tm-tahoe.h

这是完整的gcc源代码

/* Definitions of target machine for GNU compiler.  Tahoe version.
   Copyright (C) 1989 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 1, 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, 675 Mass Ave, Cambridge, MA 02139, USA.  */

/*
 * File: tm-tahoe.h
 *
 * This port made at the University of Buffalo by Devon Bowen,
 * Dale Wiles and Kevin Zachmann.
 *
 * Mail bugs reports or fixes to:	[e-mail]
 */


/*
 * Run-time Target Specification
 */

/* we want "tahoe" and "unix" auto-defined for all future compilations */

#define CPP_PREDEFINES "-Dtahoe -Dunix"

/* have cc1 print that this is the tahoe version */

#define TARGET_VERSION printf (" (tahoe)");

/* 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
 */

/* tahoe uses a big endian byte order */

#define BYTES_BIG_ENDIAN

/* tahoe uses a big endian word order */

#define WORDS_BIG_ENDIAN

/* 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

/* pointers should align every 32 bits */

#define POINTER_BOUNDARY 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

/* structures must be made of full bytes */

#define STRUCTURE_SIZE_BOUNDARY 8

/* tahoe is picky about data alignment */

#define STRICT_ALIGNMENT

/* 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) \
  if ((mode) == SFmode) \
    { \
      if ((d) > 1.7014117331926443e+38) \
	{ error ("magnitude of constant too large for `float'"); \
	  (d) = 1.7014117331926443e+38; } \
      else if ((d) < -1.7014117331926443e+38) \
	{ error ("magnitude of constant too large for `float'"); \
	  (d) = -1.7014117331926443e+38; } \
      else if (((d) > 0) && ((d) < 2.9387358770557188e-39)) \
	{ warning ("`float' constant truncated to zero"); \
	  (d) = 0.0; } \
      else if (((d) < 0) && ((d) > -2.9387358770557188e-39)) \
	{ warning ("`float' constant truncated to zero"); \
	  (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 guarenteed 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}

/* The FPP can handle any type, but the others may require as many as */
/* two regs depending on the mode needed 			      */

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

/* 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_SIZE (MODE) <= 4 ? 1 : (REGNO % 2 - 1)) : \
	(MODE == SFmode || MODE == DFmode))

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

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

/* 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. GENERALY_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 gereral registers can be used as a base reg */

#define BASE_REG_CLASS GENERAL_REGS

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

#define INDEX_REG_CLASS GENERAL_REGS

/* 'a' as a contraint 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(FUNTYPE) 1

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

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

/* libarary 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)	\
 ((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); }

/* 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));

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

#define EXIT_IGNORE_STACK 1

/* this never gets executed since the system knows it always gets  */
/* an fp to work with. It just prints a friendly message since the */
/* person must be playing with the tm file defs 		   */

#define FIX_FRAME_POINTER_ADDRESS(ADDR,DEPTH) \
 { abort(); }


/*
 * 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 */

#define UMODSI3_LIBCALL "*urem"


/*
 * Addressing Modes
 */

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

#define CONSTANT_ADDRESS_P(X) CONSTANT_P (X)

/* 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 identicle.	      */

/* 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))				\