.386
public polydr
code segment para use16
assume cs:code
start:
polydr proc near
arg data_buf:dword,n:word,Point_mas:dword =  Param_size
;arg data_buf:dword = Param_size
psz EQU 5
coll    EQU word ptr ds:[bx+12+16+4+2*0]
colr    EQU word ptr ds:[bx+12+16+4+2*1]
dcoll   EQU word ptr ds:[bx+12+16+4+2*2]
dcolr   EQU word ptr ds:[bx+12+16+4+2*3]
const5757 EQU ds:[bx+12+16+4+2*4]
public polydr
       push bp
       mov bp,sp
       push ds
       lgs di,point_mas
       lds bx,Data_buf
       mov word ptr const5757,5757
       mov ax,ds:[bx+0];segA000
       mov es,ax
       mov ds:[bx+0],di
       mov si,n
       dec si                   ;because mas [0..n-1]
       imul si,si,psz           ; *psz:structure "point" need psz bytes.
       ;shl si,2
       ;add si,
       add si,di
       mov ds:[bx+1*2],si
       xor cx,cx
       mov ax,-32000
       mov dx,+32000
c1:    cmp cx,n                 ;for cx:= 0 to n-1 do ...
       je endc1
       cmp ax,gs:[di+2]
       jge l1_in_c1
       mov ax,gs:[di+2]
       mov si,di
l1_in_c1:
       cmp dx,gs:[di+2]
       jle l2_in_c1
       mov dx,gs:[di+2]
l2_in_c1:
       add di,psz
       inc cx
       jmp c1
endc1:
IF 1
       cmp ax,dx                ;if ymax = ymin, then goto enddr
       je enddr
       mov di,si                ;"save"  si in di. si == index of ymax in point_mas.
c2:    cmp gs:[si+2],ax         ;ax = ymax now.
       jne endc2
       cmp si,ds:[bx+1*2]
       je l1_c2
       add si,psz
       jmp short  l2_c2
l1_c2: mov si,ds:[bx+0]
l2_c2: jmp short c2
endc2: mov ds:[bx+2*2],si       ;si == il
       mov si,di                ;index of ymax was saved in di
c3:    cmp gs:[si+2],ax         ;ax == ymax now.
       jne endc3
       cmp si,ds:[bx+0*2]
       je l1_c3
       sub si,psz
       jmp short  l2_c3
l1_c3: mov si,ds:[bx+1*2]
l2_c3: jmp short c3
endc3: mov ds:[bx+3*2],si       ;si == ir
       mov ds:[bx+4*2],ax       ;ytec:=ymax
ENDIF
       mov ds:[bx+5*2],dx       ;ymin
if 1
       mov si,ds:[bx+2*2]       ;si:= il
       cmp si,ds:[bx+0*2]
       je l1
       sub si,psz
       jmp short l2
l1:    mov si,ds:[bx+1*2]
l2:    mov ax,gs:[si+0]         ;ax := int(xl)
       shl eax,16
       mov ds:[bx+12+0*4],eax   ;xl
       xor ax,ax
       mov ah,gs:[si+4]
       mov coll,ax
       mov si,ds:[bx+3*2]       ;SI := ir
       cmp si,ds:[bx+1*2]
       je l3
       add si,psz
       jmp short l4
l3:    mov si,ds:[bx+0*2]
l4:    mov ax,gs:[si+0]
       shl eax,16
       mov ds:[bx+12 + 1*4],eax         ;xr
       xor ax,ax
       mov ah,gs:[si+4]
       mov colr,ax
;Count dxl:
       mov si,ds:[bx+2*2]               ;si := il
       mov ax,gs:[si+0]                 ;ax:= round(x[il])
       shl eax,16
       sub eax,ds:[bx+12+0*4]           ;x[il]-xl
       xor ecx,ecx                      ;ecx := 0
       mov cx,[bx+4*2]                  ;cx:=ytec
       sub cx,gs:[si+2]                 ;cx:= ytec - y[il]
       cdq                      ;(edx:eax)/ecx
       idiv ecx                 ;(edx:eax)/ecx
       mov ds:[bx+12+2*4],eax   ;dxl
       xor ax,ax
       mov ah,gs:[si+4]
       sub ax,coll
       cwd
       idiv cx
       mov dcoll,ax

;Count dxr:
       mov si,ds:[bx+3*2]               ;si := ir
       mov ax,gs:[si+0]                 ;ax:= x[ir]
       shl eax,16
       sub eax,ds:[bx+12+1*4]           ;x[ir]-xr
       xor ecx,ecx                      ;ecx := 0
       mov cx,[bx+4*2]                  ;cx:=ytec
       sub cx,gs:[si+2]                 ;ytec - y[ir]
       cdq                      ;(edx:eax)/ecx
       idiv ecx                 ;(edx:eax)/ecx
