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/*

 *  ARMv4 code generator for TCC

 *

 *  Copyright (c) 2003 Daniel Glöckner

 *  Copyright (c) 2012 Thomas Preud'homme

 *

 *  Based on i386-gen.c by Fabrice Bellard

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library 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

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

#ifdef TARGET_DEFS_ONLY

#if defined(TCC_ARM_EABI) && !defined(TCC_ARM_VFP)

#error "Currently TinyCC only supports float computation with VFP instructions"

#endif

/* number of available registers */

#ifdef TCC_ARM_VFP

#define NB_REGS            13

#else

#define NB_REGS             9

#endif

#ifndef TCC_ARM_VERSION

# define TCC_ARM_VERSION 5

#endif

/* a register can belong to several classes. The classes must be

   sorted from more general to more precise (see gv2() code which does

   assumptions on it). */

#define RC_INT     0x0001 /* generic integer register */

#define RC_FLOAT   0x0002 /* generic float register */

#define RC_R0      0x0004

#define RC_R1      0x0008

#define RC_R2      0x0010

#define RC_R3      0x0020

#define RC_R12     0x0040

#define RC_F0      0x0080

#define RC_F1      0x0100

#define RC_F2      0x0200

#define RC_F3      0x0400

#ifdef TCC_ARM_VFP

#define RC_F4      0x0800

#define RC_F5      0x1000

#define RC_F6      0x2000

#define RC_F7      0x4000

#endif

#define RC_IRET    RC_R0  /* function return: integer register */

#define RC_LRET    RC_R1  /* function return: second integer register */

#define RC_FRET    RC_F0  /* function return: float register */

/* pretty names for the registers */

enum {

    TREG_R0 = 0,

    TREG_R1,

    TREG_R2,

    TREG_R3,

    TREG_R12,

    TREG_F0,

    TREG_F1,

    TREG_F2,

    TREG_F3,

#ifdef TCC_ARM_VFP

    TREG_F4,

    TREG_F5,

    TREG_F6,

    TREG_F7,

#endif

};

#ifdef TCC_ARM_VFP

#define T2CPR(t) (((t) & VT_BTYPE) != VT_FLOAT ? 0x100 : 0)

#endif

/* return registers for function */

#define REG_IRET TREG_R0 /* single word int return register */

#define REG_LRET TREG_R1 /* second word return register (for long long) */

#define REG_FRET TREG_F0 /* float return register */

#ifdef TCC_ARM_EABI

#define TOK___divdi3 TOK___aeabi_ldivmod

#define TOK___moddi3 TOK___aeabi_ldivmod

#define TOK___udivdi3 TOK___aeabi_uldivmod

#define TOK___umoddi3 TOK___aeabi_uldivmod

#endif

/* defined if function parameters must be evaluated in reverse order */

#define INVERT_FUNC_PARAMS

/* defined if structures are passed as pointers. Otherwise structures

   are directly pushed on stack. */

/* #define FUNC_STRUCT_PARAM_AS_PTR */

/* pointer size, in bytes */

#define PTR_SIZE 4

/* long double size and alignment, in bytes */

#ifdef TCC_ARM_VFP

#define LDOUBLE_SIZE  8

#endif

#ifndef LDOUBLE_SIZE

#define LDOUBLE_SIZE  8

#endif

#ifdef TCC_ARM_EABI

#define LDOUBLE_ALIGN 8

#else

#define LDOUBLE_ALIGN 4

#endif

/* maximum alignment (for aligned attribute support) */

#define MAX_ALIGN     8

#define CHAR_IS_UNSIGNED

/******************************************************/

/* ELF defines */

#define EM_TCC_TARGET EM_ARM

/* relocation type for 32 bit data relocation */

#define R_DATA_32   R_ARM_ABS32

#define R_DATA_PTR  R_ARM_ABS32

#define R_JMP_SLOT  R_ARM_JUMP_SLOT

#define R_COPY      R_ARM_COPY

#define ELF_START_ADDR 0x00008000

#define ELF_PAGE_SIZE  0x1000

enum float_abi {

    ARM_SOFTFP_FLOAT,

    ARM_HARD_FLOAT,

};

/******************************************************/

#else /* ! TARGET_DEFS_ONLY */

/******************************************************/

#include "tcc.h"

enum float_abi float_abi;

