tc-vax.c

基于4个mips核的noc设计

  switch (fragP->fr_subtype)
    {

    case ENCODE_RELAX (STATE_PC_RELATIVE, STATE_BYTE):
      know (*addressP == 0 || *addressP == 0x10);	/* '@' bit.  */
      addressP[0] |= 0xAF;	/* Byte displacement.  */
      addressP[1] = target_address - (address_of_var + 2);
      extension = 2;
      break;

    case ENCODE_RELAX (STATE_PC_RELATIVE, STATE_WORD):
      know (*addressP == 0 || *addressP == 0x10);	/* '@' bit.  */
      addressP[0] |= 0xCF;	/* Word displacement.  */
      md_number_to_chars (addressP + 1, target_address - (address_of_var + 3), 2);
      extension = 3;
      break;

    case ENCODE_RELAX (STATE_PC_RELATIVE, STATE_LONG):
      know (*addressP == 0 || *addressP == 0x10);	/* '@' bit.  */
      addressP[0] |= 0xEF;	/* Long word displacement.  */
      md_number_to_chars (addressP + 1, target_address - (address_of_var + 5), 4);
      extension = 5;
      break;

    case ENCODE_RELAX (STATE_CONDITIONAL_BRANCH, STATE_BYTE):
      addressP[0] = target_address - (address_of_var + 1);
      extension = 1;
      break;

    case ENCODE_RELAX (STATE_CONDITIONAL_BRANCH, STATE_WORD):
      opcodeP[0] ^= 1;		/* Reverse sense of test.  */
      addressP[0] = 3;
      addressP[1] = VAX_BRB + VAX_WIDEN_WORD;
      md_number_to_chars (addressP + 2, target_address - (address_of_var + 4), 2);
      extension = 4;
      break;

    case ENCODE_RELAX (STATE_CONDITIONAL_BRANCH, STATE_LONG):
      opcodeP[0] ^= 1;		/* Reverse sense of test.  */
      addressP[0] = 6;
      addressP[1] = VAX_JMP;
      addressP[2] = VAX_PC_RELATIVE_MODE;
      md_number_to_chars (addressP + 3, target_address - (address_of_var + 7), 4);
      extension = 7;
      break;

    case ENCODE_RELAX (STATE_ALWAYS_BRANCH, STATE_BYTE):
      addressP[0] = target_address - (address_of_var + 1);
      extension = 1;
      break;

    case ENCODE_RELAX (STATE_ALWAYS_BRANCH, STATE_WORD):
      opcodeP[0] += VAX_WIDEN_WORD;	/* brb -> brw, bsbb -> bsbw */
      md_number_to_chars (addressP, target_address - (address_of_var + 2), 2);
      extension = 2;
      break;

    case ENCODE_RELAX (STATE_ALWAYS_BRANCH, STATE_LONG):
      opcodeP[0] += VAX_WIDEN_LONG;	/* brb -> jmp, bsbb -> jsb */
      addressP[0] = VAX_PC_RELATIVE_MODE;
      md_number_to_chars (addressP + 1, target_address - (address_of_var + 5), 4);
      extension = 5;
      break;

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

    case ENCODE_RELAX (STATE_COMPLEX_BRANCH, STATE_LONG):
      addressP[0] = 2;
      addressP[1] = 0;
      addressP[2] = VAX_BRB;
      addressP[3] = 6;
      addressP[4] = VAX_JMP;
      addressP[5] = VAX_PC_RELATIVE_MODE;
      md_number_to_chars (addressP + 6, target_address - (address_of_var + 10), 4);
      extension = 10;
      break;

    case ENCODE_RELAX (STATE_COMPLEX_HOP, STATE_BYTE):
      addressP[0] = target_address - (address_of_var + 1);
      extension = 1;
      break;

    case ENCODE_RELAX (STATE_COMPLEX_HOP, STATE_WORD):
      addressP[0] = 2;
      addressP[1] = VAX_BRB;
      addressP[2] = 3;
      addressP[3] = VAX_BRW;
      md_number_to_chars (addressP + 4, target_address - (address_of_var + 6), 2);
      extension = 6;
      break;

    case ENCODE_RELAX (STATE_COMPLEX_HOP, STATE_LONG):
      addressP[0] = 2;
      addressP[1] = VAX_BRB;
      addressP[2] = 6;
      addressP[3] = VAX_JMP;
      addressP[4] = VAX_PC_RELATIVE_MODE;
      md_number_to_chars (addressP + 5, target_address - (address_of_var + 9), 4);
      extension = 9;
      break;

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

/* Translate internal format of relocation info into target format.

