• gcc does not generate correct code while building PIC

    Hey guys,

    I have been exploring building PIC using the gcc toolchain and I think there is a bug.

    I first build a shared library using 

    arm-none-eabi-gcc -shared -mcpu=cortex-m4 -mthumb -Wall -g -fPIC -fmessage-length=0 --specs=nosys.specs mylib.c -o libmylib…

  • UXTB only Thumb2?

    Note: This was originally posted on 12th February 2009 at http://forums.arm.com

    Hi All,

    Arm9 crashed on UXTB instruction because it is not able to decode it. It caused Undef-Instruction exception.

    I have been trying to find if UXTB which is a Thumb2 instruction…

  • [Cortex-M0] Thumb mode & code size

    Hi,

    I'm somewhat confused with the Thumb mode code size.  My understanding is compiling with ARM mode will generate 32-bit instructions and compiling with Thumb mode will generate 16-bit instructions.  When I compile my Cortex-M0+ project (which should…

  • From the CPU's point of view, how does it distinguish an assembly code is an ARM code or a Thumb code?

    From the CPU's point of view, how does it distinguish an assembly code is an ARM code or a Thumb code?

    Is there some signal bit represent the code is ARM or Thumb code, this is just my guess.

  • How many states for an ARM Cortex A8?

    Hi,

    When I read about Thumb2 instructions, I have such a question: How many states for a Coretx A8? I know it has ARM and Thumb states. Thumb2 instruction is belong to Thumb state? Then does A8 have a pure Thumb instruction besides Thumb2 set?

    Thanks,

  • Condition Codes 4: Floating-Point Comparisons Using VFP

    • vcmpdemo.tar.gz

  • Branch and Call Sequences Explained

    What Does a Branch Do?

    A branch, quite simply, is a break in the sequential flow of instructions that the processor is executing. Some other architectures call them jumps, but they're essentially the same thing. The following is a trivial, and hopefully…

  • Condition Codes 3: Conditional Execution in Thumb-2