tahoe.h

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/* Definitions of target machine for GNU compiler.  Tahoe version.
   Copyright (C) 1989, 1993, 1994, 1995, 1996 Free Software Foundation, Inc.

This file is part of GNU CC.

GNU CC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU CC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

/*
 * Original port made at the University of Buffalo by Devon Bowen,
 * Dale Wiles and Kevin Zachmann.
 *
 * HCX/UX version by Piet van Oostrum ([e-mail])
 *
 * Performance hacking by Michael Tiemann ([e-mail])
 */

/* define this for the HCX/UX version */

/* #define HCX_UX */

/*
 * Run-time Target Specification
 */

#ifdef HCX_UX
/* no predefines, see Makefile and hcx-universe.c */
/* have cc1 print that this is the hcx version */
#define TARGET_VERSION printf (" (hcx)");
#else
/* we want "tahoe" and "unix" defined for all future compilations */
#define CPP_PREDEFINES "-Dtahoe -Dunix -Asystem(unix) -Acpu(tahoe) -Amachine(tahoe)"
/* have cc1 print that this is the tahoe version */
#define TARGET_VERSION printf (" (tahoe)");
#endif

/* this is required in all tm files to hold flags */

extern int target_flags;

/* Zero if it is safe to output .dfloat and .float pseudos.  */
#define TARGET_HEX_FLOAT (target_flags & 1)

#define TARGET_DEFAULT 1

#define TARGET_SWITCHES		\
  { {"hex-float", 1},		\
    {"no-hex-float", -1},	\
    { "", TARGET_DEFAULT} }


/*
 * Storage Layout
 */

/* This symbol was previously not mentioned, so apparently the tahoe
   is little-endian for bits, or else doesn't care.  */
#define BITS_BIG_ENDIAN 0

/* tahoe uses a big endian byte order */

#define BYTES_BIG_ENDIAN 1

/* tahoe uses a big endian word order */

#define WORDS_BIG_ENDIAN 1

/* standard byte size is usable on tahoe */

#define BITS_PER_UNIT 8

/* longs on the tahoe are 4 byte groups */

#define BITS_PER_WORD 32

/* from the last two params we get 4 bytes per word */

#define UNITS_PER_WORD 4

/* addresses are 32 bits (one word) */

#define POINTER_SIZE 32

/* all parameters line up on 32 boundaries */

#define PARM_BOUNDARY 32

/* stack should line up on 32 boundaries */

#define STACK_BOUNDARY 32

/* line functions up on 32 bits */

#define FUNCTION_BOUNDARY 32

/* the biggest alignment the tahoe needs in 32 bits */

#define BIGGEST_ALIGNMENT 32

/* we have to align after an 'int : 0' in a structure */

#define EMPTY_FIELD_BOUNDARY 32

#ifdef HCX_UX
/* structures must be made of full words */

#define STRUCTURE_SIZE_BOUNDARY 32
#else
/* structures must be made of full bytes */

#define STRUCTURE_SIZE_BOUNDARY 8
#endif

/* tahoe is picky about data alignment */

#define STRICT_ALIGNMENT 1

/* keep things standard with pcc */

#define PCC_BITFIELD_TYPE_MATTERS 1

/* this section is borrowed from the vax version since the */
/* formats are the same in both of the architectures	   */

#define CHECK_FLOAT_VALUE(MODE, D, OVERFLOW) \
  if (OVERFLOW)								\
    (D) = 1.7014117331926443e+38;					\
  else if ((MODE) == SFmode)						\
    {									\
      if ((D) > 1.7014117331926443e+38)					\
	(OVERFLOW) = 1, (D) = 1.7014117331926443e+38;			\
      else if ((D) < -1.7014117331926443e+38)				\
	(OVERFLOW) = 1, (D) = -1.7014117331926443e+38;			\
      else if (((D) > 0) && ((D) < 2.9387358770557188e-39))		\
	(OVERFLOW) = 1, (D) = 0.0;					\
      else if (((D) < 0) && ((D) > -2.9387358770557188e-39))		\
	(OVERFLOW) = 1, (D) = 0.0;					\
    }


/*
 * Register Usage
 */

/* define 15 general regs plus one for the floating point reg (FPP) */

#define FIRST_PSEUDO_REGISTER 17

/* let the compiler know what the fp, sp and pc are */

#define FIXED_REGISTERS {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0}

/* lots of regs aren't guaranteed to return from a call. The FPP reg */
/* must be included in these since it can't be saved by the reg mask */

