Question

I am having trouble with understanding the difference between ADDNES and ADDSNE in ARM assembly. Please can someone help me, with some examples?

Answer 1

They’re different spellings for the same instruction. Clang, for example, can only handle the addnes format, but otool outputs addsne when disassembling it.

Example:

$ cat example.s
  addnes r0, r0, #1
$ clang -arch arm -c -o example.o example.s
$ otool -tV example.o 
example.o:
(__TEXT,__text) section
00000000    12900001    addsne  r0, r0, #1  @ 0x1

But if trying to use the addnse spelling in clang:

$ cat example.s
  addsne r0, r0, #1
$ clang -arch arm -c -o example.o example.s
example.s:1:bad instruction `addsne r0,r0,#1'
clang: error: assembler command failed with exit code 1 (use -v to see invocation)