ST_DATA const int reg_classes[NB_REGS] = {

    /* r0 */ RC_INT | RC_R0,

    /* r1 */ RC_INT | RC_R1,

    /* r2 */ RC_INT | RC_R2,

    /* r3 */ RC_INT | RC_R3,

    /* r12 */ RC_INT | RC_R12,

    /* f0 */ RC_FLOAT | RC_F0,

    /* f1 */ RC_FLOAT | RC_F1,

    /* f2 */ RC_FLOAT | RC_F2,

    /* f3 */ RC_FLOAT | RC_F3,

#ifdef TCC_ARM_VFP

 /* d4/s8 */ RC_FLOAT | RC_F4,

/* d5/s10 */ RC_FLOAT | RC_F5,

/* d6/s12 */ RC_FLOAT | RC_F6,

/* d7/s14 */ RC_FLOAT | RC_F7,

#endif

};

static int func_sub_sp_offset, last_itod_magic;

static int leaffunc;

#if defined(TCC_ARM_EABI) && defined(TCC_ARM_VFP)

static CType float_type, double_type, func_float_type, func_double_type;

ST_FUNC void arm_init(struct TCCState *s)

{

    float_type.t = VT_FLOAT;

    double_type.t = VT_DOUBLE;

    func_float_type.t = VT_FUNC;

    func_float_type.ref = sym_push(SYM_FIELD, &float_type, FUNC_CDECL, FUNC_OLD);

    func_double_type.t = VT_FUNC;

    func_double_type.ref = sym_push(SYM_FIELD, &double_type, FUNC_CDECL, FUNC_OLD);

    float_abi = s->float_abi;

#ifndef TCC_ARM_HARDFLOAT

    tcc_warning("soft float ABI currently not supported: default to softfp");

#endif

}

#else

#define func_float_type func_old_type

#define func_double_type func_old_type

#define func_ldouble_type func_old_type

ST_FUNC void arm_init(struct TCCState *s)

{

#if !defined (TCC_ARM_VFP)

    tcc_warning("Support for FPA is deprecated and will be removed in next"

                " release");

#endif

#if !defined (TCC_ARM_EABI)

    tcc_warning("Support for OABI is deprecated and will be removed in next"

                " release");

#endif

}

#endif

static int two2mask(int a,int b) {

  return (reg_classes[a]|reg_classes[b])&~(RC_INT|RC_FLOAT);

}

static int regmask(int r) {

  return reg_classes[r]&~(RC_INT|RC_FLOAT);

}

/******************************************************/

#if defined(TCC_ARM_EABI) && !defined(CONFIG_TCC_ELFINTERP)

char *default_elfinterp(struct TCCState *s)

{

    if (s->float_abi == ARM_HARD_FLOAT)

        return "/lib/ld-linux-armhf.so.3";

    else

        return "/lib/ld-linux.so.3";

}

#endif

void o(uint32_t i)

{

  /* this is a good place to start adding big-endian support*/

  int ind1;

  ind1 = ind + 4;

  if (!cur_text_section)

    tcc_error("compiler error! This happens f.ex. if the compiler\n"

         "can't evaluate constant expressions outside of a function.");

  if (ind1 > cur_text_section->data_allocated)

    section_realloc(cur_text_section, ind1);

  cur_text_section->data[ind++] = i&255;

  i>>=8;

  cur_text_section->data[ind++] = i&255;

  i>>=8;

  cur_text_section->data[ind++] = i&255;

  i>>=8;

  cur_text_section->data[ind++] = i;

}

static uint32_t stuff_const(uint32_t op, uint32_t c)

{

  int try_neg=0;

  uint32_t nc = 0, negop = 0;

  switch(op&0x1F00000)

  {

    case 0x800000: //add

    case 0x400000: //sub

      try_neg=1;

      negop=op^0xC00000;

      nc=-c;

      break;

    case 0x1A00000: //mov

    case 0x1E00000: //mvn

      try_neg=1;

      negop=op^0x400000;

      nc=~c;

      break;

    case 0x200000: //xor

      if(c==~0)

	return (op&0xF010F000)|((op>>16)&0xF)|0x1E00000;

      break;

    case 0x0: //and

      if(c==~0)

	return (op&0xF010F000)|((op>>16)&0xF)|0x1A00000;

    case 0x1C00000: //bic

      try_neg=1;

      negop=op^0x1C00000;

      nc=~c;

      break;

    case 0x1800000: //orr

      if(c==~0)

	return (op&0xFFF0FFFF)|0x1E00000;

      break;

  }

  do {

    uint32_t m;

    int i;

    if(c<256) /* catch undefined <<32 */

      return op|c;

    for(i=2;i<32;i+=2) {

      m=(0xff>>i)|(0xff<<(32-i));

      if(!(c&~m))

	return op|(i<<7)|(c<>(32-i));

    }

    op=negop;

    c=nc;

  } while(try_neg--);

  return 0;

