tc-tahoe.c

基于4个mips核的noc设计

	bit 4 as extern and the last nibble as 'undefined'.  */

#if comment
void
md_ri_to_chars (ri_p, ri)
     struct relocation_info *ri_p, ri;
{
  byte the_bytes[sizeof (struct relocation_info)];
  /* The reason I can't just encode these directly into ri_p is that
     ri_p may point to ri.  */

  /* This is easy */
  md_number_to_chars (the_bytes, ri.r_address, sizeof (ri.r_address));

  /* now the fun stuff */
  the_bytes[4] = (ri.r_symbolnum >> 16) & 0x0ff;
  the_bytes[5] = (ri.r_symbolnum >> 8) & 0x0ff;
  the_bytes[6] = ri.r_symbolnum & 0x0ff;
  the_bytes[7] = (((ri.r_extern << 4) & 0x10) | ((ri.r_length << 5) & 0x60) |
		  ((ri.r_pcrel << 7) & 0x80)) & 0xf0;

  bcopy (the_bytes, (char *) ri_p, sizeof (struct relocation_info));
}

#endif /* comment */

/* Put the bits in an order that a tahoe will understand, despite the ordering
   of the native machine.
   On Tahoe: first 4 bytes are normal unsigned big endian long,
   next three bytes are symbolnum, in kind of 3 byte big endian (least sig. byte last).
   The last byte is broken up with bit 7 as pcrel,
   	bits 6 & 5 as length,
	bit 4 as extern and the last nibble as 'undefined'.  */

void
tc_aout_fix_to_chars (where, fixP, segment_address_in_file)
     char *where;
     fixS *fixP;
     relax_addressT segment_address_in_file;
{
  long r_symbolnum;

  know (fixP->fx_addsy != NULL);

  md_number_to_chars (where,
       fixP->fx_frag->fr_address + fixP->fx_where - segment_address_in_file,
		      4);

  r_symbolnum = (S_IS_DEFINED (fixP->fx_addsy)
		 ? S_GET_TYPE (fixP->fx_addsy)
		 : fixP->fx_addsy->sy_number);

  where[4] = (r_symbolnum >> 16) & 0x0ff;
  where[5] = (r_symbolnum >> 8) & 0x0ff;
  where[6] = r_symbolnum & 0x0ff;
  where[7] = (((is_pcrel (fixP) << 7) & 0x80)
	      | ((((fixP->fx_type == FX_8 || fixP->fx_type == FX_PCREL8
		    ? 0
		    : (fixP->fx_type == FX_16 || fixP->fx_type == FX_PCREL16
		       ? 1
		    : (fixP->fx_type == FX_32 || fixP->fx_type == FX_PCREL32
		       ? 2
		       : 42)))) << 5) & 0x60)
	      | ((!S_IS_DEFINED (fixP->fx_addsy) << 4) & 0x10));
}

/* Relocate byte stuff */

/* This is for broken word.  */
const int md_short_jump_size = 3;

void
md_create_short_jump (ptr, from_addr, to_addr, frag, to_symbol)
     char *ptr;
     addressT from_addr, to_addr;
     fragS *frag;
     symbolS *to_symbol;
{
  valueT offset;

  offset = to_addr - (from_addr + 1);
  *ptr++ = TAHOE_BRW;
  md_number_to_chars (ptr, offset, 2);
}

const int md_long_jump_size = 6;
const int md_reloc_size = 8;	/* Size of relocation record */

void
md_create_long_jump (ptr, from_addr, to_addr, frag, to_symbol)
     char *ptr;
     addressT from_addr, to_addr;
     fragS *frag;
     symbolS *to_symbol;
{
  valueT offset;

  offset = to_addr - (from_addr + 4);
  *ptr++ = TAHOE_JMP;
  *ptr++ = TAHOE_PC_REL_LONG;
  md_number_to_chars (ptr, offset, 4);
}

/* md_estimate_size_before_relax(), called just before relax().
   Any symbol that is now undefined will not become defined.
   Return the correct fr_subtype in the frag and the growth beyond
   fr_fix.  */
int
md_estimate_size_before_relax (fragP, segment_type)
     register fragS *fragP;
     segT segment_type;		/* N_DATA or N_TEXT.  */
{
  if (RELAX_LENGTH (fragP->fr_subtype) == STATE_UNDF)
    {
      if (S_GET_SEGMENT (fragP->fr_symbol) != segment)
	{
	  /* Non-relaxable cases.  */
	  char *p;
	  int old_fr_fix;

