[RESOLVED] Help me understand the $ in hex notation

[Scuba_Steve]

I grasp the basic concept behind hex, but I have yet to figure out what this type of notation means.

Example:
change the byte at $D0B5 from $2C to $28

Can anyone please explain how to translate this?

 

[Ceddy]

$ is just a way to notate you are using a base 16 numbering system.
$FF style is usually used with the BASIC language, 0xFF style is also commonly used, they both mean base 16.

Base 10 goes from 0-9
Base 16 goes from 0-F

The Letters A-F are used for 10-15 in Hex

10,16
1=1
2=2
3=3
4=4
5=5
6=6
7=7
8=8
9=9
10=A
11=B
12=C
13=D
14=E
15=F
16=10
17=11
etc...

Get a cheap calculator that converts to HEX, and its easy.

There is loads of info on the internet about HEX notation.


For the example you gave, all you would do is open your file in a HexEditor, scroll down to D0B5, then change 2C to 28.

 

[Scuba_Steve]

That's exactly what I thought it meant. What confused me and made me think this is more complicated is the D0B5 part. The standard E931C6F5 bin only goes from 0000 to 7FF0. How can you edit line D0B5 when it doesn't exist? Maybe I'm just overlooking something...

 

[Ceddy]

That's exactly what I thought it meant. What confused me and made me think this is more complicated is the D0B5 part. The standard E931C6F5 bin only goes from 0000 to 7FF0. How can you edit line D0B5 when it doesn't exist? Maybe I'm just overlooking something...

The 1G code is offset 0x8000, I think.

So in you ROM you would look for, D0B5-8000= 50B5

At 50B5 you should find 2C.

 

[Scuba_Steve]

And there it is! Makes complete sense now! You rock!

 

[tenn-gsx]

WOW I feel like a complete moron right now. I have no idea what the hell you guys are talking about.

 

[Scuba_Steve]

The hex code used to program eprom chips

 

[->PrOjEcTGS<-]

 

[tenn-gsx]

Ahh HAA. I have link so I dont need to worry about learning that any time soon. . Thank god because you had me completely lost!