h8300.c

Mac OS X 10.4.9 for x86 Source Code gcc 实现源代码

    default:
      return NO_REGS;
    }
}

/* Return the byte register name for a register rtx X.  B should be 0
   if you want a lower byte register.  B should be 1 if you want an
   upper byte register.  */

static const char *
byte_reg (rtx x, int b)
{
  static const char *const names_small[] = {
    "r0l", "r0h", "r1l", "r1h", "r2l", "r2h", "r3l", "r3h",
    "r4l", "r4h", "r5l", "r5h", "r6l", "r6h", "r7l", "r7h"
  };

  if (!REG_P (x))
    abort ();

  return names_small[REGNO (x) * 2 + b];
}

/* REGNO must be saved/restored across calls if this macro is true.  */

#define WORD_REG_USED(regno)						\
  (regno < SP_REG							\
   /* No need to save registers if this function will not return.  */	\
   && ! TREE_THIS_VOLATILE (current_function_decl)			\
   && (h8300_saveall_function_p (current_function_decl)			\
       /* Save any call saved register that was used.  */		\
       || (regs_ever_live[regno] && !call_used_regs[regno])		\
       /* Save the frame pointer if it was used.  */			\
       || (regno == HARD_FRAME_POINTER_REGNUM && regs_ever_live[regno])	\
       /* Save any register used in an interrupt handler.  */		\
       || (h8300_current_function_interrupt_function_p ()		\
	   && regs_ever_live[regno])					\
       /* Save call clobbered registers in non-leaf interrupt		\
	  handlers.  */							\
       || (h8300_current_function_interrupt_function_p ()		\
	   && call_used_regs[regno]					\
	   && !current_function_is_leaf)))

/* Output assembly language to FILE for the operation OP with operand size
   SIZE to adjust the stack pointer.  */

static void
h8300_emit_stack_adjustment (int sign, unsigned int size)
{
  /* If the frame size is 0, we don't have anything to do.  */
  if (size == 0)
    return;

  /* H8/300 cannot add/subtract a large constant with a single
     instruction.  If a temporary register is available, load the
     constant to it and then do the addition.  */
  if (TARGET_H8300
      && size > 4
      && !h8300_current_function_interrupt_function_p ()
      && !(cfun->static_chain_decl != NULL && sign < 0))
    {
      rtx r3 = gen_rtx_REG (Pmode, 3);
      emit_insn (gen_movhi (r3, GEN_INT (sign * size)));
      emit_insn (gen_addhi3 (stack_pointer_rtx,
			     stack_pointer_rtx, r3));
    }
  else
    {
      /* The stack adjustment made here is further optimized by the
	 splitter.  In case of H8/300, the splitter always splits the
	 addition emitted here to make the adjustment
	 interrupt-safe.  */
      if (Pmode == HImode)
	emit_insn (gen_addhi3 (stack_pointer_rtx,
			       stack_pointer_rtx, GEN_INT (sign * size)));
      else
	emit_insn (gen_addsi3 (stack_pointer_rtx,
			       stack_pointer_rtx, GEN_INT (sign * size)));
    }
}

/* Round up frame size SIZE.  */

static int
round_frame_size (int size)
{
  return ((size + STACK_BOUNDARY / BITS_PER_UNIT - 1)
	  & -STACK_BOUNDARY / BITS_PER_UNIT);
}

/* Compute which registers to push/pop.
   Return a bit vector of registers.  */

static unsigned int
compute_saved_regs (void)
{
  unsigned int saved_regs = 0;
  int regno;

  /* Construct a bit vector of registers to be pushed/popped.  */
  for (regno = 0; regno <= HARD_FRAME_POINTER_REGNUM; regno++)
    {
      if (WORD_REG_USED (regno))
	saved_regs |= 1 << regno;
    }

