README update

This commit is contained in:
Jeff Parsons 2016-04-25 18:43:31 -07:00
commit e936815bb6
2 changed files with 35 additions and 120 deletions

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@ -23,7 +23,7 @@ The idea is to make [PC8080](/modules/pc8080/) sufficiently configurable so that
terminal-based systems, like the CP/M-based systems of old.
In fact, as soon as Space Invaders is working, my next adaptation will be a DEC VT100 terminal emulator (itself
an 8080-based machine) which can then "wired up" to other PCjs machine simulations.
an 8080-based machine) which can then be "wired up" to other PCjs machine simulations.
Assorted [Space Invaders Hardware Notes](#space-invaders-hardware-notes) are collected below.
@ -32,121 +32,5 @@ Assorted [Space Invaders Hardware Notes](#space-invaders-hardware-notes) are col
Space Invaders Hardware Notes
---
From [emutalk.net](http://www.emutalk.net/threads/38177-Space-Invaders):
Space Invaders, (C) Taito 1978, Midway 1979
CPU: Intel 8080 @ 2MHz (CPU similar to the (newer) Zilog Z80)
Interrupts: $cf (RST 8) at the start of vblank, $d7 (RST $10) at the end of vblank.
Video: 256(x)*224(y) @ 60Hz, vertical monitor. Colours are simulated with a
plastic transparent overlay and a background picture.
Video hardware is very simple: 7168 bytes 1bpp bitmap (32 bytes per scanline).
Sound: SN76477 and samples.
Memory map:
ROM
$0000-$07ff: invaders.h
$0800-$0fff: invaders.g
$1000-$17ff: invaders.f
$1800-$1fff: invaders.e
RAM
$2000-$23ff: work RAM
$2400-$3fff: video RAM
$4000-: RAM mirror
Ports:
Read 1
BIT 0 coin (0 when active)
1 P2 start button
2 P1 start button
3 ?
4 P1 shoot button
5 P1 joystick left
6 P1 joystick right
7 ?
Read 2
BIT 0,1 dipswitch number of lives (0:3,1:4,2:5,3:6)
2 tilt 'button'
3 dipswitch bonus life at 1:1000,0:1500
4 P2 shoot button
5 P2 joystick left
6 P2 joystick right
7 dipswitch coin info 1:off,0:on
Read 3 shift register result
Write 2 shift register result offset (bits 0,1,2)
Write 3 sound related
Write 4 fill shift register
Write 5 sound related
Write 6 strange 'debug' port? eg. it writes to this port when
it writes text to the screen (0=a,1=b,2=c, etc)
(write ports 3,5,6 can be left unemulated, read port 1=$01 and 2=$00
will make the game run, but but only in attract mode)
I haven't looked into sound details.
16 bit shift register:
f 0 bit
xxxxxxxxyyyyyyyy
Writing to port 4 shifts x into y, and the new value into x, eg.
$0000,
write $aa -> $aa00,
write $ff -> $ffaa,
write $12 -> $12ff, ..
Writing to port 2 (bits 0,1,2) sets the offset for the 8 bit result, eg.
offset 0:
rrrrrrrr result=xxxxxxxx
xxxxxxxxyyyyyyyy
offset 2:
rrrrrrrr result=xxxxxxyy
xxxxxxxxyyyyyyyy
offset 7:
rrrrrrrr result=xyyyyyyy
xxxxxxxxyyyyyyyy
Reading from port 3 returns said result.
Overlay dimensions (screen rotated 90 degrees anti-clockwise):
,_______________________________.
|WHITE ^ |
| 32 |
| v |
|-------------------------------|
|RED ^ |
| 32 |
| v |
|-------------------------------|
|WHITE |
| < 224 > |
| |
| ^ |
| 120 |
| v |
| |
| |
| |
|-------------------------------|
|GREEN |
| ^ ^ |
|56 ^ 56 |
| v 72 v |
|____ v ______________|
| ^ | | ^ |
|<16> | < 118 > |16 < 122 > |
| v | | v |
|WHITE| | WHITE|
`-------------------------------'
Way of out of proportion :P
See [Computer Archeology](http://www.computerarcheology.com/Arcade/SpaceInvaders/) for an excellent collection
of materials on the original Space Invaders, including commented ROM disassemblies.

