kc3-lang/libffi/src/powerpc/ffi_sysv.c

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• Hash : 43fc5bca
  Author :
  Date : 2015-08-03T23:34:05
  

  Correct powerpc sysv stack argument accounting ppc32 starts using the stack for integer arg passing when we run out of integer arg passing registers. Similarly, we start using the stack for floating point args when we run out of floating point registers. The decision on where an integer arg goes does not depend on number of floating point args, nor does the decision on where a floating point arg goes depend on number of integer args. Alignment of stack args also simply depends on number of stack args. This patch untangles the horrible mess we had, with intarg_count being wrongly used to count both integer args and stack words. * src/powerpc/ffi_sysv.c (ffi_prep_cif_sysv_core): Count fprs, gprs, and stack words separately. (ffi_prep_args_SYSV): Similarly.

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• src/powerpc/ffi_sysv.c

• /* -----------------------------------------------------------------------
     ffi_sysv.c - Copyright (C) 2013 IBM
                  Copyright (C) 2011 Anthony Green
                  Copyright (C) 2011 Kyle Moffett
                  Copyright (C) 2008 Red Hat, Inc
                  Copyright (C) 2007, 2008 Free Software Foundation, Inc
                  Copyright (c) 1998 Geoffrey Keating
  
     PowerPC Foreign Function Interface
  
     Permission is hereby granted, free of charge, to any person obtaining
     a copy of this software and associated documentation files (the
     ``Software''), to deal in the Software without restriction, including
     without limitation the rights to use, copy, modify, merge, publish,
     distribute, sublicense, and/or sell copies of the Software, and to
     permit persons to whom the Software is furnished to do so, subject to
     the following conditions:
  
     The above copyright notice and this permission notice shall be included
     in all copies or substantial portions of the Software.
  
     THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND, EXPRESS
     OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
     IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY CLAIM, DAMAGES OR
     OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
     ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     OTHER DEALINGS IN THE SOFTWARE.
     ----------------------------------------------------------------------- */
  
  #include "ffi.h"
  
  #ifndef POWERPC64
  #include "ffi_common.h"
  #include "ffi_powerpc.h"
  
  
  /* About the SYSV ABI.  */
  #define ASM_NEEDS_REGISTERS 6
  #define NUM_GPR_ARG_REGISTERS 8
  #define NUM_FPR_ARG_REGISTERS 8
  
  
  #if HAVE_LONG_DOUBLE_VARIANT && FFI_TYPE_LONGDOUBLE != FFI_TYPE_DOUBLE
  /* Adjust size of ffi_type_longdouble.  */
  void FFI_HIDDEN
  ffi_prep_types_sysv (ffi_abi abi)
  {
    if ((abi & (FFI_SYSV | FFI_SYSV_LONG_DOUBLE_128)) == FFI_SYSV)
      {
        ffi_type_longdouble.size = 8;
        ffi_type_longdouble.alignment = 8;
      }
    else
      {
        ffi_type_longdouble.size = 16;
        ffi_type_longdouble.alignment = 16;
      }
  }
  #endif
  
  /* Transform long double, double and float to other types as per abi.  */
  static int
  translate_float (int abi, int type)
  {
  #if FFI_TYPE_LONGDOUBLE != FFI_TYPE_DOUBLE
    if (type == FFI_TYPE_LONGDOUBLE
        && (abi & FFI_SYSV_LONG_DOUBLE_128) == 0)
      type = FFI_TYPE_DOUBLE;
  #endif
    if ((abi & FFI_SYSV_SOFT_FLOAT) != 0)
      {
        if (type == FFI_TYPE_FLOAT)
  	type = FFI_TYPE_UINT32;
        else if (type == FFI_TYPE_DOUBLE)
  	type = FFI_TYPE_UINT64;
  #if FFI_TYPE_LONGDOUBLE != FFI_TYPE_DOUBLE
        else if (type == FFI_TYPE_LONGDOUBLE)
  	type = FFI_TYPE_UINT128;
      }
    else if ((abi & FFI_SYSV_IBM_LONG_DOUBLE) == 0)
      {
        if (type == FFI_TYPE_LONGDOUBLE)
  	type = FFI_TYPE_STRUCT;
  #endif
      }
    return type;
  }
  