  /* Don't push/pop the frame pointer as it is treated separately.  */
  if (frame_pointer_needed)
    saved_regs &= ~(1 << HARD_FRAME_POINTER_REGNUM);

  return saved_regs;
}

/* Emit an insn to push register RN.  */

static void
push (int rn)
{
  rtx reg = gen_rtx_REG (word_mode, rn);
  rtx x;

  if (TARGET_H8300)
    x = gen_push_h8300 (reg);
  else if (!TARGET_NORMAL_MODE)
    x = gen_push_h8300hs_advanced (reg);
  else
    x = gen_push_h8300hs_normal (reg);
  x = emit_insn (x);
  REG_NOTES (x) = gen_rtx_EXPR_LIST (REG_INC, stack_pointer_rtx, 0);
}

/* Emit an insn to pop register RN.  */

static void
pop (int rn)
{
  rtx reg = gen_rtx_REG (word_mode, rn);
  rtx x;

  if (TARGET_H8300)
    x = gen_pop_h8300 (reg);
  else if (!TARGET_NORMAL_MODE)
    x = gen_pop_h8300hs_advanced (reg);
  else
    x = gen_pop_h8300hs_normal (reg);
  x = emit_insn (x);
  REG_NOTES (x) = gen_rtx_EXPR_LIST (REG_INC, stack_pointer_rtx, 0);
}

/* Emit an instruction to push or pop NREGS consecutive registers
   starting at register REGNO.  POP_P selects a pop rather than a
   push and RETURN_P is true if the instruction should return.

   It must be possible to do the requested operation in a single
   instruction.  If NREGS == 1 && !RETURN_P, use a normal push
   or pop insn.  Otherwise emit a parallel of the form:

     (parallel
       [(return)  ;; if RETURN_P
	(save or restore REGNO)
	(save or restore REGNO + 1)
	...
	(save or restore REGNO + NREGS - 1)
	(set sp (plus sp (const_int adjust)))]  */

static void
h8300_push_pop (int regno, int nregs, int pop_p, int return_p)
{
  int i, j;
  rtvec vec;
  rtx sp, offset;

  /* See whether we can use a simple push or pop.  */
  if (!return_p && nregs == 1)
    {
      if (pop_p)
	pop (regno);
      else
	push (regno);
      return;
    }

  /* We need one element for the return insn, if present, one for each
     register, and one for stack adjustment.  */
  vec = rtvec_alloc ((return_p != 0) + nregs + 1);
  sp = stack_pointer_rtx;
  i = 0;

  /* Add the return instruction.  */
  if (return_p)
    {
      RTVEC_ELT (vec, i) = gen_rtx_RETURN (VOIDmode);
      i++;
    }

  /* Add the register moves.  */
  for (j = 0; j < nregs; j++)
    {
      rtx lhs, rhs;

      if (pop_p)
	{
	  /* Register REGNO + NREGS - 1 is popped first.  Before the
	     stack adjustment, its slot is at address @sp.  */
	  lhs = gen_rtx_REG (SImode, regno + j);
	  rhs = gen_rtx_MEM (SImode, plus_constant (sp, (nregs - j - 1) * 4));
	}
      else
	{
	  /* Register REGNO is pushed first and will be stored at @(-4,sp).  */
	  lhs = gen_rtx_MEM (SImode, plus_constant (sp, (j + 1) * -4));
	  rhs = gen_rtx_REG (SImode, regno + j);
	}
      RTVEC_ELT (vec, i + j) = gen_rtx_SET (VOIDmode, lhs, rhs);
    }

  /* Add the stack adjustment.  */
  offset = GEN_INT ((pop_p ? nregs : -nregs) * 4);
  RTVEC_ELT (vec, i + j) = gen_rtx_SET (VOIDmode, sp,
					gen_rtx_PLUS (Pmode, sp, offset));

  emit_insn (gen_rtx_PARALLEL (VOIDmode, vec));
}

/* Return true if X has the value sp + OFFSET.  */

static int
h8300_stack_offset_p (rtx x, int offset)
{
  if (offset == 0)
    return x == stack_pointer_rtx;

  return (GET_CODE (x) == PLUS
	  && XEXP (x, 0) == stack_pointer_rtx
	  && GET_CODE (XEXP (x, 1)) == CONST_INT
	  && INTVAL (XEXP (x, 1)) == offset);
}

/* A subroutine of h8300_ldm_stm_parallel.  X is one pattern in
   something that may be an ldm or stm instruction.  If it fits
   the required template, return the register it loads or stores,
   otherwise return -1.