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@ -1036,10 +1036,41 @@
<xsl:otherwise>false</xsl:otherwise>
</xsl:choose>
</xsl:variable>
<xsl:variable name="aspectRatio">
<xsl:choose>
<xsl:when test="@aspect"><xsl:value-of select="@aspect"/></xsl:when>
<xsl:when test="@aspectRatio"><xsl:value-of select="@aspectRatio"/></xsl:when>
<xsl:otherwise>0</xsl:otherwise>
</xsl:choose>
</xsl:variable>
<xsl:variable name="frameBuffer">
<xsl:choose>
<xsl:when test="@frameBuffer"><xsl:value-of select="@frameBuffer"/></xsl:when>
<xsl:otherwise>0</xsl:otherwise>
</xsl:choose>
</xsl:variable>
<xsl:variable name="interruptRate">
<xsl:choose>
<xsl:when test="@interruptRate"><xsl:value-of select="@interruptRate"/></xsl:when>
<xsl:otherwise>0</xsl:otherwise>
</xsl:choose>
</xsl:variable>
<xsl:variable name="refreshRate">
<xsl:choose>
<xsl:when test="@refreshRate"><xsl:value-of select="@refreshRate"/></xsl:when>
<xsl:otherwise>60</xsl:otherwise>
</xsl:choose>
</xsl:variable>
<xsl:variable name="rotation">
<xsl:choose>
<xsl:when test="@rotation"><xsl:value-of select="@rotation"/></xsl:when>
<xsl:otherwise>0</xsl:otherwise>
</xsl:choose>
</xsl:variable>
<xsl:call-template name="component">
<xsl:with-param name="machine" select="$machine"/>
<xsl:with-param name="class">video</xsl:with-param>
<xsl:with-param name="parms">,model:'<xsl:value-of select="$model"/>',mode:<xsl:value-of select="$mode"/>,screenWidth:<xsl:value-of select="$screenWidth"/>,screenHeight:<xsl:value-of select="$screenHeight"/>,memory:<xsl:value-of select="$memory"/>,switches:'<xsl:value-of select="$switches"/>',scale:<xsl:value-of select="$scale"/>,charCols:<xsl:value-of select="$charCols"/>,charRows:<xsl:value-of select="$charRows"/>,fontROM:'<xsl:value-of select="$fontROM"/>',screenColor:'<xsl:value-of select="$screenColor"/>',touchScreen:'<xsl:value-of select="$touchScreen"/>',autoLock:<xsl:value-of select="$autoLock"/></xsl:with-param>
<xsl:with-param name="parms">,model:'<xsl:value-of select="$model"/>',mode:<xsl:value-of select="$mode"/>,screenWidth:<xsl:value-of select="$screenWidth"/>,screenHeight:<xsl:value-of select="$screenHeight"/>,memory:<xsl:value-of select="$memory"/>,switches:'<xsl:value-of select="$switches"/>',scale:<xsl:value-of select="$scale"/>,charCols:<xsl:value-of select="$charCols"/>,charRows:<xsl:value-of select="$charRows"/>,fontROM:'<xsl:value-of select="$fontROM"/>',screenColor:'<xsl:value-of select="$screenColor"/>',touchScreen:'<xsl:value-of select="$touchScreen"/>',autoLock:<xsl:value-of select="$autoLock"/>,aspectRatio:<xsl:value-of select="$aspectRatio"/>,frameBuffer:<xsl:value-of select="$frameBuffer"/>,interruptRate:<xsl:value-of select="$interruptRate"/>,refreshRate:<xsl:value-of select="$refreshRate"/>,rotation:<xsl:value-of select="$rotation"/></xsl:with-param>
</xsl:call-template>
</xsl:template>