i386.h

GCC编译器源代码

  AD_REGS,			/* %eax/%edx for DImode */
  Q_REGS,			/* %eax %ebx %ecx %edx */
  SIREG, DIREG,
  INDEX_REGS,			/* %eax %ebx %ecx %edx %esi %edi %ebp */
  GENERAL_REGS,			/* %eax %ebx %ecx %edx %esi %edi %ebp %esp */
  FP_TOP_REG, FP_SECOND_REG,	/* %st(0) %st(1) */
  FLOAT_REGS,
  ALL_REGS, LIM_REG_CLASSES
};

#define N_REG_CLASSES (int) LIM_REG_CLASSES

#define FLOAT_CLASS_P(CLASS) (reg_class_subset_p (CLASS, FLOAT_REGS))

/* Give names of register classes as strings for dump file.   */

#define REG_CLASS_NAMES \
{  "NO_REGS",				\
   "AREG", "DREG", "CREG", "BREG",	\
   "AD_REGS",				\
   "Q_REGS",				\
   "SIREG", "DIREG",			\
   "INDEX_REGS",			\
   "GENERAL_REGS",			\
   "FP_TOP_REG", "FP_SECOND_REG",	\
   "FLOAT_REGS",			\
   "ALL_REGS" }

/* Define which registers fit in which classes.
   This is an initializer for a vector of HARD_REG_SET
   of length N_REG_CLASSES.  */

#define REG_CLASS_CONTENTS \
{      0,							\
     0x1,    0x2,  0x4,	 0x8,	/* AREG, DREG, CREG, BREG */	\
     0x3,			/* AD_REGS */			\
     0xf,			/* Q_REGS */			\
    0x10,   0x20,		/* SIREG, DIREG */		\
 0x7f,				/* INDEX_REGS */		\
 0x100ff,			/* GENERAL_REGS */		\
  0x0100, 0x0200,		/* FP_TOP_REG, FP_SECOND_REG */	\
  0xff00,			/* FLOAT_REGS */		\
 0x1ffff }

/* The same information, inverted:
   Return the class number of the smallest class containing
   reg number REGNO.  This could be a conditional expression
   or could index an array.  */

#define REGNO_REG_CLASS(REGNO) (regclass_map[REGNO])

/* When defined, the compiler allows registers explicitly used in the
   rtl to be used as spill registers but prevents the compiler from
   extending the lifetime of these registers. */

#define SMALL_REGISTER_CLASSES 1

#define QI_REG_P(X) \
  (REG_P (X) && REGNO (X) < 4)
#define NON_QI_REG_P(X) \
  (REG_P (X) && REGNO (X) >= 4 && REGNO (X) < FIRST_PSEUDO_REGISTER)

#define FP_REG_P(X) (REG_P (X) && FP_REGNO_P (REGNO (X)))
#define FP_REGNO_P(n) ((n) >= FIRST_STACK_REG && (n) <= LAST_STACK_REG)
  
#define STACK_REG_P(xop) (REG_P (xop) &&		       	\
			  REGNO (xop) >= FIRST_STACK_REG &&	\
			  REGNO (xop) <= LAST_STACK_REG)

#define NON_STACK_REG_P(xop) (REG_P (xop) && ! STACK_REG_P (xop))

#define STACK_TOP_P(xop) (REG_P (xop) && REGNO (xop) == FIRST_STACK_REG)

/* Try to maintain the accuracy of the death notes for regs satisfying the
   following.  Important for stack like regs, to know when to pop. */

/* #define PRESERVE_DEATH_INFO_REGNO_P(x) FP_REGNO_P(x) */

/* 1 if register REGNO can magically overlap other regs.
   Note that nonzero values work only in very special circumstances. */

