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arm-gen.c

/*
 *  ARMv4 code generator for TCC
 * 
 *  Copyright (c) 2003 Daniel Glöckner
 *
 *  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
 */

/* number of available registers */
#define NB_REGS             9

/* 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
#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,
};

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,
};

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);
}

/* 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 */

/* 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 */
#define LDOUBLE_SIZE  8
#define LDOUBLE_ALIGN 4
/* 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_JMP_SLOT  R_ARM_JUMP_SLOT
#define R_COPY      R_ARM_COPY

#define ELF_START_ADDR 0x00008000
#define ELF_PAGE_SIZE  0x1000

/******************************************************/
static unsigned long func_sub_sp_offset,last_itod_magic;

void o(unsigned long i)
{
  /* this is a good place to start adding big-endian support*/
  int ind1;

  ind1 = ind + 4;
  if (!cur_text_section)
    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 unsigned long stuff_const(unsigned long op,unsigned long c)
{
  int try_neg=0;
  unsigned long 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 {
    unsigned long 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<<i)|(c>>(32-i));
    }
    op=negop;
    c=nc;
  } while(try_neg--);
  return 0;
}


//only add,sub
void stuff_const_harder(unsigned long op,unsigned long v) {
  unsigned long x;
  x=stuff_const(op,v);
  if(x)
    o(x);
  else {
    unsigned long 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<13+i;i++)
      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<13+i;i++)
      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;i<12;i++)
      for(k=j+4;k<13+i;i++)
        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;i<12;i++)
      for(k=j+4;k<13+i;i++)
        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]));
  }
}

unsigned long encbranch(int pos,int addr,int fail)
{
  addr-=pos+8;
  addr/=4;
  if(addr>=0x1000000 || addr<-0x1000000) {
    if(fail)
      error("FIXME: function bigger than 32MB");
    return 0;
  }
  return 0x0A000000|(addr&0xffffff);
}

int decbranch(int pos)
{
  int x;
  x=*(int *)(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)
{
  unsigned long *x;
  int lt;
  while(t) {
    x=(unsigned long *)(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);
}

static unsigned long fpr(int r)
{
  if(r<TREG_F0 || r>TREG_F3)
    error("compiler error! register %i is no fp register\n",r);
  return r-5;
}

static unsigned long intr(int r)
{
  if(r==4)
    return 12;
  if((r<0 || r>4) && r!=14)
    error("compiler error! register %i is no int register\n",r);
  return r;
}

static void calcaddr(unsigned long *base,int *off,int *sgn,int maxoff,unsigned shift)
{
  if(*off>maxoff || *off&((1<<shift)-1)) {
    unsigned long 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 unsigned long mapcc(int cc)
{
  switch(cc)
  {
    case TOK_ULT:
      return 0x30000000;
    case TOK_UGE:
      return 0x20000000;
    case TOK_EQ:
      return 0x00000000;
    case TOK_NE:
      return 0x10000000;
    case TOK_ULE:
      return 0x90000000;
    case TOK_UGT:
      return 0x80000000;
    case TOK_LT:
      return 0xB0000000;
    case TOK_GE:
      return 0xA0000000;
    case TOK_LE:
      return 0xD0000000;
    case TOK_GT:
      return 0xC0000000;
  }
  error("unexpected condition code");
  return 0xE0000000;
}

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_LT:
      return TOK_GE;
    case TOK_GE:
      return TOK_LT;
    case TOK_LE:
      return TOK_GT;
    case TOK_GT:
      return TOK_LE;
  }
  error("unexpected condition code");
  return TOK_NE;
}

