manual/plugins/chip8emulator.tex

   1 \subsection{\label{ref:Chip8emulator}Chip{}-8 Emulator}
   2 Chip8 is a kind of assembly language for a long-gone architecture.
   3 This plugin runs games written using the chip8 instructions.
   4 To start a game open a \fname{.ch8} file in the \setting{File Browser}
   5
   6 There are lots of tiny Chip8 games (usually only about 256 bytes to a
   7 couple of KB) which were made popular by the HP48
   8 calculator's emulator for them. The original Chip8 had
   9 64$\times$32 pixel graphics, and the new superchip emulator supports 128$\times$64
  10 graphics.
  11
  12 The only problem is that they are based on a 4$\times$4 keyboard, but since most
  13 games do not use all of the buttons, this can easily be worked around.
  14
  15 To do this, one may put a \fname{.c8k} file with the same name as the
  16 original program which contains new key mappings (for \fname{BLINKY.ch8}, one
  17 writes a \fname{BLINKY.c8k} file). That \fname{.c8k} file contains 16
  18 characters describing the mapping from the Chip8 keyboard to the default key
  19 mapping (that way, several Chip8 keys can be pressed using only one
  20 Rockbox key). For example, a file containing the single line:
  21 \begin{code}
  22     0122458469ABCDEF
  23 \end{code}
  24 would correspond to the following non-default mappings:
  25
  26 3 $\rightarrow$ 2, 6 $\rightarrow$ 8, 7 $\rightarrow$4, 8 $\rightarrow$ 6.
  27
  28 The default keymappings are:
  29 \begin{table}
  30     \begin{center}
  31     \begin{tabularx}{.9\textwidth}{c|ccccccccccccccccc}
  32     \toprule
  33     Chip8 & Off & 0 & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9
  34         & A & B & C & D & E & F\\
  35     \midrule
  36     \begin{sideways}Key\end{sideways}
  37         &
  38         % key "off"
  39         \begin{sideways}
  40         \opt{RECORDER_PAD,ONDIO_PAD,IRIVER_H100_PAD,IRIVER_H300_PAD}{\ButtonOff}
  41         \opt{IPOD_4G_PAD,IPOD_3G_PAD}{\ButtonMenu}
  42         \opt{IAUDIO_X5_PAD,IRIVER_H10_PAD,SANSA_E200_PAD,SANSA_C200_PAD%
  43             ,GIGABEAT_PAD,MROBE100_PAD,SANSA_FUZE_PAD}
  44             {\ButtonPower}
  45         \opt{GIGABEAT_S_PAD}{\ButtonBack}
  46         \opt{PBELL_VIBE500_PAD}{\ButtonRec}
  47         \end{sideways}
  48         &
  49         % Key "0"
  50         &
  51         % "Key "1"
  52         \begin{sideways}
  53         \opt{RECORDER_PAD}{\ButtonFOne}
  54         \opt{ONDIO_PAD}{\ButtonUp}
  55         \opt{GIGABEAT_PAD,GIGABEAT_S_PAD,MROBE100_PAD}{\ButtonMenu}
  56         \end{sideways}
  57         &
  58         % Key "2"
  59         \begin{sideways}
  60         \opt{RECORDER_PAD,ONDIO_PAD}{\ButtonUp}
  61         \opt{IPOD_4G_PAD,IPOD_3G_PAD,SANSA_E200_PAD,SANSA_FUZE_PAD}
  62             {\ButtonScrollBack}
  63         \opt{IRIVER_H100_PAD,IRIVER_H300_PAD,IAUDIO_X5_PAD,GIGABEAT_PAD%
  64           ,GIGABEAT_S_PAD,MROBE100_PAD,PBELL_VIBE500_PAD}{\ButtonUp}
  65         \opt{IRIVER_H10_PAD}{\ButtonScrollUp}
  66         \opt{SANSA_C200_PAD}{\ButtonVolUp}
  67         \end{sideways}
  68         &
  69         % Key "3"
  70         \begin{sideways}
  71         \opt{RECORDER_PAD}{\ButtonFThree}
  72         \opt{MROBE100_PAD}{\ButtonPlay}