}

//only add,sub

void stuff_const_harder(uint32_t op, uint32_t v) {

  uint32_t x;

  x=stuff_const(op,v);

  if(x)

    o(x);

  else {

    uint32_t a[16], nv, no, o2, n2;

    int i,j,k;

    a[0]=0xff;

    o2=(op&0xfff0ffff)|((op&0xf000)<<4);;

    for(i=1;i<16;i++)

      a[i]=(a[i-1]>>2)|(a[i-1]<<30);

    for(i=0;i<12;i++)

      for(j=i<4?i+12:15;j>=i+4;j--)

	if((v&(a[i]|a[j]))==v) {

	  o(stuff_const(op,v&a[i]));

	  o(stuff_const(o2,v&a[j]));

	  return;

	}

    no=op^0xC00000;

    n2=o2^0xC00000;

    nv=-v;

    for(i=0;i<12;i++)

      for(j=i<4?i+12:15;j>=i+4;j--)

	if((nv&(a[i]|a[j]))==nv) {

	  o(stuff_const(no,nv&a[i]));

	  o(stuff_const(n2,nv&a[j]));

	  return;

	}

    for(i=0;i<8;i++)

      for(j=i+4;j<12;j++)

	for(k=i<4?i+12:15;k>=j+4;k--)

	  if((v&(a[i]|a[j]|a[k]))==v) {

	    o(stuff_const(op,v&a[i]));

	    o(stuff_const(o2,v&a[j]));

	    o(stuff_const(o2,v&a[k]));

	    return;

	  }

    no=op^0xC00000;

    nv=-v;

    for(i=0;i<8;i++)

      for(j=i+4;j<12;j++)

	for(k=i<4?i+12:15;k>=j+4;k--)

	  if((nv&(a[i]|a[j]|a[k]))==nv) {

	    o(stuff_const(no,nv&a[i]));

	    o(stuff_const(n2,nv&a[j]));

	    o(stuff_const(n2,nv&a[k]));

	    return;

	  }

    o(stuff_const(op,v&a[0]));

    o(stuff_const(o2,v&a[4]));

    o(stuff_const(o2,v&a[8]));

    o(stuff_const(o2,v&a[12]));

  }

}

ST_FUNC uint32_t encbranch(int pos, int addr, int fail)

{

  addr-=pos+8;

  addr/=4;

  if(addr>=0x1000000 || addr<-0x1000000) {

    if(fail)

      tcc_error("FIXME: function bigger than 32MB");

    return 0;

  }

  return 0x0A000000|(addr&0xffffff);

}

int decbranch(int pos)

{

  int x;

  x=*(uint32_t *)(cur_text_section->data + pos);

  x&=0x00ffffff;

  if(x&0x800000)

    x-=0x1000000;

  return x*4+pos+8;

}

/* output a symbol and patch all calls to it */

void gsym_addr(int t, int a)

{

  uint32_t *x;

  int lt;

  while(t) {

    x=(uint32_t *)(cur_text_section->data + t);

    t=decbranch(lt=t);

    if(a==lt+4)

      *x=0xE1A00000; // nop

    else {

      *x &= 0xff000000;

      *x |= encbranch(lt,a,1);

    }

  }

}

void gsym(int t)

{

  gsym_addr(t, ind);

}

#ifdef TCC_ARM_VFP

static uint32_t vfpr(int r)

{

  if(rTREG_F7)

    tcc_error("compiler error! register %i is no vfp register",r);

  return r-5;

}

#else

static uint32_t fpr(int r)

{

  if(rTREG_F3)

    tcc_error("compiler error! register %i is no fpa register",r);

  return r-5;

}

#endif

static uint32_t intr(int r)

{

  if(r==4)

    return 12;

  if((r<0 || r>4) && r!=14)

    tcc_error("compiler error! register %i is no int register",r);

  return r;

}

static void calcaddr(uint32_t *base, int *off, int *sgn, int maxoff, unsigned shift)

{

  if(*off>maxoff || *off&((1<

    uint32_t x, y;

    x=0xE280E000;

    if(*sgn)

      x=0xE240E000;

    x|=(*base)<<16;

    *base=14; // lr

    y=stuff_const(x,*off&~maxoff);

    if(y) {

      o(y);

      *off&=maxoff;

      return;

    }

    y=stuff_const(x,(*off+maxoff)&~maxoff);

    if(y) {

      o(y);

      *sgn=!*sgn;

      *off=((*off+maxoff)&~maxoff)-*off;

      return;

    }

    stuff_const_harder(x,*off&~maxoff);

    *off&=maxoff;

  }

}

static uint32_t mapcc(int cc)

{

  switch(cc)