	  old_fr_fix = fragP->fr_fix;
	  p = fragP->fr_literal + old_fr_fix;
	  switch (RELAX_STATE (fragP->fr_subtype))
	    {
	    case STATE_PC_RELATIVE:
	      *p |= TAHOE_PC_OR_LONG;
	      /* We now know how big it will be, one long word.  */
	      fragP->fr_fix += 1 + 4;
	      fix_new (fragP, old_fr_fix + 1, fragP->fr_symbol,
		       fragP->fr_offset, FX_PCREL32, NULL);
	      break;

	    case STATE_CONDITIONAL_BRANCH:
	      *fragP->fr_opcode ^= 0x10;	/* Reverse sense of branch.  */
	      *p++ = 6;
	      *p++ = TAHOE_JMP;
	      *p++ = TAHOE_PC_REL_LONG;
	      fragP->fr_fix += 1 + 1 + 1 + 4;
	      fix_new (fragP, old_fr_fix + 3, fragP->fr_symbol,
		       fragP->fr_offset, FX_PCREL32, NULL);
	      break;

	    case STATE_BIG_REV_BRANCH:
	      *fragP->fr_opcode ^= 0x10;	/* Reverse sense of branch.  */
	      *p++ = 0;
	      *p++ = 6;
	      *p++ = TAHOE_JMP;
	      *p++ = TAHOE_PC_REL_LONG;
	      fragP->fr_fix += 2 + 2 + 4;
	      fix_new (fragP, old_fr_fix + 4, fragP->fr_symbol,
		       fragP->fr_offset, FX_PCREL32, NULL);
	      break;

	    case STATE_BIG_NON_REV_BRANCH:
	      *p++ = 2;
	      *p++ = 0;
	      *p++ = TAHOE_BRB;
	      *p++ = 6;
	      *p++ = TAHOE_JMP;
	      *p++ = TAHOE_PC_REL_LONG;
	      fragP->fr_fix += 2 + 2 + 2 + 4;
	      fix_new (fragP, old_fr_fix + 6, fragP->fr_symbol,
		       fragP->fr_offset, FX_PCREL32, NULL);
	      break;

	    case STATE_ALWAYS_BRANCH:
	      *fragP->fr_opcode = TAHOE_JMP;
	      *p++ = TAHOE_PC_REL_LONG;
	      fragP->fr_fix += 1 + 4;
	      fix_new (fragP, old_fr_fix + 1, fragP->fr_symbol,
		       fragP->fr_offset, FX_PCREL32, NULL);
	      break;

	    default:
	      abort ();
	    }
	  frag_wane (fragP);

	  /* Return the growth in the fixed part of the frag.  */
	  return fragP->fr_fix - old_fr_fix;
	}

      /* Relaxable cases.  Set up the initial guess for the variable
	 part of the frag.  */
      switch (RELAX_STATE (fragP->fr_subtype))
	{
	case STATE_PC_RELATIVE:
	  fragP->fr_subtype = ENCODE_RELAX (STATE_PC_RELATIVE, STATE_BYTE);
	  break;
	case STATE_CONDITIONAL_BRANCH:
	  fragP->fr_subtype = ENCODE_RELAX (STATE_CONDITIONAL_BRANCH, STATE_BYTE);
	  break;
	case STATE_BIG_REV_BRANCH:
	  fragP->fr_subtype = ENCODE_RELAX (STATE_BIG_REV_BRANCH, STATE_WORD);
	  break;
	case STATE_BIG_NON_REV_BRANCH:
	  fragP->fr_subtype = ENCODE_RELAX (STATE_BIG_NON_REV_BRANCH, STATE_WORD);
	  break;
	case STATE_ALWAYS_BRANCH:
	  fragP->fr_subtype = ENCODE_RELAX (STATE_ALWAYS_BRANCH, STATE_BYTE);
	  break;
	}
    }

  if (fragP->fr_subtype >= sizeof (md_relax_table) / sizeof (md_relax_table[0]))
    abort ();

  /* Return the size of the variable part of the frag.  */
  return md_relax_table[fragP->fr_subtype].rlx_length;
}

/*
 *			md_convert_frag();
 *
 * Called after relax() is finished.
 * In:	Address of frag.
 *	fr_type == rs_machine_dependent.
 *	fr_subtype is what the address relaxed to.
 *
 * Out:	Any fixSs and constants are set up.
 *	Caller will turn frag into a ".space 0".
 */
void
md_convert_frag (headers, seg, fragP)
     object_headers *headers;
     segT seg;
     register fragS *fragP;
{
  register char *addressP;	/* -> _var to change.  */
  register char *opcodeP;	/* -> opcode char(s) to change.  */
  register short int extension = 0;	/* Size of relaxed address.
				   Added to fr_fix: incl. ALL var chars.  */
  register symbolS *symbolP;
  register long int where;
  register long int address_of_var;
  /* Where, in file space, is _var of *fragP? */
  register long int target_address;
  /* Where, in file space, does addr point? */

