/ vim: set sw=8 noexpandtab :

*000

INTRET,	0
	JMP GOTINT

*010

IHEAD,	7777		/ because preincrement
ITAIL,	7777

OHEAD,	7777		/ because preincrement
OTAIL,	7777

*100

OBUSY,	0

*200

	CLA IAC
	KIE
	ION
LOOP,	CLA
	TAD ITAIL
	CMA IAC
	TAD IHEAD
	SNA
	JMP LOOP
	CLA
	CDF 0010
	TAD I ITAIL
	CDF 0020
	DCA I OHEAD
	CDF 0000
	IOF		/ critical section
	TAD OBUSY
	SNA
	TFL
	ION
	JMP LOOP	/ end critical section

*400

GOTINT,	DCA SAVEA
	GTF
	AND (7577)
	DCA SAVEF
	TSF
	JMP KBIN
	TCF
	CLA
	DCA OBUSY
	TAD OTAIL
	CMA IAC
	TAD OHEAD
	SNA
	JMP KBIN
	CLA
	CDF 0020
	TAD I OTAIL
	CDF 0000
	TPC
	CLA IAC
	DCA OBUSY
KBIN,	KSF
	JMP RETINT
	KRB
	CDF 0010
	DCA I IHEAD
	CDF 0000
RETINT,	CLA
	TAD SAVEF
	RTF
	CLA
	TAD SAVEA
	ION
	JMP I INTRET

SAVEA,	0
SAVEF,	0