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/*
** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
** Copyright (C) 2003-2004 M. Bakker, Ahead Software AG, http://www.nero.com
**  
** 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.
**
** Any non-GPL usage of this software or parts of this software is strictly
** forbidden.
**
** Commercial non-GPL licensing of this software is possible.
** For more info contact Ahead Software through Mpeg4AAClicense@nero.com.
**
** $Id$
**/

#ifndef __DRM_DEC_H__
#define __DRM_DEC_H__

#ifdef __cplusplus
extern "C" {
#endif

#include "bits.h"

#define DRM_PARAMETRIC_STEREO    0
#define DRM_NUM_SA_BANDS         8
#define DRM_NUM_PAN_BANDS       20
#define NUM_OF_LINKS             3
#define NUM_OF_QMF_CHANNELS     64
#define NUM_OF_SUBSAMPLES       30
#define MAX_SA_BAND             46
#define MAX_PAN_BAND            64
#define MAX_DELAY                5

typedef struct
{   
    uint8_t drm_ps_data_available;
    uint8_t bs_enable_sa;
    uint8_t bs_enable_pan;

    uint8_t bs_sa_dt_flag;
    uint8_t bs_pan_dt_flag;

    uint8_t g_last_had_sa;
    uint8_t g_last_had_pan;

    int8_t bs_sa_data[DRM_NUM_SA_BANDS];
    int8_t bs_pan_data[DRM_NUM_PAN_BANDS];
        
    int8_t g_sa_index[DRM_NUM_SA_BANDS];
    int8_t g_pan_index[DRM_NUM_PAN_BANDS];                        
    int8_t g_prev_sa_index[DRM_NUM_SA_BANDS];
    int8_t g_prev_pan_index[DRM_NUM_PAN_BANDS];    

    int8_t sa_decode_error;
    int8_t pan_decode_error;

    int8_t g_last_good_sa_index[DRM_NUM_SA_BANDS];
    int8_t g_last_good_pan_index[DRM_NUM_PAN_BANDS];
    
    qmf_t SA[NUM_OF_SUBSAMPLES][MAX_SA_BAND];               

    complex_t d_buff[2][MAX_SA_BAND];
    complex_t d2_buff[NUM_OF_LINKS][MAX_DELAY][MAX_SA_BAND];

    uint8_t delay_buf_index_ser[NUM_OF_LINKS];    
            
    real_t prev_nrg[MAX_SA_BAND];
    real_t prev_peakdiff[MAX_SA_BAND];
    real_t peakdecay_fast[MAX_SA_BAND]; 
} drm_ps_info;


uint16_t drm_ps_data(drm_ps_info *ps, bitfile *ld);

drm_ps_info *drm_ps_init(void);
void drm_ps_free(drm_ps_info *ps);

uint8_t drm_ps_decode(drm_ps_info *ps, uint8_t guess, uint32_t samplerate, qmf_t X_left[38][64], qmf_t X_right[38][64]);

#ifdef __cplusplus
}
#endif
#endif

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/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Orginal from Vision-8 Emulator / Copyright (C) 1997-1999  Marcel de Kogel
 * Modified for Archos by Blueloop (a.wenger@gmx.de)
 *
 * 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/
#include "plugin.h"



#define EXTERN static
#define STATIC static
#define memset rb->memset
#define memcpy rb->memcpy
#define printf DEBUGF
#define rand rb->rand
/* #define CHIP8_DEBUG */

#if (LCD_WIDTH >= 112) && (LCD_HEIGHT >= 64)
#define CHIP8_SUPER /* SCHIP even on the archos recorder (112x64) */
#endif

/****************************************************************************/
/**        (S)CHIP-8 core emulation, from Vision-8 + mods by Fdy           **/
/** The core is completely generic and can be used outside of Rockbox,     **/
/** thus the STATIC, EXTERN etc.  Please do not modify.                    **/
/****************************************************************************/
/** Vision8: CHIP8 emulator *************************************************/
/**                                                                        **/
/**                                CHIP8.h                                 **/
/**                                                                        **/
/** This file contains the portable CHIP8 emulation engine definitions     **/
/**                                                                        **/
/** Copyright (C) Marcel de Kogel 1997                                     **/
/**     You are not allowed to distribute this software commercially       **/
/**     Please, notify me, if you make any changes to this file            **/
/****************************************************************************/

