;	FILE NAME		TURTLE.M80
	;	CODED BY		  TOSHIHUMI MURATA
	;				B U G   sapporo japan
	;	1ST  EDITING		Aug.  3, 1983
	;	LAST EDITING		Aug.  4, 1983

	ENTRY	DSP_TURTLE

;	dsp_turtle (x, y, sec)
;	int x [-16384..16383], y [-16384..16383], sec [0..59];

	DSEG
T0_X:	DS	2
T0_Y:	DS	2
T1_X:	DS	2
T1_Y:	DS	2
T2_X:	DS	2
T2_Y:	DS	2
T3_X:	DS	2
T3_Y:	DS	2

	CSEG
DSP_TURTLE:
	PUSH	BC
	LD	HL,4
	ADD	HL,SP
	LD	E,(HL)
	INC	HL
	LD	D,(HL)
	INC	HL
	LD	(T0_X),DE
	LD	E,(HL)
	INC	HL
	LD	D,(HL)
	INC	HL
	LD	(T0_Y),DE

	; set up vertices

	LD	L,(HL)		;HL := SECTION
	LD	H,0		 ;
	ADD	HL,HL		;IX := TTL_TBL + SECTION * 6
	LD	E,L		 ;
	LD	D,H		  ;
	ADD	HL,HL		   ;
	ADD	HL,DE		    ;
	LD	DE,TTL_TBL	     ;
	ADD	HL,DE		      ;
	PUSH	HL		       ;
	POP	IX			;
	LD	DE,T1_X
	CALL	CALOFS
	CALL	CALOFS
	CALL	CALOFS

	; draw turtle

	; line t1 - t2
	LD	HL,(T1_X)
	LD	(X1),HL
	LD	HL,(T1_Y)
	LD	(Y1),HL
	LD	HL,(T2_X)
	LD	DE,(T2_Y)
	LD	BC,4*100H+15		;COLOR = 15, MODE = XOR
	CALL	LINPLT

	; line    - t0
	LD	HL,(T0_X)
	LD	DE,(T0_Y)
	LD	BC,4*100H+15
	CALL	.LINE

	; line    - t3
	LD	HL,(T3_X)
	LD	DE,(T3_Y)
	LD	BC,4*100H+15
	CALL	LINPLT

	; line    - t1
	LD	HL,(T1_X)
	LD	DE,(T1_Y)
	LD	BC,4*100H+15
	CALL	LINPLT

	POP	BC
	RET



CALOFS:	LD	BC,(T0_X)
	CALL	CALOF1
	LD	BC,(T0_Y)
CALOF1:	LD	A,(IX+0)
	INC	IX
	LD	L,A		;HL := SIGN_EXTEND [ A ]
	ADD	A,A		 ;
	SBC	A,A		  ;
	LD	H,A		   ;
	ADD	HL,BC
	EX	DE,HL
	LD	(HL),E
	INC	HL
	LD	(HL),D
	INC	HL
	EX	DE,HL
	RET



