Index for Section 4

Alphabetical listing for R

Bottom of page

reloc(4)
NAME
  reloc - Relocation information for an object file

SYNOPSIS
  #include  <reloc.h>

DESCRIPTION
  Object files have one relocation entry for each relocatable reference in
  the text or data.  If relocation information is present, it will be in the
  following format.

  struct  reloc
  {
    long       r_vaddr ;      /* (virtual) address of
				  reference */
    unsigned   r_symndx ;     /* index into symbol table */
    unsigned   r_type:8 ;     /* relocation type */
    unsigned   r_extern:1 ;   /* if 1 symndx is an index
				 into the external table
				 the external table, else
				 symndx is a section #	*/
    unsigned   r_offset;6 ;   /* for R_OP_STORE, quad
				 based LE bit offset */
    unsigned   r_reserved;11; /* Must be zero */
    unsigned   r_size;6 ;     /* R_OP_STORE, bit size */
  } ;


  /* Relocation types */
  #define  R_ABS	0
  #define  R_REFLONG	1
  #define  R_REFQUAD	2
  #define  R_GPREL32	3
  #define  R_LITERAL	4
  #define  R_LITUSE	5
  #define  R_GPDISP	6
  #define  R_BRADDR	7
  #define  R_HINT	8
  #define  R_SREL16	9  /* self relative 16 bit
			      offset */
  #define  R_SREL32	10 /* self relative 32 bit
			      offset */
  #define  R_SREL64	11 /* self relative 64-bit
			      offset */
  #define  R_OP_PUSH	12 /* stack[++tos] =
			      relocate(vaddr) */
  #define  R_OP_STORE	13 /* vaddr(r_offset:r_size =
			      stack[tos--] */
  #define  R_OP_PSUB	14 /* stack[tos] = stack[tos] -
			      relocate(vaddr) */
  #define  R_OP_PRSHIFT 15 /* stack[tos] = stack[tos] >>
			      relocate(vaddr) */
  #define  R_GPVALUE	16

  /* Section numbers */
  #define  R_SN_NULL	0
  #define  R_SN_TEXT	1
  #define  R_SN_RDATA	2
  #define  R_SN_DATA	3
  #define  R_SN_SDATA	4
  #define  R_SN_SBSS	5
  #define  R_SN_BSS	6
  #define  R_SN_INIT	7
  #define  R_SN_LIT8	8
  #define  R_SN_LIT4	9
  #define  R_SN_XDATA	10
  #define  R_SN_PDATE	11
  #define  R_SN_FINI	12
  #define  R_SN_LITA	13
  #define  R_SN_ABS	14

  The link editor (ld) reads each input section and performs relocation.  The
  relocation entries direct how references found within the input section are
  treated.

  If r_extern is zero then it is a local relocation entry and then r_symndx
  is a section number (R_SN_*).	 For these entries the starting address for
  the section referenced by the section number is used in place of an
  external symbol table entry's value.

  For every external relocation (except R_ABS) a signed constant is added to
  the symbol's virtual address that the relocation entry refers to.  This
  constant is assembled at the address being relocated.

  R_ABS		    A relocation has already been performed.

  R_REFLONG	    A 32-bit reference to the symbol's virtual address.

  R_REFQUAD	    A 64-bit reference to the symbol's virtual address.

  R_GPREL32	    A 32-bit displacement from the global pointer to the
		    symbol's virtual address.

  R_LITERAL	    A reference to a literal in the literal address pool as
		    an offset from the global pointer.	R_LITUSE Identifies
		    usage of a lteral address previously loaded into a
		    register.  The r_symndx field identifies the specific
		    usage of the register.  See the Assembly Language
		    Programmer's Guide for more information.

  R_GPDISP	    Identifies an lda/ldah instruction pair that is used to
		    initialize a procedure's global-pointer register. The
		    r_symndx contains a byte offset, which, when added to the
		    r_vaddr field results in the address of the other
		    instruction of the pair.

  R_BRADDR	    A 21-bit branch reference to the symbol's virtual
		    address.

  R_HINT	    A 14-bit jsr hint reference to the symbol's virtual
		    address.

  R_SREL16	    A 16-bit self-relative reference to the symbol's virtual
		    address.

  R_SREL32	    A 32-bit self-relative reference to the symbols's virtual
		    address.

  R_SREL64	    A 64-bit self-relative reference to the symbol's virtual
		    address.

  R_OP_PUSH	    Push symbol's virtual address on relocation expression
		    stack.

  R_OP_STORE	    Pop value from the relocation expression stack and store
		    at the symbol's virtual address. The r_size field
		    determines the number of bits stored. The r_offset field
		    designates the bit offset from the symbol to the target.

  R_OP_PSUB	    Pop value from the relocation expression stack and
		    subtract the symbol's virtual address. The result is
		    pushed on the relocation expression stack.

  R_OP_PRSHIFT	    Pop value from the relocation expression stack and shift
		    right by the symbol's value. The result is pushed on the
		    relocation stack.

  R_GPVALUE	    Specifies a new gp value is to be used starting with the
		    address specified by the r_vaddr field. The gp value is
		    the sum of the optional header's gp_value field and the
		    r_symndx field.  The r_extern field must be zero.

RELATED INFORMATION
  as(1), ld(1), a.out(4), syms(4), scnhdr(4).

  Assembly Language Programmer's Guide

Index for Section 4

Alphabetical listing for R

Top of page