mm2 snap to ladder routine

-:
 0E:87AE: 60        RTS ----------------------
snap_to_ladder:
; Return if neither up nor down are pressed
 0E:87AF: A5 23     LDA p1_buttons_held
 0E:87B1: 29 30     AND #$30
 0E:87B3: F0 F9     BEQ -
; Certain flag/button combos mean we can return early.
; Not quite sure what they mean yet.
; $11 = pressing up and atop ladder.
;  But if you're also pressing down...
 0E:87B5: 05 35     ORA ladder_flags
 0E:87B7: C9 11     CMP #$11
 0E:87B9: F0 F3     BEQ -
 0E:87BB: C9 2E     CMP #$2E
 0E:87BD: F0 EF     BEQ -
; Set x pixel to middle of the nearest tile.
; That is, round down, then add 8.
 0E:87BF: AD 60 04  LDA x_pixel[0]
 0E:87C2: 85 2E     STA temp_x
 0E:87C4: 29 F0     AND #$F0
 0E:87C6: 09 08     ORA #$08
 0E:87C8: 38        SEC
 0E:87C9: 8D 60 04  STA x_pixel[0]
; Check which way the ladder snapped Mega Man
 0E:87CC: E5 2E     SBC temp_x
 0E:87CE: 90 08     BCC +
 0E:87D0: 85 00     STA $00
 0E:87D2: 20 F5 8D  JSR ladder_scroll_adjustment_right
 0E:87D5: 4C E2 87  JMP ++
+:
; Manual twos complement
 0E:87D8: 49 FF     EOR #$FF
 0E:87DA: 18        CLC
 0E:87DB: 69 01     ADC #$01
 0E:87DD: 85 00     STA $00
 0E:87DF: 20 65 8E  JSR ladder_scroll_adjustment_left
++:
; Make Mega Man face the opposide direction.
; It's a feature!!
; Where does the ladder fidget or B holding glitch live?
 0E:87E2: AD 20 04  LDA sprite_flags[0]
 0E:87E5: 49 40     EOR #$40
 0E:87E7: 8D 20 04  STA sprite_flags[0]
 0E:87EA: 20 A5 D3  JSR update_anim_index?
; Ditch a return address and do ladder physics
 0E:87ED: 68        PLA
 0E:87EE: 68        PLA
 0E:87EF: 4C BC 86  JMP ladder_physics