   On vax: first 4 bytes are normal unsigned long, next three bytes
   are symbolnum, least sig. byte first.  Last byte is broken up with
   the upper nibble as nuthin, bit 3 as extern, bits 2 & 1 as length, and
   bit 0 as pcrel.  */
#ifdef comment
void
md_ri_to_chars (the_bytes, ri)
     char *the_bytes;
     struct reloc_info_generic ri;
{
  /* this is easy */
  md_number_to_chars (the_bytes, ri.r_address, sizeof (ri.r_address));
  /* now the fun stuff */
  the_bytes[6] = (ri.r_symbolnum >> 16) & 0x0ff;
  the_bytes[5] = (ri.r_symbolnum >> 8) & 0x0ff;
  the_bytes[4] = ri.r_symbolnum & 0x0ff;
  the_bytes[7] = (((ri.r_extern << 3) & 0x08) | ((ri.r_length << 1) & 0x06) |
		  ((ri.r_pcrel << 0) & 0x01)) & 0x0F;
}

#endif /* comment */

void
tc_aout_fix_to_chars (where, fixP, segment_address_in_file)
     char *where;
     fixS *fixP;
     relax_addressT segment_address_in_file;
{
  /*
   * In: length of relocation (or of address) in chars: 1, 2 or 4.
   * Out: GNU LD relocation length code: 0, 1, or 2.
   */

  static const unsigned char nbytes_r_length[] = {42, 0, 1, 42, 2};
  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[6] = (r_symbolnum >> 16) & 0x0ff;
  where[5] = (r_symbolnum >> 8) & 0x0ff;
  where[4] = r_symbolnum & 0x0ff;
  where[7] = ((((!S_IS_DEFINED (fixP->fx_addsy)) << 3) & 0x08)
	      | ((nbytes_r_length[fixP->fx_size] << 1) & 0x06)
	      | (((fixP->fx_pcrel << 0) & 0x01) & 0x0f));
}

/*
 *       BUGS, GRIPES,  APOLOGIA, etc.
 *
 * The opcode table 'votstrs' needs to be sorted on opcode frequency.
 * That is, AFTER we hash it with hash_...(), we want most-used opcodes
 * to come out of the hash table faster.
 *
 * I am sorry to inflict yet another VAX assembler on the world, but
 * RMS says we must do everything from scratch, to prevent pin-heads
 * restricting this software.
 */

/*
 * This is a vaguely modular set of routines in C to parse VAX
 * assembly code using DEC mnemonics. It is NOT un*x specific.
 *
 * The idea here is that the assembler has taken care of all:
 *   labels
 *   macros
 *   listing
 *   pseudo-ops
 *   line continuation
 *   comments
 *   condensing any whitespace down to exactly one space
 * and all we have to do is parse 1 line into a vax instruction
 * partially formed. We will accept a line, and deliver:
 *   an error message (hopefully empty)
 *   a skeleton VAX instruction (tree structure)
 *   textual pointers to all the operand expressions
 *   a warning message that notes a silly operand (hopefully empty)
 */

/*
 *		E D I T   H I S T O R Y
 *
 * 17may86 Dean Elsner. Bug if line ends immediately after opcode.
 * 30apr86 Dean Elsner. New vip_op() uses arg block so change call.
 *  6jan86 Dean Elsner. Crock vip_begin() to call vip_op_defaults().
 *  2jan86 Dean Elsner. Invent synthetic opcodes.
 *	Widen vax_opcodeT to 32 bits. Use a bit for VIT_OPCODE_SYNTHETIC,
 *	which means this is not a real opcode, it is like a macro; it will
 *	be relax()ed into 1 or more instructions.
 *	Use another bit for VIT_OPCODE_SPECIAL if the op-code is not optimised
 *	like a regular branch instruction. Option added to vip_begin():
 *	exclude	synthetic opcodes. Invent synthetic_votstrs[].
 * 31dec85 Dean Elsner. Invent vit_opcode_nbytes.
 *	Also make vit_opcode into a char[]. We now have n-byte vax opcodes,
 *	so caller's don't have to know the difference between a 1-byte & a
 *	2-byte op-code. Still need vax_opcodeT concept, so we know how
 *	big an object must be to hold an op.code.
 * 30dec85 Dean Elsner. Widen typedef vax_opcodeT in "vax-inst.h"
 *	because vax opcodes may be 16 bits. Our crufty C compiler was
 *	happily initialising 8-bit vot_codes with 16-bit numbers!
 *	(Wouldn't the 'phone company like to compress data so easily!)
 * 29dec85 Dean Elsner. New static table vax_operand_width_size[].
 *	Invented so we know hw many bytes a "I^#42" needs in its immediate
 *	operand. Revised struct vop in "vax-inst.h": explicitly include
 *	byte length of each operand, and it's letter-code datum type.
 * 17nov85 Dean Elsner. Name Change.
 *	Due to ar(1) truncating names, we learned the hard way that
 *	"vax-inst-parse.c" -> "vax-inst-parse." dropping the "o" off
 *	the archived object name. SO... we shortened the name of this
 *	source file, and changed the makefile.
 */

