Re: [Patch AArch64] gprof support for AArch64

[Marcus Shawcroft <marcus dot shawcroft at arm dot com>]

On 21/05/13 15:22, Venkataramanan Kumar wrote:
> +/* Opcode of the "bl" and "b" instructions.  */
> +#define BRANCHANDLINK (0x94000000)
> +#define BRANCH        (0x14000000)
> +
> +void aarch64_find_call (Sym *, bfd_vma, bfd_vma);
> +
> +void
> +aarch64_find_call (Sym *parent, bfd_vma p_lowpc, bfd_vma p_highpc)
> +{
> +  bfd_vma pc, dest_pc, offset;
> +  unsigned int insn;
> +  Sym *child;
> +
> +  DBG (CALLDEBUG, printf ("[find_call] %s: 0x%lx to 0x%lx\n",
> +			  parent->name, (unsigned long) p_lowpc,
> +			  (unsigned long) p_highpc));
> +
> +  for (pc = p_lowpc; pc < p_highpc; pc += 4)
> +    {
> +
> +      insn = bfd_get_32 (core_bfd, ((unsigned char *) core_text_space
> +				    + pc - core_text_sect->vma));
> +
> +      if (((insn & 0xfc000000) == BRANCHANDLINK)
> +	  ||((insn & 0xfc000000) == BRANCH))
> +	{

The encoding for the branch instruction is:

31 30 29 28 27 26 25 .. 0
 L  0  0  1  0  1 imm26

.. where L is the link flag that distinguishes between BRANCH and 
BRANCHANDLINK, therefore the above can be written as:

#define BRANCH_MASK    0x7c000000
#define BRANCH_PATTERN 0x14000000

(insn & BRANCH_MASK) == BRANCH_PATTERN

/Marcus