//
// Official Kernal routine, described in:
//
// - [RG64] C64 Programmer's Reference Guide   - page 301
// - [CM64] Compute's Mapping the Commodore 64 - page 232
//
// CPU registers that has to be preserved (see [RG64]): .Y
//

STOP:
	// Bit 7 of STKEY contains the state of the STOP key
	// (Compute's Mapping the 64, p27)

	// BASIC checks carry flag to indicate STOP or not
	lda STKEY
	bpl stop_pressed

	// By trial and error, we know that Z + C = BREAK
	// and that neither should be set otherwise
	lda #$FF
	clc
	rts

stop_pressed:
	sec
	lda #$00
	rts