ould someone please explain how the BIT op is working in these two

routines? I've verified the branch and jump instructions lead to valid

routines. This is from Kwik Copy, extracted form a freeze file. I have

100% of the routines seperated from it's text. Is it that the program is

entering these routines from multiple angles?

17df:17df:1 8a txa

17e0:17e0:1 18 clc

17e1:17e1:1 69 01 adc #$01

17e3:17e3:1 d0 ea bne $17cf

17e5:17e5:1 24 1f bit $1f

17e7:17e7:1 19 12 0c ora $0c12,y

17ea:17ea:1 0c ???

17eb:17eb:1 0d 0e a6 ora $a60e

17ee:17ee:1 40 rti

17ef:17ef:1 48 pha

17f0:17f0:1 4a lsr a

17f1:17f1:1 4a lsr a

17f2:17f2:1 4a lsr a

17f3:17f3:1 85 29 sta $29

17f5:17f5:1 8a txa

17f6:17f6:1 0a asl a

17f7:17f7:1 0a asl a

17f8:17f8:1 05 29 ora $29

17fa:17fa:1 a8 tay

17fb:17fb:1 68 pla

17fc:17fc:1 29 07 and #$07

17fe:17fe:1 aa tax

17ff:17ff:1 b9 01 2d lda $2d01,y

1802:1802:1 3d 06 18 and $1806,x

1805:1805:1 60 rts

1806:1806:1 01 02 ora ($02,x)

1808:1808:1 04 ???

1809:1809:1 08 php

180a:180a:1 10 20 bpl $182c

180c:180c:1 40 rti

180d:180d:1 80 ???

180e:180e:1 a9 12 lda #$12

1810:1810:1 85 40 sta $40

1812:1812:1 a9 00 lda #$00

1814:1814:1 85 41 sta $41

1816:1816:1 4c 7b 23 jmp $237b

This is the same routines auto labled, where you can see seperate

routines entering at different points (not all of the labels are valid I

suspect).

17df:17df:1 8a skip17df txa

17e0:17e0:1 18 clc

17e1:17e1:1 69 01 adc #$01

17e3:17e3:1 d0 ???

17e4:17e4:1 ea lbl_17e4 nop

17e5:17e5:1 24 1f bit zp_1f

17e7:17e7:1 19 ???

17e8:17e8:1 12 ???

17e9:17e9:1 0c lbl_17e9 ???

17ea:17ea:1 0c ???

17eb:17eb:1 0d ???

17ec:17ec:1 0e ???

17ed:17ed:1 a6 40 sub_17ed ldx zp_40

17ef:17ef:1 48 sub_17ef pha

17f0:17f0:1 4a lsr a

17f1:17f1:1 4a lsr a

17f2:17f2:1 4a lsr a

17f3:17f3:1 85 29 sta zp_29

17f5:17f5:1 8a txa

17f6:17f6:1 0a asl a

17f7:17f7:1 0a asl a

17f8:17f8:1 05 29 ora zp_29

17fa:17fa:1 a8 tay

17fb:17fb:1 68 pla

17fc:17fc:1 29 07 and #$07

17fe:17fe:1 aa tax

17ff:17ff:1 b9 ???

1800:1800:1 01 2d lbl_1800 ora (zp_2d,x)

1802:1802:1 3d 06 18 and lbl_1806,x

1805:1805:1 60 rts

1806:1806:1 01 02 lbl_1806 ora (zp_02,x)

1808:1808:1 04 ???

1809:1809:1 08 php

180a:180a:1 10 20 bpl skip182c

180c:180c:1 40 rti

180d:180d:1 80 ???

180e:180e:1 a9 12 sub_180e lda #$12

1810:1810:1 85 40 sta zp_40

1812:1812:1 a9 00 lda #$00

1814:1814:1 85 41 sta zp_41

1816:1816:1 4c 7b 23 jmp sub_237b