x86 Inline Assembly

Discussion in 'Mac Programming' started by kainjow, Jan 27, 2007.

  1. kainjow Moderator emeritus


    Jun 15, 2000
    I am trying to play around with some assembly commands in Xcode and I'm getting a "Invalid mnemonic 'mov'" error. I have a basic Foundation Tool project setup:

    #import <Foundation/Foundation.h>
    int main (int argc, const char * argv[])
        mov 0x1, eax
      return 0;
    I have Google'd a lot and haven't found anything helpful really. I'm assuming I'm missing a compiler switch or something?

    (I eventually want to get the CPUID opcode to work, but that gives the same error)
  2. iMeowbot macrumors G3


    Aug 30, 2003
    Is gcc getting an -arch i386 somewhere? I can duplicate that message if I force ppc.

    For that mov in your example, I'd also check the operand order (the att vs. intel syntax thing drives me nuts, I always forget which is which and ultimately do the right thing, go back to C :p )
  3. Flynnstone macrumors 65816


    Feb 25, 2003
    Cold beer land
    This is my opinion : avoid assembler.
    Just about anything can be done in C. I write embedded firmware. I / my project, limit assembler to bootup code. That is setting basic access and peripherals. Such as turning on RAM systems and setting up stacks.
    You want to access a certain memory location, you can use C.
    Sorry if sounds like a rant. I suppose it is. Just trying to help.

    I've done much x86 assembler in the mid 80s. So this is similar to me saying don't put your hand in a meat grinder. I'm not sure which is worse :eek:
  4. gnasher729 macrumors G5


    Nov 25, 2005
    Spotlight is your friend: Command-space, type in "cpuid", and it finds a file "cpuid.h" which should contain everything you need.
  5. aLoC macrumors 6502a

    Nov 10, 2006
    I don't get that error, I get "suffix or operands invalid for 'mov' "
    If I reverse the operands, e.g. mov eax, 0x1 it compiles and runs fine.

    This is an Intel iMac, opening XCode and doing a new "Foundation Tool" project.

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