8.5. DONGLES
loading a value into a register). The first instruction is at0x001186B0—and frankly speaking, it’s hard to
say what it means.
What we see next is, however, easier to understand:.RBEFINDFIRST()is called: if it fails, 0 is written into
r3 and we jump toexit, otherwise another function is called (check3())—if it fails too,.RBEFINDNEXT()is
called, probably in order to look for another USB device.
N.B.:clrlwi. %r0, %r3, 16it is analogical to what we already saw, but it clears 16 bits, i.e.,
.RBEFINDFIRST()probably returns a 16-bit value.
B(stands forbranch) unconditional jump.
BEQis the inverse instruction ofBNE.
Let’s seecheck3():
seg000:0011873C check3: # CODE XREF: check2+88p
seg000:0011873C
seg000:0011873C .set var_18, -0x18
seg000:0011873C .set var_C, -0xC
seg000:0011873C .set var_8, -8
seg000:0011873C .set var_4, -4
seg000:0011873C .set arg_8, 8
seg000:0011873C
seg000:0011873C 93 E1 FF FC stw %r31, var_4(%sp)
seg000:00118740 7C 08 02 A6 mflr %r0
seg000:00118744 38 A0 00 00 li %r5, 0
seg000:00118748 93 C1 FF F8 stw %r30, var_8(%sp)
seg000:0011874C 83 C2 95 A8 lwz %r30, off_1485E8 # dword_24B704
seg000:00118750 .using dword_24B704, %r30
seg000:00118750 93 A1 FF F4 stw %r29, var_C(%sp)
seg000:00118754 3B A3 00 00 addi %r29, %r3, 0
seg000:00118758 38 60 00 00 li %r3, 0
seg000:0011875C 90 01 00 08 stw %r0, arg_8(%sp)
seg000:00118760 94 21 FF B0 stwu %sp, -0x50(%sp)
seg000:00118764 80 DE 00 00 lwz %r6, dword_24B704
seg000:00118768 38 81 00 38 addi %r4, %sp, 0x50+var_18
seg000:0011876C 48 00 C0 5D bl .RBEREAD
seg000:00118770 60 00 00 00 nop
seg000:00118774 54 60 04 3F clrlwi. %r0, %r3, 16
seg000:00118778 41 82 00 0C beq loc_118784
seg000:0011877C 38 60 00 00 li %r3, 0
seg000:00118780 48 00 02 F0 b exit
seg000:00118784
seg000:00118784 loc_118784: # CODE XREF: check3+3Cj
seg000:00118784 A0 01 00 38 lhz %r0, 0x50+var_18(%sp)
seg000:00118788 28 00 04 B2 cmplwi %r0, 0x1100
seg000:0011878C 41 82 00 0C beq loc_118798
seg000:00118790 38 60 00 00 li %r3, 0
seg000:00118794 48 00 02 DC b exit
seg000:00118798
seg000:00118798 loc_118798: # CODE XREF: check3+50j
seg000:00118798 80 DE 00 00 lwz %r6, dword_24B704
seg000:0011879C 38 81 00 38 addi %r4, %sp, 0x50+var_18
seg000:001187A0 38 60 00 01 li %r3, 1
seg000:001187A4 38 A0 00 00 li %r5, 0
seg000:001187A8 48 00 C0 21 bl .RBEREAD
seg000:001187AC 60 00 00 00 nop
seg000:001187B0 54 60 04 3F clrlwi. %r0, %r3, 16
seg000:001187B4 41 82 00 0C beq loc_1187C0
seg000:001187B8 38 60 00 00 li %r3, 0
seg000:001187BC 48 00 02 B4 b exit
seg000:001187C0
seg000:001187C0 loc_1187C0: # CODE XREF: check3+78j
seg000:001187C0 A0 01 00 38 lhz %r0, 0x50+var_18(%sp)
seg000:001187C4 28 00 06 4B cmplwi %r0, 0x09AB
seg000:001187C8 41 82 00 0C beq loc_1187D4
seg000:001187CC 38 60 00 00 li %r3, 0
seg000:001187D0 48 00 02 A0 b exit
seg000:001187D4
seg000:001187D4 loc_1187D4: # CODE XREF: check3+8Cj
seg000:001187D4 4B F9 F3 D9 bl sub_B7BAC