  /* Perform machine dependent cif processing */
  static ffi_status
  ffi_prep_cif_sysv_core (ffi_cif *cif)
  {
    ffi_type **ptr;
    unsigned bytes;
    unsigned i, fpr_count = 0, gpr_count = 0, stack_count = 0;
    unsigned flags = cif->flags;
    unsigned struct_copy_size = 0;
    unsigned type = cif->rtype->type;
    unsigned size = cif->rtype->size;
  
    /* The machine-independent calculation of cif->bytes doesn't work
       for us.  Redo the calculation.  */
  
    /* Space for the frame pointer, callee's LR, and the asm's temp regs.  */
    bytes = (2 + ASM_NEEDS_REGISTERS) * sizeof (int);
  
    /* Space for the GPR registers.  */
    bytes += NUM_GPR_ARG_REGISTERS * sizeof (int);
  
    /* Return value handling.  The rules for SYSV are as follows:
       - 32-bit (or less) integer values are returned in gpr3;
       - Structures of size <= 4 bytes also returned in gpr3;
       - 64-bit integer values and structures between 5 and 8 bytes are returned
       in gpr3 and gpr4;
       - Larger structures are allocated space and a pointer is passed as
       the first argument.
       - Single/double FP values are returned in fpr1;
       - long doubles (if not equivalent to double) are returned in
       fpr1,fpr2 for Linux and as for large structs for SysV.  */
  
    type = translate_float (cif->abi, type);
  
    switch (type)
      {
  #if FFI_TYPE_LONGDOUBLE != FFI_TYPE_DOUBLE
      case FFI_TYPE_LONGDOUBLE:
        flags |= FLAG_RETURNS_128BITS;
        /* Fall through.  */
  #endif
      case FFI_TYPE_DOUBLE:
        flags |= FLAG_RETURNS_64BITS;
        /* Fall through.  */
      case FFI_TYPE_FLOAT:
        flags |= FLAG_RETURNS_FP;
  #ifdef __NO_FPRS__
        return FFI_BAD_ABI;
  #endif
        break;
  
      case FFI_TYPE_UINT128:
        flags |= FLAG_RETURNS_128BITS;
        /* Fall through.  */
      case FFI_TYPE_UINT64:
      case FFI_TYPE_SINT64:
        flags |= FLAG_RETURNS_64BITS;
        break;
  
      case FFI_TYPE_STRUCT:
        /* The final SYSV ABI says that structures smaller or equal 8 bytes
  	 are returned in r3/r4.  A draft ABI used by linux instead
  	 returns them in memory.  */
        if ((cif->abi & FFI_SYSV_STRUCT_RET) != 0 && size <= 8)
  	{
  	  flags |= FLAG_RETURNS_SMST;
  	  break;
  	}
        gpr_count++;
        flags |= FLAG_RETVAL_REFERENCE;
        /* Fall through.  */
      case FFI_TYPE_VOID:
        flags |= FLAG_RETURNS_NOTHING;
        break;
  
      default:
        /* Returns 32-bit integer, or similar.  Nothing to do here.  */
        break;
      }
  
    /* The first NUM_GPR_ARG_REGISTERS words of integer arguments, and the
       first NUM_FPR_ARG_REGISTERS fp arguments, go in registers; the rest
       goes on the stack.  Structures and long doubles (if not equivalent
       to double) are passed as a pointer to a copy of the structure.
       Stuff on the stack needs to keep proper alignment.  */
    for (ptr = cif->arg_types, i = cif->nargs; i > 0; i--, ptr++)
      {
        unsigned short typenum = (*ptr)->type;
  
        typenum = translate_float (cif->abi, typenum);
  
        switch (typenum)
  	{
  #if FFI_TYPE_LONGDOUBLE != FFI_TYPE_DOUBLE
  	case FFI_TYPE_LONGDOUBLE:
  	  if (fpr_count >= NUM_FPR_ARG_REGISTERS - 1)
  	    {
  	      fpr_count = NUM_FPR_ARG_REGISTERS;
  	      /* 8-byte align long doubles.  */
  	      stack_count += stack_count & 1;
  	      stack_count += 4;
  	    }
  	  else
  	    fpr_count += 2;
  #ifdef __NO_FPRS__
  	  return FFI_BAD_ABI;
  #endif
  	  break;
  #endif
  