/* handle of the OPCODE hash table */
static struct hash_control *op_hash;

/*
 * In:	1 character, from "bdfghloqpw" being the data-type of an operand
 *	of a vax instruction.
 *
 * Out:	the length of an operand of that type, in bytes.
 *	Special branch operands types "-?!" have length 0.
 */

static const short int vax_operand_width_size[256] =
{
  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 1, 0, 8, 0, 4, 8, 16, 0, 0, 0, 4, 0, 0,16,	/* ..b.d.fgh...l..o  */
  0, 8, 0, 0, 0, 0, 0, 2,  0, 0, 0, 0, 0, 0, 0, 0,	/* .q.....w........  */
  0, 0, 1, 0, 8, 0, 4, 8, 16, 0, 0, 0, 4, 0, 0,16,	/* ..b.d.fgh...l..o  */
  0, 8, 0, 0, 0, 0, 0, 2,  0, 0, 0, 0, 0, 0, 0, 0,	/* .q.....w........  */
  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0,  0, 0, 0, 0, 0, 0, 0, 0,
};

/*
 * This perversion encodes all the vax opcodes as a bunch of strings.
 * RMS says we should build our hash-table at run-time. Hmm.
 * Please would someone arrange these in decreasing frequency of opcode?
 * Because of the way hash_...() works, the most frequently used opcode
 * should be textually first and so on.
 *
 * Input for this table was 'vax.opcodes', awk(1)ed by 'vax.opcodes.c.awk' .
 * So change 'vax.opcodes', then re-generate this table.
 */

#include "opcode/vax.h"

/*
 * This is a table of optional op-codes. All of them represent
 * 'synthetic' instructions that seem popular.
 *
 * Here we make some pseudo op-codes. Every code has a bit set to say
 * it is synthetic. This lets you catch them if you want to
 * ban these opcodes. They are mnemonics for "elastic" instructions
 * that are supposed to assemble into the fewest bytes needed to do a
 * branch, or to do a conditional branch, or whatever.
 *
 * The opcode is in the usual place [low-order n*8 bits]. This means
 * that if you mask off the bucky bits, the usual rules apply about
 * how long the opcode is.
 *
 * All VAX branch displacements come at the end of the instruction.
 * For simple branches (1-byte opcode + 1-byte displacement) the last
 * operand is coded 'b?' where the "data type" '?' is a clue that we
 * may reverse the sense of the branch (complement lowest order bit)
 * and branch around a jump. This is by far the most common case.
 * That is why the VIT_OPCODE_SYNTHETIC bit is set: it says this is
 * a 0-byte op-code followed by 2 or more bytes of operand address.
 *
 * If the op-code has VIT_OPCODE_SPECIAL set, then we have a more unusual
 * case.
 *
 * For JBSB & JBR the treatment is the similar, except (1) we have a 'bw'
 * option before (2) we can directly JSB/JMP because there is no condition.
 * These operands have 'b-' as their access/data type.
 *
 * That leaves a bunch of random opcodes: JACBx, JxOBxxx. In these
 * cases, we do the same idea. JACBxxx are all marked with a 'b!'
 * JAOBxxx & JSOBxxx are marked with a 'b:'.
 *
 */
#if (VIT_OPCODE_SYNTHETIC != 0x80000000)
You have just broken the encoding below, which assumes the sign bit
  means 'I am an imaginary instruction'.
#endif

