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# 6809 OS9 Flex Disassembler

FLEX is the name of the Operating System for the Motorola 6800 and 6809. IDA can disassemble OS9 object and FLEX STX files and is probably the most powerful disassembler for that platform.

Assembler code

    TEXT:54A5
    TEXT:54A5 * =============== S U B R O U T I N E =======================================
    TEXT:54A5
    TEXT:54A5
    TEXT:54A5 sub_54A5                                * CODE XREF: sub_4F06+78↑P
    TEXT:54A5                                         * sub_5048+1CB↑P ...
    TEXT:54A5                 pshs    dpr,y,u
    TEXT:54A7                 ldy     7,s
    TEXT:54AA                 ldx     ,y
    TEXT:54AC                 ldd     9,s
    TEXT:54AE                 aslb
    TEXT:54AF                 leay    b,y
    TEXT:54B1                 ldd     $B,s
    TEXT:54B3                 pshs    a,b,x
    TEXT:54B5                 tfr     b,a
    TEXT:54B7                 ldu     ,y
    TEXT:54B9                 beq     loc_54BD
    TEXT:54BB                 jsr     ,u
    TEXT:54BD
    TEXT:54BD loc_54BD                                * CODE XREF: sub_54A5+14↑j
    TEXT:54BD                 tfr     a,b
    TEXT:54BF                 clra
    TEXT:54C0                 leas    4,s
    TEXT:54C2                 puls    pcr,u,y,dpr
    TEXT:54C2 * End of function sub_54A5
    TEXT:54C2
    TEXT:54C4
    TEXT:54C4 * =============== S U B R O U T I N E =======================================
    TEXT:54C4
    TEXT:54C4
    TEXT:54C4 sub_54C4                                * CODE XREF: sub_4C67+63↑P
    TEXT:54C4                                         * sub_4C67+87↑P ...
    TEXT:54C4                 pshs    dpr,y,u
    TEXT:54C6                 lda     $C,s
    TEXT:54C8                 ldx     7,s