+{
+ Z80Byte *scr=mem+WORD(DFILE);
+ int x,y;
+
+ x=0;
+ y=0;
+
+ while(y<TXT_H)
+ {
+ scr++;
+ x=0;
+
+ while((*scr!=118)&&(x<TXT_W))
+ {
+ PrintZX81Char(x,y,*scr++,z80->I);
+ x++;
+ }
+
+ y++;
+ }
+}
+
+
+static void DrawSnow(Z80 *z80)
+{
+ int x,y;
+
+ x=0;
+ y=0;
+
+ for(x=0;x<SCR_W;x++)
+ {
+ for(y=0;y<SCR_H;y++)
+ {
+ GFXFastPlot(OFF_X+x,OFF_Y+y,rand()&1 ? white:black);
+ }
+ }
+}
+
+
+/* Perform ZX81 housekeeping functions like updating FRAMES and updating LASTK
+*/
+static void ZX81HouseKeeping(Z80 *z80)
+{
+ static unsigned prev_lk1,prev_lk2;
+ unsigned row;
+ unsigned lastk1;
+ unsigned lastk2;
+
+ /* British ZX81
+ */
+ mem[MARGIN]=55;
+
+ /* Update FRAMES
+ */
+ if (FRAME_TSTATES==SLOW_TSTATES)
+ {
+ Z80Word frame=PEEKW(FRAMES)&0x7fff;
+
+ if (frame)
+ {
+ frame--;
+ }
+
+ POKEW(FRAMES,frame|0x8000);
+ }
+
+ if (!started)
+ {
+ prev_lk1=0;
+ prev_lk2=0;
+ return;
+ }
+
+ /* Update LASTK
+ */
+ lastk1=0;
+ lastk2=0;
+
+ for(row=0;row<8;row++)
+ {
+ unsigned b;
+
+ b=(~matrix[row]&0x1f)<<1;
+
+ if (row==0)
+ {
+ unsigned shift;
+
+ shift=b&2;
+ b&=~2;
+ b|=(shift>>1);
+ }
+
+ if (b)
+ {
+ if (b>1)
+ {
+ lastk1|=(1<<row);
+ }
+
+ lastk2|=b;
+ }
+ }
+
+ /* if ((lastk1 || lastk2) && (lastk1!=prev_lk1 || lastk2!=prev_lk2)) */
+ if (lastk1 && (lastk1!=prev_lk1 || lastk2!=prev_lk2))
+ {
+ mem[CDFLAG]|=1;
+ }
+
+ prev_lk1=lastk1;
+ prev_lk2=lastk2;
+
+ mem[LASTK1]=lastk1^0xff;
+ mem[LASTK2]=lastk2^0xff;
+}
+
+
+static int CheckTimers(Z80 *z80, Z80Val val)
+{
+ if (val>=FRAME_TSTATES)
+ {
+ Z80ResetCycles(z80,val-FRAME_TSTATES);
+
+ GFXLock();
+
+ if (started && ((mem[CDFLAG] & 0x80) || waitkey))
+ {
+ DrawScreen(z80);
+ FRAME_TSTATES=SLOW_TSTATES;
+ }
+ else
+ {
+ DrawSnow(z80);
+ FRAME_TSTATES=FAST_TSTATES;
+ }
+
+ /* Update FRAMES (if in SLOW) and scan the keyboard. This only happens
+ once we've got to a decent point in the boot cycle (detected with
+ a valid stack pointer).
