.TITLE  PLTSEG
        .GLOBL  PLTSEG
R0=%0
R1=%1
R2=%2
R3=%3
R4=%4
R5=%5
SP=%6
PC=%7
        .PSECT  VXDES,RW,D,GBL,REL,OVR
XFAC:   .BLKW   2
XOFF:   .BLKW   2
XTYPE:  .BLKW   1
XMAXB:  .BLKW   1
XSMINB: .BLKW   1
XSMAXB: .BLKW   1
XSNOWB: .BLKW   1
        .PSECT
        .PSECT  VXADES,RW,D,GBL,REL,OVR
XAFDU:  .BLKW   2
XADDU:  .BLKW   2
XADDB:  .BLKW   2
XAFDB:  .BLKW   1
XANDB:  .BLKW   1
XAIND:  .BLKW   1
XAGRID: .BLKW   1
XANGB:  .BLKW   1
XAING:  .BLKW   1
XATICK: .BLKW   1
XANTB:  .BLKW   1
XAINT:  .BLKW   1
        .PSECT
        .PSECT  VXTDES,RW,D,GBL,REL,OVR
XTA:    .BLKW   1
XTL:    .BLKW   1
XTOFFB: .BLKW   1
XTIND:  .BLKW   1
        .PSECT
        .PSECT  VYDES,RW,D,GBL,REL,OVR
YFAC:   .BLKW   2
YOFF:   .BLKW   2
YTYPE:  .BLKW   1
YMINB:  .BLKW   1
YMAXB:  .BLKW   1
        .PSECT
        .PSECT  VYADES,RW,D,GBL,REL,OVR
YAFDU:  .BLKW   2
YADDU:  .BLKW   2
YADDB:  .BLKW   2
YAFDB:  .BLKW   1
YAGRID: .BLKW   1
YATICK: .BLKW   1
        .PSECT
        .PSECT  VADES,RW,D,GBL,REL,OVR
AMAX:   .BLKW   1
ALAST:  .BLKW   1
ALEN:   .BLKW   1
A:      .BLKW   1
        .PSECT
ANPTS=0
ATYPE=2
AXA=4
AXMIN=4
AXF=6
AXI=8.
ADELX=6
AYA=10.
AYF=12.
AYI=14.
AEA=16.
AJOIN=18.
AOFF=20.
AXP=22.
AYP=24.
AEP=26.
AXC=28.
AYC=30.
AEC=32.
AXN=34.
AYN=36.
AEN=38.
AIC=40.
        .PSECT  VABORT,RW,D,GBL,REL,OVR
ABORT:  .BLKW   1
        .PSECT
        .PSECT  VPDP,RW,D,GBL,REL,OVR
PSPP:   .BLKW   1
PBUFL:  .BLKW   1
PCY:    .BLKW   1
PCYSPP: .BLKW   1
PBY:    .BLKW   1
POFBY:  .BLKW   1
PBPIY:  .BLKW   2
PBPCY:  .BLKW   2
PBCIX:  .BLKW   2
        .PSECT
        .PSECT  VPNTBF,RW,D,GBL,REL,OVR
RPSPP:  .BLKW   1
PNTBUF: .BLKW   1
        .PSECT  VPLTBF,RW,D,GBL,REL,OVR
PLTBUF: .BLKW   1
        .PSECT  VPLTYG,RW,D,GBL,REL,OVR
PLTYGB: .BLKW   1
        .PSECT
        .GLOBL  VSINIT,VSBSET,VBSET,VXLAB,VXGRID,VPSYM,VIPLTB,VPLT
        .GLOBL  VCNCT,VGETXY,VXTICK
IOFF:   .WORD   0
XL:     .WORD   0
YL:     .WORD   0
IYL:    .WORD   0
XH:     .WORD   0
YH:     .WORD   0
IYH:    .WORD   0
YPL:    .WORD   0
YPH:    .WORD   0
TIME:   .WORD   0
ID:     .WORD   0
DUMMY:  .WORD   0
ALST0:  .BYTE   0,0
ALST1:  .BYTE   1,0
        .WORD   PLTYGB
ALST2:  .BYTE   1,0
        .WORD   YMINB
ALST3:  .BYTE   1,0
        .WORD   YMAXB
ALST4:  .BYTE   2,0
        .WORD   YMINB
        .WORD   YMAXB
ALST5:  .BYTE   1,0
L2070:  .WORD   0
ALST6:  .BYTE   6,0
        .WORD   XL,YL,XH,YH,YPL,YPH
ALST7:  .BYTE   1,0
        .WORD   YPL
ALST8:  .BYTE   2,0
        .WORD   YPL,YPH
ALST9:  .BYTE   5,0
L2920:  .WORD   0,ID,XH,YH,DUMMY
PLTSEG: MOV     #ALST0,R5
        JSR     PC,VSINIT
        CMP     XSMAXB,XSMINB
        BGE     L2010
        JMP     L5000
L2010:  MOV     XSMINB,XSNOWB   ;INIT LOAD
;DO L4000 XSNOWB=XSMINB,XSMAXB
LOOP:   TST     ABORT
        BEQ     L2015
        RTS     PC
L2015:  TST     YAGRID
        BEQ     L2020
        MOV     XSNOWB,R0
        BIT     #1,R0
        BNE     L2020
        MOV     #ALST1,R5
        JSR     PC,VIPLTB
        BR      L2035
L2020:  MOV     #ALST0,R5
        JSR     PC,VIPLTB
L2035:  MOV     #ALST2,R5
        JSR     PC,VSBSET
        MOV     #ALST3,R5
        JSR     PC,VSBSET
        TST     XSNOWB
        BLE     L2038
        CMP     XSNOWB,XMAXB
        BNE     L2040
L2038:  MOV     #ALST4,R5
        JSR     PC,VBSET
L2040:  CMP     XANDB,XSNOWB
        BEQ     L2042
        TST     XTA
        BEQ     L2045
        CMP     XTIND,XTL
        BGE     L2045
        CMP     XTOFFB,XSNOWB
        BGT     L2045
        TST     RPSPP
        BNE     L2045
L2042:  MOV     #ALST0,R5
        JSR     PC,VXLAB
L2045:  CMP     XANGB,XSNOWB
        BNE     L2050
        MOV     #ALST0,R5
        JSR     PC,VXGRID
L2050:  CMP     XANTB,XSNOWB
        BNE     L2055
