Function Name: SETNAM

Purpose: Set filename pointers
Call address: $FFBD (hex) 65469 (decimal)

	Registers:	.A = string length
			.X = string adr low
			.Y = string adr high
	Memory:		system map
	Flags:		none
	Calls:		SETBNK
	Registers:	none
	Memory:		FNLEN, FNADR updated
	Flags:		none

Description: SETNAM sets up the filename or command string for higher-level Kernal I/O calls such as OPEN, LOAD and SAVE. The string (filename or command) length is passed in .A and updates FNLEN ($B7). The address of the string is passed in .X (low) and .Y (high). See the companion call, SETBNK, which specifies in which RAM bank the string is found. If there is no string, SETNAM should still be called and a null ($00) length specified (the address does not matter). SETNAM is often used along with SETBNK and SETLFS calls prior to OPENs. See the Kernal OPEN, LOAD and SAVE calls for examples.