Introduction

I'm really new to emulating so I am creating a cheetsheat to help me and others :) Some of this information might be incorrect as i'm not an expert :(

Index

1. Significant Bit
   • Examples
   • Code
2. Bitwize Operators
   • Shifting

Significant Bit

LSB (Least Significant Bit) and MSB (Most Significant Bit) is 1 bit (1 or 0) which is is at the start or end of a byte.

Examples

LSB: 00000001
            ^
LSB is 1

MSB: 10000000
     ^
MSB is 1

Code

This is how you would get the MSB and LSB in Javascript. This should apply in most programming languages as well.

// LSB of 0xf2 (11110010)
//                     ^
0xf2 & 1
// Result: 0

// MSB of 0xf2 (11110010)
//              ^
0xf2 & 0x80 ? 1 : 0
// Result: 1

Notice: I dont know if this is the proper way to get the MSB but I think it works :)

Bitwize Operators

Shifting

Shifting moves all the bits 1 to the left or 1 to the right depending on the operator you use.

Shifting 4 bits to the left:
0x23 << 4 (100011 << 4)
Result: 0x230 (1000110000)

Shifting 4 bits to the right:
0x23 >> 4 (00100011 << 4)
Result: 0x2 (00000010)