        MOV     #ALST0,R5
        JSR     PC,VXTICK
L2055:  CLR     IOFF
        MOV     XSNOWB,R0
;DO L3000 IOFF=0.ALAST,ALEN
LOOP2:  CMP     IOFF,ALAST
        BLE     L2060
        JMP     L4000
L2060:  MOV     #A,R1
        ADD     IOFF,R1
        ADD     IOFF,R1         ;R1=ADDR(A(IOFF))
        MOV     R0,R2
        ADD     #2,R2
        CMP     AXC(R1),R2
        BGT     L2080
        MOV     R1,L2070
        MOV     R0,-(SP)
        MOV     R1,-(SP)
        MOV     #ALST5,R5
        JSR     PC,VPSYM
        MOV     (SP)+,R1
        MOV     (SP)+,R0
L2080:  TSTB    AJOIN+1(R1)
        BNE     L2090
        JMP     L3000
L2090:  MOV     AXP(R1),XL
        MOV     AYP(R1),YL
        MOV     AXC(R1),XH
        MOV     AYC(R1),YH
        MOV     #1,TIME
L2100:  CMP     R0,XL
        BGE     L2105
        JMP     L2900
L2105:  CMP     XH,#77777
        BNE     L2110
        JMP     L2900
L2110:  CMPB    AJOIN+1(R1),#2
        BEQ     L2200
        MOV     R0,-(SP)
        MOV     R1,-(SP)
        MOV     #ALST6,R5
        JSR     PC,VCNCT
        MOV     (SP)+,R1
        MOV     (SP)+,R0
        BR      L2300
L2200:  CMP     R0,XH
        BEQ     L2210
        BGT     L2220
L2205:  MOV     YL,YPL
        MOV     YL,YPH
        BR      L2300
L2210:  MOV     YL,YPL
        MOV     YH,YPH
        CMP     YPL,YPH
        BLE     L2300
        MOV     YPL,R2
        MOV      YPH,YPL
        MOV     R2,YPH
        BR      L2300
L2220:  MOV     YH,YPL
        MOV     YH,YPH
L2300:  MOV     YL,IYL
        MOV     YH,IYH
        CMP     IYL,IYH
        BLE     L2310
        MOV     IYL,R2
        MOV     IYH,IYL
        MOV     R2,IYH
L2310:  CLR     R2              ;R2=INC
        TSTB    AJOIN(R1)
        BEQ     L2320
        MOV     XL,R3
        SUB     #2,R3
        CMP     R0,R3
        BLT     L2315
        ADD     #4,R3
        CMP     R0,R3
        BGT     L2315
        MOV     #3,R2
        BR      L2320
L2315:  MOV     XH,R3
        SUB     #2,R3
        CMP     R0,R3
        BLT     L2320
        ADD     #4,R3
        CMP     R0,R3
        BGT     L2320
        MOV     #3,R2
L2320:  MOV     IYL,R3
        ADD     R2,R3
        CMP     YPL,R3
        BGE     L2325
        MOV     R3,YPL
L2325:  MOV     IYH,R3
        SUB     R2,R3
        CMP     YPH,R3
        BLE     L2330
        MOV     R3,YPH
L2330:  CMP     YPL,YMINB
        BGE     L2335
        MOV     YMINB,YPL
L2335:  CMP     YPH,YMAXB
        BLE     L2340
        MOV     YMAXB,YPH
L2340:  MOV     R0,-(SP)
        MOV     R1,-(SP)
        CMP     YPL,YPH
        BGT     L2410
        BLT     L2400
        MOV     #ALST7,R5
        JSR     PC,VSBSET
        BR      L2410
L2400:  MOV     #ALST8,R5
        JSR     PC,VBSET
L2410:  MOV     (SP)+,R1
        MOV     (SP)+,R0
L2900:  CMP      XH,R0
        BGT     L3000
        CMP     TIME,#2
        BEQ     L2910
        MOV     #2,TIME
        MOV     AXC(R1),XL
        MOV     AYC(R1),YL
        MOV     AXN(R1),XH
        MOV     AYN(R1),YH
        MOV     AIC(R1),ID
        INC     ID
        JMP     L2100
L2910:  CMP     ID,ANPTS(R1)
        BGT     L3000
        MOV     XH,XL
        MOV     YH,YL
        INC     ID
        MOV     R0,-(SP)
        MOV     R1,-(SP)
        MOV     R1,L2920
        MOV     #ALST9,R5
        JSR     PC,VGETXY
        MOV     (SP)+,R1
        MOV     (SP)+,R0
        JMP     L2100
L3000:  ADD     ALEN,IOFF
        JMP     LOOP2
L4000:  MOV     #ALST0,R5
        JSR     PC,VPLT
        INC     XSNOWB
        CMP     XSNOWB,XSMAXB
        BGT     L4010
        JMP     LOOP
L4010:  MOV     XSMAXB,R0
        INC     R0
        MOV     R0,XSMINB
L5000:  MOV     ALEN,R0
        NEG     R0
        MOV     R0,ALAST
        RTS     PC
        .END