#ifndef __CHIP8_H
#define __CHIP8_H

#ifndef EXTERN
#define EXTERN extern
#endif
 
typedef unsigned char byte;                     /* sizeof(byte)==1          */
typedef unsigned short word;                    /* sizeof(word)>=2          */

struct chip8_regs_struct
{
 byte alg[16];                                  /* 16 general registers     */
 byte delay,sound;                              /* delay and sound timer    */
 word i;                                        /* index register           */
 word pc;                                       /* program counter          */
 word sp;                                       /* stack pointer            */
};

EXTERN struct chip8_regs_struct chip8_regs;

#ifdef CHIP8_SUPER
#define CHIP8_WIDTH 128
#define CHIP8_HEIGHT 64
EXTERN byte chip8_super;        /* != 0 if in SCHIP display mode */
#else
#define CHIP8_WIDTH 64
#define CHIP8_HEIGHT 32
#endif

EXTERN byte chip8_iperiod;                      /* number of opcodes per    */
                                                /* timeslice (1/50sec.)     */
EXTERN byte chip8_keys[16];                     /* if 1, key is held down   */
EXTERN byte chip8_display[CHIP8_WIDTH*CHIP8_HEIGHT];/* 0xff if pixel is set,    */
                                                /* 0x00 otherwise           */
EXTERN byte chip8_mem[4096];                    /* machine memory. program  */
                                                /* is loaded at 0x200       */
EXTERN byte chip8_running;                      /* if 0, emulation stops    */

EXTERN void chip8_execute (void);               /* execute chip8_iperiod    */
                                                /* opcodes                  */
EXTERN void chip8_reset (void);                 /* reset virtual machine    */
EXTERN void chip8 (void);                       /* start chip8 emulation    */

EXTERN void chip8_sound_on (void);              /* turn sound on            */
EXTERN void chip8_sound_off (void);             /* turn sound off           */
EXTERN void chip8_interrupt (void);             /* update keyboard,         */
                                                /* display, etc.            */

#ifdef CHIP8_DEBUG
EXTERN byte chip8_trace;                        /* if 1, call debugger      */
                                                /* every opcode             */
EXTERN word chip8_trap;                         /* if pc==trap, set trace   */
                                                /* flag                     */
EXTERN void chip8_debug (word opcode,struct chip8_regs_struct *regs);
#endif

#endif          /* __CHIP8_H */

/** Vision8: CHIP8 emulator *************************************************/
/**                                                                        **/
/**                                CHIP8.c                                 **/
/**                                                                        **/
/** This file contains the portable CHIP8 emulation engine                 **/
/** SCHIP emulation (C) Frederic Devernay 2005                             **/
/**                                                                        **/
/** Copyright (C) Marcel de Kogel 1997                                     **/
/**     You are not allowed to distribute this software commercially       **/
/**     Please, notify me, if you make any changes to this file            **/
/****************************************************************************/

/* you can
   #define STATIC static
   #define EXTERN static
   and include this file for single-object generation
*/

#ifndef STATIC
#include <stdlib.h>             /* for memset, etc. */
#include <string.h>
#define STATIC
#endif

#ifdef CHIP8_DEBUG
#include <stdio.h>
#define DBG_(_x)       ((void)(_x))
#else
#define DBG_(_x)       ((void)0)
#endif

STATIC struct chip8_regs_struct chip8_regs;

static byte chip8_key_pressed;
STATIC byte chip8_keys[16];                     /* if 1, key is held down   */
STATIC byte chip8_display[CHIP8_WIDTH*CHIP8_HEIGHT]; /* 0xff if pixel is set,    */
                                                /* 0x00 otherwise           */
#ifdef CHIP8_SUPER
STATIC byte chip8_super;        /* != 0 if in SCHIP display mode */
#endif
STATIC byte chip8_mem[4096];                    /* machine memory. program  */
                                                /* is loaded at 0x200       */

#define read_mem(a)     (chip8_mem[(a)&4095])
#define write_mem(a,v)  (chip8_mem[(a)&4095]=(v))

STATIC byte chip8_iperiod;

STATIC byte chip8_running;                     /* Flag for End-of-Emulation */

#define get_reg_offset(opcode)          (chip8_regs.alg+(opcode>>8))
#define get_reg_value(opcode)           (*get_reg_offset(opcode))
#define get_reg_offset_2(opcode)        (chip8_regs.alg+((opcode>>4)&0x0f))
#define get_reg_value_2(opcode)         (*get_reg_offset_2(opcode))

typedef void (*opcode_fn) (word opcode);
typedef void (*math_fn) (byte *reg1,byte reg2);



