CRACK Solution

One Compare

CRACK single cmp

In-game screenshot of One Compare
In-game view
FamilyCRACK Graph0.063 DifficultyTutorial Ring01 IDu01_one_compare

Prerequisites

ECHOMASK WRONG

Unlocks

DECAYTHREE STEP

Accepted input Y
Techniquesingle cmp Rulenonzero SampleY

Walkthrough

Recover the accepted input below, then submit it to the CRACK verifier.

Reject Samples

  • X
  • Z
  • y
Verifier Listing 
; u01_one_compare: the absolute minimum: load one byte, compare it to one
; constant, return the verdict. Technique: a single cmp. Look the immediate up in
; the ASCII table. r0 = 1 on accept. Accept rule: nonzero.
;
; 0x59 = 'Y'. (Like the original, only the first byte is checked.)

        mov   r7, 0
        ldb   r0, [r7]
        cmp   r0, 0x59      ; 'Y'
        jz    ok
        mov   r0, 0
        ret
ok:     mov   r0, 1
        ret