3.9 _sys

Function

Call a subroutine passing register values.

Header

6502.h

Declaration

void __fastcall__ _sys (struct regs* r);

Description

The function will call the subroutine at the address specified in the pc member of the passed regs structure. All registers and the CPU flags are set to the values given in the regs structure. On return from the subroutine, the new values of the registers and flags are stored back overwriting the old values.

Limits

• Bits 4 and 5 of the flags value in the regs structure are ignored when calling the subroutine (they are unchanged from their current values).
• The function is only available as fastcall function, so it may only be used in presence of a prototype.

Availability

cc65

Example

None.