; in simh:
; simh> set console telnet=3333
; then invoke telnet to port 3333 on the simh systm
; simh> load test.bin
; simh> run


; initialize stack pointer
start:	MOV	#1000, R6

	MOV	#textstart, R0
	CALL	print_start

	CALL	psw_store_retrieve

	CALL	psw_flags_trigger

	MOV	#textfin, R0
	CALL	print_start
	TRAP	7

psw_store_retrieve:
; set PSW to all bits set
	MOV	#65535,R1
	MTPS	R1
; clear PSW status bits
	CLC
	CLV
	CLZ
	CLN
; retrieve PSW and verify the flags are 0
	MFPS	R2

; clear uninteresting flags
	BIC 	#4,R2
	BIC 	#5,R2
	BIC 	#6,R2
	BIC 	#7,R2

	TSTB	R2
	BNE	psw_store_retrieve_fail

	RET

psw_store_retrieve_fail:
	MOV	R2,R0
	CALL	print_binary
	MOV	#psw_fail_text, R0
	CALL	print_start
	RET

psw_flags_trigger:
	CLC
	CLV
	CLZ
	CLN

	RET

psw_fail_text:	.ASCII	"MFPS / MTPS handling FAIL\r\n\x00"

; store copy of R0 on the stack
print_start:	MOV	R0,-(SP)
; store PSW (status register) on stack
	MFPS	-(SP)

; string ends with 0x00
print:	TSTB	(R0)
	BEQ	pdone

; put character in tty buffer
	MOVB	(R0), @#TTYTX

; wait for it to be transmitted
waittx:	TSTB	@#TTYST
	BPL	waittx

	INC	R0
	JMP	print

; retrieve stored r0, r1 and psw from stack
pdone:	MTPS	(SP)+

	MOV	(SP)+,R0
	RET

print_binary:
	MOV	R0,-(SP)
	MOV	R1,-(SP)
; 8 bits in a byte
	MOV	#8.,R1

print_bit:
	BIT	#0,R0
	BEQ	print_1:
waittx0:
	TSTB	@#TTYST
	BPL	waittx0
	MOVB	#33, @#TTYTX
	BR	print_next_bit
print_1:
waittxt1:
	TSTB	@#TTYST
	BPL	waittx1
	MOVB	#34, @#TTYTX

print_next_bit:
; move R0 contents to the next bit
	ASR	R0
; keep track of the number of bits emitted
	DEC	R1
	TST	R1
	BNE	print_bit

	MOV	(SP)+,R1
	MOV	(SP)+,R0
	RET

	make_raw

textstart:	.ASCII	"tester running...\r\n\x00"
textfin:	.ASCII	"tester finished\r\n\x00"

textbuffer:	.BLKB	256.

TTYST	=	177564
TTYTX	=	177566