CallWin32_ParsInit
(SWI &C1002)

On entry: 
R0 =  ptr to workspace
R1 =  Number of parameters (zero if you want it calculated dynamically). Ignored if unreasonable value.
On exit: -
Interrupts: Interrupt status is unaltered
Fast interrupts are enabled
Processor Mode:  Processor is in SVC mode
Re-entrancy: SWI is reentrant
Use: This call prepares a parameter workspace for use with CallWin32_WithPars. You must initialise a workspace with this call before use with any other call and there must be at least R1 from CallWin32_Info bytes allocated to this workspace.

If you want the parameter number to be whatever the largest parameter index passed to any other CallWin32_Pars* call, pass zero for R1.
Related SWIs: CallWin32_ParsAddInt32 (SWI &C1003), CallWin32_ParsAddInt16 (SWI &C1004), CallWin32_ParsAddInt8 (SWI &C1005), CallWin32_ParsAddMemBlk (SWI &C1006), CallWin32_ParsAddString (SWI &C1007), CallWin32_WithPars (SWI &C1008)