+ */
+ if (z80->SP<0x8000)
+ {
+ ZX81HouseKeeping(z80);
+ }
+
+ GFXUnlock();
+ GFXEndFrame(TRUE);
+ GFXStartFrame();
+ }
+
+ return TRUE;
+}
+
+
+static int EDCallback(Z80 *z80, Z80Val data)
+{
+ Z80Word pause;
+
+ switch((Z80Byte)data)
+ {
+ case ED_SAVE:
+ SaveTape(z80);
+ break;
+
+ case ED_LOAD:
+ LoadTape(z80);
+ mem[CDFLAG]=0xc0;
+ break;
+
+ case ED_WAITKEY:
+ waitkey=TRUE;
+ started=TRUE;
+ break;
+
+ case ED_ENDWAITKEY:
+ waitkey=FALSE;
+ break;
+
+ case ED_PAUSE:
+ waitkey=TRUE;
+
+ pause=z80->BC.w;
+
+ while(pause-- && !(mem[CDFLAG]&1))
+ {
+ SDL_Event *e;
+
+ e=GFXGetKey();
+
+ if (e)
+ {
+ ZX81KeyEvent(e);
+ }
+
+ CheckTimers(z80,FRAME_TSTATES);
+ }
+
+ waitkey=FALSE;
+ break;
+
+ default:
+ break;
+ }
+
+ return TRUE;
+}
+
+
+/* ---------------------------------------- EXPORTED INTERFACES
+*/
+void ZX81Init(Z80 *z80)
+{
+ FILE *fp;
+ Z80Word f;
+
+ if (!(fp=fopen(SConfig(CONF_ROMFILE),"rb")))
+ {
+ GUIMessage(eMessageBox,
+ "ERROR","Failed to open ZX81 ROM\n%s",SConfig(CONF_ROMFILE));
+ Exit("");
+ }
+
+ if (fread(mem,1,ROMLEN,fp)!=ROMLEN)
+ {
+ fclose(fp);
+ GUIMessage(eMessageBox,
+ "ERROR","ROM file must be %d bytes long\n",ROMLEN);
+ Exit("");
+ }
+
+ /* Patch the ROM
+ */
+ RomPatch();
+ Z80LodgeCallback(z80,eZ80_EDHook,EDCallback);
+ Z80LodgeCallback(z80,eZ80_Instruction,CheckTimers);
+
+ /* Mirror the ROM
+ */
+ memcpy(mem+ROMLEN,mem,ROMLEN);
+
+ RAMBOT=0x4000;
+
+ /* Memory size (1 or 16K)
+ */
+ if (IConfig(CONF_MEMSIZE)==16)
+ RAMLEN=0x4000;
+ else
+ RAMLEN=0x400;
+
+ RAMTOP=RAMBOT+RAMLEN;
+
+ 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);
+
+ 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++;
+ }
+}
+
+
+Z80Byte ZX81ReadMem(Z80 *z80, Z80Word addr)
+{
+ /* Hopefully by simply returning RET for ULA reads we save a lot of
+ ROM patching shenanigans.
+ */
+ if (addr>0x7fff)
+ {
+ return 0xc9;
+ }
+ else
+ {
+ return mem[addr];
+ }
+}
+
+
+void ZX81WriteMem(Z80 *z80, Z80Word addr, Z80Byte val)
+{
+ if (addr>=RAMBOT && addr<=RAMTOP)
+ {
+ mem[addr]=val;
+ }
+}
+
+
+Z80Byte ZX81ReadPort(Z80 *z80, Z80Word port)
+{
+ Z80Byte b=0;
+
+ 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;
+ }
+ break;
+
+ default:
+ break;
+ }
+
+ return b;
+}
+
+
+void ZX81WritePort(Z80 *z80, Z80Word port, Z80Byte val)
+{
+ switch(port&0xff)
+ {
+ case 0xfd:
+ break;
+
+ case 0xfe:
+ break;
+ }
+}
+
+
+Z80Byte ZX81ReadForDisassem(Z80 *z80, Z80Word addr)
+{
+ return mem[addr&0x7fff];
+}
+
+
+const char *ZX81Info(Z80 *z80)
+{
+ static char buff[80];
+
+ sprintf(buff,"T-State/frame: %lu",FRAME_TSTATES);
+ return buff;
+}
+
+
+void ZX81Reset(Z80 *z80)
+{
+ int f;
+
+ for(f=0;f<8;f++)
+ matrix[f]=0x1f;
+
+ Z80ResetCycles(z80,0);
+
+ started=FALSE;
+
+ GFXStartFrame();
+}
+
+#endif
+
+
+/* END OF FILE */
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