rs6000.h

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/* Place that structure value return address is placed.

   On the RS/6000, it is passed as an extra parameter.  */
#define STRUCT_VALUE	0

/* Define the classes of registers for register constraints in the
   machine description.  Also define ranges of constants.

   One of the classes must always be named ALL_REGS and include all hard regs.
   If there is more than one class, another class must be named NO_REGS
   and contain no registers.

   The name GENERAL_REGS must be the name of a class (or an alias for
   another name such as ALL_REGS).  This is the class of registers
   that is allowed by "g" or "r" in a register constraint.
   Also, registers outside this class are allocated only when
   instructions express preferences for them.

   The classes must be numbered in nondecreasing order; that is,
   a larger-numbered class must never be contained completely
   in a smaller-numbered class.

   For any two classes, it is very desirable that there be another
   class that represents their union.  */
   
/* The RS/6000 has three types of registers, fixed-point, floating-point,
   and condition registers, plus three special registers, MQ, CTR, and the
   link register.

   However, r0 is special in that it cannot be used as a base register.
   So make a class for registers valid as base registers.

   Also, cr0 is the only condition code register that can be used in
   arithmetic insns, so make a separate class for it. */

enum reg_class { NO_REGS, BASE_REGS, GENERAL_REGS, FLOAT_REGS,
  NON_SPECIAL_REGS, MQ_REGS, LINK_REGS, CTR_REGS, LINK_OR_CTR_REGS,
  SPECIAL_REGS, SPEC_OR_GEN_REGS, CR0_REGS, CR_REGS, NON_FLOAT_REGS,
  ALL_REGS, LIM_REG_CLASSES };

#define N_REG_CLASSES (int) LIM_REG_CLASSES

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

#define REG_CLASS_NAMES					 	\
  { "NO_REGS", "BASE_REGS", "GENERAL_REGS", "FLOAT_REGS",	\
    "NON_SPECIAL_REGS", "MQ_REGS", "LINK_REGS", "CTR_REGS",	\
    "LINK_OR_CTR_REGS", "SPECIAL_REGS", "SPEC_OR_GEN_REGS",	\
    "CR0_REGS", "CR_REGS", "NON_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, 0, 0}, {0xfffffffe, 0, 8}, {~0, 0, 8},		\
    {0, ~0, 0}, {~0, ~0, 8}, {0, 0, 1}, {0, 0, 2},	\
    {0, 0, 4}, {0, 0, 6}, {0, 0, 7}, {~0, 0, 15},	\
    {0, 0, 16}, {0, 0, 0xff0}, {~0, 0, 0xffff},		\
    {~0, ~0, 0xffff} }

/* 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)	\
 ((REGNO) == 0 ? GENERAL_REGS	\
  : (REGNO) < 32 ? BASE_REGS	\
  : FP_REGNO_P (REGNO) ? FLOAT_REGS \
  : (REGNO) == 68 ? CR0_REGS	\
  : CR_REGNO_P (REGNO) ? CR_REGS \
  : (REGNO) == 64 ? MQ_REGS	\
  : (REGNO) == 65 ? LINK_REGS	\
  : (REGNO) == 66 ? CTR_REGS	\
  : (REGNO) == 67 ? BASE_REGS	\
  : NO_REGS)

/* The class value for index registers, and the one for base regs.  */
#define INDEX_REG_CLASS GENERAL_REGS
#define BASE_REG_CLASS BASE_REGS

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

#define REG_CLASS_FROM_LETTER(C) \
  ((C) == 'f' ? FLOAT_REGS	\
   : (C) == 'b' ? BASE_REGS	\
   : (C) == 'h' ? SPECIAL_REGS	\
   : (C) == 'q' ? MQ_REGS	\
   : (C) == 'c' ? CTR_REGS	\
   : (C) == 'l' ? LINK_REGS	\
   : (C) == 'x' ? CR0_REGS	\
   : (C) == 'y' ? CR_REGS	\
   : NO_REGS)

/* The letters I, J, K, L, M, N, and P 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 signed 16-bit constants 
   `J' is a constant with only the high-order 16 bits non-zero
   `K' is a constant with only the low-order 16 bits non-zero
   `L' is a constant that can be placed into a mask operand
   `M' is a constant that is greater than 31
   `N' is a constant that is an exact power of two
   `O' is the constant zero
   `P' is a constant whose negation is a signed 16-bit constant */