  73         \opt{GIGABEAT_PAD,GIGABEAT_S_PAD}{\ButtonVolDown}
  74         \end{sideways}
  75         &
  76         % Key "4"
  77         \begin{sideways}
  78         \opt{RECORDER_PAD,ONDIO_PAD,IRIVER_H100_PAD,IRIVER_H300_PAD,IPOD_4G_PAD%
  79             ,IPOD_3G_PAD,IAUDIO_X5_PAD,IRIVER_H10_PAD,SANSA_E200_PAD%
  80             ,SANSA_C200_PAD,GIGABEAT_PAD,GIGABEAT_S_PAD,MROBE100_PAD%
  81             ,SANSA_FUZE_PAD,PBELL_VIBE500_PAD}
  82             {\ButtonLeft}
  83         \end{sideways}
  84         &
  85         % Key "5"
  86         \begin{sideways}
  87         \opt{RECORDER_PAD}{\ButtonPlay}
  88         \opt{ONDIO_PAD}{\ButtonMenu}
  89         \opt{IRIVER_H100_PAD,IRIVER_H300_PAD,IAUDIO_X5_PAD,SANSA_E200_PAD%
  90             ,SANSA_C200_PAD,GIGABEAT_PAD,GIGABEAT_S_PAD,MROBE100_PAD%
  91             ,SANSA_FUZE_PAD}
  92             {\ButtonSelect}
  93         \opt{IPOD_4G_PAD,IPOD_3G_PAD,IRIVER_H10_PAD}{\ButtonPlay}
  94         \opt{PBELL_VIBE500_PAD}{\ButtonOK}
  95         \end{sideways}
  96         &
  97         % Key "6"
  98         \begin{sideways}
  99         \opt{RECORDER_PAD,ONDIO_PAD,IRIVER_H100_PAD,IRIVER_H300_PAD,IPOD_4G_PAD%
 100             ,IPOD_3G_PAD,IAUDIO_X5_PAD,IRIVER_H10_PAD,SANSA_E200_PAD%
 101             ,SANSA_C200_PAD,GIGABEAT_PAD,GIGABEAT_S_PAD,MROBE100_PAD%
 102             ,SANSA_FUZE_PAD,PBELL_VIBE500_PAD}
 103             {\ButtonRight}
 104         \end{sideways}
 105         &
 106         % Key "7"
 107         \begin{sideways}
 108         \opt{RECORDER_PAD}{\ButtonFTwo}
 109         \opt{MROBE100_PAD}{\ButtonDisplay}
 110         \opt{GIGABEAT_PAD,GIGABEAT_S_PAD}{\ButtonVolUp}
 111         \end{sideways}
 112         &
 113         % Key "8"
 114         \begin{sideways}
 115         \opt{RECORDER_PAD,ONDIO_PAD,IRIVER_H100_PAD,IRIVER_H300_PAD%
 116             ,GIGABEAT_PAD,GIGABEAT_S_PAD,MROBE100_PAD,PBELL_VIBE500_PAD}{\ButtonDown}
 117         \opt{IPOD_4G_PAD,IPOD_3G_PAD,SANSA_E200_PAD,SANSA_FUZE_PAD}
 118             {\ButtonScrollFwd}
 119         \opt{IAUDIO_X5_PAD}{\ButtonDown}
 120         \opt{IRIVER_H10_PAD}{\ButtonScrollDown}
 121         \opt{SANSA_C200_PAD}{\ButtonVolDown}
 122         \end{sideways}
 123         &
 124         % Key "9"
 125         \begin{sideways}
 126         \opt{RECORDER_PAD}{\ButtonOn}
 127         \opt{GIGABEAT_PAD}{\ButtonA}
 128         \opt{GIGABEAT_S_PAD}{\ButtonPlay}
 129         \end{sideways}
 130         &
 131         % Key "A"
 132         &
 133         % Key "B"
 134         &
 135         % Key "C"
 136         &
 137         % Key "D"
 138         &
 139         % Key "E"
 140         &
 141         % Key "F"
 142     \\\bottomrule
 143     \end{tabularx}
 144     \end{center}
 145 \end{table}
 146
 147 Some places where can you can find \fname{.ch8} files:
 148 \begin{itemize}
 149 \item The PluginChip8 page on www.rockbox.org has several attached:
 150 \wikilink{PluginChip8}
 151 \item Check out the HP48 chip games section:
 152 \url{http://www.hpcalc.org/hp48/games/chip/}
 153 \item PC emulator by the guy who wrote the HP48 emulator:
 154 \url{http://www.pdc.kth.se/~lfo/chip8/CHIP8.htm}
 155 \item Links to other chip8 emulators:
 156 \url{http://www.zophar.net/chip8.html}
 157 \end{itemize}