#if (VIT_OPCODE_SPECIAL != 0x40000000)
  You have just broken the encoding below, which assumes the 0x40 M bit means
  'I am not to be "optimised" the way normal branches are'.
#endif

static const struct vot
  synthetic_votstrs[] =
{
  {"jbsb",	{"b-", 0xC0000010}},		/* BSD 4.2 */
/* jsb used already */
  {"jbr",	{"b-", 0xC0000011}},		/* BSD 4.2 */
  {"jr",	{"b-", 0xC0000011}},		/* consistent */
  {"jneq",	{"b?", 0x80000012}},
  {"jnequ",	{"b?", 0x80000012}},
  {"jeql",	{"b?", 0x80000013}},
  {"jeqlu",	{"b?", 0x80000013}},
  {"jgtr",	{"b?", 0x80000014}},
  {"jleq",	{"b?", 0x80000015}},
/* un-used opcodes here */
  {"jgeq",	{"b?", 0x80000018}},
  {"jlss",	{"b?", 0x80000019}},
  {"jgtru",	{"b?", 0x8000001a}},
  {"jlequ",	{"b?", 0x8000001b}},
  {"jvc",	{"b?", 0x8000001c}},
  {"jvs",	{"b?", 0x8000001d}},
  {"jgequ",	{"b?", 0x8000001e}},
  {"jcc",	{"b?", 0x8000001e}},
  {"jlssu",	{"b?", 0x8000001f}},
  {"jcs",	{"b?", 0x8000001f}},

  {"jacbw",	{"rwrwmwb!", 0xC000003d}},
  {"jacbf",	{"rfrfmfb!", 0xC000004f}},
  {"jacbd",	{"rdrdmdb!", 0xC000006f}},
  {"jacbb",	{"rbrbmbb!", 0xC000009d}},
  {"jacbl",	{"rlrlmlb!", 0xC00000f1}},
  {"jacbg",	{"rgrgmgb!", 0xC0004ffd}},
  {"jacbh",	{"rhrhmhb!", 0xC0006ffd}},

  {"jbs",	{"rlvbb?", 0x800000e0}},
  {"jbc",	{"rlvbb?", 0x800000e1}},
  {"jbss",	{"rlvbb?", 0x800000e2}},
  {"jbcs",	{"rlvbb?", 0x800000e3}},
  {"jbsc",	{"rlvbb?", 0x800000e4}},
  {"jbcc",	{"rlvbb?", 0x800000e5}},
  {"jlbs",	{"rlb?", 0x800000e8}},
  {"jlbc",	{"rlb?", 0x800000e9}},

  {"jaoblss",	{"rlmlb:", 0xC00000f2}},
  {"jaobleq",	{"rlmlb:", 0xC00000f3}},
  {"jsobgeq",	{"mlb:", 0xC00000f4}},
  {"jsobgtr",	{"mlb:", 0xC00000f5}},

/* CASEx has no branch addresses in our conception of it.  */
/* You should use ".word ..." statements after the "case ...".  */

  {"",	{"", 0}}			/* empty is end sentinel */

};				/* synthetic_votstrs */

/*
 *                  v i p _ b e g i n ( )
 *
 * Call me once before you decode any lines.
 * I decode votstrs into a hash table at op_hash (which I create).
 * I return an error text or null.
 * If you want, I will include the 'synthetic' jXXX instructions in the
 * instruction table.
 * You must nominate metacharacters for eg DEC's "#", "@", "^".
 */

static const char *
vip_begin (synthetic_too, immediate, indirect, displen)
     int synthetic_too;		/* 1 means include jXXX op-codes.  */
     const char *immediate, *indirect, *displen;
{
  const struct vot *vP;		/* scan votstrs */
  const char *retval = 0;	/* error text */

  op_hash = hash_new ();

  for (vP = votstrs; *vP->vot_name && !retval; vP++)
    retval = hash_insert (op_hash, vP->vot_name, (PTR) &vP->vot_detail);

  if (synthetic_too)
    for (vP = synthetic_votstrs; *vP->vot_name && !retval; vP++)
      retval = hash_insert (op_hash, vP->vot_name, (PTR) &vP->vot_detail);

#ifndef CONST_TABLE
  vip_op_defaults (immediate, indirect, displen);
#endif

  return retval;
}

/*
 *                  v i p ( )
 *
 * This converts a string into a vax instruction.
 * The string must be a bare single instruction in dec-vax (with BSD4 frobs)
 * format.
 * It provides some error messages: at most one fatal error message (which
 * stops the scan) and at most one warning message for each operand.
 * The vax instruction is returned in exploded form, since we have no
 * knowledge of how you parse (or evaluate) your expressions.
 * We do however strip off and decode addressing modes and operation
 * mnemonic.
 *
 * The exploded instruction is returned to a struct vit of your choice.
 * #include "vax-inst.h" to know what a struct vit is.
 *
 * This function's value is a string. If it is not "" then an internal
 * logic error was found: read this code to assign meaning to the string.
 * No argument string should generate such an error string:
 * it means a bug in our code, not in the user's text.
 *