  {

    case TOK_ULT:

      return 0x30000000; /* CC/LO */

    case TOK_UGE:

      return 0x20000000; /* CS/HS */

    case TOK_EQ:

      return 0x00000000; /* EQ */

    case TOK_NE:

      return 0x10000000; /* NE */

    case TOK_ULE:

      return 0x90000000; /* LS */

    case TOK_UGT:

      return 0x80000000; /* HI */

    case TOK_Nset:

      return 0x40000000; /* MI */

    case TOK_Nclear:

      return 0x50000000; /* PL */

    case TOK_LT:

      return 0xB0000000; /* LT */

    case TOK_GE:

      return 0xA0000000; /* GE */

    case TOK_LE:

      return 0xD0000000; /* LE */

    case TOK_GT:

      return 0xC0000000; /* GT */

  }

  tcc_error("unexpected condition code");

  return 0xE0000000; /* AL */

}

static int negcc(int cc)

{

  switch(cc)

  {

    case TOK_ULT:

      return TOK_UGE;

    case TOK_UGE:

      return TOK_ULT;

    case TOK_EQ:

      return TOK_NE;

    case TOK_NE:

      return TOK_EQ;

    case TOK_ULE:

      return TOK_UGT;

    case TOK_UGT:

      return TOK_ULE;

    case TOK_Nset:

      return TOK_Nclear;

    case TOK_Nclear:

      return TOK_Nset;

    case TOK_LT:

      return TOK_GE;

    case TOK_GE:

      return TOK_LT;

    case TOK_LE:

      return TOK_GT;

    case TOK_GT:

      return TOK_LE;

  }

  tcc_error("unexpected condition code");

  return TOK_NE;

}

/* load 'r' from value 'sv' */

void load(int r, SValue *sv)

{

  int v, ft, fc, fr, sign;

  uint32_t op;

  SValue v1;

  fr = sv->r;

  ft = sv->type.t;

  fc = sv->c.i;

  if(fc>=0)

    sign=0;

  else {

    sign=1;

    fc=-fc;

  }

  v = fr & VT_VALMASK;

  if (fr & VT_LVAL) {

    uint32_t base = 0xB; // fp

    if(v == VT_LLOCAL) {

      v1.type.t = VT_PTR;

      v1.r = VT_LOCAL | VT_LVAL;

      v1.c.i = sv->c.i;

      load(base=14 /* lr */, &v1);

      fc=sign=0;

      v=VT_LOCAL;

    } else if(v == VT_CONST) {

      v1.type.t = VT_PTR;

      v1.r = fr&~VT_LVAL;

      v1.c.i = sv->c.i;

      v1.sym=sv->sym;

      load(base=14, &v1);

      fc=sign=0;

      v=VT_LOCAL;

    } else if(v < VT_CONST) {

      base=intr(v);

      fc=sign=0;

      v=VT_LOCAL;

    }

    if(v == VT_LOCAL) {

      if(is_float(ft)) {

	calcaddr(&base,&fc,&sign,1020,2);

#ifdef TCC_ARM_VFP

        op=0xED100A00; /* flds */

        if(!sign)

          op|=0x800000;

        if ((ft & VT_BTYPE) != VT_FLOAT)

          op|=0x100;   /* flds -> fldd */

        o(op|(vfpr(r)<<12)|(fc>>2)|(base<<16));

#else

	op=0xED100100;

	if(!sign)

	  op|=0x800000;

#if LDOUBLE_SIZE == 8

	if ((ft & VT_BTYPE) != VT_FLOAT)

	  op|=0x8000;

#else

	if ((ft & VT_BTYPE) == VT_DOUBLE)

	  op|=0x8000;

	else if ((ft & VT_BTYPE) == VT_LDOUBLE)

	  op|=0x400000;

#endif

	o(op|(fpr(r)<<12)|(fc>>2)|(base<<16));

#endif

      } else if((ft & (VT_BTYPE|VT_UNSIGNED)) == VT_BYTE

                || (ft & VT_BTYPE) == VT_SHORT) {

	calcaddr(&base,&fc,&sign,255,0);

	op=0xE1500090;

	if ((ft & VT_BTYPE) == VT_SHORT)

	  op|=0x20;

	if ((ft & VT_UNSIGNED) == 0)

	  op|=0x40;

	if(!sign)

	  op|=0x800000;

	o(op|(intr(r)<<12)|(base<<16)|((fc&0xf0)<<4)|(fc&0xf));

      } else {

	calcaddr(&base,&fc,&sign,4095,0);

	op=0xE5100000;

	if(!sign)

	  op|=0x800000;

        if ((ft & VT_BTYPE) == VT_BYTE || (ft & VT_BTYPE) == VT_BOOL)

          op|=0x400000;

        o(op|(intr(r)<<12)|fc|(base<<16));

