All posts categorized amd64

x86-64 TUTORIAL: CONDITIONAL OPERATIONS WITHOUT BRANCHING

The regular JMP and conditional Jcc jump instructions change the course of working code, the latter based on the runtime status of certain bits in the RFLAGS register. The x86 and x86-64 processors implement pipelining of instructions where they prefetch a certain number of instructions and evaluate them before time. The number of instructions prefetched is dependent on the prefetch input queue (PIQ).

x86-64 TUTORIAL: FACTORIAL WITH RECURSION

The calculation of a factorial of a number can be done using recursion. Below is the algorithm:

x86-64 TUTORIAL: DOUBLY LINKED LIST

THE LABOUCHERE SYSTEM

The Labouchere system for roulette is played as follows. Write down a list of numbers, usually 1, 2, 3, 4. Bet the sum of the first and last, i.e. 1 + 4 = 5, on red. If you win, delete the first and last numbers from the list. If you lose, add the amount that you last bet to the end of the list. Then use the new list and bet the sum of the first and last numbers (if there is only one number, bet that amount). Continue until your list becomes empty. You will see that, if this happens, you will always win the sum 1 + 2 + 3 + 4 = 10, of the original list. The below program simulates this system. Execute the program, and see if you always win!

LABOUCHERE SYSTEM C PROGRAM

Here is the full C code for the Doubly Linked List: Labouchere System.

LABOUCHERE SYSTEM PROGRAM USING x86-64 REGISTERS

This program does not use any fixed memory locations for the head or tail of the link list, but uses all the registers available to it. However, for some of the functions it does not follow the convention of saving all the registers RBX, R12-R15 on the stack at every function call since some of these registers contain pointers to the head and tail of the link list. Even if we did that, the program would hardly change much.