  	case FFI_TYPE_DOUBLE:
  	  if (fpr_count >= NUM_FPR_ARG_REGISTERS)
  	    {
  	      /* 8-byte align doubles.  */
  	      stack_count += stack_count & 1;
  	      stack_count += 2;
  	    }
  	  else
  	    fpr_count += 1;
  #ifdef __NO_FPRS__
  	  return FFI_BAD_ABI;
  #endif
  	  break;
  
  	case FFI_TYPE_FLOAT:
  	  if (fpr_count >= NUM_FPR_ARG_REGISTERS)
  	    /* Yes, we don't follow the ABI, but neither does gcc.  */
  	    stack_count += 1;
  	  else
  	    fpr_count += 1;
  #ifdef __NO_FPRS__
  	  return FFI_BAD_ABI;
  #endif
  	  break;
  
  	case FFI_TYPE_UINT128:
  	  /* A long double in FFI_LINUX_SOFT_FLOAT can use only a set
  	     of four consecutive gprs. If we do not have enough, we
  	     have to adjust the gpr_count value.  */
  	  if (gpr_count >= NUM_GPR_ARG_REGISTERS - 3)
  	    gpr_count = NUM_GPR_ARG_REGISTERS;
  	  if (gpr_count >= NUM_GPR_ARG_REGISTERS)
  	    stack_count += 4;
  	  else
  	    gpr_count += 4;
  	  break;
  
  	case FFI_TYPE_UINT64:
  	case FFI_TYPE_SINT64:
  	  /* 'long long' arguments are passed as two words, but
  	     either both words must fit in registers or both go
  	     on the stack.  If they go on the stack, they must
  	     be 8-byte-aligned.
  
  	     Also, only certain register pairs can be used for
  	     passing long long int -- specifically (r3,r4), (r5,r6),
  	     (r7,r8), (r9,r10).  */
  	  gpr_count += gpr_count & 1;
  	  if (gpr_count >= NUM_GPR_ARG_REGISTERS)
  	    {
  	      stack_count += stack_count & 1;
  	      stack_count += 2;
  	    }
  	  else
  	    gpr_count += 2;
  	  break;
  
  	case FFI_TYPE_STRUCT:
  	  /* We must allocate space for a copy of these to enforce
  	     pass-by-value.  Pad the space up to a multiple of 16
  	     bytes (the maximum alignment required for anything under
  	     the SYSV ABI).  */
  	  struct_copy_size += ((*ptr)->size + 15) & ~0xF;
  	  /* Fall through (allocate space for the pointer).  */
  
  	case FFI_TYPE_POINTER:
  	case FFI_TYPE_INT:
  	case FFI_TYPE_UINT32:
  	case FFI_TYPE_SINT32:
  	case FFI_TYPE_UINT16:
  	case FFI_TYPE_SINT16:
  	case FFI_TYPE_UINT8:
  	case FFI_TYPE_SINT8:
  	  /* Everything else is passed as a 4-byte word in a GPR, either
  	     the object itself or a pointer to it.  */
  	  if (gpr_count >= NUM_GPR_ARG_REGISTERS)
  	    stack_count += 1;
  	  else
  	    gpr_count += 1;
  	  break;
  
  	default:
  	  FFI_ASSERT (0);
  	}
      }
  
    if (fpr_count != 0)
      flags |= FLAG_FP_ARGUMENTS;
    if (gpr_count > 4)
      flags |= FLAG_4_GPR_ARGUMENTS;
    if (struct_copy_size != 0)
      flags |= FLAG_ARG_NEEDS_COPY;
  
    /* Space for the FPR registers, if needed.  */
    if (fpr_count != 0)
      bytes += NUM_FPR_ARG_REGISTERS * sizeof (double);
  
    /* Stack space.  */
    bytes += stack_count * sizeof (int);
  
    /* The stack space allocated needs to be a multiple of 16 bytes.  */
    bytes = (bytes + 15) & ~0xF;
  