       mov ds:[bx+12+3*4],eax   ;dxr
       xor ax,ax
       mov ah,gs:[si+4]
       sub ax,colr
       cwd
       idiv cx
       mov dcolr,ax
;count adress of sreen line start
       mov ax,ds:[bx+4*2]
       mov cx,320
       mul cx
       mov ds:[bx+12+16+0*2],ax ;line start
endif
if 1
BIG_c: ;Line:
       mov ecx,ds:[bx+12+1*4]   ;ecx := xr
       mov eax,ds:[bx+12+0*4]   ;eax := xl
       rol ecx,16
       rol eax,16
       sub cx,ax
       jl enddr
       jcxz eppix
       mov di,ds:[bx+12+16+0*2]
       add di,ax
       mov ax,colr
       sub ax,coll
       cwd
       idiv cx
       mov dx,ax
       mov ax,coll
ppix:  mov es:[di],ah
       add ax,dx
       inc di
       loop ppix
eppix:
       ;mov al,c
;   rep stosb
       mov dx,ds:[bx+4*2]      ;dx:= ytec
       cmp dx,ds:[bx+5*2]      ;cmp ytec,ymin
       jle enddr
;Redefine xr and xl:
       mov si,ds:[bx+2*2]       ;si:= il
       mov ax,gs:[si+2]
       cmp ax,dx                ;cmp y[il],ytec
       jne end_def_xl
       mov cx,gs:[si+0]
       shl ecx,16
       mov ds:[bx+12+0*4],ecx
       xor cx,cx
       mov ch,gs:[si+4]
       mov coll,cx
c1bc:  cmp ax,dx
       jne endc1bc
       cmp si,ds:[bx+1*2]
       je l1c1bc
       add si,psz
       jmp short l2c1bc
l1c1bc:mov si,ds:[bx+0*2]
l2c1bc:mov ax,gs:[si+2]
       jmp c1bc
endc1bc:
       mov ax,gs:[si+0]                 ;ax:= x[il]
       shl eax,16
       sub eax,ds:[bx+12+0*4]           ;x[il]-xl
       xor ecx,ecx                      ;ecx := 0
       mov cx,[bx+4*2]                  ;cx:=ytec
       sub cx,gs:[si+2]                 ;ytec - y[il]
       cdq                      ;(edx:eax)/ecx
       idiv ecx                 ;(edx:eax)/ecx
       mov ds:[bx+2*2],si       ;il
       mov ds:[bx+12+2*4],eax   ;dxl
       xor ax,ax
       mov ah,gs:[si+4]
       sub ax,coll
       cwd
       idiv cx
       mov dcoll,ax
end_def_xl:
       mov dx,ds:[bx+4*2]      ;dx:= ytec
       mov si,ds:[bx+3*2]       ;si:= ir
       mov ax,gs:[si+2]         ;ax:= y[ir]
       cmp ax,dx                ;cmp y[ir],ytec
       jne end_def_xr
       mov cx,gs:[si+0]
       shl ecx,16
       mov ds:[bx+12+1*4],ecx
       xor cx,cx
       mov ch,gs:[si+4]
       mov colr,cx
c2bc:  cmp ax,dx
       jne endc2bc
       cmp si,ds:[bx+0*2]
       je l1c2bc
       sub si,psz
       jmp short l2c2bc
l1c2bc:mov si,ds:[bx+1*2]
l2c2bc:mov ax,gs:[si+2]
       jmp c2bc
endc2bc:
       mov ax,gs:[si+0]                 ;ax:= x[ir]
       shl eax,16
       sub eax,ds:[bx+12+1*4]           ;x[ir]-xr
       xor ecx,ecx                      ;ecx := 0
       mov cx,[bx+4*2]                  ;cx:=ytec
       sub cx,gs:[si+2]                 ;ytec - y[ir]
       cdq                      ;(edx:eax)/ecx
       idiv ecx                 ;(edx:eax)/ecx
       mov ds:[bx+3*2],si
       mov ds:[bx+12+3*4],eax   ;dxr
;       xor eax,eax
;       mov ah,gs:[si+4]
;       sub ax,colr
;      div cx
;       mov dcolr,ax
       xor ax,ax
       mov ah,gs:[si+4]
       sub ax,colr
       cwd
       idiv cx
       mov dcolr,ax
end_def_xr:
       ;Incs:
       mov ax,coll
       add ax,dcoll
       mov coll,ax
       mov ax,colr
       add ax,dcolr
       mov colr,ax
       mov eax,ds:[bx+12+0*4]
       add eax,ds:[bx+12+2*4]
       mov ds:[bx+12+0*4],eax
       mov eax,ds:[bx+12+1*4]
       add eax,ds:[bx+12+3*4]
       mov ds:[bx+12+1*4],eax
       sub word ptr ds:[bx+12+16+0*2],320
       dec word ptr ds:[bx+4*2]
       jmp BIG_c
ENDIF
enddr:

       pop ds
       pop bp
       ret  Param_size
polydr endp
code ends
end start