;GR1に格納された数値を表示
ITOA	START
	PUSH 0,GR2
	PUSH 0,GR3
	PUSH 0,GR4
    LAD	GR0,0
    LAD	GR2,0
    AND GR1,GR1
    JPL ILOOP
    JZE ILOOP
    LAD GR0,1
    CALL INV
ILOOP	CPA	GR1,TEN
	JMI	INEXT
	CALL	DIV
    ADDA	GR4,ZCHAR
    ST	GR4,STR,GR2
    LAD	GR2,1,GR2
    LD	GR1,GR3
    JUMP	ILOOP
INEXT	ADDA	GR1,ZCHAR
	ST	GR1,STR,GR2
	LAD	GR2,1,GR2
    CPA GR0,=1
    JPL	PRT
    JMI	PRT
    LD	GR1,MINUS
	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
TEN	DC	10
ZCHAR DC '0'
MINUS DC '-'
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,TEN
	JMI	DFIN
    SUBL GR4,TEN
    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
INV	START
	XOR	GR1,=#FFFF
    LAD	GR1,1,GR1
    RET
	END