Added constructor support (contributed by Stefan Haubenthal).

git-svn-id: svn://svn.cc65.org/cc65/trunk@3757 b7a2c559-68d2-44c3-8de9-860c34a00d81

doc/pet.sgml

@@ -145,7 +145,15 @@ No extended memory drivers are currently available for the PET.
 
 <sect1>Joystick drivers<p>
 
-No joystick drivers are currently available for the PET.
+<descrip>
+
+  <tag><tt/pet-ptvjoy.joy/</tag>
+  Driver for the Protovision 4-player adapter contributed by Groepaz. See
+  <htmlurl url="http://www.protovision-online.de/hardw/hardwstart.htm"
+  name="http://www.protovision-online.de/hardw/hardwstart.htm"> for prices and
+  building instructions. Up to two joysticks are supported.
+
+</descrip><p>
 
 
 <sect1>Mouse drivers<p>
@@ -191,6 +199,15 @@ The program return code (low byte) is passed back to BASIC by use of the
 <tt/ST/ variable.
 
 
+<sect1>Interrupts<p>
+
+The runtime for the PET uses routines marked as <tt/.CONDES/ type 2 for
+interrupt handlers. Such routines must be written as simple machine language
+subroutines and will be called automatically by the interrupt handler code
+when they are linked into a program. See the discussion of the <tt/.CONDES/
+feature in the <htmlurl url="ca65.html" name="assembler manual">.
+
+
 <sect1>Using extended memory<p>
 
 The extended memory at $9000 of the CBM 8x96 may be added to the heap by using