    /* Add in the space for the copied structures.  */
    bytes += struct_copy_size;
  
    cif->flags = flags;
    cif->bytes = bytes;
  
    return FFI_OK;
  }
  
  ffi_status FFI_HIDDEN
  ffi_prep_cif_sysv (ffi_cif *cif)
  {
    if ((cif->abi & FFI_SYSV) == 0)
      {
        /* This call is from old code.  Translate to new ABI values.  */
        cif->flags |= FLAG_COMPAT;
        switch (cif->abi)
  	{
  	default:
  	  return FFI_BAD_ABI;
  
  	case FFI_COMPAT_SYSV:
  	  cif->abi = FFI_SYSV | FFI_SYSV_STRUCT_RET | FFI_SYSV_LONG_DOUBLE_128;
  	  break;
  
  	case FFI_COMPAT_GCC_SYSV:
  	  cif->abi = FFI_SYSV | FFI_SYSV_LONG_DOUBLE_128;
  	  break;
  
  	case FFI_COMPAT_LINUX:
  	  cif->abi = (FFI_SYSV | FFI_SYSV_IBM_LONG_DOUBLE
  		      | FFI_SYSV_LONG_DOUBLE_128);
  	  break;
  
  	case FFI_COMPAT_LINUX_SOFT_FLOAT:
  	  cif->abi = (FFI_SYSV | FFI_SYSV_SOFT_FLOAT | FFI_SYSV_IBM_LONG_DOUBLE
  		      | FFI_SYSV_LONG_DOUBLE_128);
  	  break;
  	}
      }
    return ffi_prep_cif_sysv_core (cif);
  }
  
  /* ffi_prep_args_SYSV is called by the assembly routine once stack space
     has been allocated for the function's arguments.
  
     The stack layout we want looks like this:
  
     |   Return address from ffi_call_SYSV 4bytes	|	higher addresses
     |--------------------------------------------|
     |   Previous backchain pointer	4	|       stack pointer here
     |--------------------------------------------|<+ <<<	on entry to
     |   Saved r28-r31			4*4	| |	ffi_call_SYSV
     |--------------------------------------------| |
     |   GPR registers r3-r10		8*4	| |	ffi_call_SYSV
     |--------------------------------------------| |
     |   FPR registers f1-f8 (optional)	8*8	| |
     |--------------------------------------------| |	stack	|
     |   Space for copied structures		| |	grows	|
     |--------------------------------------------| |	down    V
     |   Parameters that didn't fit in registers  | |
     |--------------------------------------------| |	lower addresses
     |   Space for callee's LR		4	| |
     |--------------------------------------------| |	stack pointer here
     |   Current backchain pointer	4	|-/	during
     |--------------------------------------------|   <<<	ffi_call_SYSV
  
  */
  
  void FFI_HIDDEN
  ffi_prep_args_SYSV (extended_cif *ecif, unsigned *const stack)
  {
    const unsigned bytes = ecif->cif->bytes;
    const unsigned flags = ecif->cif->flags;
  
    typedef union
    {
      char *c;
      unsigned *u;
      long long *ll;
      float *f;
      double *d;
    } valp;
  
    /* 'stacktop' points at the previous backchain pointer.  */
    valp stacktop;
  
    /* 'gpr_base' points at the space for gpr3, and grows upwards as
       we use GPR registers.  */
    valp gpr_base;
    valp gpr_end;
  
  #ifndef __NO_FPRS__
    /* 'fpr_base' points at the space for fpr1, and grows upwards as
       we use FPR registers.  */
    valp fpr_base;
    valp fpr_end;
  #endif
  
    /* 'copy_space' grows down as we put structures in it.  It should
       stay 16-byte aligned.  */
    valp copy_space;
  
    /* 'next_arg' grows up as we put parameters in it.  */
    valp next_arg;
  
    int i;
    ffi_type **ptr;
  #ifndef __NO_FPRS__
    double double_tmp;
  #endif
    union
    {
      void **v;
      char **c;
      signed char **sc;
      unsigned char **uc;
      signed short **ss;
      unsigned short **us;
      unsigned int **ui;
      long long **ll;
      float **f;
      double **d;
    } p_argv;
    size_t struct_copy_size;
    unsigned gprvalue;
  
    stacktop.c = (char *) stack + bytes;
    gpr_end.u = stacktop.u - ASM_NEEDS_REGISTERS;
    gpr_base.u = gpr_end.u - NUM_GPR_ARG_REGISTERS;
  #ifndef __NO_FPRS__
    fpr_end.d = gpr_base.d;
    fpr_base.d = fpr_end.d - NUM_FPR_ARG_REGISTERS;
    copy_space.c = ((flags & FLAG_FP_ARGUMENTS) ? fpr_base.c : gpr_base.c);
  #else
    copy_space.c = gpr_base.c;
  #endif
    next_arg.u = stack + 2;
  