      }

      return;

    }

  } else {

    if (v == VT_CONST) {

      op=stuff_const(0xE3A00000|(intr(r)<<12),sv->c.i);

      if (fr & VT_SYM || !op) {

        o(0xE59F0000|(intr(r)<<12));

        o(0xEA000000);

        if(fr & VT_SYM)

	  greloc(cur_text_section, sv->sym, ind, R_ARM_ABS32);

        o(sv->c.i);

      } else

        o(op);

      return;

    } else if (v == VT_LOCAL) {

      op=stuff_const(0xE28B0000|(intr(r)<<12),sv->c.i);

      if (fr & VT_SYM || !op) {

	o(0xE59F0000|(intr(r)<<12));

	o(0xEA000000);

	if(fr & VT_SYM) // needed ?

	  greloc(cur_text_section, sv->sym, ind, R_ARM_ABS32);

	o(sv->c.i);

	o(0xE08B0000|(intr(r)<<12)|intr(r));

      } else

	o(op);

      return;

    } else if(v == VT_CMP) {

      o(mapcc(sv->c.i)|0x3A00001|(intr(r)<<12));

      o(mapcc(negcc(sv->c.i))|0x3A00000|(intr(r)<<12));

      return;

    } else if (v == VT_JMP || v == VT_JMPI) {

      int t;

      t = v & 1;

      o(0xE3A00000|(intr(r)<<12)|t);

      o(0xEA000000);

      gsym(sv->c.i);

      o(0xE3A00000|(intr(r)<<12)|(t^1));

      return;

    } else if (v < VT_CONST) {

      if(is_float(ft))

#ifdef TCC_ARM_VFP

        o(0xEEB00A40|(vfpr(r)<<12)|vfpr(v)|T2CPR(ft)); /* fcpyX */

#else

	o(0xEE008180|(fpr(r)<<12)|fpr(v));

#endif

      else

	o(0xE1A00000|(intr(r)<<12)|intr(v));

      return;

    }

  }

  tcc_error("load unimplemented!");

}

/* store register 'r' in lvalue 'v' */

void store(int r, SValue *sv)

{

  SValue v1;

  int v, ft, fc, fr, sign;

  uint32_t op;

  fr = sv->r;

  ft = sv->type.t;

  fc = sv->c.i;

  if(fc>=0)

    sign=0;

  else {

    sign=1;

    fc=-fc;

  }

  v = fr & VT_VALMASK;

  if (fr & VT_LVAL || fr == VT_LOCAL) {

    uint32_t base = 0xb;

    if(v < VT_CONST) {

      base=intr(v);

      v=VT_LOCAL;

      fc=sign=0;

    } else if(v == VT_CONST) {

      v1.type.t = ft;

      v1.r = fr&~VT_LVAL;

      v1.c.i = sv->c.i;

      v1.sym=sv->sym;

      load(base=14, &v1);

      fc=sign=0;

      v=VT_LOCAL;

    }

    if(v == VT_LOCAL) {

       if(is_float(ft)) {

	calcaddr(&base,&fc,&sign,1020,2);

#ifdef TCC_ARM_VFP

        op=0xED000A00; /* fsts */

        if(!sign)

          op|=0x800000;

        if ((ft & VT_BTYPE) != VT_FLOAT)

          op|=0x100;   /* fsts -> fstd */

        o(op|(vfpr(r)<<12)|(fc>>2)|(base<<16));

#else

	op=0xED000100;

	if(!sign)

	  op|=0x800000;

#if LDOUBLE_SIZE == 8

	if ((ft & VT_BTYPE) != VT_FLOAT)

	  op|=0x8000;

#else

	if ((ft & VT_BTYPE) == VT_DOUBLE)

	  op|=0x8000;

	if ((ft & VT_BTYPE) == VT_LDOUBLE)

	  op|=0x400000;

#endif

	o(op|(fpr(r)<<12)|(fc>>2)|(base<<16));

#endif

	return;

      } else if((ft & VT_BTYPE) == VT_SHORT) {

	calcaddr(&base,&fc,&sign,255,0);

	op=0xE14000B0;

	if(!sign)

	  op|=0x800000;

	o(op|(intr(r)<<12)|(base<<16)|((fc&0xf0)<<4)|(fc&0xf));

      } else {

	calcaddr(&base,&fc,&sign,4095,0);

	op=0xE5000000;

	if(!sign)

	  op|=0x800000;

        if ((ft & VT_BTYPE) == VT_BYTE || (ft & VT_BTYPE) == VT_BOOL)

          op|=0x400000;

        o(op|(intr(r)<<12)|fc|(base<<16));

