MAIN	START
BEGIN	LD	GR1,A
	SUBA	GR1,B
    CALL	ITOA
    RET
A	DC	0
B	DC	#7FFF
C	DS	1
	END
ITOA	START
	PUSH 0,GR2
	PUSH 0,GR3
	PUSH 0,GR4
    LAD	GR0,0
    LAD	GR2,0
    AND GR1,GR1
    JPL LOOP
    JZE LOOP
    LAD GR0,1
    CALL MINUS
LOOP	CPA	GR1,=10
	JMI	NEXT
	CALL	DIV
    ADDA	GR4,='0'
    ST	GR4,STR,GR2
    LAD	GR2,1,GR2
    LD	GR1,GR3
    JUMP	LOOP
NEXT	ADDA	GR1,='0'
	ST	GR1,STR,GR2
	LAD	GR2,1,GR2
    CPA GR0,=1
    JPL	PRT
    JMI	PRT
    LD	GR1,='-'
	ST	GR1,STR,GR2
	LAD	GR2,1,GR2
PRT	ST	GR2,LEN
	LAD	GR1,STR
    LD	GR2,LEN
    CALL REV
	OUT	STR,LEN
	POP GR4
	POP GR3
	POP GR2
	RET
STR	DS	6
LEN	DS	1
    END
;GR1を10で割ったときの商をGR3、剰余をGR4に格納
DIV	LD	GR4,GR1
	LAD	GR3,0
DLOOP	CPA	GR4,=10
	JMI	DFIN
    SUBL GR4,=10
    LAD	GR3,1,GR3
    JUMP	DLOOP
DFIN RET
	END
;アドレスがGR1、長さがGR2の文字列を逆順に並べ替える
;例: 12345 -> 54321
REV	START
	PUSH	0,GR3
    PUSH	0,GR4
    PUSH	0,GR5
	LAD	GR3,1
RPU	CPA	GR2,GR3
	JMI	RNEXT
    LD	GR4,GR1
    ADDA	GR4,GR3
    LD	GR4,-1,GR4
	PUSH 0,GR4
    LAD	GR3,1,GR3
    JUMP	RPU
RNEXT    LAD	GR3,1
RPO	CPA	GR2,GR3
	JMI	RFIN
    POP GR4
    LD GR5,GR1
    ADDA GR5,GR3
    ST GR4,-1,GR5
    LAD	GR3,1,GR3
    JUMP RPO
RFIN POP GR5
	POP	GR4
    POP	GR3
	RET
	END
;GR1の内容をマイナス値にする
;例: 10 -> -10, -20 -> 20
MINUS	START
	XOR	GR1,=#FFFF
    LAD	GR1,1,GR1
    RET
	END