    /* Check that everything starts aligned properly.  */
    FFI_ASSERT (((unsigned long) (char *) stack & 0xF) == 0);
    FFI_ASSERT (((unsigned long) copy_space.c & 0xF) == 0);
    FFI_ASSERT (((unsigned long) stacktop.c & 0xF) == 0);
    FFI_ASSERT ((bytes & 0xF) == 0);
    FFI_ASSERT (copy_space.c >= next_arg.c);
  
    /* Deal with return values that are actually pass-by-reference.  */
    if (flags & FLAG_RETVAL_REFERENCE)
      *gpr_base.u++ = (unsigned) (char *) ecif->rvalue;
  
    /* Now for the arguments.  */
    p_argv.v = ecif->avalue;
    for (ptr = ecif->cif->arg_types, i = ecif->cif->nargs;
         i > 0;
         i--, ptr++, p_argv.v++)
      {
        unsigned int typenum = (*ptr)->type;
  
        typenum = translate_float (ecif->cif->abi, typenum);
  
        /* Now test the translated value */
        switch (typenum)
  	{
  #ifndef __NO_FPRS__
  # if FFI_TYPE_LONGDOUBLE != FFI_TYPE_DOUBLE
  	case FFI_TYPE_LONGDOUBLE:
  	  double_tmp = (*p_argv.d)[0];
  
  	  if (fpr_base.d >= fpr_end.d - 1)
  	    {
  	      fpr_base.d = fpr_end.d;
  	      if (((next_arg.u - stack) & 1) != 0)
  		next_arg.u += 1;
  	      *next_arg.d = double_tmp;
  	      next_arg.u += 2;
  	      double_tmp = (*p_argv.d)[1];
  	      *next_arg.d = double_tmp;
  	      next_arg.u += 2;
  	    }
  	  else
  	    {
  	      *fpr_base.d++ = double_tmp;
  	      double_tmp = (*p_argv.d)[1];
  	      *fpr_base.d++ = double_tmp;
  	    }
  	  FFI_ASSERT (flags & FLAG_FP_ARGUMENTS);
  	  break;
  # endif
  	case FFI_TYPE_DOUBLE:
  	  double_tmp = **p_argv.d;
  
  	  if (fpr_base.d >= fpr_end.d)
  	    {
  	      if (((next_arg.u - stack) & 1) != 0)
  		next_arg.u += 1;
  	      *next_arg.d = double_tmp;
  	      next_arg.u += 2;
  	    }
  	  else
  	    *fpr_base.d++ = double_tmp;
  	  FFI_ASSERT (flags & FLAG_FP_ARGUMENTS);
  	  break;
  
  	case FFI_TYPE_FLOAT:
  	  double_tmp = **p_argv.f;
  	  if (fpr_base.d >= fpr_end.d)
  	    {
  	      *next_arg.f = (float) double_tmp;
  	      next_arg.u += 1;
  	    }
  	  else
  	    *fpr_base.d++ = double_tmp;
  	  FFI_ASSERT (flags & FLAG_FP_ARGUMENTS);
  	  break;
  #endif /* have FPRs */
  
  	case FFI_TYPE_UINT128:
  	  /* The soft float ABI for long doubles works like this, a long double
  	     is passed in four consecutive GPRs if available.  A maximum of 2
  	     long doubles can be passed in gprs.  If we do not have 4 GPRs
  	     left, the long double is passed on the stack, 4-byte aligned.  */
  	  if (gpr_base.u >= gpr_end.u - 3)
  	    {
  	      unsigned int ii;
  	      gpr_base.u = gpr_end.u;
  	      for (ii = 0; ii < 4; ii++)
  		{
  		  unsigned int int_tmp = (*p_argv.ui)[ii];
  		  *next_arg.u++ = int_tmp;
  		}
  	    }
  	  else
  	    {
  	      unsigned int ii;
  	      for (ii = 0; ii < 4; ii++)
  		{
  		  unsigned int int_tmp = (*p_argv.ui)[ii];
  		  *gpr_base.u++ = int_tmp;
  		}
  	    }
  	  break;
  