  know (fragP->fr_type == rs_machine_dependent);
  where = fragP->fr_fix;
  addressP = fragP->fr_literal + where;
  opcodeP = fragP->fr_opcode;
  symbolP = fragP->fr_symbol;
  know (symbolP);
  target_address = S_GET_VALUE (symbolP) + fragP->fr_offset;
  address_of_var = fragP->fr_address + where;
  switch (fragP->fr_subtype)
    {
    case ENCODE_RELAX (STATE_PC_RELATIVE, STATE_BYTE):
      /* *addressP holds the registers number, plus 0x10, if it's deferred
       mode. To set up the right mode, just OR the size of this displacement */
      /* Byte displacement.  */
      *addressP++ |= TAHOE_PC_OR_BYTE;
      *addressP = target_address - (address_of_var + 2);
      extension = 2;
      break;

    case ENCODE_RELAX (STATE_PC_RELATIVE, STATE_WORD):
      /* Word displacement.  */
      *addressP++ |= TAHOE_PC_OR_WORD;
      md_number_to_chars (addressP, target_address - (address_of_var + 3), 2);
      extension = 3;
      break;

    case ENCODE_RELAX (STATE_PC_RELATIVE, STATE_LONG):
      /* Long word displacement.  */
      *addressP++ |= TAHOE_PC_OR_LONG;
      md_number_to_chars (addressP, target_address - (address_of_var + 5), 4);
      extension = 5;
      break;

    case ENCODE_RELAX (STATE_CONDITIONAL_BRANCH, STATE_BYTE):
      *addressP = target_address - (address_of_var + 1);
      extension = 1;
      break;

    case ENCODE_RELAX (STATE_CONDITIONAL_BRANCH, STATE_WORD):
      *opcodeP ^= 0x10;		/* Reverse sense of test.  */
      *addressP++ = 3;		/* Jump over word branch */
      *addressP++ = TAHOE_BRW;
      md_number_to_chars (addressP, target_address - (address_of_var + 4), 2);
      extension = 4;
      break;

    case ENCODE_RELAX (STATE_CONDITIONAL_BRANCH, STATE_LONG):
      *opcodeP ^= 0x10;		/* Reverse sense of test.  */
      *addressP++ = 6;
      *addressP++ = TAHOE_JMP;
      *addressP++ = TAHOE_PC_REL_LONG;
      md_number_to_chars (addressP, target_address, 4);
      extension = 7;
      break;

    case ENCODE_RELAX (STATE_ALWAYS_BRANCH, STATE_BYTE):
      *addressP = target_address - (address_of_var + 1);
      extension = 1;
      break;

    case ENCODE_RELAX (STATE_ALWAYS_BRANCH, STATE_WORD):
      *opcodeP = TAHOE_BRW;
      md_number_to_chars (addressP, target_address - (address_of_var + 2), 2);
      extension = 2;
      break;

    case ENCODE_RELAX (STATE_ALWAYS_BRANCH, STATE_LONG):
      *opcodeP = TAHOE_JMP;
      *addressP++ = TAHOE_PC_REL_LONG;
      md_number_to_chars (addressP, target_address - (address_of_var + 5), 4);
      extension = 5;
      break;

    case ENCODE_RELAX (STATE_BIG_REV_BRANCH, STATE_WORD):
      md_number_to_chars (addressP, target_address - (address_of_var + 2), 2);
      extension = 2;
      break;

    case ENCODE_RELAX (STATE_BIG_REV_BRANCH, STATE_LONG):
      *opcodeP ^= 0x10;
      *addressP++ = 0;
      *addressP++ = 6;
      *addressP++ = TAHOE_JMP;
      *addressP++ = TAHOE_PC_REL_LONG;
      md_number_to_chars (addressP, target_address, 4);
      extension = 8;
      break;

    case ENCODE_RELAX (STATE_BIG_NON_REV_BRANCH, STATE_WORD):
      md_number_to_chars (addressP, target_address - (address_of_var + 2), 2);
      extension = 2;
      break;

    case ENCODE_RELAX (STATE_BIG_NON_REV_BRANCH, STATE_LONG):
      *addressP++ = 0;
      *addressP++ = 2;
      *addressP++ = TAHOE_BRB;
      *addressP++ = 6;
      *addressP++ = TAHOE_JMP;
      *addressP++ = TAHOE_PC_REL_LONG;
      md_number_to_chars (addressP, target_address, 4);
      extension = 10;
      break;

    default:
      BAD_CASE (fragP->fr_subtype);
      break;
    }
  fragP->fr_fix += extension;
}				/* md_convert_frag */


/* This is the stuff for md_assemble.  */
#define FP_REG 13
#define SP_REG 14
#define PC_REG 15
#define BIGGESTREG PC_REG

