tc-vax.c

基于4个mips核的noc设计

 * You MUST have called vip_begin() once before using this function.
 */

static void
vip (vitP, instring)
     struct vit *vitP;		/* We build an exploded instruction here.  */
     char *instring;		/* Text of a vax instruction: we modify.  */
{
  /* How to bit-encode this opcode.  */
  struct vot_wot *vwP;
  /* 1/skip whitespace.2/scan vot_how */
  char *p;
  char *q;
  /* counts number of operands seen */
  unsigned char count;
  /* scan operands in struct vit */
  struct vop *operandp;
  /* error over all operands */
  const char *alloperr;
  /* Remember char, (we clobber it with '\0' temporarily).  */
  char c;
  /* Op-code of this instruction.  */
  vax_opcodeT oc;

  if (*instring == ' ')
    ++instring;			/* Skip leading whitespace.  */
  for (p = instring; *p && *p != ' '; p++);;	/* MUST end in end-of-string or exactly 1 space.  */
  /* Scanned up to end of operation-code.  */
  /* Operation-code is ended with whitespace.  */
  if (p - instring == 0)
    {
      vitP->vit_error = _("No operator");
      count = 0;
      memset (vitP->vit_opcode, '\0', sizeof (vitP->vit_opcode));
    }
  else
    {
      c = *p;
      *p = '\0';
      /*
       * Here with instring pointing to what better be an op-name, and p
       * pointing to character just past that.
       * We trust instring points to an op-name, with no whitespace.
       */
      vwP = (struct vot_wot *) hash_find (op_hash, instring);
      *p = c;			/* Restore char after op-code.  */
      if (vwP == 0)
	{
	  vitP->vit_error = _("Unknown operator");
	  count = 0;
	  memset (vitP->vit_opcode, '\0', sizeof (vitP->vit_opcode));
	}
      else
	{
	  /*
	   * We found a match! So let's pick up as many operands as the
	   * instruction wants, and even gripe if there are too many.
	   * We expect comma to seperate each operand.
	   * We let instring track the text, while p tracks a part of the
	   * struct vot.
	   */
	  const char *howp;
	  /*
	   * The lines below know about 2-byte opcodes starting FD,FE or FF.
	   * They also understand synthetic opcodes. Note:
	   * we return 32 bits of opcode, including bucky bits, BUT
	   * an opcode length is either 8 or 16 bits for vit_opcode_nbytes.
	   */
	  oc = vwP->vot_code;	/* The op-code.  */
	  vitP->vit_opcode_nbytes = (oc & 0xFF) >= 0xFD ? 2 : 1;
	  md_number_to_chars (vitP->vit_opcode, oc, 4);
	  count = 0;		/* no operands seen yet */
	  instring = p;		/* point just past operation code */
	  alloperr = "";
	  for (howp = vwP->vot_how, operandp = vitP->vit_operand;
	       !(alloperr && *alloperr) && *howp;
	       operandp++, howp += 2)
	    {
	      /*
	       * Here to parse one operand. Leave instring pointing just
	       * past any one ',' that marks the end of this operand.
	       */
	      if (!howp[1])
		as_fatal (_("odd number of bytes in operand description"));
	      else if (*instring)
		{
		  for (q = instring; (c = *q) && c != ','; q++)
		    ;
		  /*
		   * Q points to ',' or '\0' that ends argument. C is that
		   * character.
		   */
		  *q = 0;
		  operandp->vop_width = howp[1];
		  operandp->vop_nbytes = vax_operand_width_size[(unsigned) howp[1]];
		  operandp->vop_access = howp[0];
		  vip_op (instring, operandp);
		  *q = c;	/* Restore input text.  */
		  if (operandp->vop_error)
		    alloperr = _("Bad operand");
		  instring = q + (c ? 1 : 0);	/* next operand (if any) */
		  count++;	/*  won another argument, may have an operr */
		}
	      else
		alloperr = _("Not enough operands");
	    }
	  if (!*alloperr)
	    {
	      if (*instring == ' ')
		instring++;	/* Skip whitespace.  */
	      if (*instring)
		alloperr = _("Too many operands");
	    }
	  vitP->vit_error = alloperr;
	}
    }
  vitP->vit_operands = count;
}

