CHAPTER 78. DONGLES CHAPTER 78. DONGLES
seg000:001189F8
seg000:001189F8 loc_1189F8: # CODE XREF: check3+29Cj
seg000:001189F8 80 DE 00 00 lwz %r6, dword_24B704
seg000:001189FC 38 81 00 38 addi %r4, %sp, 0x50+var_18
seg000:00118A00 38 60 00 05 li %r3, 5
seg000:00118A04 38 A0 00 00 li %r5, 0
seg000:00118A08 48 00 BD C1 bl .RBEREAD
seg000:00118A0C 60 00 00 00 nop
seg000:00118A10 54 60 04 3F clrlwi. %r0, %r3, 16
seg000:00118A14 41 82 00 0C beq loc_118A20
seg000:00118A18 38 60 00 00 li %r3, 0
seg000:00118A1C 48 00 00 54 b exit
seg000:00118A20
seg000:00118A20 loc_118A20: # CODE XREF: check3+2D8j
seg000:00118A20 A0 01 00 38 lhz %r0, 0x50+var_18(%sp)
seg000:00118A24 28 00 11 D3 cmplwi %r0, 0xD300
seg000:00118A28 40 82 00 0C bne loc_118A34
seg000:00118A2C 3B E0 00 01 li %r31, 1
seg000:00118A30 48 00 00 14 b good1
seg000:00118A34
seg000:00118A34 loc_118A34: # CODE XREF: check3+2ECj
seg000:00118A34 28 00 1A EB cmplwi %r0, 0xEBA1
seg000:00118A38 41 82 00 0C beq good1
seg000:00118A3C 38 60 00 00 li %r3, 0
seg000:00118A40 48 00 00 30 b exit
seg000:00118A44
seg000:00118A44 good1: # CODE XREF: check3+2F4j
seg000:00118A44 # check3+2FCj
seg000:00118A44 57 A0 06 3E clrlwi %r0, %r29, 24
seg000:00118A48 28 00 00 03 cmplwi %r0, 3
seg000:00118A4C 40 82 00 20 bne error
seg000:00118A50 57 E0 06 3F clrlwi. %r0, %r31, 24
seg000:00118A54 41 82 00 10 beq good
seg000:00118A58 48 00 4B F5 bl sub_11D64C
seg000:00118A5C 60 00 00 00 nop
seg000:00118A60 48 00 00 10 b exit
seg000:00118A64
seg000:00118A64 good: # CODE XREF: check3+318j
seg000:00118A64 38 60 00 01 li %r3, 1
seg000:00118A68 48 00 00 08 b exit
seg000:00118A6C
seg000:00118A6C error: # CODE XREF: check3+19Cj
seg000:00118A6C # check3+238j ...
seg000:00118A6C 38 60 00 00 li %r3, 0
seg000:00118A70
seg000:00118A70 exit: # CODE XREF: check3+44j
seg000:00118A70 # check3+58j ...
seg000:00118A70 80 01 00 58 lwz %r0, 0x50+arg_8(%sp)
seg000:00118A74 38 21 00 50 addi %sp, %sp, 0x50
seg000:00118A78 83 E1 FF FC lwz %r31, var_4(%sp)
seg000:00118A7C 7C 08 03 A6 mtlr %r0
seg000:00118A80 83 C1 FF F8 lwz %r30, var_8(%sp)
seg000:00118A84 83 A1 FF F4 lwz %r29, var_C(%sp)
seg000:00118A88 4E 80 00 20 blr
seg000:00118A88 # End of function check3
There are a lot of calls to.RBEREAD(). The function probably returns some values from the dongle, so they are compared
here with some hard-coded variables usingCMPLWI.
We also see that the r3 register is also filled before each call to.RBEREAD()with one of these values: 0, 1, 8, 0xA, 0xB,
0xC, 0xD, 4, 5. Probably a memory address or something like that?
Yes, indeed, by googling these function names it is easy to find the Sentinel Eve3 dongle manual!
Perhaps, we don’t even need to learn any other PowerPC instructions: all this function does is just call.RBEREAD(), compare
its results with the constants and returns 1 if the comparisons are fine or 0 otherwise.
OK, all we’ve got is thatcheck1()has always to return 1 or any other non-zero value. But since we are not very confident in
our knowledge of PowerPC instructions, we are going to be careful: we will patch the jumps incheck2()at0x001186FC
and0x00118718.