static void op_call (word opcode)
{
    chip8_regs.sp--;
    write_mem (chip8_regs.sp,chip8_regs.pc&0xff);
    chip8_regs.sp--;
    write_mem (chip8_regs.sp,chip8_regs.pc>>8);
    chip8_regs.pc=opcode;
#ifdef CHIP8_DEBUG
    if(chip8_regs.sp < 0x1c0)
        printf("warning: more than 16 subroutine calls, sp=%x\n", chip8_regs.sp);
#endif
}

static void op_jmp (word opcode)
{
    chip8_regs.pc=opcode;
}

static void op_key (word opcode)
{
#ifdef CHIP8_DEBUG
    static byte tested[16] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
#endif
    byte key, key_value,cp_value;
    if ((opcode&0xff)==0x9e) /* skp */
        cp_value=1;
    else if ((opcode&0xff)==0xa1) /* sknp */
        cp_value=0;
    else {
        DBG_(printf("unhandled key opcode 0x%x\n", opcode));
        return;
    }
    key = get_reg_value(opcode)&0x0f;
#ifdef CHIP8_DEBUG
    if (!tested[key]) {
        tested[key] = 1;
        DBG_(printf("testing key %d\n", key));
    }
#endif
    key_value=chip8_keys[key];
    if (cp_value==key_value)
        chip8_regs.pc+=2;
}

static void op_skeq_const (word opcode)
{
    if (get_reg_value(opcode)==(opcode&0xff))
        chip8_regs.pc+=2;
}

static void op_skne_const (word opcode)
{
    if (get_reg_value(opcode)!=(opcode&0xff))
        chip8_regs.pc+=2;
}

static void op_skeq_reg (word opcode)
{
    if (get_reg_value(opcode)==get_reg_value_2(opcode))
        chip8_regs.pc+=2;
}

static void op_skne_reg (word opcode)
{
    if (get_reg_value(opcode)!=get_reg_value_2(opcode))
        chip8_regs.pc+=2;
}

static void op_mov_const (word opcode)
{
    *get_reg_offset(opcode)=opcode&0xff;
}

static void op_add_const (word opcode)
{
    *get_reg_offset(opcode)+=opcode&0xff;
}

static void op_mvi (word opcode)
{
    chip8_regs.i=opcode;
}

static void op_jmi (word opcode)
{
    chip8_regs.pc=opcode+chip8_regs.alg[0];
}

static void op_rand (word opcode)
{
    *get_reg_offset(opcode)=rand()&(opcode&0xff);
}

static void math_or (byte *reg1,byte reg2)
{
    *reg1|=reg2;
}

static void math_mov (byte *reg1,byte reg2)
{
    *reg1=reg2;
}

static void math_nop (byte *reg1,byte reg2)
{
    (void)reg1;
    (void)reg2;
    DBG_(printf("Warning: math nop!\n"));
}

static void math_and (byte *reg1,byte reg2)
{
    *reg1&=reg2;
}

static void math_xor (byte *reg1,byte reg2)
{
 *reg1^=reg2;
}

static void math_add (byte *reg1,byte reg2)
{
    word tmp;
    tmp=*reg1+reg2;
    *reg1=(byte)tmp;
    chip8_regs.alg[15]=tmp>>8;
}

static void math_sub (byte *reg1,byte reg2)
{
    word tmp;
    tmp=*reg1-reg2;
    *reg1=(byte)tmp;
    chip8_regs.alg[15]=((byte)(tmp>>8))+1;
}

static void math_shr (byte *reg1,byte reg2)
{
    (void)reg2;
    chip8_regs.alg[15]=*reg1&1;
    *reg1>>=1;
}

static void math_shl (byte *reg1,byte reg2)
{
    (void)reg2;
    chip8_regs.alg[15]=*reg1>>7;
    *reg1<<=1;
}

static void math_rsb (byte *reg1,byte reg2)
{
    word tmp;
    tmp=reg2-*reg1;
    *reg1=(byte)tmp;
    chip8_regs.alg[15]=((byte)(tmp>>8))+1;
}