      }

      return;

    }

  }

  tcc_error("store unimplemented");

}

static void gadd_sp(int val)

{

  stuff_const_harder(0xE28DD000,val);

}

/* 'is_jmp' is '1' if it is a jump */

static void gcall_or_jmp(int is_jmp)

{

  int r;

  if ((vtop->r & (VT_VALMASK | VT_LVAL)) == VT_CONST) {

    uint32_t x;

    /* constant case */

    x=encbranch(ind,ind+vtop->c.i,0);

    if(x) {

      if (vtop->r & VT_SYM) {

	/* relocation case */

	greloc(cur_text_section, vtop->sym, ind, R_ARM_PC24);

      } else

	put_elf_reloc(symtab_section, cur_text_section, ind, R_ARM_PC24, 0);

      o(x|(is_jmp?0xE0000000:0xE1000000));

    } else {

      if(!is_jmp)

	o(0xE28FE004); // add lr,pc,#4

      o(0xE51FF004);   // ldr pc,[pc,#-4]

      if (vtop->r & VT_SYM)

	greloc(cur_text_section, vtop->sym, ind, R_ARM_ABS32);

      o(vtop->c.i);

    }

  } else {

    /* otherwise, indirect call */

    r = gv(RC_INT);

    if(!is_jmp)

      o(0xE1A0E00F);       // mov lr,pc

    o(0xE1A0F000|intr(r)); // mov pc,r

  }

}

/* Return whether a structure is an homogeneous float aggregate or not.

   The answer is true if all the elements of the structure are of the same

   primitive float type and there is less than 4 elements.

   type: the type corresponding to the structure to be tested */

static int is_hgen_float_aggr(CType *type)

{

  if ((type->t & VT_BTYPE) == VT_STRUCT) {

    struct Sym *ref;

    int btype, nb_fields = 0;

    ref = type->ref->next;

    btype = ref->type.t & VT_BTYPE;

    if (btype == VT_FLOAT || btype == VT_DOUBLE) {

      for(; ref && btype == (ref->type.t & VT_BTYPE); ref = ref->next, nb_fields++);

      return !ref && nb_fields <= 4;

    }

  }

  return 0;

}

struct avail_regs {

  signed char avail[3]; /* 3 holes max with only float and double alignments */

  int first_hole; /* first available hole */

  int last_hole; /* last available hole (none if equal to first_hole) */

  int first_free_reg; /* next free register in the sequence, hole excluded */

};

#define AVAIL_REGS_INITIALIZER (struct avail_regs) { { 0, 0, 0}, 0, 0, 0 }

/* Find suitable registers for a VFP Co-Processor Register Candidate (VFP CPRC

   param) according to the rules described in the procedure call standard for

   the ARM architecture (AAPCS). If found, the registers are assigned to this

   VFP CPRC parameter. Registers are allocated in sequence unless a hole exists

   and the parameter is a single float.

   avregs: opaque structure to keep track of available VFP co-processor regs

   align: alignment contraints for the param, as returned by type_size()

   size: size of the parameter, as returned by type_size() */

int assign_vfpreg(struct avail_regs *avregs, int align, int size)

{

  int first_reg = 0;

  if (avregs->first_free_reg == -1)

    return -1;

  if (align >> 3) { /* double alignment */

    first_reg = avregs->first_free_reg;

    /* alignment contraint not respected so use next reg and record hole */

    if (first_reg & 1)

      avregs->avail[avregs->last_hole++] = first_reg++;

  } else { /* no special alignment (float or array of float) */

    /* if single float and a hole is available, assign the param to it */

    if (size == 4 && avregs->first_hole != avregs->last_hole)

      return avregs->avail[avregs->first_hole++];

    else

      first_reg = avregs->first_free_reg;

  }

  if (first_reg + size / 4 <= 16) {

    avregs->first_free_reg = first_reg + size / 4;

    return first_reg;

  }

  avregs->first_free_reg = -1;

  return -1;

}

/* Returns whether all params need to be passed in core registers or not.