/* load 'r' from value 'sv' */
void load(int r, SValue *sv)
{
  int v, ft, fc, fr, sign;
  unsigned long op;
  SValue v1;

  fr = sv->r;
  ft = sv->type.t;
  fc = sv->c.ul;

  if(fc>=0)
    sign=0;
  else {
    sign=1;
    fc=-fc;
  }
  
  v = fr & VT_VALMASK;
  if (fr & VT_LVAL) {
    unsigned long base=0xB; // fp
    if(v == VT_LLOCAL) {
      v1.type.t = VT_PTR;
      v1.r = VT_LOCAL | VT_LVAL;
      v1.c.ul = sv->c.ul;
      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.ul = sv->c.ul;
      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);
      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));
      } else if((ft & VT_TYPE) == 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)
          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.ul);
      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.ul);
      } else
        o(op);
      return;
    } else if (v == VT_LOCAL) {
      op=stuff_const(0xE28B0000|(intr(r)<<12),sv->c.ul);
      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.ul);
      o(0xE08B0000|(intr(r)<<12)|intr(r));
      } else
      o(op);
      return;
    } else if(v == VT_CMP) {
      o(mapcc(sv->c.ul)|0x3A00001|(intr(r)<<12));
      o(mapcc(negcc(sv->c.ul))|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.ul);
      o(0xE3A00000|(intr(r)<<12)|(t^1));
      return;
    } else if (v < VT_CONST) {
      if(is_float(ft))
      o(0xEE008180|(fpr(r)<<12)|fpr(v));
      else
      o(0xE1A00000|(intr(r)<<12)|intr(v));
      return;
    }
  }
  error("load unimplemented!");
}

/* store register 'r' in lvalue 'v' */
void store(int r, SValue *sv)
{
  SValue v1;
  int v, ft, fc, fr, sign;
  unsigned long op;

  fr = sv->r;
  ft = sv->type.t;
  fc = sv->c.ul;

  if(fc>=0)
    sign=0;
  else {
    sign=1;
    fc=-fc;
  }
  
  v = fr & VT_VALMASK; 
  if (fr & VT_LVAL || fr == VT_LOCAL) {
    unsigned long 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.ul = sv->c.ul;
      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);
      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));
      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)
          op|=0x400000;
        o(op|(intr(r)<<12)|fc|(base<<16));
      }
      return;
    }
  }
  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) {
    unsigned long x;
    /* constant case */
    x=encbranch(ind,ind+vtop->c.ul,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.ul);
    }
  } else {
    /* otherwise, indirect call */
    r = gv(RC_INT);
    if(!is_jmp)
      o(0xE1A0E00F);       // mov lr,pc
    o(0xE1A0F000|intr(r)); // mov pc,r
  }
}

/* Generate function call. The function address is pushed first, then
   all the parameters in call order. This functions pops all the
   parameters and the function address. */
void gfunc_call(int nb_args)
{
  int size, align, r, args_size, i;
  Sym *func_sym;
  signed char plan[4][2]={{-1,-1},{-1,-1},{-1,-1},{-1,-1}};
  int todo=0xf, keep, plan2[4]={0,0,0,0};

  r = vtop->r & VT_VALMASK;
  if (r == VT_CMP || (r & ~1) == VT_JMP)
    gv(RC_INT);
  args_size = 0;
  for(i = nb_args ; i-- && args_size < 16 ;) {
    if ((vtop[-i].type.t & VT_BTYPE) == VT_STRUCT) {
      size = type_size(&vtop[-i].type, &align);
      size = (size + 3) & ~3;
      args_size += size;
    } else if ((vtop[-i].type.t & VT_BTYPE) == VT_FLOAT)
      args_size += 4;
    else if ((vtop[-i].type.t & VT_BTYPE) == VT_DOUBLE)
      args_size += 8;
    else if ((vtop[-i].type.t & VT_BTYPE) == VT_LDOUBLE)
      args_size += LDOUBLE_SIZE;
    else {
      plan[nb_args-1-i][0]=args_size/4;
      args_size += 4;
      if ((vtop[-i].type.t & VT_BTYPE) == VT_LLONG && args_size < 16) {
      plan[nb_args-1-i][1]=args_size/4;
      args_size += 4;
      }
    }
  }
  args_size = keep = 0;
  for(i = 0;i < nb_args; i++) {
    vnrott(keep+1);
    if ((vtop->type.t & VT_BTYPE) == VT_STRUCT) {
      size = type_size(&vtop->type, &align);
      /* align to stack align size */
      size = (size + 3) & ~3;
      /* allocate the necessary size on stack */
      gadd_sp(-size);
      /* generate structure store */
      r = get_reg(RC_INT);
      o(0xE1A0000D|(intr(r)<<12));
      vset(&vtop->type, r | VT_LVAL, 0);
      vswap();
      vstore();
      vtop--;
      args_size += size;
    } else if (is_float(vtop->type.t)) {
      r=fpr(gv(RC_FLOAT))<<12;
      if ((vtop->type.t & VT_BTYPE) == VT_FLOAT)
        size = 4;
      else if ((vtop->type.t & VT_BTYPE) == VT_DOUBLE)
        size = 8;
      else
        size = LDOUBLE_SIZE;
      