#ifdef test

/*
 * Test program for above.
 */

struct vit myvit;		/* build an exploded vax instruction here */
char answer[100];		/* human types a line of vax assembler here */
char *mybug;			/* "" or an internal logic diagnostic */
int mycount;			/* number of operands */
struct vop *myvop;		/* scan operands from myvit */
int mysynth;			/* 1 means want synthetic opcodes.  */
char my_immediate[200];
char my_indirect[200];
char my_displen[200];

main ()
{
  char *p;

  printf ("0 means no synthetic instructions.   ");
  printf ("Value for vip_begin?  ");
  gets (answer);
  sscanf (answer, "%d", &mysynth);
  printf ("Synthetic opcodes %s be included.\n", mysynth ? "will" : "will not");
  printf ("enter immediate symbols eg enter #   ");
  gets (my_immediate);
  printf ("enter indirect symbols  eg enter @   ");
  gets (my_indirect);
  printf ("enter displen symbols   eg enter ^   ");
  gets (my_displen);
  if (p = vip_begin (mysynth, my_immediate, my_indirect, my_displen))
    {
      error ("vip_begin=%s", p);
    }
  printf ("An empty input line will quit you from the vax instruction parser\n");
  for (;;)
    {
      printf ("vax instruction: ");
      fflush (stdout);
      gets (answer);
      if (!*answer)
	{
	  break;		/* out of for each input text loop */
	}
      vip (&myvit, answer);
      if (*myvit.vit_error)
	{
	  printf ("ERR:\"%s\"\n", myvit.vit_error);
	}
      printf ("opcode=");
      for (mycount = myvit.vit_opcode_nbytes, p = myvit.vit_opcode;
	   mycount;
	   mycount--, p++
	)
	{
	  printf ("%02x ", *p & 0xFF);
	}
      printf ("   operand count=%d.\n", mycount = myvit.vit_operands);
      for (myvop = myvit.vit_operand; mycount; mycount--, myvop++)
	{
	  printf ("mode=%xx reg=%xx ndx=%xx len='%c'=%c%c%d. expr=\"",
		  myvop->vop_mode, myvop->vop_reg, myvop->vop_ndx,
		  myvop->vop_short, myvop->vop_access, myvop->vop_width,
		  myvop->vop_nbytes);
	  for (p = myvop->vop_expr_begin; p <= myvop->vop_expr_end; p++)
	    {
	      putchar (*p);
	    }
	  printf ("\"\n");
	  if (myvop->vop_error)
	    {
	      printf ("  err:\"%s\"\n", myvop->vop_error);
	    }
	  if (myvop->vop_warn)
	    {
	      printf ("  wrn:\"%s\"\n", myvop->vop_warn);
	    }
	}
    }
  vip_end ();
  exit (EXIT_SUCCESS);
}

#endif /* #ifdef test */

/* end of vax_ins_parse.c */

/* vax_reg_parse.c - convert a VAX register name to a number */

/* Copyright (C) 1987 Free Software Foundation, Inc. A part of GNU.  */

/*
 *          v a x _ r e g _ p a r s e ( )
 *
 * Take 3 char.s, the last of which may be `\0` (non-existent)
 * and return the VAX register number that they represent.
 *
 * Return -1 if they don't form a register name. Good names return
 * a number from 0:15 inclusive.
 *
 * Case is not important in a name.
 *
 * Register names understood are:
 *
 *	R0
 *	R1
 *	R2
 *	R3
 *	R4
 *	R5
 *	R6
 * 	R7
 *	R8
 *	R9
 *	R10
 *	R11
 *	R12	AP
 *	R13	FP
 *	R14	SP
 *	R15	PC
 *
 */

#include <ctype.h>
#define AP (12)
#define FP (13)
#define SP (14)
#define PC (15)

int				/* return -1 or 0:15 */
vax_reg_parse (c1, c2, c3)	/* 3 chars of register name */
     char c1, c2, c3;		/* c3 == 0 if 2-character reg name */
{
  int retval;		/* return -1:15 */

  retval = -1;

  if (isupper (c1))
    c1 = tolower (c1);
  if (isupper (c2))
    c2 = tolower (c2);
  if (isdigit (c2) && c1 == 'r')
    {
      retval = c2 - '0';
      if (isdigit (c3))
	{
	  retval = retval * 10 + c3 - '0';
	  retval = (retval > 15) ? -1 : retval;
	  /* clamp the register value to 1 hex digit */
	}
      else if (c3)
	retval = -1;		/* c3 must be '\0' or a digit */
    }
  else if (c3)			/* There are no three letter regs */
    retval = -1;
  else if (c2 == 'p')
    {
      switch (c1)
	{
	case 's':
	  retval = SP;
	  break;
	case 'f':
	  retval = FP;
	  break;
	case 'a':
	  retval = AP;
	  break;
	default:
	  retval = -1;
	}
    }
  else if (c1 == 'p' && c2 == 'c')
    retval = PC;
  else
    retval = -1;
  return (retval);
}

/*
 *               v i p _ o p ( )
 *
 * Parse a vax operand in DEC assembler notation.
 * For speed, expect a string of whitespace to be reduced to a single ' '.
 * This is the case for GNU AS, and is easy for other DEC-compatible
 * assemblers.
 *
 * Knowledge about DEC VAX assembler operand notation lives here.
 * This doesn't even know what a register name is, except it believes
 * all register names are 2 or 3 characters, and lets vax_reg_parse() say
 * what number each name represents.
 * It does, however, know that PC, SP etc are special registers so it can
 * detect addressing modes that are silly for those registers.
 *
 * Where possible, it delivers 1 fatal or 1 warning message if the operand
 * is suspect. Exactly what we test for is still evolving.
 */

