setting a bit on a ram variable

Lets say i have a Byte variable called flags. As you know an integer has 8 bits.

Code:

7-6-5-4-3-2-1-0

How would I set bit X where x is 0 to 7? For example:

Code:

flags       equ (audio_clock+SizeByte)

FLAG_FRET_GREEN       equ 0x1
FLAG_FRET_RED           equ 0x2
FLAG_FRET_YELLOW    equ 0x4

// now set it
?????

I want to set a bit without effecting the other ones. Any assistance in this matter would be greatly appreciated.

Sincerely,

Scorpion Illuminati

 

Simply OR the current value with the bitmask. And re-/unset by ANDing it with the inverse of the mask.