/* #define OVERLAPPING_REGNO_P(REGNO) FP_REGNO_P (REGNO) */

/* The class value for index registers, and the one for base regs.  */

#define INDEX_REG_CLASS INDEX_REGS
#define BASE_REG_CLASS GENERAL_REGS

/* Get reg_class from a letter such as appears in the machine description.  */

#define REG_CLASS_FROM_LETTER(C)	\
  ((C) == 'r' ? GENERAL_REGS :					\
   (C) == 'q' ? Q_REGS :					\
   (C) == 'f' ? (TARGET_80387 || TARGET_FLOAT_RETURNS_IN_80387	\
		 ? FLOAT_REGS					\
		 : NO_REGS) :					\
   (C) == 't' ? (TARGET_80387 || TARGET_FLOAT_RETURNS_IN_80387	\
		 ? FP_TOP_REG					\
		 : NO_REGS) :					\
   (C) == 'u' ? (TARGET_80387 || TARGET_FLOAT_RETURNS_IN_80387	\
		 ? FP_SECOND_REG				\
		 : NO_REGS) :					\
   (C) == 'a' ? AREG :						\
   (C) == 'b' ? BREG :						\
   (C) == 'c' ? CREG :						\
   (C) == 'd' ? DREG :						\
   (C) == 'A' ? AD_REGS :					\
   (C) == 'D' ? DIREG :						\
   (C) == 'S' ? SIREG : NO_REGS)

/* The letters I, J, K, L and M in a register constraint string
   can be used to stand for particular ranges of immediate operands.
   This macro defines what the ranges are.
   C is the letter, and VALUE is a constant value.
   Return 1 if VALUE is in the range specified by C.

   I is for non-DImode shifts.
   J is for DImode shifts.
   K and L are for an `andsi' optimization.
   M is for shifts that can be executed by the "lea" opcode.
   */

#define CONST_OK_FOR_LETTER_P(VALUE, C)  \
  ((C) == 'I' ? (VALUE) >= 0 && (VALUE) <= 31 :	\
   (C) == 'J' ? (VALUE) >= 0 && (VALUE) <= 63 :	\
   (C) == 'K' ? (VALUE) == 0xff :		\
   (C) == 'L' ? (VALUE) == 0xffff :		\
   (C) == 'M' ? (VALUE) >= 0 && (VALUE) <= 3 :	\
   (C) == 'N' ? (VALUE) >= 0 && (VALUE) <= 255 :\
   (C) == 'O' ? (VALUE) >= 0 && (VALUE) <= 32 :	\
   0)

/* Similar, but for floating constants, and defining letters G and H.
   Here VALUE is the CONST_DOUBLE rtx itself.  We allow constants even if
   TARGET_387 isn't set, because the stack register converter may need to
   load 0.0 into the function value register. */

#define CONST_DOUBLE_OK_FOR_LETTER_P(VALUE, C)  \
  ((C) == 'G' ? standard_80387_constant_p (VALUE) : 0)

/* Place additional restrictions on the register class to use when it
   is necessary to be able to hold a value of mode MODE in a reload
   register for which class CLASS would ordinarily be used. */

#define LIMIT_RELOAD_CLASS(MODE, CLASS) \
  ((MODE) == QImode && ((CLASS) == ALL_REGS || (CLASS) == GENERAL_REGS) \
   ? Q_REGS : (CLASS))

/* Given an rtx X being reloaded into a reg required to be
   in class CLASS, return the class of reg to actually use.
   In general this is just CLASS; but on some machines
   in some cases it is preferable to use a more restrictive class.
   On the 80386 series, we prevent floating constants from being
   reloaded into floating registers (since no move-insn can do that)
   and we ensure that QImodes aren't reloaded into the esi or edi reg.  */

/* Put float CONST_DOUBLE in the constant pool instead of fp regs.
   QImode must go into class Q_REGS.
   Narrow ALL_REGS to GENERAL_REGS.  This supports allowing movsf and
   movdf to do mem-to-mem moves through integer regs. */

#define PREFERRED_RELOAD_CLASS(X,CLASS)	\
  (GET_CODE (X) == CONST_DOUBLE && GET_MODE (X) != VOIDmode ? NO_REGS	\
   : GET_MODE (X) == QImode && ! reg_class_subset_p (CLASS, Q_REGS) ? Q_REGS \
   : ((CLASS) == ALL_REGS						\
      && GET_MODE_CLASS (GET_MODE (X)) == MODE_FLOAT) ? GENERAL_REGS	\
   : (CLASS))