  	case FFI_TYPE_UINT64:
  	case FFI_TYPE_SINT64:
  	  if (gpr_base.u >= gpr_end.u - 1)
  	    {
  	      gpr_base.u = gpr_end.u;
  	      if (((next_arg.u - stack) & 1) != 0)
  		next_arg.u++;
  	      *next_arg.ll = **p_argv.ll;
  	      next_arg.u += 2;
  	    }
  	  else
  	    {
  	      /* The abi states only certain register pairs can be
  		 used for passing long long int specifically (r3,r4),
  		 (r5,r6), (r7,r8), (r9,r10).  If next arg is long long
  		 but not correct starting register of pair then skip
  		 until the proper starting register.  */
  	      if (((gpr_end.u - gpr_base.u) & 1) != 0)
  		gpr_base.u++;
  	      *gpr_base.ll++ = **p_argv.ll;
  	    }
  	  break;
  
  	case FFI_TYPE_STRUCT:
  	  struct_copy_size = ((*ptr)->size + 15) & ~0xF;
  	  copy_space.c -= struct_copy_size;
  	  memcpy (copy_space.c, *p_argv.c, (*ptr)->size);
  
  	  gprvalue = (unsigned long) copy_space.c;
  
  	  FFI_ASSERT (copy_space.c > next_arg.c);
  	  FFI_ASSERT (flags & FLAG_ARG_NEEDS_COPY);
  	  goto putgpr;
  
  	case FFI_TYPE_UINT8:
  	  gprvalue = **p_argv.uc;
  	  goto putgpr;
  	case FFI_TYPE_SINT8:
  	  gprvalue = **p_argv.sc;
  	  goto putgpr;
  	case FFI_TYPE_UINT16:
  	  gprvalue = **p_argv.us;
  	  goto putgpr;
  	case FFI_TYPE_SINT16:
  	  gprvalue = **p_argv.ss;
  	  goto putgpr;
  
  	case FFI_TYPE_INT:
  	case FFI_TYPE_UINT32:
  	case FFI_TYPE_SINT32:
  	case FFI_TYPE_POINTER:
  
  	  gprvalue = **p_argv.ui;
  
  	putgpr:
  	  if (gpr_base.u >= gpr_end.u)
  	    *next_arg.u++ = gprvalue;
  	  else
  	    *gpr_base.u++ = gprvalue;
  	  break;
  	}
      }
  
    /* Check that we didn't overrun the stack...  */
    FFI_ASSERT (copy_space.c >= next_arg.c);
    FFI_ASSERT (gpr_base.u <= gpr_end.u);
  #ifndef __NO_FPRS__
    FFI_ASSERT (fpr_base.u <= fpr_end.u);
  #endif
    FFI_ASSERT (((flags & FLAG_4_GPR_ARGUMENTS) != 0)
  	      == (gpr_end.u - gpr_base.u < 4));
  }
  
  #define MIN_CACHE_LINE_SIZE 8
  
  static void
  flush_icache (char *wraddr, char *xaddr, int size)
  {
    int i;
    for (i = 0; i < size; i += MIN_CACHE_LINE_SIZE)
      __asm__ volatile ("icbi 0,%0;" "dcbf 0,%1;"
  		      : : "r" (xaddr + i), "r" (wraddr + i) : "memory");
    __asm__ volatile ("icbi 0,%0;" "dcbf 0,%1;" "sync;" "isync;"
  		    : : "r"(xaddr + size - 1), "r"(wraddr + size - 1)
  		    : "memory");
  }
  
  ffi_status FFI_HIDDEN
  ffi_prep_closure_loc_sysv (ffi_closure *closure,
  			   ffi_cif *cif,
  			   void (*fun) (ffi_cif *, void *, void **, void *),
  			   void *user_data,
  			   void *codeloc)
  {
    unsigned int *tramp;
  
    if (cif->abi < FFI_SYSV || cif->abi >= FFI_LAST_ABI)
      return FFI_BAD_ABI;
  
    tramp = (unsigned int *) &closure->tramp[0];
    tramp[0] = 0x7c0802a6;  /*   mflr    r0 */
    tramp[1] = 0x429f0005;  /*   bcl     20,31,.+4 */
    tramp[2] = 0x7d6802a6;  /*   mflr    r11 */
    tramp[3] = 0x7c0803a6;  /*   mtlr    r0 */
    tramp[4] = 0x800b0018;  /*   lwz     r0,24(r11) */
    tramp[5] = 0x816b001c;  /*   lwz     r11,28(r11) */
    tramp[6] = 0x7c0903a6;  /*   mtctr   r0 */
    tramp[7] = 0x4e800420;  /*   bctr */
    *(void **) &tramp[8] = (void *) ffi_closure_SYSV; /* function */
    *(void **) &tramp[9] = codeloc;                   /* context */
  