      if (size == 12)
      r|=0x400000;
      else if(size == 8)
      r|=0x8000;

      o(0xED2D0100|r|(size>>2));
      vtop--;
      args_size += size;
    } else {
      int s;
      /* simple type (currently always same size) */
      /* XXX: implicit cast ? */
      size=4;
      if ((vtop->type.t & VT_BTYPE) == VT_LLONG) {
      lexpand_nr();
      s=RC_INT;
      if(nb_args-i<5 && plan[nb_args-i-1][1]!=-1) {
        s=regmask(plan[nb_args-i-1][1]);
        todo&=~(1<<plan[nb_args-i-1][1]);
      }
      if(s==RC_INT) {
        r = gv(s);
        o(0xE52D0004|(intr(r)<<12)); /* str r,[sp,#-4]! */
        vtop--;
      } else {
        plan2[keep]=s;
        keep++;
          vswap();
      }
      size = 8;
      }
      s=RC_INT;
      if(nb_args-i<5 && plan[nb_args-i-1][0]!=-1) {
        s=regmask(plan[nb_args-i-1][0]);
      todo&=~(1<<plan[nb_args-i-1][0]);
      }
      if(s==RC_INT) {
      r = gv(s);
      o(0xE52D0004|(intr(r)<<12)); /* str r,[sp,#-4]! */
      vtop--;
      } else {
      plan2[keep]=s;
      keep++;
      }
      args_size += size;
    }
  }
  for(i=keep;i--;) {
    gv(plan2[i]);
    vrott(keep);
  }
  save_regs(keep); /* save used temporary registers */
  keep++;
  if(args_size) {
    int n;
    n=args_size/4;
    if(n>4)
      n=4;
    todo&=((1<<n)-1);
    if(todo) {
      int i;
      o(0xE8BD0000|todo);
      for(i=0;i<4;i++)
      if(todo&(1<<i)) {
        vpushi(0);
        vtop->r=i;
        keep++;
      }
    }
    args_size-=n*4;
  }
  vnrott(keep);
  func_sym = vtop->type.ref;
  gcall_or_jmp(0);
  if (args_size)
      gadd_sp(args_size);
  vtop-=keep;
}

/* generate function prolog of type 't' */
void gfunc_prolog(CType *func_type)
{
  Sym *sym,*sym2;
  int n,addr,size,align;

  sym = func_type->ref;
  func_vt = sym->type;
  
  n=0;
  addr=12;
  if((func_vt.t & VT_BTYPE) == VT_STRUCT) {
    func_vc = addr;
    addr += 4;
    n++;
  }
  for(sym2=sym->next;sym2 && n<4;sym2=sym2->next) {
    size = type_size(&sym2->type, &align);
    size = (size + 3) & ~3;
    n+=size/4;
  }
  o(0xE1A0C00D); /* mov ip,sp */
  if(func_type->ref->c == FUNC_ELLIPSIS)
    n=4;
  if(n) {
    if(n>4)
      n=4;
    o(0xE92D0000|((1<<n)-1)); /* save r0-r4 on stack if needed */
  }
  o(0xE92D5800); /* save fp, ip, lr*/
  o(0xE1A0B00D); /* mov fp,sp */
  func_sub_sp_offset = ind;
  o(0xE1A00000); /* nop, leave space for stack adjustment */
  while ((sym = sym->next)) {
    CType *type;
    type = &sym->type;
    sym_push(sym->v & ~SYM_FIELD, type, VT_LOCAL | VT_LVAL, addr);
    size = type_size(type, &align);
    size = (size + 3) & ~3;
    addr += size;
  }
  last_itod_magic=0;
  loc = 0;
}