/* If we are copying between general and FP registers, we need a memory
   location.  */

#define SECONDARY_MEMORY_NEEDED(CLASS1,CLASS2,MODE) \
  ((FLOAT_CLASS_P (CLASS1) && ! FLOAT_CLASS_P (CLASS2))	\
   || (! FLOAT_CLASS_P (CLASS1) && FLOAT_CLASS_P (CLASS2)))

/* Return the maximum number of consecutive registers
   needed to represent mode MODE in a register of class CLASS.  */
/* On the 80386, this is the size of MODE in words,
   except in the FP regs, where a single reg is always enough.  */
#define CLASS_MAX_NREGS(CLASS, MODE)	\
 (FLOAT_CLASS_P (CLASS) ? 1 :		\
  ((GET_MODE_SIZE (MODE) + UNITS_PER_WORD - 1) / UNITS_PER_WORD))

/* A C expression whose value is nonzero if pseudos that have been
   assigned to registers of class CLASS would likely be spilled
   because registers of CLASS are needed for spill registers.

   The default value of this macro returns 1 if CLASS has exactly one
   register and zero otherwise.  On most machines, this default
   should be used.  Only define this macro to some other expression
   if pseudo allocated by `local-alloc.c' end up in memory because
   their hard registers were needed for spill registers.  If this
   macro returns nonzero for those classes, those pseudos will only
   be allocated by `global.c', which knows how to reallocate the
   pseudo to another register.  If there would not be another
   register available for reallocation, you should not change the
   definition of this macro since the only effect of such a
   definition would be to slow down register allocation.  */

#define CLASS_LIKELY_SPILLED_P(CLASS)					\
  (((CLASS) == AREG)							\
   || ((CLASS) == DREG)							\
   || ((CLASS) == CREG)							\
   || ((CLASS) == BREG)							\
   || ((CLASS) == AD_REGS)						\
   || ((CLASS) == SIREG)						\
   || ((CLASS) == DIREG))


/* Stack layout; function entry, exit and calling.  */

/* Define this if pushing a word on the stack
   makes the stack pointer a smaller address.  */
#define STACK_GROWS_DOWNWARD

/* Define this if the nominal address of the stack frame
   is at the high-address end of the local variables;
   that is, each additional local variable allocated
   goes at a more negative offset in the frame.  */
#define FRAME_GROWS_DOWNWARD

/* Offset within stack frame to start allocating local variables at.
   If FRAME_GROWS_DOWNWARD, this is the offset to the END of the
   first local allocated.  Otherwise, it is the offset to the BEGINNING
   of the first local allocated.  */
#define STARTING_FRAME_OFFSET 0

/* If we generate an insn to push BYTES bytes,
   this says how many the stack pointer really advances by.
   On 386 pushw decrements by exactly 2 no matter what the position was.
   On the 386 there is no pushb; we use pushw instead, and this
   has the effect of rounding up to 2.  */

#define PUSH_ROUNDING(BYTES) (((BYTES) + 1) & (-2))

/* Offset of first parameter from the argument pointer register value.  */
#define FIRST_PARM_OFFSET(FNDECL) 0

/* Value is the number of bytes of arguments automatically
   popped when returning from a subroutine call.
   FUNDECL is the declaration node of the function (as a tree),
   FUNTYPE is the data type of the function (as a tree),
   or for a library call it is an identifier node for the subroutine name.
   SIZE is the number of bytes of arguments passed on the stack.

   On the 80386, the RTD insn may be used to pop them if the number
     of args is fixed, but if the number is variable then the caller
     must pop them all.  RTD can't be used for library calls now
     because the library is compiled with the Unix compiler.
   Use of RTD is a selectable option, since it is incompatible with
   standard Unix calling sequences.  If the option is not selected,
   the caller must always pop the args.

