What is the specification about BFD_RELOC_AVR_7_PCREL, BFD_RELOC_AVR_13_PCREL ?

[Houda Benabderrazik]

Hello, 
I want to know, how to determine the bit size of howto
relocation?
For example, in Avr 
why the BFD_RELOC_AVR_7_PCREL and 
BFD_RELOC_AVR_13_PCREL are defined ? why 7, 13?

/* A 7 bit PC relative relocation.  */
  HOWTO (R_AVR_7_PCREL,		/* type */
	 1,			/* rightshift */
	 1,			/* size (0 = byte, 1 = short, 2 = long) */
	 7,			/* bitsize */
	 TRUE,			/* pc_relative */
	 3,			/* bitpos */
	 complain_overflow_bitfield, /* complain_on_overflow
*/
	 bfd_elf_generic_reloc, /* special_function */
	 "R_AVR_7_PCREL",	/* name */
	 FALSE,			/* partial_inplace */
	 0xffff,		/* src_mask */
	 0xffff,		/* dst_mask */
	 TRUE),			/* pcrel_offset */

  /* A 13 bit PC relative relocation.  */
  HOWTO (R_AVR_13_PCREL,	/* type */
	 1,			/* rightshift */
	 1,			/* size (0 = byte, 1 = short, 2 = long) */
	 13,			/* bitsize */
	 TRUE,			/* pc_relative */
	 0,			/* bitpos */
	 complain_overflow_bitfield, /* complain_on_overflow
*/
	 bfd_elf_generic_reloc, /* special_function */
	 "R_AVR_13_PCREL",	/* name */
	 FALSE,			/* partial_inplace */
	 0xfff,			/* src_mask */
	 0xfff,			/* dst_mask */
	 TRUE),			/* pcrel_offset */

What is the relatioship between PC and this
relocation?

Which are the dicisive elements that help the
programmer to put the size bit of relocation?

There is certainly a relationship with the mnemoniques
and the opcodes defined for the microcontrolor?

Thanks very much for any answer.

Houda



	

	
		
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