   This is the case for function part of the runtime ABI. */

int floats_in_core_regs(SValue *sval)

{

  if (!sval->sym)

    return 0;

  switch (sval->sym->v) {

    case TOK___floatundisf:

    case TOK___floatundidf:

    case TOK___fixunssfdi:

    case TOK___fixunsdfdi:

#ifndef TCC_ARM_VFP

    case TOK___fixunsxfdi:

#endif

    case TOK___floatdisf:

    case TOK___floatdidf:

    case TOK___fixsfdi:

    case TOK___fixdfdi:

      return 1;

    default:

      return 0;

  }

}

/* Return the number of registers needed to return the struct, or 0 if

   returning via struct pointer. */

ST_FUNC int gfunc_sret(CType *vt, int variadic, CType *ret, int *ret_align, int *regsize) {

#ifdef TCC_ARM_EABI

    int size, align;

    size = type_size(vt, &align);

    if (float_abi == ARM_HARD_FLOAT && !variadic &&

        (is_float(vt->t) || is_hgen_float_aggr(vt))) {

        *ret_align = 8;

	*regsize = 8;

        ret->ref = NULL;

        ret->t = VT_DOUBLE;

        return (size + 7) >> 3;

    } else if (size <= 4) {

        *ret_align = 4;

	*regsize = 4;

        ret->ref = NULL;

        ret->t = VT_INT;

        return 1;

    } else

        return 0;

#else

    return 0;

#endif

}

/* Parameters are classified according to how they are copied to their final

   destination for the function call. Because the copying is performed class

   after class according to the order in the union below, it is important that

   some constraints about the order of the members of this union are respected:

   - CORE_STRUCT_CLASS must come after STACK_CLASS;

   - CORE_CLASS must come after STACK_CLASS, CORE_STRUCT_CLASS and

     VFP_STRUCT_CLASS;

   - VFP_STRUCT_CLASS must come after VFP_CLASS.

   See the comment for the main loop in copy_params() for the reason. */

enum reg_class {

	STACK_CLASS = 0,

	CORE_STRUCT_CLASS,

	VFP_CLASS,

	VFP_STRUCT_CLASS,

	CORE_CLASS,

	NB_CLASSES

};

struct param_plan {

    int start; /* first reg or addr used depending on the class */

    int end; /* last reg used or next free addr depending on the class */

    SValue *sval; /* pointer to SValue on the value stack */

    struct param_plan *prev; /*  previous element in this class */

};

struct plan {

    struct param_plan *pplans; /* array of all the param plans */

    struct param_plan *clsplans[NB_CLASSES]; /* per class lists of param plans */

};

#define add_param_plan(plan,pplan,class)                        \

    do {                                                        \

        pplan.prev = plan->clsplans[class];                     \

        plan->pplans[plan ## _nb] = pplan;                      \

        plan->clsplans[class] = &plan->pplans[plan ## _nb++];   \

    } while(0)

/* Assign parameters to registers and stack with alignment according to the

   rules in the procedure call standard for the ARM architecture (AAPCS).

   The overall assignment is recorded in an array of per parameter structures

   called parameter plans. The parameter plans are also further organized in a

   number of linked lists, one per class of parameter (see the comment for the

   definition of union reg_class).

   nb_args: number of parameters of the function for which a call is generated

   float_abi: float ABI in use for this function call

   plan: the structure where the overall assignment is recorded

   todo: a bitmap that record which core registers hold a parameter

   Returns the amount of stack space needed for parameter passing

   Note: this function allocated an array in plan->pplans with tcc_malloc. It

   is the responsibility of the caller to free this array once used (ie not

   before copy_params). */

static int assign_regs(int nb_args, int float_abi, struct plan *plan, int *todo)

{

  int i, size, align;

  int ncrn /* next core register number */, nsaa /* next stacked argument address*/;

  int plan_nb = 0;

  struct param_plan pplan;

  struct avail_regs avregs = AVAIL_REGS_INITIALIZER;

  ncrn = nsaa = 0;

  *todo = 0;

  plan->pplans = tcc_malloc(nb_args * sizeof(*plan->pplans));

  memset(plan->clsplans, 0, sizeof(plan->clsplans));

  for(i = nb_args; i-- ;) {

    int j, start_vfpreg = 0;

    CType type = vtop[-i].type;

    type.t &= ~VT_ARRAY;

    size = type_size(&type, &align);

    size = (size + 3) & ~3;

    align = (align + 3) & ~3;

    switch(vtop[-i].type.t & VT_BTYPE) {

      case VT_STRUCT:

      case VT_FLOAT:

      case VT_DOUBLE:

      case VT_LDOUBLE:

      if (float_abi == ARM_HARD_FLOAT) {

        int is_hfa = 0; /* Homogeneous float aggregate */

        if (is_float(vtop[-i].type.t)

            || (is_hfa = is_hgen_float_aggr(&vtop[-i].type))) {

          int end_vfpreg;

          start_vfpreg = assign_vfpreg(&avregs, align, size);

          end_vfpreg = start_vfpreg + ((size - 1) >> 2);

          if (start_vfpreg >= 0) {

            pplan = (struct param_plan) {start_vfpreg, end_vfpreg, &vtop[-i]};

            if (is_hfa)

              add_param_plan(plan, pplan, VFP_STRUCT_CLASS);

            else

              add_param_plan(plan, pplan, VFP_CLASS);

            continue;