LINPLT:	PUSH	HL
	PUSH	DE
	PUSH	BC
	CALL	.LINE
	POP	BC
	POP	DE
	POP	HL
.PLOT:	RCALL	0F73H

.LINE:	RCALL	0E71H





TTL_TBL:
	;	t1_x	t1_y	t2_x	t2_y	t3_x	t3_y	  deg.
	DB	000H,	0F8H,	005H,	003H,	0FBH,	003H	;   0
	DB	001H,	0F8H,	005H,	003H,	0FBH,	003H	;   6
	DB	002H,	0F8H,	004H,	004H,	0FAH,	002H	;  12
	DB	003H,	0F8H,	004H,	004H,	0FAH,	002H	;  18
	DB	004H,	0F9H,	003H,	004H,	0FAH,	001H	;  24
	DB	005H,	0F9H,	002H,	005H,	0FAH,	001H	;  30
	DB	006H,	0FAH,	002H,	005H,	0FAH,	000H	;  36
	DB	007H,	0FAH,	001H,	005H,	0FAH,	000H	;  42
	DB	008H,	0FBH,	001H,	005H,	0FAH,	0FFH	;  48
	DB	008H,	0FBH,	000H,	005H,	0FAH,	0FFH	;  54
	DB	009H,	0FCH,	0FFH,	005H,	0FAH,	0FEH	;  60
	DB	009H,	0FDH,	0FFH,	005H,	0FAH,	0FEH	;  66
	DB	00AH,	0FEH,	0FEH,	005H,	0FBH,	0FDH	;  72
	DB	00AH,	0FEH,	0FDH,	005H,	0FBH,	0FDH	;  78
	DB	00AH,	0FFH,	0FDH,	004H,	0FCH,	0FCH	;  84
	DB	00AH,	000H,	0FCH,	004H,	0FCH,	0FCH	;  90
	DB	00AH,	001H,	0FCH,	004H,	0FDH,	0FCH	;  96
	DB	00AH,	002H,	0FBH,	003H,	0FDH,	0FBH	; 102
	DB	00AH,	002H,	0FBH,	003H,	0FEH,	0FBH	; 108
	DB	009H,	003H,	0FAH,	002H,	0FFH,	0FBH	; 114
	DB	009H,	004H,	0FAH,	002H,	0FFH,	0FBH	; 120
	DB	008H,	005H,	0FAH,	001H,	000H,	0FBH	; 126
	DB	008H,	005H,	0FAH,	001H,	001H,	0FBH	; 132
	DB	007H,	006H,	0FAH,	000H,	001H,	0FBH	; 138
	DB	006H,	006H,	0FAH,	000H,	002H,	0FBH	; 144
	DB	005H,	007H,	0FAH,	0FFH,	002H,	0FBH	; 150
	DB	004H,	007H,	0FAH,	0FFH,	003H,	0FCH	; 156
	DB	003H,	008H,	0FAH,	0FEH,	004H,	0FCH	; 162
	DB	002H,	008H,	0FAH,	0FEH,	004H,	0FCH	; 168
	DB	001H,	008H,	0FBH,	0FDH,	005H,	0FDH	; 174
	DB	000H,	008H,	0FBH,	0FDH,	005H,	0FDH	; 180
	DB	0FFH,	008H,	0FBH,	0FDH,	005H,	0FDH	; 186
	DB	0FEH,	008H,	0FCH,	0FCH,	006H,	0FEH	; 192
	DB	0FDH,	008H,	0FCH,	0FCH,	006H,	0FEH	; 198
	DB	0FCH,	007H,	0FDH,	0FCH,	006H,	0FFH	; 204
	DB	0FBH,	007H,	0FEH,	0FBH,	006H,	0FFH	; 210
	DB	0FAH,	006H,	0FEH,	0FBH,	006H,	000H	; 216
	DB	0F9H,	006H,	0FFH,	0FBH,	006H,	000H	; 222
	DB	0F8H,	005H,	0FFH,	0FBH,	006H,	001H	; 228
	DB	0F8H,	005H,	000H,	0FBH,	006H,	001H	; 234
	DB	0F7H,	004H,	001H,	0FBH,	006H,	002H	; 240
	DB	0F7H,	003H,	001H,	0FBH,	006H,	002H	; 246
	DB	0F6H,	002H,	002H,	0FBH,	005H,	003H	; 252
	DB	0F6H,	002H,	003H,	0FBH,	005H,	003H	; 258
	DB	0F6H,	001H,	003H,	0FCH,	004H,	004H	; 264
	DB	0F6H,	000H,	004H,	0FCH,	004H,	004H	; 270
	DB	0F6H,	0FFH,	004H,	0FCH,	003H,	004H	; 276
	DB	0F6H,	0FEH,	005H,	0FDH,	003H,	005H	; 282
	DB	0F6H,	0FEH,	005H,	0FDH,	002H,	005H	; 288
	DB	0F7H,	0FDH,	006H,	0FEH,	001H,	005H	; 294
	DB	0F7H,	0FCH,	006H,	0FEH,	001H,	005H	; 300
	DB	0F8H,	0FBH,	006H,	0FFH,	000H,	005H	; 306
	DB	0F8H,	0FBH,	006H,	0FFH,	0FFH,	005H	; 312
	DB	0F9H,	0FAH,	006H,	000H,	0FFH,	005H	; 318
	DB	0FAH,	0FAH,	006H,	000H,	0FEH,	005H	; 324
	DB	0FBH,	0F9H,	006H,	001H,	0FEH,	005H	; 330
	DB	0FCH,	0F9H,	006H,	001H,	0FDH,	004H	; 336
	DB	0FDH,	0F8H,	006H,	002H,	0FCH,	004H	; 342
	DB	0FEH,	0F8H,	006H,	002H,	0FCH,	004H	; 348
	DB	0FFH,	0F8H,	005H,	003H,	0FBH,	003H	; 354