#ifdef CHIP8_SUPER
/* SUPER: scroll down n lines (or half in CHIP8 mode) */
static void scroll_down(word opcode)
{
    int n = opcode & 0xf;
    byte *dst = chip8_display + CHIP8_WIDTH*CHIP8_HEIGHT -1;
    byte *src = dst - n*CHIP8_WIDTH;
    while(src >= chip8_display) {
        *dst-- = *src--;
    }
    while(dst >= chip8_display) {
        *dst-- = 0;
    }
}
/* SUPER: scroll 4 pixels left! */
static void scroll_left(void)
{
    byte *dst = chip8_display;
    byte *src = dst;
    byte *eol = chip8_display + CHIP8_WIDTH;
    byte *eoi = chip8_display + CHIP8_WIDTH*CHIP8_HEIGHT;
    while(eol <= eoi) {
        src+=4;
        while(src < eol) {
            *dst++ = *src++;
        }
        *dst++ = 0;
        *dst++ = 0;
        *dst++ = 0;
        *dst++ = 0;
        eol += CHIP8_WIDTH;
    }
}
static void scroll_right(void)
{
    byte *dst = chip8_display + CHIP8_WIDTH*CHIP8_HEIGHT -1;
    byte *src = dst;
    byte *bol = chip8_display + CHIP8_WIDTH*(CHIP8_HEIGHT-1);
    while(bol >= chip8_display) {
        src-=4;
        while(src >= bol) {
            *dst-- = *src--;
        }
        *dst-- = 0;
        *dst-- = 0;
        *dst-- = 0;
        *dst-- = 0;
        bol -= CHIP8_WIDTH;
    }
}
#endif

static void op_system (word opcode)
{
    switch ((byte)opcode)
    {
#ifdef CHIP8_SUPER
    case 0xfb:
        scroll_right();
        break;
    case 0xfc:
        scroll_left();
        break;  
    case 0xfd:
        DBG_(printf("SUPER: quit the emulator\n"));
        chip8_reset();
        break;  
    case 0xfe:
        DBG_(printf("SUPER: set CHIP-8 graphic mode\n"));
        memset (chip8_display,0,sizeof(chip8_display));
        chip8_super = 0;
        break;
    case 0xff:
        DBG_(printf("SUPER: set SCHIP graphic mode\n"));
        memset (chip8_display,0,sizeof(chip8_display));
        chip8_super = 1;
        break;  
#endif
        case 0xe0:
            memset (chip8_display,0,sizeof(chip8_display));
            break;
        case 0xee:
            chip8_regs.pc=read_mem(chip8_regs.sp)<<8;
            chip8_regs.sp++;
            chip8_regs.pc+=read_mem(chip8_regs.sp);
            chip8_regs.sp++;
            break;
    default:
#ifdef CHIP8_SUPER
        if ((opcode & 0xF0) == 0xC0)
            scroll_down(opcode);
        else
#endif
        {
            DBG_(printf("unhandled system opcode 0x%x\n", opcode));
            chip8_running = 3;
        }
        break;
    }
}

static void op_misc (word opcode)
{
    byte *reg,i,j;
#ifdef CHIP8_DEBUG
    static byte firstwait = 1;
#endif
    reg=get_reg_offset(opcode);
    switch ((byte)opcode)
    {
        case 0x07:              /* gdelay */
            *reg=chip8_regs.delay;
            break;
        case 0x0a:              /* key */
#ifdef CHIP8_DEBUG
            if(firstwait) {
                printf("waiting for key press\n");
                firstwait = 0;
            }
#endif
            if (chip8_key_pressed)
                *reg=chip8_key_pressed-1;
            else
                chip8_regs.pc-=2;
            break;
        case 0x15:              /* sdelay */
            chip8_regs.delay=*reg;
            break;
        case 0x18:              /* ssound */
            chip8_regs.sound=*reg;
            if (chip8_regs.sound)
                chip8_sound_on();
            break;
        case 0x1e:              /* adi */
            chip8_regs.i+=(*reg);
            break;
        case 0x29:              /* font */
            chip8_regs.i=((word)(*reg&0x0f))*5;
            break;
#ifdef CHIP8_SUPER
    case 0x30:                  /* xfont */
            chip8_regs.i=((word)(*reg&0x0f))*10+0x50;
            break;
#endif
        case 0x33:              /* bcd */
            i=*reg;
            for (j=0;i>=100;i-=100)
                j++;
            write_mem (chip8_regs.i,j);
            for (j=0;i>=10;i-=10)
                j++;
            write_mem (chip8_regs.i+1,j);
            write_mem (chip8_regs.i+2,i);
            break;
        case 0x55:              /* str */
            for (i=0,j=(opcode>>8)&0x0f; i<=j; ++i)
                write_mem(chip8_regs.i+i,chip8_regs.alg[i]);
            break;
        case 0x65:              /* ldr */
            for (i=0,j=(opcode>>8)&0x0f; i<=j; ++i)
                chip8_regs.alg[i]=read_mem(chip8_regs.i+i);
            break;
#ifdef CHIP8_SUPER
    case 0x75:
        DBG_(printf("SUPER: save V0..V%x (X<8) in the HP48 flags\n", (opcode>>8)&0x0f));
        break;
    case 0x85:
        DBG_(printf("SUPER: load V0..V%x (X<8) from the HP48 flags\n", (opcode>>8)&0x0f));
        break;
#endif
    default:
        DBG_(printf("unhandled misc opcode 0x%x\n", opcode));
        break;
    }
}