#define CALL_USED_REGISTERS {1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1}

/* A single fp reg can handle any type of float.
   CPU regs hold just 32 bits.  */

#define HARD_REGNO_NREGS(REGNO, MODE) \
 (REGNO != 16 ? ((GET_MODE_SIZE(MODE)+UNITS_PER_WORD-1) / UNITS_PER_WORD)  \
  : GET_MODE_NUNITS ((MODE)))

/* any mode greater than 4 bytes (doubles) can only go in an even regs */
/* and the FPP can only hold SFmode and DFmode 			       */

#define HARD_REGNO_MODE_OK(REGNO, MODE) \
 (REGNO != 16							\
  ? (GET_MODE_UNIT_SIZE (MODE) <= 4 ? 1 : (REGNO % 2 - 1))	\
  : ((MODE) == SFmode || (MODE) == DFmode			\
     || (MODE) == SCmode || (MODE) == DCmode))

/* if mode1 or mode2, but not both, are doubles then modes cannot be tied */

#define MODES_TIEABLE_P(MODE1, MODE2) \
 (((MODE1) == DFmode || (MODE1) == DCmode)	\
  == ((MODE2) == DFmode || (MODE2) == DCmode))

/* return nonzero if register variable of mode MODE is not
   a priori a bad idea.  Used only if defined.  */
#define MODE_OK_FOR_USERVAR(MODE)	\
  ((MODE) == SImode)

/* the program counter is reg 15 */

#define PC_REGNUM 15

/* the stack pointer is reg 14 */

#define STACK_POINTER_REGNUM 14

/* the frame pointer is reg 13 */

#define FRAME_POINTER_REGNUM 13

/* tahoe does require an fp */

#define FRAME_POINTER_REQUIRED 1

/* since tahoe doesn't have a argument pointer, make it the fp */

#define ARG_POINTER_REGNUM 13

/* this isn't currently used since C doesn't support this feature */

#define STATIC_CHAIN_REGNUM 0

/* we'll use reg 1 for structure passing cause the destination */
/* of the eventual movblk requires it to be there anyway.      */

#define STRUCT_VALUE_REGNUM 1


/*
 * Register Classes
 */

/* tahoe has two types of regs. GENERAL_REGS are all the regs up */
/* to number 15. FPP_REG is the special floating point processor  */
/* register class (only one reg).				  */

enum reg_class {NO_REGS,GENERAL_REGS,FPP_REG,ALL_REGS,LIM_REG_CLASSES};

/* defines the number of reg classes.				    */

#define N_REG_CLASSES (int) LIM_REG_CLASSES

/* this defines what the classes are officially named for debugging */

#define REG_CLASS_NAMES \
 {"NO_REGS","GENERAL_REGS","FPP_REG","ALL_REGS"}

/* set general regs to be the first 16 regs and the fpp reg to be 17th */

#define REG_CLASS_CONTENTS {0,0xffff,0x10000,0x1ffff}

/* register class for the fpp reg is FPP_REG, all others are GENERAL_REGS */

#define REGNO_REG_CLASS(REGNO) (REGNO == 16 ? FPP_REG : GENERAL_REGS)

/* only general registers can be used as a base reg */

#define BASE_REG_CLASS GENERAL_REGS

/* only general registers can be used to index */

#define INDEX_REG_CLASS GENERAL_REGS

/* 'a' as a constraint in the md file means the FFP_REG class */

#define REG_CLASS_FROM_LETTER(C) (C == 'a' ? FPP_REG : NO_REGS)

/* any general reg but the fpp can be a base reg */

#define REGNO_OK_FOR_BASE_P(regno) \
((regno) < FIRST_PSEUDO_REGISTER - 1 || reg_renumber[regno] >= 0)

/* any general reg except the pc and fpp can be an index reg */

#define REGNO_OK_FOR_INDEX_P(regno)  \
((regno) < FIRST_PSEUDO_REGISTER - 2 || reg_renumber[regno] >= 0)

/* if your loading a floating point constant, it can't be done */
/* through a register. Force it to be a memory constant.       */

#define PREFERRED_RELOAD_CLASS(X,CLASS) \
	((GET_CODE (X) == CONST_DOUBLE) ? NO_REGS : CLASS)

/* for the fpp reg, all modes fit; for any others, you need two for doubles */

#define CLASS_MAX_NREGS(CLASS, MODE)	\
 (CLASS != FPP_REG ? ((GET_MODE_SIZE (MODE) + UNITS_PER_WORD - 1) / UNITS_PER_WORD) : 1)