    /* Flush the icache.  */
    flush_icache ((char *)tramp, (char *)codeloc, 8 * 4);
  
    closure->cif = cif;
    closure->fun = fun;
    closure->user_data = user_data;
  
    return FFI_OK;
  }
  
  /* Basically the trampoline invokes ffi_closure_SYSV, and on
     entry, r11 holds the address of the closure.
     After storing the registers that could possibly contain
     parameters to be passed into the stack frame and setting
     up space for a return value, ffi_closure_SYSV invokes the
     following helper function to do most of the work.  */
  
  int
  ffi_closure_helper_SYSV (ffi_cif *cif,
  			 void (*fun) (ffi_cif *, void *, void **, void *),
  			 void *user_data,
  			 void *rvalue,
  			 unsigned long *pgr,
  			 ffi_dblfl *pfr,
  			 unsigned long *pst)
  {
    /* rvalue is the pointer to space for return value in closure assembly */
    /* pgr is the pointer to where r3-r10 are stored in ffi_closure_SYSV */
    /* pfr is the pointer to where f1-f8 are stored in ffi_closure_SYSV  */
    /* pst is the pointer to outgoing parameter stack in original caller */
  
    void **          avalue;
    ffi_type **      arg_types;
    long             i, avn;
  #ifndef __NO_FPRS__
    long             nf = 0;   /* number of floating registers already used */
  #endif
    long             ng = 0;   /* number of general registers already used */
  
    unsigned       size     = cif->rtype->size;
    unsigned short rtypenum = cif->rtype->type;
  
    avalue = alloca (cif->nargs * sizeof (void *));
  
    /* First translate for softfloat/nonlinux */
    rtypenum = translate_float (cif->abi, rtypenum);
  
    /* Copy the caller's structure return value address so that the closure
       returns the data directly to the caller.
       For FFI_SYSV the result is passed in r3/r4 if the struct size is less
       or equal 8 bytes.  */
    if (rtypenum == FFI_TYPE_STRUCT
        && !((cif->abi & FFI_SYSV_STRUCT_RET) != 0 && size <= 8))
      {
        rvalue = (void *) *pgr;
        ng++;
        pgr++;
      }
  
    i = 0;
    avn = cif->nargs;
    arg_types = cif->arg_types;
  
    /* Grab the addresses of the arguments from the stack frame.  */
    while (i < avn) {
      unsigned short typenum = arg_types[i]->type;
  
      /* We may need to handle some values depending on ABI.  */
      typenum = translate_float (cif->abi, typenum);
  
      switch (typenum)
        {
  #ifndef __NO_FPRS__
        case FFI_TYPE_FLOAT:
  	/* Unfortunately float values are stored as doubles
  	   in the ffi_closure_SYSV code (since we don't check
  	   the type in that routine).  */
  	if (nf < NUM_FPR_ARG_REGISTERS)
  	  {
  	    /* FIXME? here we are really changing the values
  	       stored in the original calling routines outgoing
  	       parameter stack.  This is probably a really
  	       naughty thing to do but...  */
  	    double temp = pfr->d;
  	    pfr->f = (float) temp;
  	    avalue[i] = pfr;
  	    nf++;
  	    pfr++;
  	  }
  	else
  	  {
  	    avalue[i] = pst;
  	    pst += 1;
  	  }
  	break;
  
        case FFI_TYPE_DOUBLE:
  	if (nf < NUM_FPR_ARG_REGISTERS)
  	  {
  	    avalue[i] = pfr;
  	    nf++;
  	    pfr++;
  	  }
  	else
  	  {
  	    if (((long) pst) & 4)
  	      pst++;
  	    avalue[i] = pst;
  	    pst += 2;
  	  }
  	break;
  