   LOAD_P is true if X should be a load, false if it should be a store.
   NREGS is the number of registers that the whole instruction is expected
   to load or store.  INDEX is the index of the register that X should
   load or store, relative to the lowest-numbered register.  */

static int
h8300_ldm_stm_regno (rtx x, int load_p, int index, int nregs)
{
  int regindex, memindex, offset;

  if (load_p)
    regindex = 0, memindex = 1, offset = (nregs - index - 1) * 4;
  else
    memindex = 0, regindex = 1, offset = (index + 1) * -4;

  if (GET_CODE (x) == SET
      && GET_CODE (XEXP (x, regindex)) == REG
      && GET_CODE (XEXP (x, memindex)) == MEM
      && h8300_stack_offset_p (XEXP (XEXP (x, memindex), 0), offset))
    return REGNO (XEXP (x, regindex));

  return -1;
}

/* Return true if the elements of VEC starting at FIRST describe an
   ldm or stm instruction (LOAD_P says which).  */

static int
h8300_ldm_stm_parallel (rtvec vec, int load_p, int first)
{
  rtx last;
  int nregs, i, regno, adjust;

  /* There must be a stack adjustment, a register move, and at least one
     other operation (a return or another register move).  */
  if (GET_NUM_ELEM (vec) < 3)
    return false;

  /* Get the range of registers to be pushed or popped.  */
  nregs = GET_NUM_ELEM (vec) - first - 1;
  regno = h8300_ldm_stm_regno (RTVEC_ELT (vec, first), load_p, 0, nregs);

  /* Check that the call to h8300_ldm_stm_regno succeeded and
     that we're only dealing with GPRs.  */
  if (regno < 0 || regno + nregs > 8)
    return false;

  /* 2-register h8s instructions must start with an even-numbered register.
     3- and 4-register instructions must start with er0 or er4.  */
  if (!TARGET_H8300SX)
    {
      if ((regno & 1) != 0)
	return false;
      if (nregs > 2 && (regno & 3) != 0)
	return false;
    }

  /* Check the other loads or stores.  */
  for (i = 1; i < nregs; i++)
    if (h8300_ldm_stm_regno (RTVEC_ELT (vec, first + i), load_p, i, nregs)
	!= regno + i)
      return false;

  /* Check the stack adjustment.  */
  last = RTVEC_ELT (vec, first + nregs);
  adjust = (load_p ? nregs : -nregs) * 4;
  return (GET_CODE (last) == SET
	  && SET_DEST (last) == stack_pointer_rtx
	  && h8300_stack_offset_p (SET_SRC (last), adjust));
}

/* Return true if X is an ldm.l pattern.  X is known to be parallel.  */

int
h8300_ldm_parallel (rtx x, enum machine_mode mode ATTRIBUTE_UNUSED)
{
  return h8300_ldm_stm_parallel (XVEC (x, 0), 1, 0);
}

/* Likewise stm.l.  */

int
h8300_stm_parallel (rtx x, enum machine_mode mode ATTRIBUTE_UNUSED)
{
  return h8300_ldm_stm_parallel (XVEC (x, 0), 0, 0);
}

/* Likewise rts/l and rte/l.  Note that the .md pattern will check
   for the return so there's no need to do that here.  */

int
h8300_return_parallel (rtx x, enum machine_mode mode ATTRIBUTE_UNUSED)
{
  return h8300_ldm_stm_parallel (XVEC (x, 0), 1, 1);
}

/* This is what the stack looks like after the prolog of
   a function with a frame has been set up:

   <args>
   PC
   FP			<- fp
   <locals>
   <saved registers>	<- sp

   This is what the stack looks like after the prolog of
   a function which doesn't have a frame:

   <args>
   PC
   <locals>
   <saved registers>	<- sp
*/

/* Generate RTL code for the function prologue.  */

void
h8300_expand_prologue (void)
{
  int regno;
  int saved_regs;
  int n_regs;