          } else

            break;

        }

      }

      ncrn = (ncrn + (align-1)/4) & ~((align/4) - 1);

      if (ncrn + size/4 <= 4 || (ncrn < 4 && start_vfpreg != -1)) {

        /* The parameter is allocated both in core register and on stack. As

	 * such, it can be of either class: it would either be the last of

	 * CORE_STRUCT_CLASS or the first of STACK_CLASS. */

        for (j = ncrn; j < 4 && j < ncrn + size / 4; j++)

          *todo|=(1<

        pplan = (struct param_plan) {ncrn, j, &vtop[-i]};

        add_param_plan(plan, pplan, CORE_STRUCT_CLASS);

        ncrn += size/4;

        if (ncrn > 4)

          nsaa = (ncrn - 4) * 4;

      } else {

        ncrn = 4;

        break;

      }

      continue;

      default:

      if (ncrn < 4) {

        int is_long = (vtop[-i].type.t & VT_BTYPE) == VT_LLONG;

        if (is_long) {

          ncrn = (ncrn + 1) & -2;

          if (ncrn == 4)

            break;

        }

        pplan = (struct param_plan) {ncrn, ncrn, &vtop[-i]};

        ncrn++;

        if (is_long)

          pplan.end = ncrn++;

        add_param_plan(plan, pplan, CORE_CLASS);

        continue;

      }

    }

    nsaa = (nsaa + (align - 1)) & ~(align - 1);

    pplan = (struct param_plan) {nsaa, nsaa + size, &vtop[-i]};

    add_param_plan(plan, pplan, STACK_CLASS);

    nsaa += size; /* size already rounded up before */

  }

  return nsaa;

}

#undef add_param_plan

/* Copy parameters to their final destination (core reg, VFP reg or stack) for

   function call.

   nb_args: number of parameters the function take

   plan: the overall assignment plan for parameters

   todo: a bitmap indicating what core reg will hold a parameter

   Returns the number of SValue added by this function on the value stack */

static int copy_params(int nb_args, struct plan *plan, int todo)

{

  int size, align, r, i, nb_extra_sval = 0;

  struct param_plan *pplan;

   /* Several constraints require parameters to be copied in a specific order:

      - structures are copied to the stack before being loaded in a reg;

      - floats loaded to an odd numbered VFP reg are first copied to the

        preceding even numbered VFP reg and then moved to the next VFP reg.

      It is thus important that:

      - structures assigned to core regs must be copied after parameters

        assigned to the stack but before structures assigned to VFP regs because

        a structure can lie partly in core registers and partly on the stack;

      - parameters assigned to the stack and all structures be copied before

        parameters assigned to a core reg since copying a parameter to the stack

        require using a core reg;

      - parameters assigned to VFP regs be copied before structures assigned to

        VFP regs as the copy might use an even numbered VFP reg that already

        holds part of a structure. */

  for(i = 0; i < NB_CLASSES; i++) {

    for(pplan = plan->clsplans[i]; pplan; pplan = pplan->prev) {

      vpushv(pplan->sval);

      pplan->sval->r = pplan->sval->r2 = VT_CONST; /* disable entry */

      switch(i) {

        case STACK_CLASS:

        case CORE_STRUCT_CLASS:

        case VFP_STRUCT_CLASS:

          if ((pplan->sval->type.t & VT_BTYPE) == VT_STRUCT) {

            int padding = 0;

            size = type_size(&pplan->sval->type, &align);

            /* align to stack align size */

            size = (size + 3) & ~3;

            if (i == STACK_CLASS && pplan->prev)

              padding = pplan->start - pplan->prev->end;

            size += padding; /* Add padding if any */

            /* allocate the necessary size on stack */

            gadd_sp(-size);

            /* generate structure store */

            r = get_reg(RC_INT);

            o(0xE28D0000|(intr(r)<<12)|padding); /* add r, sp, padding */

            vset(&vtop->type, r | VT_LVAL, 0);

            vswap();

            vstore(); /* memcpy to current sp + potential padding */

            /* Homogeneous float aggregate are loaded to VFP registers

               immediately since there is no way of loading data in multiple

               non consecutive VFP registers as what is done for other

               structures (see the use of todo). */

            if (i == VFP_STRUCT_CLASS) {

              int first = pplan->start, nb = pplan->end - first + 1;

              /* vpop.32 {pplan->start, ..., pplan->end} */

              o(0xECBD0A00|(first&1)<<22|(first>>1)<<12|nb);

              /* No need to write the register used to a SValue since VFP regs

                 cannot be used for gcall_or_jmp */

            }