Introduction to Assembly Programming with ARM - Arithmetic and CPSR Flags

[@roshinsoni]

good explanation of cpsr register and subs

[@Turjak_art]

I did same like in your first example but this site gives me different output, for example in your code the instruction MOV R1, #7 will be displayed in the left corner under registers as 00000007 but for me its output is 00000000. Although the disassembly section shows mov r1, #7 ; 0x7

[@olivestemlearning]

I've seen a few reports of this sort of problem, it seems to be an issue with cpulator. In this case, there are a few different things you can try: 1. Try running the emulator in a different browser. I use Firefox on Windows in my videos, this will help to rule out any browser issues 2. If the issue persists in other browsers, it is probably best to try running ARM through qemu. I have a video tutorial for setting this up at kzbin.info/www/bejne/jabFcqiwac2Dprs

[@Turjak_art]

@@olivestemlearning Thank you. I tried Opera, Firefox, Chrome same result. Have to be a bug or something. I was using Qemu before but cpulator has a nice representation

[@Lp-er9oj]

hi nice video, i understand all and im from argentina. How can i use the S with mov, what do the operation movs do

[@olivestemlearning]

The operation MOVS will move data from a source to a destination, as well as update the CPSR flags. Specifically, it will set the N flag if the value moved is negative and it will set the Z flag if the value moved is 0. This instruction would be used in situations where you want to ensure the Z and N flags are set properly after a move, since MOV would not set the flags by default

[@Arae_1]

@@olivestemlearning so why would you not use MOVS every time?

[@Arae_1]

woops I didn't watch 4 seconds forwards in the video

[@kiriInvestigator4597]

Great video, dude. Can I be your friend and lab partner? so you can help me and maybe I can help you later on when I become proficient in the assembly language.