/* we don't define any special constant sizes so all should fail */

#define CONST_OK_FOR_LETTER_P(VALUE, C)  0

/* we don't define any special double sizes so all should fail */

#define CONST_DOUBLE_OK_FOR_LETTER_P(VALUE, C) 0


/*
 * Describing Stack Layout
 */

/* tahoe stack grows from high to low memory */

#define STACK_GROWS_DOWNWARD

/* Define this if longjmp restores from saved registers
   rather than from what setjmp saved.  */
#define LONGJMP_RESTORE_FROM_STACK

/* tahoe call frames grow from high to low memory on the stack */

#define FRAME_GROWS_DOWNWARD

/* the tahoe fp points to the *top* of the frame instead of the   */
/* bottom, so we have to make this offset a constant large enough */
/* to jump over the biggest frame possible.			  */

#define STARTING_FRAME_OFFSET -52

/* tahoe always pushes 4 bytes unless it's a double in which case */
/* it pushes a full 8 bytes.					  */

#define PUSH_ROUNDING(BYTES) (BYTES <= 4 ? 4 : 8)

/* the first parameter in a function is at the fp + 4 */

#define FIRST_PARM_OFFSET(FNDECL) 4

/* the tahoe return function takes care of everything on the stack */

#define RETURN_POPS_ARGS(FUNDECL,FUNTYPE,SIZE) (SIZE)

/* function values for all types are returned in register 0 */

#define FUNCTION_VALUE(VALTYPE, FUNC)  \
  gen_rtx (REG, TYPE_MODE (VALTYPE), 0)

/* library routines also return things in reg 0 */

#define LIBCALL_VALUE(MODE)  gen_rtx (REG, MODE, 0)

/* Tahoe doesn't return structures in a reentrant way */

#define PCC_STATIC_STRUCT_RETURN

/* we only return values from a function in reg 0 */

#define FUNCTION_VALUE_REGNO_P(N) ((N) == 0)

/* we never pass args through a register */

#define FUNCTION_ARG(CUM, MODE, TYPE, NAMED) 0

/* int is fine to hold the argument summary in FUNCTION_ARG */

#define CUMULATIVE_ARGS int

/* we just set CUM to 0 before the FUNCTION_ARG call. No matter what */
/* we make it, FUNCTION_ARG will return 0 anyway		     */

#define INIT_CUMULATIVE_ARGS(CUM,FNTYPE,LIBNAME,INDIRECT)	\
 ((CUM) = 0)

/* all modes push their size rounded to the nearest word boundary */
/* except block which is the size of the block rounded up	  */

#define FUNCTION_ARG_ADVANCE(CUM, MODE, TYPE, NAMED)	\
 ((CUM) += ((MODE) != BLKmode			\
	    ? (GET_MODE_SIZE (MODE) + 3) & ~3	\
	    : (int_size_in_bytes (TYPE) + 3) & ~3))

/* this is always false since we never pass params in regs */

#define FUNCTION_ARG_REGNO_P(N) 0

/* this code calculates the register entry mask and sets up    */
/* the stack pointer for the function. The stack is set down   */
/* far enough from the fp to jump over any push regs and local */
/* vars. This is a problem since the tahoe has the fp pointing */
/* to the top of the frame and the compiler must know the off- */
/* set off the fp to the local vars.			       */

#define FUNCTION_PROLOGUE(FILE, SIZE)     \
{ register int regno;						\
  register int mask = 0;					\
  extern char call_used_regs[];					\
  for (regno = 0; regno < FIRST_PSEUDO_REGISTER-1; regno++)	\
    if (regs_ever_live[regno] && !call_used_regs[regno])	\
       mask |= 1 << regno;					\
  fprintf (FILE, "\t.word 0x%x\n", mask);			\
  if (SIZE != 0) fprintf (FILE, "\tsubl3 $%d,fp,sp\n", (SIZE) - STARTING_FRAME_OFFSET); }

/* Zero out global variable in case it was used in this function.  */
#define FUNCTION_EPILOGUE(FILE, SIZE)	\
{ extern rtx tahoe_reg_conversion_loc;				\
  tahoe_reg_conversion_loc = 0;					\
}

#ifdef HCX_UX

/* to call the profiler, the address of the counter var is placed */
/* on the stack and then passed into mcount this way			  */

#define FUNCTION_PROFILER(FILE, LABELNO)  \
   fprintf (FILE, "\tpushal LP%d\n\tcallf $8,mcount\n", (LABELNO));