static void op_sprite (word opcode)
{
    byte *q;
    byte n,x,x2,y,collision;
    word p;
    x=get_reg_value(opcode);
    y=get_reg_value_2(opcode);
    p=chip8_regs.i;
    n=opcode&0x0f;
#ifdef CHIP8_SUPER
    if (chip8_super) {
        /*printf("SUPER: sprite(%x)\n", opcode);*/
        x &= 128-1;
        y &= 64-1;
        q=chip8_display+y*CHIP8_WIDTH;
        if(n == 0)
        {               /* 16x16 sprite */
            n = 16;
            if (n+y>64)
                n=64-y;
            for (collision=1;n;--n,q+=CHIP8_WIDTH)
            {
                /* first 8 bits */
                for (y=read_mem(p++),x2=x;y;y<<=1,x2=(x2+1)&(CHIP8_WIDTH-1))
                    if (y&0x80)
                        collision&=(q[x2]^=0xff);
                x2=(x+8)&(CHIP8_WIDTH-1);
                /* last 8 bits */
                for (y=read_mem(p++);y;y<<=1,x2=(x2+1)&(CHIP8_WIDTH-1))
                    if (y&0x80)
                        collision&=(q[x2]^=0xff);
            }
        }
        else {
            /* 8xn sprite */
            if (n+y>64)
                n=64-y;
            for (collision=1;n;--n,q+=CHIP8_WIDTH)
            {
                for (y=read_mem(p++),x2=x;y;y<<=1,x2=(x2+1)&(CHIP8_WIDTH-1))
                    if (y&0x80)
                        collision&=(q[x2]^=0xff);
            }
        }
    }
    else {
        x &= 64-1;
        y &= 32-1;
        q=chip8_display+y*CHIP8_WIDTH*2;
        if(n == 0) 
            n = 16;
        if (n+y>32)
            n=32-y;
        for (collision=1;n;--n,q+=CHIP8_WIDTH*2)
        {
            for (y=read_mem(p++),x2=x*2;y;y<<=1,x2=(x2+2)&(CHIP8_WIDTH-1))
                if (y&0x80) {
                    q[x2]^=0xff;
                    q[x2+1]^=0xff;
                    q[x2+CHIP8_WIDTH]^=0xff;
                    q[x2+CHIP8_WIDTH+1]^=0xff;
                    collision &= q[x2]|q[x2+1]|q[x2+CHIP8_WIDTH]|q[x2+CHIP8_WIDTH+1];
                }
        }
    }
#else
    x &= 64-1;
    y &= 32-1;
    q=chip8_display+y*CHIP8_WIDTH;
    if (n+y>32)
        n=32-y;
    for (collision=1;n;--n,q+=CHIP8_WIDTH)
    {
        for (y=read_mem(p++),x2=x;y;y<<=1,x2=(x2+1)&(CHIP8_WIDTH-1))
            if (y&0x80)
                collision&=(q[x2]^=0xff);
    }
#endif
    chip8_regs.alg[15]=collision^1;
}

static const math_fn math_opcodes[16]=
{
    math_mov,
    math_or,
    math_and,
    math_xor,
    math_add,
    math_sub,
    math_shr,
    math_rsb,
    math_nop,
    math_nop,
    math_nop,
    math_nop,
    math_nop,
    math_nop,
    math_shl,
    math_nop
};

static void op_math (word opcode)
{
    (*(math_opcodes[opcode&0x0f]))
        (get_reg_offset(opcode),get_reg_value_2(opcode));
}

static const opcode_fn main_opcodes[16]=
{
    op_system,
    op_jmp,
    op_call,
    op_skeq_const,
    op_skne_const,
    op_skeq_reg,
    op_mov_const,
    op_add_const,
    op_math,
    op_skne_reg,
    op_mvi,
    op_jmi,
    op_rand,
    op_sprite,
    op_key,
    op_misc
};

#ifdef CHIP8_DEBUG
STATIC byte chip8_trace;
STATIC word chip8_trap;

