Function Name: READST

Purpose: Read status byte
Call address: $FFB7 (hex) 65463 (decimal)
Preparation:

	Registers:	none
	Memory:		system map
	Flags:		none
	Calls:		none

	Registers:	.A = STATUS ($90 or $A14)
	Memory:		STATUS cleared if RS-232
	Flags:		none

Description: READST (alias READSS) returns the status byte associated with the last I/O operation (serial, cassette or RS-232) performed. Serial and cassette tape operations update STATUS ($90) and RS-232 I/O updates RSSTAT ($A14). Note that to simulate an ACIA, RSSTAT is cleared after it is read via READST. The last I/O operation is determined by the contents of FA ($BA); thus applications that drive I/O devices using the lower-level Kernal calls should not use READST.

EXAMPLE:

	JSR	$FFB7	;STATUS for last I/O