#else

/* to call the profiler, push the variable value onto the stack */
/* and call mcount like a regular function.			*/

#define FUNCTION_PROFILER(FILE, LABELNO)  \
   fprintf (FILE, "\tpushl $LP%d\n\tcallf $8,mcount\n", (LABELNO));

#endif

/* all stack handling at the end of a function is handled by the */
/* return command.						 */

#define EXIT_IGNORE_STACK 1

/*
 * Library Subroutine Names
 */

/* udiv is a valid C library routine in libc.a, so we call that */

#define UDIVSI3_LIBCALL "*udiv"

/* urem is a valid C library routine in libc.a, so we call that */
/* but not so on hcx/ux */

#ifdef HCX_UX
#undef UMODSI3_LIBCALL
#else
#define UMODSI3_LIBCALL "*urem"
#endif


/*
 * Addressing Modes
 */

/* constant addresses can be treated exactly the same as normal constants */

#define CONSTANT_ADDRESS_P(X)   \
  (GET_CODE (X) == LABEL_REF || GET_CODE (X) == SYMBOL_REF		\
   || GET_CODE (X) == CONST_INT || GET_CODE (X) == CONST		\
   || GET_CODE (X) == HIGH)

/* we can have as many as two regs in any given address */

#define MAX_REGS_PER_ADDRESS 2

/* The following is all the code for GO_IF_LEGITIMATE_ADDRESS */
/* most of this taken directly from the vax tm file since the */
/* tahoe and vax addressing modes are nearly identical.	      */

/* Is x an indirectable address? */

#define INDIRECTABLE_ADDRESS_P(X)  \
  (CONSTANT_ADDRESS_P (X)						\
   || (GET_CODE (X) == REG && REG_OK_FOR_BASE_P (X))			\
   || (GET_CODE (X) == PLUS						\
       && GET_CODE (XEXP (X, 0)) == REG					\
       && REG_OK_FOR_BASE_P (XEXP (X, 0))				\
       && CONSTANT_ADDRESS_P (XEXP (X, 1))))

/* If x is a non-indexed-address, go to ADDR. */

#define GO_IF_NONINDEXED_ADDRESS(X, ADDR)  \
{ register rtx xfoob = (X);						\
  if (GET_CODE (xfoob) == REG) goto ADDR;				\
  if (INDIRECTABLE_ADDRESS_P (xfoob)) goto ADDR;			\
  xfoob = XEXP (X, 0);							\
  if (GET_CODE (X) == MEM && INDIRECTABLE_ADDRESS_P (xfoob))		\
    goto ADDR;								\
  if ((GET_CODE (X) == PRE_DEC || GET_CODE (X) == POST_INC)		\
      && GET_CODE (xfoob) == REG && REGNO (xfoob) == 14)		\
    goto ADDR; }

/* Is PROD an index term in mode MODE. */

#define INDEX_TERM_P(PROD, MODE)   \
(GET_MODE_SIZE (MODE) == 1						\
 ? (GET_CODE (PROD) == REG && REG_OK_FOR_BASE_P (PROD))			\
 : (GET_CODE (PROD) == MULT						\
    &&									\
    (xfoo0 = XEXP (PROD, 0), xfoo1 = XEXP (PROD, 1),			\
     ((GET_CODE (xfoo0) == CONST_INT					\
       && INTVAL (xfoo0) == GET_MODE_SIZE (MODE)			\
       && GET_CODE (xfoo1) == REG					\
       && REG_OK_FOR_INDEX_P (xfoo1))					\
      ||								\
      (GET_CODE (xfoo1) == CONST_INT					\
       && INTVAL (xfoo1) == GET_MODE_SIZE (MODE)			\
       && GET_CODE (xfoo0) == REG					\
       && REG_OK_FOR_INDEX_P (xfoo0))))))

/* Is the addition to the index a reg? */

#define GO_IF_REG_PLUS_INDEX(X, MODE, ADDR)	\
{ register rtx xfooa;							\
  if (GET_CODE (X) == PLUS)						\
    { if (GET_CODE (XEXP (X, 0)) == REG					\
	  && REG_OK_FOR_BASE_P (XEXP (X, 0))				\
	  && (xfooa = XEXP (X, 1),					\
	      INDEX_TERM_P (xfooa, MODE)))				\
	goto ADDR;							\
      if (GET_CODE (XEXP (X, 1)) == REG					\
	  && REG_OK_FOR_BASE_P (XEXP (X, 1))				\