DC_Dis, Disassemble

IN : A = options
        A7 = 1, DI_FLW : follow PC (alter next instruction pointer according jump/call and condition)
        A6 = 1, DI_BYE : catch OS_Bye (exit with RC_Eof if encountered)
        A5 = 1, DI_LWR : low ram protection check (exit with RC_Wrap)
    BHL = extended address to be decoded (B = 0, local)
    DE = buffer for null terminated disassembled intruction string
    IX = registers frame (required if A7=1, see DD_Dbg for frame content)

OUT: Fc = 0, success
    DE = points to byte after null terminator of mnemonic string
    HL = points to next instruction
    C = number of bytes decoded for instruction
    A = type of instruction
        A0 = 1, DO_OZCALL : RST 20h system call
        A4 = 1, DO_FALSE  : condition is false (jump or call cc instructions)
        A5 = 1, DO_JMP    : jump (absolute or relative) instruction
        A6 = 1, DO_RET    : ret instruction
        A7 = 1, DO_CALL   : call instruction

Fc = 1, failure
    A = Rc_Fail, illegal instruction (returns NOP string, BHL and C updated)
    A = Rc_Eof, OS_Bye encountered (if DI_BYE option enabled)
    A = Rc_Wrap, next instruction is in lowram (if DI_LWR option enabled)

Registers affected after return:

    ......../IXIY same

    AFBCDEHL/.... different