/* generate function epilog */
void gfunc_epilog(void)
{
  unsigned long x;
  o(0xE89BA800); /* restore fp, sp, pc */
  if(loc) {
    x=stuff_const(0xE24DD000, (-loc + 3) & -4); /* sub sp,sp,# */
    if(x)
      *(unsigned long *)(cur_text_section->data + func_sub_sp_offset) = x;
    else {
      unsigned long addr;
      addr=ind;
      o(0xE59FC004); /* ldr ip,[pc+4] */
      o(0xE04DD00C); /* sub sp,sp,ip  */
      o(0xE1A0F00E); /* mov pc,lr */
      o((-loc + 3) & -4);
      *(unsigned long *)(cur_text_section->data + func_sub_sp_offset) = 0xE1000000|encbranch(func_sub_sp_offset,addr,1);
    }
  }
}

/* generate a jump to a label */
int gjmp(int t)
{
  int r;
  r=ind;
  o(0xE0000000|encbranch(r,t,1));
  return r;
}

/* generate a jump to a fixed address */
void gjmp_addr(int a)
{
  gjmp(a);
}

/* generate a test. set 'inv' to invert test. Stack entry is popped */
int gtst(int inv, int t)
{
  int v, r;
  unsigned long op;
  v = vtop->r & VT_VALMASK;
  r=ind;
  if (v == VT_CMP) {
    op=mapcc(inv?negcc(vtop->c.i):vtop->c.i);
    op|=encbranch(r,t,1);
    o(op);
    t=r;
  } else if (v == VT_JMP || v == VT_JMPI) {
    if ((v & 1) == inv) {
      if(!vtop->c.i)
      vtop->c.i=t;
      else {
      unsigned long *x;
      int p,lp;
      if(t) {
          p = vtop->c.i;
          do {
          p = decbranch(lp=p);
          } while(p);
        x = (unsigned long *)(cur_text_section->data + lp);
        *x &= 0xff000000;
        *x |= encbranch(lp,t,1);
      }
      t = vtop->c.i;
      }
    } else {
      t = gjmp(t);
      gsym(vtop->c.i);
    }
  } else {
    if (is_float(vtop->type.t)) {
      r=gv(RC_FLOAT);
      o(0xEE90F118|fpr(r)<<16);
      vtop->r = VT_CMP;
      vtop->c.i = TOK_NE;
      return gtst(inv, t);
    } else if ((vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST) {
      /* constant jmp optimization */
      if ((vtop->c.i != 0) != inv) 
      t = gjmp(t);
    } else {
      v = gv(RC_INT);
      o(0xE3300000|(intr(v)<<16));
      vtop->r = VT_CMP;
      vtop->c.i = TOK_NE;
      return gtst(inv, t);
    }   
  }
  vtop--;
  return t;
}

/* generate an integer binary operation */
void gen_opi(int op)
{
  int c, func = 0;
  unsigned long opc = 0,r,fr;

