Assembly code in C?

Technical Programming
1

I have a quick question: is it possible to use assembly code in C?

My experience was that in C++ (oh, how I miss C++), you could have code like this:

_asm
{
     /* Assembly code goes here */
}

I was wondering if the same thing would be possible with the compiler supplied by FIRST?

Thanks in advance!

2

This is called ‘inline assembly’ and is a nonstandard feature of most compilers, and they all seem to implement it in a slightly different way. Luckily, though, you don’t have to look any further than the default code to find an example.

From ifi_startup.c:


void _startup (void)
{
  _asm
    /* Initialize the stack pointer */
    lfsr 1, _stack lfsr 2, _stack clrf TBLPTRU, 0 /* 1st silicon doesn't do this on POR */
    bcf  FPFLAGS,RND,0 /* Initialize rounding flag for floating point libs */

    /* initialize the flash memory access configuration. this is harmless */
    /* for non-flash devices, so we do it on all parts. */
    bsf 0xa6, 7, 0
    bcf 0xa6, 6, 0
  _endasm

loop:

    Clear_Memory();
  _do_cinit ();
  /* Call the user's main routine */
  main ();

  goto loop;
}                               /* end _startup() */

There’s several other examples in that file as well.

3

Thanks for your response! That clears up a lot of questions.

4

Just in case anyone else might find assembly code useful, I found a link containing a list of commands - I’ll have to test it but from the source code I’ve seen these are the commands used to program low level functions for the robot controller.

http://www.picbasic.co.uk/forum/showthread.php?t=222