/****************************************************************************/
/* This routine is called every opcode when chip8_trace==1. It prints the   */
/* current register contents and the opcode being executed                  */
/****************************************************************************/
STATIC void chip8_debug (word opcode,struct chip8_regs_struct *regs)
{
    int i;
    static const byte hextable[16] = "0123456789ABCDEF";
    byte v1[3] = "Vx\0";
    byte v2[3] = "Vx\0";
    v1[1] = hextable[(opcode>>8)&0x0f];
    v2[1] = hextable[(opcode>>8)&0x0f];
    printf ("PC=%04X: %04X - ",regs->pc,opcode);
    switch (opcode>>12) {
    case 0:
        if ((opcode&0xff0) == 0xc0) {
            printf ("SCD  %01X       ; Scroll down n lines",opcode&0xf);
        }
        else switch (opcode&0xfff) {
        case 0xe0:
            printf ("CLS          ; Clear screen");
            break;
        case 0xee:
            printf ("RET          ; Return from subroutine call");
            break;
        case 0xfb:
            printf("SCR           ; Scroll right");
            break;
        case 0xfc:
            printf("SCL           ; Scroll left");
            break;
        case 0xfd:
            printf("EXIT          ; Terminate the interpreter");
            break;
        case 0xfe:
            printf("LOW           ; Disable extended screen mode");
            break;
        case 0xff:
            printf("HIGH          ; Enable extended screen mode");
            break;
        default:
            printf ("SYS  %03X     ; Unknown system call",opcode&0xff);
        }
        break;
    case 1:
        printf ("JP   %03X     ; Jump to address",opcode&0xfff);
        break;
    case 2:
        printf ("CALL %03X     ; Call subroutine",opcode&0xfff);
        break;
    case 3:
        printf ("SE   %s,%02X   ; Skip if register == constant",v1,opcode&0xff);
        break;
    case 4:
        printf ("SNE  %s,%02X   ; Skip if register <> constant",v1,opcode&0xff);
        break;
    case 5:
        printf ("SE   %s,%s   ; Skip if register == register",v1,v2);
        break;
    case 6:
        printf ("LD   %s,%02X   ; Set VX = Byte",v1,opcode&0xff);
        break;
    case 7:
        printf ("ADD  %s,%02X   ; Set VX = VX + Byte",v1,opcode&0xff);
        break;
    case 8:
        switch (opcode&0x0f) {
        case 0:
            printf ("LD   %s,%s   ; Set VX = VY, VF updates",v1,v2);
            break;
        case 1:
            printf ("OR   %s,%s   ; Set VX = VX | VY, VF updates",v1,v2);
            break;
        case 2:
            printf ("AND  %s,%s   ; Set VX = VX & VY, VF updates",v1,v2);
            break;
        case 3:
            printf ("XOR  %s,%s   ; Set VX = VX ^ VY, VF updates",v1,v2);
            break;
        case 4:
            printf ("ADD  %s,%s   ; Set VX = VX + VY, VF = carry",v1,v2);
            break;
        case 5:
            printf ("SUB  %s,%s   ; Set VX = VX - VY, VF = !borrow",v1,v2);
            break;
        case 6:
            printf ("SHR  %s,%s   ; Set VX = VX >> 1, VF = carry",v1,v2);
            break;
        case 7:
            printf ("SUBN %s,%s   ; Set VX = VY - VX, VF = !borrow",v1,v2);
            break;
        case 14:
            printf ("SHL  %s,%s   ; Set VX = VX << 1, VF = carry",v1,v2);
            break;
        default:
            printf ("Illegal opcode");
        }
        break;
    case 9:
        printf ("SNE  %s,%s   ; Skip next instruction iv VX!=VY",v1,v2);
        break;
    case 10:
        printf ("LD   I,%03X   ; Set I = Addr",opcode&0xfff);
        break;
    case 11:
        printf ("JP   V0,%03X  ; Jump to Addr + V0",opcode&0xfff);
        break;
    case 12:
        printf ("RND  %s,%02X   ; Set VX = random & Byte",v1,opcode&0xff);
        break;
    case 13:
        printf ("DRW  %s,%s,%X ; Draw n byte sprite stored at [i] at VX,VY. Set VF = collision",v1,v2,opcode&0x0f);
        break;
    case 14:
        switch (opcode&0xff) {
        case 0x9e:
            printf ("SKP  %s      ; Skip next instruction if key VX down",v1);
            break;
        case 0xa1:
            printf ("SKNP %s      ; Skip next instruction if key VX up",v1);
            break;
        default:
            printf ("%04X        ; Illegal opcode", opcode);
        }
        break;
    case 15:
        switch (opcode&0xff) {
        case 0x07:
            printf ("LD   %s,DT   ; Set VX = delaytimer",v1);
            break;
        case 0x0a:
            printf ("LD   %s,K    ; Set VX = key, wait for keypress",v1);
            break;
        case 0x15:
            printf ("LD   DT,%s   ; Set delaytimer = VX",v1);
            break;
        case 0x18:
            printf ("LD   ST,%s   ; Set soundtimer = VX",v1);
            break;
        case 0x1e:
            printf ("ADD  I,%s    ; Set I = I + VX",v1);
            break;
        case 0x29:
            printf ("LD  LF,%s    ; Point I to 5 byte numeric sprite for value in VX",v1);
            break;
        case 0x30:
            printf ("LD  HF,%s    ; Point I to 10 byte numeric sprite for value in VX",v1);
            break;
        case 0x33:
            printf ("LD   B,%s    ; Store BCD of VX in [I], [I+1], [I+2]",v1);
            break;
        case 0x55:
            printf ("LD   [I],%s  ; Store V0..VX in [I]..[I+X]",v1);
            break;
        case 0x65:
            printf ("LD   %s,[I]  ; Read V0..VX from [I]..[I+X]",v1);
            break;
        case 0x75:
            printf ("LD   R,%s    ; Store V0..VX in RPL user flags (X<=7)",v1);
            break;
        case 0x85:
            printf ("LD   %s,R    ; Read V0..VX from RPL user flags (X<=7)",v1);
            break;
        default:
            printf ("%04X        ; Illegal opcode", opcode);
        }
        break;
    }
    printf ("\n; Registers: ");
    for (i=0;i<16;++i) printf ("%02x ",(regs->alg[i])&0xff);
    printf ("\n; Index: %03x Stack:%03x Delay:%02x Sound:%02x\n",
            regs->i&0xfff,regs->sp&0xfff,regs->delay&0xff,regs->sound&0xff);
}
#endif

