SYS COMMAND

The SYS command is used to transfer control from a BASIC program to a machine language program. The format for the SYS command is SYS N, where is any memory location. The computer will start executing the machine language at the address specified by N.

SYS is user-controlled. That is, in the VIC and the 64, you can SYS to any memory location between 1 and 65535. The memory location can be the start of a machine language program in user RAM, or an ML routine within BASIC or Kernal ROM. The SYS command is not a prewritten package of routines.

There is only one SYS command, but it can access many routines within the computer (such as "cold start," which simulates turning the computer on). To learn these addresses you need a map of your computer's memory. These maps are found in various COMPUTE! books such as COMPUTE!'s First Book of VIC, Mapping the VIC, Mapping the 64, The 64 Toolkit, and Machine Language for Beginners.


Commonly Used SYS Commands

SYS49152 = Prime location freq. used
SYS30120 = Plays Many Music Files
SYS64738 = Resets Computer