#define CONST_OK_FOR_LETTER_P(VALUE, C)				\
   ( (C) == 'I' ? (unsigned) ((VALUE) + 0x8000) < 0x10000	\
   : (C) == 'J' ? ((VALUE) & 0xffff) == 0			\
   : (C) == 'K' ? ((VALUE) & 0xffff0000) == 0			\
   : (C) == 'L' ? mask_constant (VALUE)				\
   : (C) == 'M' ? (VALUE) > 31					\
   : (C) == 'N' ? exact_log2 (VALUE) >= 0			\
   : (C) == 'O' ? (VALUE) == 0					\
   : (C) == 'P' ? (unsigned) ((- (VALUE)) + 0x8000) < 0x1000	\
   : 0)

/* Similar, but for floating constants, and defining letters G and H.
   Here VALUE is the CONST_DOUBLE rtx itself.

   We flag for special constants when we can copy the constant into
   a general register in two insns for DF and one insn for SF.  */

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

/* Optional extra constraints for this machine.

   For the RS/6000, `Q' means that this is a memory operand that is just
   an offset from a register.  */

#define EXTRA_CONSTRAINT(OP, C)						\
  ((C) == 'Q' ? GET_CODE (OP) == MEM && GET_CODE (XEXP (OP, 0)) == REG	\
   : (C) == 'R' ? LEGITIMATE_CONSTANT_POOL_ADDRESS_P (OP)		\
   : 0)

/* 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 RS/6000, we have to return NO_REGS when we want to reload a
   floating-point CONST_DOUBLE to force it to be copied to memory.  */

#define PREFERRED_RELOAD_CLASS(X,CLASS)	\
  ((GET_CODE (X) == CONST_DOUBLE			\
    && GET_MODE_CLASS (GET_MODE (X)) == MODE_FLOAT)	\
   ? NO_REGS : (CLASS))
   
/* Return the register class of a scratch register needed to copy IN into
   or out of a register in CLASS in MODE.  If it can be done directly,
   NO_REGS is returned.  */

#define SECONDARY_RELOAD_CLASS(CLASS,MODE,IN) \
  secondary_reload_class (CLASS, MODE, IN)

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

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

/* Return the maximum number of consecutive registers
   needed to represent mode MODE in a register of class CLASS.

   On RS/6000, this is the size of MODE in words,
   except in the FP regs, where a single reg is enough for two words.  */
#define CLASS_MAX_NREGS(CLASS, MODE)	\
 ((CLASS) == FLOAT_REGS			\
  ? ((GET_MODE_SIZE (MODE) + UNITS_PER_FP_WORD - 1) / UNITS_PER_FP_WORD) \
  : ((GET_MODE_SIZE (MODE) + UNITS_PER_WORD - 1) / UNITS_PER_WORD))

/* If defined, gives a class of registers that cannot be used as the
   operand of a SUBREG that changes the size of the object.  */

#define CLASS_CANNOT_CHANGE_SIZE	FLOAT_REGS

/* Stack layout; function entry, exit and calling.  */

/* Enumeration to give which calling sequence to use.  */
enum rs6000_abi {
  ABI_NONE,
  ABI_AIX,			/* IBM's AIX */
  ABI_V4			/* System V.4/eabi */
};

/* Structure used to define the rs6000 stack */
typedef struct rs6000_stack {
  int first_gp_reg_save;	/* first callee saved GP register used */
  int first_fp_reg_save;	/* first callee saved FP register used */
  int lr_save_p;		/* true if the link reg needs to be saved */
  int cr_save_p;		/* true if the CR reg needs to be saved */
  int push_p;			/* true if we need to allocate stack space */
  int calls_p;			/* true if the function makes any calls */
  enum rs6000_abi abi;		/* which ABI to use */
  int gp_save_offset;		/* offset to save GP regs from initial SP */
  int fp_save_offset;		/* offset to save FP regs from initial SP */
  int lr_save_offset;		/* offset to save LR from initial SP */
  int cr_save_offset;		/* offset to save CR from initial SP */
  int varargs_save_offset;	/* offset to save the varargs registers */
  int reg_size;			/* register size (4 or 8) */
  int varargs_size;		/* size to hold V.4 args passed in regs */
  int vars_size;		/* variable save area size */
  int parm_size;		/* outgoing parameter size */
  int save_size;		/* save area size */
  int fixed_size;		/* fixed size of stack frame */
  int gp_size;			/* size of saved GP registers */
  int fp_size;			/* size of saved FP registers */
  int cr_size;			/* size to hold CR if not in save_size */
  int total_size;		/* total bytes allocated for stack */
} rs6000_stack_t;

/* 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.