/****************************************************************************/
/* Execute chip8_iperiod opcodes                                            */
/****************************************************************************/
STATIC void chip8_execute(void)
{
    byte i;
    byte key_pressed=0;
    word opcode;
    for (i = chip8_iperiod ; i ;--i)
    {
        /* Fetch the opcode */
        opcode=(read_mem(chip8_regs.pc)<<8)+read_mem(chip8_regs.pc+1);
#ifdef CHIP8_DEBUG
        /* Check if trap address has been reached */
        if ((chip8_regs.pc&4095)==chip8_trap)
            chip8_trace=1;
        /* Call the debugger if chip8_trace!=0 */
        if (chip8_trace)
            chip8_debug (opcode,&chip8_regs);
#endif
        chip8_regs.pc+=2;
        (*(main_opcodes[opcode>>12]))(opcode&0x0fff); /* Emulate this opcode */
    }
    /* Update timers */
    if (chip8_regs.delay)
        --chip8_regs.delay;
    if (chip8_regs.sound)
        if (--chip8_regs.sound == 0)
            chip8_sound_off();       

    /* Update the machine status */
    chip8_interrupt ();

    for (i=key_pressed=0;i<16;++i)              /* check if a key was first */
        if (chip8_keys[i])                      /* pressed                  */
            key_pressed=i+1;
    if (key_pressed && key_pressed!=chip8_key_pressed)
        chip8_key_pressed=key_pressed;
    else
        chip8_key_pressed=0;
}

