Help/Support ARM - what is .W ?

[ThePianoGuy 2.9k 14]

Hello

 

I have 3 questions

 

- What is .W?

- what does it do?

- what happen if i remove the .W?

 

in some games, they have ADD.W, LDR.W, STR.W, MOVW and MOVT.W. i did look into ARM online book but i can't find it and i don't know what W is called

 

EDIT: now i know what .W means.

 

 

.W means wide. ex. ADD Wide. Wide is only used in thumb binaries. This allows the instruction to hold a larger integer value greater than the standard 255 which is the max on non wide thumb instructions. Wide also has other uses but generally you would only use it to get a higher integer value.

 

You have 2 options when editing a wide instruction. You can replace it with another wide instruction or you can do something like this

 

ADD.W -> NOP MOV

 

2 non wide instructions together = 4 bytes which is the size of a wide instruction.

Updated January 31, 2015 by evildog1