;;; $B6B9: Pre-instruction - eye door projectile - moving ;;;
{
; BUG: the $B707 branch assumes the enemy projectile index is in X, but this is only true if the branch on $B6BC/C1 is taken,
; otherwise the enemy projectile index is in Y, and the door bit array index is in X,
; causing misaligned writes to enemy projectile RAM if X is odd, eventually causing a crash when the garbage instruction pointer gets executed
; (which happens after a delay of 100h+ frames due to the misaligned write to the instruction timer)

; The X/Y velocity calculations were already done as a part of calculating the angle to Samus in $82A5,
; they don't need to be here

$86:B6B9 20 B6 88    JSR $88B6  [$86:88B6]  ; Move enemy projectile horizontally
$86:B6BC B0 49       BCS $49    [$B707]     ; If collision: go to BRANCH_COLLISION
$86:B6BE 20 7B 89    JSR $897B  [$86:897B]  ; Move enemy projectile vertically
$86:B6C1 B0 44       BCS $44    [$B707]     ; If collision: go to BRANCH_COLLISION
$86:B6C3 9B          TXY                    ; Y = [enemy projectile index]
$86:B6C4 BD FF 1A    LDA $1AFF,x[$7E:1B21]  ;\
$86:B6C7 AA          TAX                    ;} X = [enemy projectile angle to Samus]
$86:B6C8 BF 43 B4 A0 LDA $A0B443,x[$A0:B5B3];\
$86:B6CC 4A          LSR A                  ;|
$86:B6CD 4A          LSR A                  ;|
$86:B6CE 4A          LSR A                  ;|
$86:B6CF 4A          LSR A                  ;|
$86:B6D0 89 00 08    BIT #$0800             ;|
$86:B6D3 F0 03       BEQ $03    [$B6D8]     ;} Enemy projectile X velocity = 10h * sin([A] * pi / 80h)
$86:B6D5 09 00 F0    ORA #$F000             ;|
                                            ;|
$86:B6D8 18          CLC                    ;|
$86:B6D9 79 B7 1A    ADC $1AB7,y[$7E:1AD9]  ;|
$86:B6DC 99 B7 1A    STA $1AB7,y[$7E:1AD9]  ;/
$86:B6DF BF C3 B3 A0 LDA $A0B3C3,x[$A0:B533];\
$86:B6E3 4A          LSR A                  ;|
$86:B6E4 4A          LSR A                  ;|
$86:B6E5 4A          LSR A                  ;|
$86:B6E6 4A          LSR A                  ;|
$86:B6E7 89 00 08    BIT #$0800             ;|
$86:B6EA F0 03       BEQ $03    [$B6EF]     ;} Enemy projectile Y velocity = 10h * -cos([A] * pi / 80h)
$86:B6EC 09 00 F0    ORA #$F000             ;|
                                            ;|
$86:B6EF 18          CLC                    ;|
$86:B6F0 79 DB 1A    ADC $1ADB,y[$7E:1AFD]  ;|
$86:B6F3 99 DB 1A    STA $1ADB,y[$7E:1AFD]  ;/
$86:B6F6 B9 23 1B    LDA $1B23,y[$7E:1B45]  ;\
$86:B6F9 22 8E 81 80 JSL $80818E[$80:818E]  ;|
$86:B6FD BF B0 D8 7E LDA $7ED8B0,x[$7E:D8B8];} If enemy projectile PLM room argument door is not marked:
$86:B701 2D E7 05    AND $05E7  [$7E:05E7]  ;|
$86:B704 D0 01       BNE $01    [$B707]     ;/
$86:B706 60          RTS                    ; Return
; BRANCH_COLLISION
$86:B707 A9 F3 B5    LDA #$B5F3             ;\
$86:B70A 9D 47 1B    STA $1B47,x[$7E:1B67]  ;} Enemy projectile instruction list pointer = $B5F3 (explode)
$86:B70D A9 01 00    LDA #$0001             ;\
$86:B710 9D 8F 1B    STA $1B8F,x[$7E:1BAF]  ;} Enemy projectile instruction timer = 1
$86:B713 60          RTS
}