  /* If the current function has the OS_Task attribute set, then
     we have a naked prologue.  */
  if (h8300_os_task_function_p (current_function_decl))
    return;

  if (h8300_monitor_function_p (current_function_decl))
    /* My understanding of monitor functions is they act just like
       interrupt functions, except the prologue must mask
       interrupts.  */
    emit_insn (gen_monitor_prologue ());

  if (frame_pointer_needed)
    {
      /* Push fp.  */
      push (HARD_FRAME_POINTER_REGNUM);
      emit_move_insn (hard_frame_pointer_rtx, stack_pointer_rtx);
    }

  /* Push the rest of the registers in ascending order.  */
  saved_regs = compute_saved_regs ();
  for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno += n_regs)
    {
      n_regs = 1;
      if (saved_regs & (1 << regno))
	{
	  if (TARGET_H8300S)
	    {
	      /* See how many registers we can push at the same time.  */
	      if ((!TARGET_H8300SX || (regno & 3) == 0)
		  && ((saved_regs >> regno) & 0x0f) == 0x0f)
		n_regs = 4;

	      else if ((!TARGET_H8300SX || (regno & 3) == 0)
		       && ((saved_regs >> regno) & 0x07) == 0x07)
		n_regs = 3;

	      else if ((!TARGET_H8300SX || (regno & 1) == 0)
		       && ((saved_regs >> regno) & 0x03) == 0x03)
		n_regs = 2;
	    }

	  h8300_push_pop (regno, n_regs, 0, 0);
	}
    }

  /* Leave room for locals.  */
  h8300_emit_stack_adjustment (-1, round_frame_size (get_frame_size ()));
}

/* Return nonzero if we can use "rts" for the function currently being
   compiled.  */

int
h8300_can_use_return_insn_p (void)
{
  return (reload_completed
	  && !frame_pointer_needed
	  && get_frame_size () == 0
	  && compute_saved_regs () == 0);
}

/* Generate RTL code for the function epilogue.  */

void
h8300_expand_epilogue (void)
{
  int regno;
  int saved_regs;
  int n_regs;
  HOST_WIDE_INT frame_size;
  bool returned_p;

  if (h8300_os_task_function_p (current_function_decl))
    /* OS_Task epilogues are nearly naked -- they just have an
       rts instruction.  */
    return;

  frame_size = round_frame_size (get_frame_size ());
  returned_p = false;

  /* Deallocate locals.  */
  h8300_emit_stack_adjustment (1, frame_size);

  /* Pop the saved registers in descending order.  */
  saved_regs = compute_saved_regs ();
  for (regno = FIRST_PSEUDO_REGISTER - 1; regno >= 0; regno -= n_regs)
    {
      n_regs = 1;
      if (saved_regs & (1 << regno))
	{
	  if (TARGET_H8300S)
	    {
	      /* See how many registers we can pop at the same time.  */
	      if ((TARGET_H8300SX || (regno & 3) == 3)
		  && ((saved_regs << 3 >> regno) & 0x0f) == 0x0f)
		n_regs = 4;

	      else if ((TARGET_H8300SX || (regno & 3) == 2)
		       && ((saved_regs << 2 >> regno) & 0x07) == 0x07)
		n_regs = 3;

	      else if ((TARGET_H8300SX || (regno & 1) == 1)
		       && ((saved_regs << 1 >> regno) & 0x03) == 0x03)
		n_regs = 2;
	    }

	  /* See if this pop would be the last insn before the return.
	     If so, use rte/l or rts/l instead of pop or ldm.l.  */
	  if (TARGET_H8300SX
	      && !frame_pointer_needed
	      && frame_size == 0
	      && (saved_regs & ((1 << (regno - n_regs + 1)) - 1)) == 0)
	    returned_p = true;

	  h8300_push_pop (regno - n_regs + 1, n_regs, 1, returned_p);
	}
    }

  /* Pop frame pointer if we had one.  */
  if (frame_pointer_needed)
    {
      if (TARGET_H8300SX)
	returned_p = true;
      h8300_push_pop (HARD_FRAME_POINTER_REGNUM, 1, 1, returned_p);
    }

  if (!returned_p)