/****************************************************************************/
/* Reset the virtual chip8 machine                                          */
/****************************************************************************/
STATIC void chip8_reset(void)
{
    static const byte chip8_sprites[0x50]=
     {
         0xf9,0x99,0xf2,0x62,0x27,
         0xf1,0xf8,0xff,0x1f,0x1f,
         0x99,0xf1,0x1f,0x8f,0x1f,
         0xf8,0xf9,0xff,0x12,0x44,
         0xf9,0xf9,0xff,0x9f,0x1f,
         0xf9,0xf9,0x9e,0x9e,0x9e,
         0xf8,0x88,0xfe,0x99,0x9e,
         0xf8,0xf8,0xff,0x8f,0x88,
     }; /* 4x5 pixel hexadecimal character font patterns */
#ifdef CHIP8_SUPER
    static const byte schip_sprites[10*10]=
     {
         0x3C, 0x7E, 0xC3, 0xC3, 0xC3, 0xC3, 0xC3, 0xC3, 0x7E, 0x3C, /* 0 */
         0x18, 0x38, 0x58, 0x18, 0x18, 0x18, 0x18, 0x18, 0x18, 0x3C, /* 1 */
         0x3E, 0x7F, 0xC3, 0x06, 0x0C, 0x18, 0x30, 0x60, 0xFF, 0xFF, /* 2 */
         0x3C, 0x7E, 0xC3, 0x03, 0x0E, 0x0E, 0x03, 0xC3, 0x7E, 0x3C, /* 3 */
         0x06, 0x0E, 0x1E, 0x36, 0x66, 0xC6, 0xFF, 0xFF, 0x06, 0x06, /* 4 */
         0xFF, 0xFF, 0xC0, 0xC0, 0xFC, 0xFE, 0x03, 0xC3, 0x7E, 0x3C, /* 5 */
         0x3E, 0x7C, 0xC0, 0xC0, 0xFC, 0xFE, 0xC3, 0xC3, 0x7E, 0x3C, /* 6 */
         0xFF, 0xFF, 0x03, 0x06, 0x0C, 0x18, 0x30, 0x60, 0x60, 0x60, /* 7 */
         0x3C, 0x7E, 0xC3, 0xC3, 0x7E, 0x7E, 0xC3, 0xC3, 0x7E, 0x3C, /* 8 */
         0x3C, 0x7E, 0xC3, 0xC3, 0x7F, 0x3F, 0x03, 0x03, 0x3E, 0x7C, /* 9 */
     }; /* 8x10 pixel font patterns (only 10) */
#endif
    byte i;
    for (i=0;i<16*5;++i)
    {
        write_mem (i<<1,chip8_sprites[i]&0xf0);
        write_mem ((i<<1)+1,chip8_sprites[i]<<4);
    }
#ifdef CHIP8_SUPER
    /*
    for (i=0; i<100; i++)
        write_mem (i+0x50,schip_sprites[i]);
    */
    memcpy(chip8_mem+0x50, schip_sprites, 100);
    chip8_super = 0;
#endif
    memset (chip8_regs.alg,0,sizeof(chip8_regs.alg));
    memset (chip8_keys,0,sizeof(chip8_keys));
    chip8_key_pressed=0;
    memset (chip8_display,0,sizeof(chip8_display));
    chip8_regs.delay=chip8_regs.sound=chip8_regs.i=0;
    chip8_regs.sp=0x1e0;
    chip8_regs.pc=0x200;
    chip8_sound_off ();
    chip8_running=1;
#ifdef CHIP8_DEBUG
    chip8_trace=0;
#endif
}


/****************************************************************************/
/* Start CHIP8 emulation                                                    */
/****************************************************************************/
STATIC void chip8 (void)
{
 chip8_reset ();
 while (chip8_running==1) chip8_execute ();
}

/****************************************************************************/
/** END OF (S)CHIP-8 core emulation, from Vision-8 + mods by Fdy           **/
/****************************************************************************/

/* size of the displayed area */
#if (CHIP8_WIDTH == 128) && (LCD_WIDTH < 128)
#define CHIP8_LCDWIDTH 112
#else
#define CHIP8_LCDWIDTH CHIP8_WIDTH
#endif

#if (LCD_WIDTH > CHIP8_LCDWIDTH)
#define CHIP8_X ((LCD_WIDTH - CHIP8_LCDWIDTH)/2)
#else
#define CHIP8_X 0
#endif
#if (LCD_HEIGHT > CHIP8_HEIGHT)
#define CHIP8_Y (((LCD_HEIGHT - CHIP8_HEIGHT)>>4)<<3)
#else
#define CHIP8_Y 0
#endif

/* variable button definitions */
#if CONFIG_KEYPAD == RECORDER_PAD /* only 9 out of 16 chip8 buttons */
#define CHIP8_OFF  BUTTON_OFF
#define CHIP8_KEY1 BUTTON_F1
#define CHIP8_KEY2 BUTTON_UP
#define CHIP8_KEY3 BUTTON_F3
#define CHIP8_KEY4 BUTTON_LEFT
#define CHIP8_KEY5 BUTTON_PLAY
#define CHIP8_KEY6 BUTTON_RIGHT
#define CHIP8_KEY7 BUTTON_F2
#define CHIP8_KEY8 BUTTON_DOWN
#define CHIP8_KEY9 BUTTON_ON

#elif CONFIG_KEYPAD == ARCHOS_AV300_PAD /* only 9 out of 16 chip8 buttons */
#define CHIP8_OFF  BUTTON_OFF
#define CHIP8_KEY1 BUTTON_F1
#define CHIP8_KEY2 BUTTON_UP
#define CHIP8_KEY3 BUTTON_F3
#define CHIP8_KEY4 BUTTON_LEFT
#define CHIP8_KEY5 BUTTON_SELECT
#define CHIP8_KEY6 BUTTON_RIGHT
#define CHIP8_KEY7 BUTTON_F2
#define CHIP8_KEY8 BUTTON_DOWN
#define CHIP8_KEY9 BUTTON_ON

#elif CONFIG_KEYPAD == ONDIO_PAD /* even more limited */