Présentation technologie numérique

Branchless Programming

PRESENTATIONbyRémi Del Medico

01

Programming

Programming language

• Instructions
• If (condition) then ...
• else ...
• For (...) do ...
• While (condition) do ...
• ...

• Types of variables
• Int
• Char

• Boolean
• ...

The art of assembling instructions

int a = 10;int b = 5; int max = 0; if (a < b) thenmax = b;elsemax = a; print(max);

02

What is a branche?

Execution

int a = 10;int b = 5; int max = 0; if (a < b) thenmax = b;elsemax = a; print(max);

Execution

int a = 10;int b = 5; int max = 0; if (a < b) thenmax = b;elsemax = a; print(max);

Execution

int a = 10;int b = 5; int max = 0; if (a < b) thenmax = b;elsemax = a; print(max);

Execution

int a = 10;int b = 5; int max = 0; if (a < b) thenmax = b;elsemax = a; print(max);

Execution

int a = 10;int b = 5; int max = 0; if (a < b) thenmax = b;elsemax = a; print(max);

Execution

int a = 10;int b = 5; int max = 0; if (a < b) thenmax = b;elsemax = a; print(max);

What is a branche

int a = 10;int b = 5; int max = 0; if (a < b) {max = b;} else {max = a;} print(max);

int a = 10;int b = 5; int max = 0; max = maximum(a, b); print(max);

for (...) { }

03

Why branche should be avoided?

CPU Prediction

int a = 10;int b = 5; int max = 0; if (a < b) {max = b;} else {max = a;} print(max);

50%

50%

04

How to avoid branches?

10

Boolean condition

False <=> 0True <=> 1

int a = 10; boolean b = false; int c = a * b; // 10 * false = 10 * 0 = 0

11

Max function without branchment

int a = 10;int b = 5; int max = 0; if (a < b) {max = b;} else {max = a;} print(max);

12

Max function without branchment

int a = 10;int b = 5; int max = 0; if (a < b) {max = b;} else {max = a;} print(max);

int a = 10;int b = 5; int max = 0; max = a * (a > b) + b * (a < b); print(max);

13

THANK YOU!

Let's do a little Kahoot!