SPC8106 S-MOS Systems, SPC8106 Datasheet - Page 285

• Manufacturer Part Number: SPC8106
• Description: LCD/CRT VGA CONTROLLER
• Manufacturer: S-MOS Systems

SPC8106
411-1.0
outp (CRTC +1, nXstart);
// Program the X position. As the X position may be > 255
// two data register writes are required.
// IMPORTANT - The position registers do not latch until the
// high position is written.
outp (CRTC, 31H);
outp (CRTC +1, LOBYTE(Xpos));
outp (CRTC, 30H);
outp (CRTC +1, HIBYTE(Xpos));
/* Calculate the Yposition and Ystart. */
// As this is a cursor programming sample we will assume the
// cursor has been loaded into the bottom left quadrant of the
// sprite image for performance considerations.
// The logic for setting Y position under these circumstances
// is much the same however the Y start will always be at
// least 32 pixels into the image area.
nCursorY = nCursorPos - nHotSpot
if (nCursorY > 0) {
else {
/* Now program the Y position registers. */
// First the Y start register is set. This value informs the
// hardware how many pixels to count down into the image before starting display.
outp (CRTC, 35H);
outp (CRTC +1, nYstart);
// Program the Y position. As the Y position may be > 255
// two data register writes are required.
// IMPORTANT - The position registers do not latch until the
// high position is written.
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nYpos = nCursorY;
nYstart = 32;
}
nYpos = 0;
nYstart = 0 - nCursorY + 32;
}
// nCursorY = raw Y position
X12-AN-003-02
// (SpriteTop)
Programming Notes and Examples
SP3-59