[1C 09 XX] - Store XX in (window root + 0x12), which is unknown. :P

C1/40EF: C2 31        REP #$31                  Flag manipulation.
C1/40F1: 8A           TXA                       A = arg1
C1/40F2: 20 B4 0E     JSR $0EB4

C1/0EB4: C2 31        REP #$31                  Flags and direct page manipulation.
C1/0EB6: 0B           PHD 
C1/0EB7: 48           PHA 
C1/0EB8: 7B           TDC 
C1/0EB9: 69 F0 FF     ADC #$FFF0
C1/0EBC: 5B           TCD 
C1/0EBD: 68           PLA 
C1/0EBE: 85 0E        STA $0E                   A, X, $0E = arg1
C1/0EC0: AD 58 89     LDA $8958                 If no windows are open, end.
C1/0EC3: C9 FF FF     CMP #$FFFF
C1/0EC6: F0 17        BEQ $0EDF
C1/0EC8: AD 58 89     LDA $8958                 Get the current active window...
C1/0ECB: 0A           ASL 
C1/0ECC: AA           TAX 
C1/0ECD: BD E4 88     LDA $88E4,X               ...and an entry from the window existence table...
C1/0ED0: A0 52 00     LDY #$0052
C1/0ED3: 22 F7 8F C0  JSR $C08FF7
C1/0ED7: AA           TAX                       ...and store (window root - 0x8650) in X.
C1/0ED8: A5 0E        LDA $0E                   A = arg1
C1/0EDA: E2 20        SEP #$20
C1/0EDC: 9D 62 86     STA $8662,X               Store arg1 in (window root + 0x12), which is unknown. :P
C1/0EDF: C2 20        REP #$20
C1/0EE1: 2B           PLD 
C1/0EE2: 60           RTS 

C1/40F5: A9 00 00     LDA #$0000                A = 0x0
C1/40F8: 60           RTS                       End.