   The attribute stdcall is equivalent to RTD on a per module basis.  */

#define RETURN_POPS_ARGS(FUNDECL,FUNTYPE,SIZE) \
  (i386_return_pops_args (FUNDECL, FUNTYPE, SIZE))

/* Define how to find the value returned by a function.
   VALTYPE is the data type of the value (as a tree).
   If the precise function being called is known, FUNC is its FUNCTION_DECL;
   otherwise, FUNC is 0.  */
#define FUNCTION_VALUE(VALTYPE, FUNC)  \
   gen_rtx (REG, TYPE_MODE (VALTYPE), \
	    VALUE_REGNO (TYPE_MODE (VALTYPE)))

/* Define how to find the value returned by a library function
   assuming the value has mode MODE.  */

#define LIBCALL_VALUE(MODE) \
  gen_rtx (REG, MODE, VALUE_REGNO (MODE))

/* Define the size of the result block used for communication between
   untyped_call and untyped_return.  The block contains a DImode value
   followed by the block used by fnsave and frstor.  */

#define APPLY_RESULT_SIZE (8+108)

/* 1 if N is a possible register number for function argument passing.  */
#define FUNCTION_ARG_REGNO_P(N) ((N) >= 0 && (N) < REGPARM_MAX)

/* Define a data type for recording info about an argument list
   during the scan of that argument list.  This data type should
   hold all necessary information about the function itself
   and about the args processed so far, enough to enable macros
   such as FUNCTION_ARG to determine where the next arg should go.  */

typedef struct i386_args {
  int words;			/* # words passed so far */
  int nregs;			/* # registers available for passing */
  int regno;			/* next available register number */
} CUMULATIVE_ARGS;

/* Initialize a variable CUM of type CUMULATIVE_ARGS
   for a call to a function whose data type is FNTYPE.
   For a library call, FNTYPE is 0.  */

#define INIT_CUMULATIVE_ARGS(CUM,FNTYPE,LIBNAME,INDIRECT)	\
  (init_cumulative_args (&CUM, FNTYPE, LIBNAME))

/* Update the data in CUM to advance over an argument
   of mode MODE and data type TYPE.
   (TYPE is null for libcalls where that information may not be available.)  */

#define FUNCTION_ARG_ADVANCE(CUM, MODE, TYPE, NAMED)	\
  (function_arg_advance (&CUM, MODE, TYPE, NAMED))

/* Define where to put the arguments to a function.
   Value is zero to push the argument on the stack,
   or a hard register in which to store the argument.

   MODE is the argument's machine mode.
   TYPE is the data type of the argument (as a tree).
    This is null for libcalls where that information may
    not be available.
   CUM is a variable of type CUMULATIVE_ARGS which gives info about
    the preceding args and about the function being called.
   NAMED is nonzero if this argument is a named parameter
    (otherwise it is an extra parameter matching an ellipsis).  */

#define FUNCTION_ARG(CUM, MODE, TYPE, NAMED) \
  (function_arg (&CUM, MODE, TYPE, NAMED))

/* For an arg passed partly in registers and partly in memory,
   this is the number of registers used.
   For args passed entirely in registers or entirely in memory, zero.  */

#define FUNCTION_ARG_PARTIAL_NREGS(CUM, MODE, TYPE, NAMED) \
  (function_arg_partial_nregs (&CUM, MODE, TYPE, NAMED))

/* This macro is invoked just before the start of a function.
   It is used here to output code for -fpic that will load the
   return address into %ebx.  */

#undef ASM_OUTPUT_FUNCTION_PREFIX
#define ASM_OUTPUT_FUNCTION_PREFIX(FILE, FNNAME) \
  asm_output_function_prefix (FILE, FNNAME)

/* This macro generates the assembly code for function entry.
   FILE is a stdio stream to output the code to.
   SIZE is an int: how many units of temporary storage to allocate.
   Refer to the array `regs_ever_live' to determine which registers
   to save; `regs_ever_live[I]' is nonzero if register number I
   is ever used in the function.  This macro is responsible for
   knowing which registers should not be saved even if used.  */