#MSG Hamlin V1.1

#CONFIG ARMOR=2
#CONFIG SCANNER=4
#CONFIG ENGINE=4
#CONFIG MINES=0
#CONFIG SHIELD=0
#CONFIG WEAPON=2
#CONFIG HEATSINKS=0

#DEF    Arrival

	mov     ax, 1           ; (AX) = Keepshift status.
	int     3               ; Turn Keepshift on.
	opo     20, 450         ; Set shutdown level to 450 BTU's.

:0001
	mov     dx, 64          ; (DX) = 64; scan arc will extend the full
				; 128 degree half of the radius of the scan
				; range.

:0004
	opo     17, dx          ; Set the scan arc via scanner port 17.
	opo     11, 100         ; Reset throttle, just in case we stopped for some reason.

:0006
	ipo     7, ax           ; (AX) = range to nearest target.
	cmp     ax, 7FFFh       ; Valid range?
	je      0012            ; No. Modify turret position and try again.
	ipo     8, bx           ; (BX) = accuracy rating of last scan.
	call    0007
	ipo     2, ax           ; (AX) = Current heat level.
	
	cmp     ax, 400         ; Heat under 400 BTUs?
	jge     0005            ; No. Let the heat dissipate for a bit before
				; firing again, or turning on the shield.
	
	cmp     dx, 32          ; How's that accuracy?
	ja      0005            ; Shitty. Don't waste the heat on plasma.
	
	opo     15, bx          ; Fire!

:0005
	mov     fx, dx          ; (FX) = scan width.
	mpy     fx, bx          ; (FX) = scanwidth*accuracy.
	sar     fx, 1           ; (FX) = scanwidth*accruacy/2
	opo     12, fx          ; Rotate turret to new offset for improved
				; chances of accuracy.
	cmp     dx, 2           ; Scan arc 2 or less?
	jbe     0006            ; Yes. Do not adjust further.
	shr     dx, 1           ; Adjust scan arc down to zero in on target.
	jmp     0004            ; Repeat.

:0012
	opo     12, 128         ; Rotate turret by additive.
	jmp     0001            ; Repeat.

;-----------------------------------------------------------------------------

:0007
	push    ax              ; Preserve AX register.
	push    bx              ; Preserve BX register.
	push    cx              ; Preserve CX register.
	push    dx              ; Preserve DX register.
	cmp     Arrival, 0
	jne     0010
	ipo     5, ax           ; (AX) = Turret heading.
	ipo     3, dx           ; (DX) = Robot heading.
	cmp     ax, dx          ; (Turret heading greater than Robot heading?
	ja      0008            ; Yes. Resolve new heading: (AX - DX).
	sub     dx, ax          ; No. Resolve new heading: (DX - AX).
	mov     ax, dx          ; (AX) = New heading additive.

:0009
	opo     14, ax          ; Set new heading.
	mov     Arrival, 9

:0010
	dec     Arrival
	pop     dx              ; Restore DX register.
	pop     cx              ; Restore CX register.
	pop     bx              ; Restore BX register.
	pop     ax              ; Restore AX register.
	ret                     ; Return to caller.

:0008
	sub     ax, dx          ; (AX) = New heading additive.
	jmp     0009            ; Go set it up.