  # if FFI_TYPE_LONGDOUBLE != FFI_TYPE_DOUBLE
        case FFI_TYPE_LONGDOUBLE:
  	if (nf < NUM_FPR_ARG_REGISTERS - 1)
  	  {
  	    avalue[i] = pfr;
  	    pfr += 2;
  	    nf += 2;
  	  }
  	else
  	  {
  	    if (((long) pst) & 4)
  	      pst++;
  	    avalue[i] = pst;
  	    pst += 4;
  	    nf = 8;
  	  }
  	break;
  # endif
  #endif
  
        case FFI_TYPE_UINT128:
  	/* Test if for the whole long double, 4 gprs are available.
  	   otherwise the stuff ends up on the stack.  */
  	if (ng < NUM_GPR_ARG_REGISTERS - 3)
  	  {
  	    avalue[i] = pgr;
  	    pgr += 4;
  	    ng += 4;
  	  }
  	else
  	  {
  	    avalue[i] = pst;
  	    pst += 4;
  	    ng = 8+4;
  	  }
  	break;
  
        case FFI_TYPE_SINT8:
        case FFI_TYPE_UINT8:
  #ifndef __LITTLE_ENDIAN__
  	if (ng < NUM_GPR_ARG_REGISTERS)
  	  {
  	    avalue[i] = (char *) pgr + 3;
  	    ng++;
  	    pgr++;
  	  }
  	else
  	  {
  	    avalue[i] = (char *) pst + 3;
  	    pst++;
  	  }
  	break;
  #endif
  
        case FFI_TYPE_SINT16:
        case FFI_TYPE_UINT16:
  #ifndef __LITTLE_ENDIAN__
  	if (ng < NUM_GPR_ARG_REGISTERS)
  	  {
  	    avalue[i] = (char *) pgr + 2;
  	    ng++;
  	    pgr++;
  	  }
  	else
  	  {
  	    avalue[i] = (char *) pst + 2;
  	    pst++;
  	  }
  	break;
  #endif
  
        case FFI_TYPE_SINT32:
        case FFI_TYPE_UINT32:
        case FFI_TYPE_POINTER:
  	if (ng < NUM_GPR_ARG_REGISTERS)
  	  {
  	    avalue[i] = pgr;
  	    ng++;
  	    pgr++;
  	  }
  	else
  	  {
  	    avalue[i] = pst;
  	    pst++;
  	  }
  	break;
  
        case FFI_TYPE_STRUCT:
  	/* Structs are passed by reference. The address will appear in a
  	   gpr if it is one of the first 8 arguments.  */
  	if (ng < NUM_GPR_ARG_REGISTERS)
  	  {
  	    avalue[i] = (void *) *pgr;
  	    ng++;
  	    pgr++;
  	  }
  	else
  	  {
  	    avalue[i] = (void *) *pst;
  	    pst++;
  	  }
  	break;
  
        case FFI_TYPE_SINT64:
        case FFI_TYPE_UINT64:
  	/* Passing long long ints are complex, they must
  	   be passed in suitable register pairs such as
  	   (r3,r4) or (r5,r6) or (r6,r7), or (r7,r8) or (r9,r10)
  	   and if the entire pair aren't available then the outgoing
  	   parameter stack is used for both but an alignment of 8
  	   must will be kept.  So we must either look in pgr
  	   or pst to find the correct address for this type
  	   of parameter.  */
  	if (ng < NUM_GPR_ARG_REGISTERS - 1)
  	  {
  	    if (ng & 1)
  	      {
  		/* skip r4, r6, r8 as starting points */
  		ng++;
  		pgr++;
  	      }
  	    avalue[i] = pgr;
  	    ng += 2;
  	    pgr += 2;
  	  }
  	else
  	  {
  	    if (((long) pst) & 4)
  	      pst++;
  	    avalue[i] = pst;
  	    pst += 2;
  	    ng = NUM_GPR_ARG_REGISTERS;
  	  }
  	break;
  
        default:
  	FFI_ASSERT (0);
        }
  
      i++;
    }
  
    (*fun) (cif, rvalue, avalue, user_data);
  
    /* Tell ffi_closure_SYSV how to perform return type promotions.
       Because the FFI_SYSV ABI returns the structures <= 8 bytes in
       r3/r4 we have to tell ffi_closure_SYSV how to treat them.  We
       combine the base type FFI_SYSV_TYPE_SMALL_STRUCT with the size of
       the struct less one.  We never have a struct with size zero.
       See the comment in ffitarget.h about ordering.  */
    if (rtypenum == FFI_TYPE_STRUCT
        && (cif->abi & FFI_SYSV_STRUCT_RET) != 0 && size <= 8)
      return FFI_SYSV_TYPE_SMALL_STRUCT - 1 + size;
    return rtypenum;
  }
  #endif
  

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