(SWI &C2000)

On entry:  -
On exit:
R0 =  Current wheel position
Interrupts: Interrupt status is unaltered
Fast interrupts are enabled
Processor Mode:  Processor is in SVC mode
Re-entrancy: SWI is reentrant
Use: The value returned is an unsigned 32 bit number which either rises or falls according to which way the mouse wheel is turned. To calculate the delta use:

delta=(old R0)-R0

This method permits multiple users of the wheel.

Related SWIs: -