/*
 * Parse the string pointed to by START
 * If it represents a valid register, point START to the character after
 * the last valid register char, and return the register number (0-15).
 * If invalid, leave START alone, return -1.
 * The format has to be exact. I don't do things like eat leading zeros
 * or the like.
 * Note: This doesn't check for the next character in the string making
 * this invalid. Ex: R123 would return 12, it's the callers job to check
 * what start is point to apon return.
 *
 * Valid registers are R1-R15, %1-%15, FP (13), SP (14), PC (15)
 * Case doesn't matter.
 */
int
tahoe_reg_parse (start)
     char **start;		/* A pointer to the string to parse.  */
{
  register char *regpoint = *start;
  register int regnum = -1;

  switch (*regpoint++)
    {
    case '%':			/* Registers can start with a %,
				   R or r, and then a number.  */
    case 'R':
    case 'r':
      if (isdigit (*regpoint))
	{
	  /* Got the first digit.  */
	  regnum = *regpoint++ - '0';
	  if ((regnum == 1) && isdigit (*regpoint))
	    {
	      /* Its a two digit number.  */
	      regnum = 10 + (*regpoint++ - '0');
	      if (regnum > BIGGESTREG)
		{		/* Number too big? */
		  regnum = -1;
		}
	    }
	}
      break;
    case 'F':			/* Is it the FP */
    case 'f':
      switch (*regpoint++)
	{
	case 'p':
	case 'P':
	  regnum = FP_REG;
	}
      break;
    case 's':			/* How about the SP */
    case 'S':
      switch (*regpoint++)
	{
	case 'p':
	case 'P':
	  regnum = SP_REG;
	}
      break;
    case 'p':			/* OR the PC even */
    case 'P':
      switch (*regpoint++)
	{
	case 'c':
	case 'C':
	  regnum = PC_REG;
	}
      break;
    }

  if (regnum != -1)
    {				/* No error, so move string pointer */
      *start = regpoint;
    }
  return regnum;		/* Return results */
}				/* tahoe_reg_parse */

/*
 * This chops up an operand and figures out its modes and stuff.
 * It's a little touchy about extra characters.
 * Optex to start with one extra character so it can be overwritten for
 * the backward part of the parsing.
 * You can't put a bunch of extra characters in side to
 * make the command look cute. ie: * foo ( r1 ) [  r0 ]
 * If you like doing a lot of typing, try COBOL!
 * Actually, this parser is a little weak all around. It's designed to be
 * used with compliers, so I emphisise correct decoding of valid code quickly
 * rather that catching every possable error.
 * Note: This uses the expression function, so save input_line_pointer before
 * calling.
 *
 * Sperry defines the semantics of address modes (and values)
 * by a two-letter code, explained here.
 *
 *   letter 1:   access type
 *
 *     a         address calculation - no data access, registers forbidden
 *     b         branch displacement
 *     m         read - let go of bus - write back "modify"
 *     r         read
 *     w         write
 *     v         bit field address: like 'a' but registers are OK
 *
 *   letter 2:   data type (i.e. width, alignment)
 *
 *     b         byte
 *     w         word
 *     l         longword
 *     q         quadword (Even regs < 14 allowed) (if 12, you get a warning)
 *     -	 unconditional synthetic jbr operand
 *     ?	 simple synthetic reversable branch operand
 *     !	 complex synthetic reversable branch operand
 *     :	 complex synthetic non-reversable branch operand
 *
 * The '-?!:' letter 2's are not for external consumption. They are used
 * by GAS for psuedo ops relaxing code.
 *
 * After parsing topP has:
 *
 *   top_ndx:        -1, or the index register. eg 7=[R7]
 *   top_reg:        -1, or register number. eg 7 = R7 or (R7)
 *   top_mode:       The addressing mode byte. This byte, defines which of
 *                   the 11 modes opcode is.
 *   top_access:     Access type wanted for this opperand 'b'branch ' '
 *                   no-instruction 'amrvw'
 *   top_width:      Operand width expected, one of "bwlq?-:!"
 *   exp_of_operand: The expression as parsed by expression()
 *   top_dispsize:   Number of bytes in the displacement if we can figure it
 *                   out and it's relavent.
 *
 * Need syntax checks built.
 */

void
tip_op (optex, topP)
     char *optex;		/* The users text input, with one leading character */
     struct top *topP;		/* The tahoe instruction with some fields already set:
			 in: access, width
			 out: ndx, reg, mode, error, dispsize */

{
  int mode = 0;			/* This operand's mode.  */
  char segfault = *optex;	/* To keep the back parsing from freaking.  */
  char *point = optex + 1;	/* Parsing from front to back.  */
  char *end;			/* Parsing from back to front.  */