   On the RS/6000, we grow upwards, from the area after the outgoing
   arguments.  */
/* #define FRAME_GROWS_DOWNWARD */

/* Size of the outgoing register save area */
#define RS6000_REG_SAVE (TARGET_64BIT ? 64 : 32)

/* Size of the fixed area on the stack */
#define RS6000_SAVE_AREA (TARGET_64BIT ? 48 : 24)

/* Size of the V.4 varargs area if needed */
#define RS6000_VARARGS_AREA 0

/* Whether a V.4 varargs area is needed */
extern int rs6000_sysv_varargs_p;

/* Align an address */
#define ALIGN(n,a) (((n) + (a) - 1) & ~((a) - 1))

/* Size of V.4 varargs area in bytes */
#define RS6000_VARARGS_SIZE \
  ((GP_ARG_NUM_REG * (TARGET_64BIT ? 8 : 4)) + (FP_ARG_NUM_REG * 8) + 8)

/* Offset of V.4 varargs area */
#define RS6000_VARARGS_OFFSET \
  (ALIGN (current_function_outgoing_args_size, 8) + RS6000_SAVE_AREA)

/* 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. 

   On the RS/6000, the frame pointer is the same as the stack pointer,
   except for dynamic allocations.  So we start after the fixed area and
   outgoing parameter area.  */

#define STARTING_FRAME_OFFSET (ALIGN (current_function_outgoing_args_size, 8) \
			       + RS6000_VARARGS_AREA \
			       + RS6000_SAVE_AREA)

/* If we generate an insn to push BYTES bytes,
   this says how many the stack pointer really advances by.
   On RS/6000, don't define this because there are no push insns.  */
/*  #define PUSH_ROUNDING(BYTES) */

/* Offset of first parameter from the argument pointer register value.
   On the RS/6000, we define the argument pointer to the start of the fixed
   area.  */
#define FIRST_PARM_OFFSET(FNDECL) RS6000_SAVE_AREA

/* Define this if stack space is still allocated for a parameter passed
   in a register.  The value is the number of bytes allocated to this
   area.  */
#define REG_PARM_STACK_SPACE(FNDECL)	RS6000_REG_SAVE

/* Define this if the above stack space is to be considered part of the
   space allocated by the caller.  */
#define OUTGOING_REG_PARM_STACK_SPACE

/* This is the difference between the logical top of stack and the actual sp.

   For the RS/6000, sp points past the fixed area. */
#define STACK_POINTER_OFFSET RS6000_SAVE_AREA

/* Define this if the maximum size of all the outgoing args is to be
   accumulated and pushed during the prologue.  The amount can be
   found in the variable current_function_outgoing_args_size.  */
#define ACCUMULATE_OUTGOING_ARGS

/* 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.  */

#define RETURN_POPS_ARGS(FUNDECL,FUNTYPE,SIZE) 0

/* 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.

   On RS/6000 an integer value is in r3 and a floating-point value is in 
   fp1, unless -msoft-float.  */

#define FUNCTION_VALUE(VALTYPE, FUNC)	\
  gen_rtx (REG, TYPE_MODE (VALTYPE),	\
	   TREE_CODE (VALTYPE) == REAL_TYPE && TARGET_HARD_FLOAT ? 33 : 3)

/* 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, GET_MODE_CLASS (MODE) == MODE_FLOAT && TARGET_HARD_FLOAT ? 33 : 3)

/* The definition of this macro implies that there are cases where
   a scalar value cannot be returned in registers.

   For the RS/6000, any structure or union type is returned in memory.  */

#define RETURN_IN_MEMORY(TYPE) \
  (TYPE_MODE (TYPE) == BLKmode)

/* Minimum and maximum general purpose registers used to hold arguments.  */
#define GP_ARG_MIN_REG 3
#define GP_ARG_MAX_REG 10
#define GP_ARG_NUM_REG (GP_ARG_MAX_REG - GP_ARG_MIN_REG + 1)

/* Minimum and maximum floating point registers used to hold arguments.  */
#define FP_ARG_MIN_REG 33