Retro/pcjs
Watch
1
0
Fork
You've already forked pcjs
 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Changed C1Pjs to display 25 rows instead of 24

Browse source
This commit is contained in:
Jeff Parsons 2015-02-24 13:56:26 -08:00 • committed by jeffpar
commit 9ba73970a4
15 changed files with 64 additions and 43 deletions
Download patch file Download diff file Expand all files Collapse all files

2
modules/c1pjs/lib/outline.xml
View file

@ -20,7 +20,7 @@
<rom id="romNull" size="0x8000"/>
<rom id="romBasic" size="0x2000" image="/devices/c1p/rom/basic-gcpatch.hex"/>
<rom id="romSystem" size="0x0800" image="/devices/c1p/rom/system.hex"/>
<video id="video" screenwidth="256" screenheight="192" cols="32" rows="32" charset="/devices/c1p/video/chargen1x.png" padding="8px"/>
<video id="video" screenwidth="256" screenheight="200" cols="32" rows="32" charset="/devices/c1p/video/chargen1x.png" padding="8px"/>
<keyboard id="keyboard">
<control type="button" binding="ctrl-c">CTRL-C</control>
<control type="button" binding="break">BREAK</control>

23
modules/c1pjs/lib/video.js
View file

@ -67,17 +67,21 @@
* to the lack of a "guard band feature." Similarly, BASIC defaults to a width of 24 columns
* avoid display problems near the right edge. BASIC will let you choose a width SMALLER than
* 24 but not larger. So, while the video buffer supports a theoretical maximum of 32 rows x 32
* columns, the practical maximum is 24 rows x 24 columns; the last 4 rows of the video buffer
* are never used, and while content scrolls through the top 4 lines of the buffer, it is never
* assumed that you can see the top 4 lines.
* columns, the practical maximum is 25 rows x 24 columns; the last 4 rows of the video buffer
* are never used, and while content DOES scroll through the top 4 lines of the buffer, it should
* never be assumed that you can see the top 3 lines.
*
* This is partially confirmed by the "C1P Character Graphics Reference Manual", p3, which says
* that the "the visible character field consists of 25 lines of 25 columns" and that the "first
* visible character in the upper left of the screen is accessed via address 53379," or 0xD083,
* confirming that the first 4 lines are not assumed to be visible. However, the comment
* regarding "25 lines of 25 columns" seems to be off by one in both dimensions. And why would
* they say that the first visible address is 0xD083 instead of 0xD085? An indentation of 5 bytes,
* rather than 3, would be more consistent with how the C1P ROMs use video memory.
* visible character in the upper left of the screen is accessed via address 53379," or 0xD083.
*
* They actually meant 0xD085, because as mentioned earlier, the C1P indents every row by 5
* characters, not 3. Even so, the difference between 0xD365 (where the bottom line starts)
* and 0xD085 is 0x2E0, or 736. And 736 divided by 32 gives 23; add the bottom row, and that
* gives you 24 visible rows, not 25. Since we now have screenshots of a C1P monitor displaying
* 25 rows (courtesy of Stephan Mühlstrasser <stephan.muehlstrasser@web.de>), C1Pjs now assumes
* 25 rows, which means that only the first 3 lines are not visible, which necessarily puts
* the address of the first visible character at 0xD065.
*
* Model 540 Video Board vs. Model 600 "Superboard II"
* ---------------------------------------------------
@ -274,7 +278,7 @@ C1PVideo.prototype.setModel = function(nModel)
* the only other supported model is 540 (2K video buffer).
*/
if (this.nModel == 600) {
this.setDimensions(this.nDefaultCols, this.nDefaultRows, 4, 24);
this.setDimensions(this.nDefaultCols, this.nDefaultRows, 3, 25);
if (this.cbScreen == 1024 && this.cpu) {
/*
* NOTE: We deliberately set the guard address to the LAST byte of the 2K
@ -466,7 +470,6 @@ C1PVideo.prototype.writeByte = function(offset, b)
{
var col = offset % this.nCols;
var row = Math.floor(offset / this.nCols);
// if (b == 0) this.cpu.halt(); // I must have been testing something here...
return this.updateWindow(col, row, b);
};