From: nowhere@never.at   
      
   On 11/11/2023 11:18, Robert Pengelly wrote:   
   ...   
      
   > "have you enabled IRQ4 in the PIC port 0x20"   
   > I looked at your table stuff but I'm still a little confused how I enable it.   
      
   only modify one:   
   in al,0x21   
   and al,0xEF    ;reset bit 4   
   out 0x21,al   
      
   or all if your brave :)   
   mov al,00   
   out 0x21.al    ;enables all 8 channels   
      
   and before you touch any part of the interrupt chain you should disable   
   IRQs with this single byte reserved for that, re-enable after done.   
      
   > As for the code all I'm doing is changing my timer interrupt to the IRQ4 one   
   (0x0C * 4 (+ 2) as that's what I think that's what the interrupt get fired).   
      
   [PIT(timer)] fires IRQ_0 (INT08) at default setting 18.2 Hz then:   
   * PIT handler (either BIOS or DOS or your own) may satisfy the PIT by   
      reading port_0x40 (not required if set to auto repeat mode, default).   
   * PIT handler also increments the TIMER-variable   
   altering this may cause the system to hang.   
      
   [COM1 at IRQ4 aka INT!2] fires on your chosen serial-event.   
   * I'd chose INT on Buffer full for a mouse   
   * the mouse may send several bytes and each cause an interrupt, so   
   * the IRQ4 handler must read the com-port and must be aware of how many   
   bytes may come in addition so it fills a buffer (where is yours?) and   
   then respond to the result (can be button/wheel/x/y-motions or error).   
      
   I never abused the PIT-handler for a test, this is not good practice.   
   __   
   wolfgang   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)