| ??? 12/04/05 23:46 Read: times |
#104674 - Cool algorithm Responding to: ???'s previous message |
Answer: 8 digits BCD to binary conversion routine.
(To see my answer, select above line with your cursor) The usage of jbc in the "X00ed" subroutine is really impressive. It also splendid that the conversion is done only on the accumulator without any other temporary storage in the "X00ed" subroutine. The first key to solve this quiz is what kind of numeric expression this routine relates to, as Mahmood said. The second key is realizing what "X00ed" subroutine does. The body itself is not so complicated, once you got the function of "X00ed" subroutine. Reverse engineering? Protected code is not so simple as this quiz. This code is written for efficiency. The code flow is straightforward and uses only short range forward jump. I think Jan intended to let us examine this algorithm better without any preconception. Tsuneo |