/*
 *		   	B u g s
 *
 *	Arg block.
 *
 * There were a number of 'mismatched argument type' bugs to vip_op.
 * The most general solution is to typedef each (of many) arguments.
 * We used instead a typedef'd argument block. This is less modular
 * than using seperate return pointers for each result, but runs faster
 * on most engines, and seems to keep programmers happy. It will have
 * to be done properly if we ever want to use vip_op as a general-purpose
 * module (it was designed to be).
 *
 *	G^
 *
 * Doesn't support DEC "G^" format operands. These always take 5 bytes
 * to express, and code as modes 8F or 9F. Reason: "G^" deprives you of
 * optimising to (say) a "B^" if you are lucky in the way you link.
 * When someone builds a linker smart enough to convert "G^" to "B^", "W^"
 * whenever possible, then we should implement it.
 * If there is some other use for "G^", feel free to code it in!
 *
 *
 *	speed
 *
 * If I nested if()s more, I could avoid testing (*err) which would save
 * time, space and page faults. I didn't nest all those if()s for clarity
 * and because I think the mode testing can be re-arranged 1st to test the
 * commoner constructs 1st. Does anybody have statistics on this?
 *
 *
 *
 *	error messages
 *
 * In future, we should be able to 'compose' error messages in a scratch area
 * and give the user MUCH more informative error messages. Although this takes
 * a little more code at run-time, it will make this module much more self-
 * documenting. As an example of what sucks now: most error messages have
 * hardwired into them the DEC VAX metacharacters "#^@" which are nothing like
 * the Un*x characters "$`*", that most users will expect from this AS.
 */

/*
 * The input is a string, ending with '\0'.
 *
 * We also require a 'hint' of what kind of operand is expected: so
 * we can remind caller not to write into literals for instance.
 *
 * The output is a skeletal instruction.
 *
 * The algorithm has two parts.
 * 1. extract the syntactic features (parse off all the @^#-()+[] mode crud);
 * 2. express the @^#-()+[] as some parameters suited to further analysis.
 *
 * 2nd step is where we detect the googles of possible invalid combinations
 * a human (or compiler) might write. Note that if we do a half-way
 * decent assembler, we don't know how long to make (eg) displacement
 * fields when we first meet them (because they may not have defined values).
 * So we must wait until we know how many bits are needed for each address,
 * then we can know both length and opcodes of instructions.
 * For reason(s) above, we will pass to our caller a 'broken' instruction
 * of these major components, from which our caller can generate instructions:
 *  -  displacement length      I^ S^ L^ B^ W^ unspecified
 *  -  mode                     (many)
 *  -  register                 R0-R15 or absent
 *  -  index register           R0-R15 or absent
 *  -  expression text          what we don't parse
 *  -  error text(s)            why we couldn't understand the operand
 */

/*
 * To decode output of this, test errtxt. If errtxt[0] == '\0', then
 * we had no errors that prevented parsing. Also, if we ever report
 * an internal bug, errtxt[0] is set non-zero. So one test tells you
 * if the other outputs are to be taken seriously.
 */

/*
 * Because this module is useful for both VMS and UN*X style assemblers
 * and because of the variety of UN*X assemblers we must recognise
 * the different conventions for assembler operand notation. For example
 * VMS says "#42" for immediate mode, while most UN*X say "$42".
 * We permit arbitrary sets of (single) characters to represent the
 * 3 concepts that DEC writes '#', '@', '^'.
 */

/* character tests */
#define VIP_IMMEDIATE 01	/* Character is like DEC # */
#define VIP_INDIRECT  02	/* Char is like DEC @ */
#define VIP_DISPLEN   04	/* Char is like DEC ^ */

#define IMMEDIATEP(c)	(vip_metacharacters [(c)&0xff]&VIP_IMMEDIATE)
#define INDIRECTP(c)	(vip_metacharacters [(c)&0xff]&VIP_INDIRECT)
#define DISPLENP(c)	(vip_metacharacters [(c)&0xff]&VIP_DISPLEN)

/* We assume 8 bits per byte. Use vip_op_defaults() to set these up BEFORE we
 * are ever called.
 */

#if defined(CONST_TABLE)
#define _ 0,
#define I VIP_IMMEDIATE,
#define S VIP_INDIRECT,
#define D VIP_DISPLEN,
static const char
vip_metacharacters[256] =
{
  _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _	/* ^@ ^A ^B ^C ^D ^E ^F ^G ^H ^I ^J ^K ^L ^M ^N ^O*/
  _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _	/* ^P ^Q ^R ^S ^T ^U ^V ^W ^X ^Y ^Z ^[ ^\ ^] ^^ ^_ */
  _ _