  c=0;
  switch(op) {
    case '+':
      opc = 0x8;
      c=1;
      break;
    case TOK_ADDC1: /* add with carry generation */
      opc = 0x9;
      c=1;
      break;
    case '-':
      opc = 0x4;
      c=1;
      break;
    case TOK_SUBC1: /* sub with carry generation */
      opc = 0x5;
      c=1;
      break;
    case TOK_ADDC2: /* add with carry use */
      opc = 0xA;
      c=1;
      break;
    case TOK_SUBC2: /* sub with carry use */
      opc = 0xC;
      c=1;
      break;
    case '&':
      opc = 0x0;
      c=1;
      break;
    case '^':
      opc = 0x2;
      c=1;
      break;
    case '|':
      opc = 0x18;
      c=1;
      break;
    case '*':
      gv2(RC_INT, RC_INT);
      r = vtop[-1].r;
      fr = vtop[0].r;
      vtop--;
      o(0xE0000090|(intr(r)<<16)|(intr(r)<<8)|intr(fr));
      return;
    case TOK_SHL:
      opc = 0;
      c=2;
      break;
    case TOK_SHR:
      opc = 1;
      c=2;
      break;
    case TOK_SAR:
      opc = 2;
      c=2;
      break;
    case '/':
    case TOK_PDIV:
      func=TOK___divsi3;
      c=3;
      break;
    case TOK_UDIV:
      func=TOK___udivsi3;
      c=3;
      break;
    case '%':
      func=TOK___modsi3;
      c=3;
      break;
    case TOK_UMOD:
      func=TOK___umodsi3;
      c=3;
      break;
    case TOK_UMULL:
      gv2(RC_INT, RC_INT);
      r=intr(vtop[-1].r2=get_reg(RC_INT));
      c=vtop[-1].r;
      vtop[-1].r=get_reg_ex(RC_INT,regmask(c));
      vtop--;
      o(0xE0800090|(r<<16)|(intr(vtop->r)<<12)|(intr(c)<<8)|intr(vtop[1].r));
      return;
    default:
      opc = 0x15;
      c=1;
      break;
  }
  switch(c) {
    case 1:
      if((vtop[-1].r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST) {
      if(opc == 4 || opc == 5 || opc == 0xc) {
        vswap();
        opc|=2; // sub -> rsb
      }
      }
      if ((vtop->r & VT_VALMASK) == VT_CMP ||
          (vtop->r & (VT_VALMASK & ~1)) == VT_JMP)
        gv(RC_INT);
      vswap();
      c=intr(gv(RC_INT));
      vswap();
      opc=0xE0000000|(opc<<20)|(c<<16);
      if((vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST) {
      unsigned long x;
      x=stuff_const(opc|0x2000000,vtop->c.i);
      if(x) {
        r=intr(vtop[-1].r=get_reg_ex(RC_INT,regmask(vtop[-1].r)));
        o(x|(r<<12));
        goto done;
      }
      }
      fr=intr(gv(RC_INT));
      r=intr(vtop[-1].r=get_reg_ex(RC_INT,two2mask(vtop->r,vtop[-1].r)));
      o(opc|(r<<12)|fr);
done:
      vtop--;
      if (op >= TOK_ULT && op <= TOK_GT) {
        vtop->r = VT_CMP;
        vtop->c.i = op;
      }
      break;
    case 2:
      opc=0xE1A00000|(opc<<5);
      if ((vtop->r & VT_VALMASK) == VT_CMP ||
          (vtop->r & (VT_VALMASK & ~1)) == VT_JMP)
        gv(RC_INT);
      vswap();
      r=intr(gv(RC_INT));
      vswap();
      opc|=r;
      if ((vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) == VT_CONST) {
      fr=intr(vtop[-1].r=get_reg_ex(RC_INT,regmask(vtop[-1].r)));
      c = vtop->c.i & 0x1f;
      o(opc|(c<<7)|(fr<<12));
      } else {
        fr=intr(gv(RC_INT));
      c=intr(vtop[-1].r=get_reg_ex(RC_INT,two2mask(vtop->r,vtop[-1].r)));
      o(opc|(c<<12)|(fr<<8)|0x10);
      }
      vtop--;
      break;
    case 3:
      vpush_global_sym(&func_old_type, func);
      vrott(3);
      gfunc_call(2);
      vpushi(0);
      vtop->r = REG_IRET;
      break;
    default:
      error("gen_opi %i unimplemented!",op);
  }
}

static int is_fconst()
{
  long double f;
  int r;
  if((vtop->r & (VT_VALMASK | VT_LVAL | VT_SYM)) != VT_CONST)
    return 0;
  if (vtop->type.t == VT_FLOAT)
    f = vtop->c.f;
  else if (vtop->type.t == VT_DOUBLE)
    f = vtop->c.d;
  else
    f = vtop->c.ld;
  if(!ieee_finite(f))
    return 0;
  r=0x8;
  if(f<0.0) {
    r=0x18;
    f=-f;
  }
  if(f==0.0)
    return r;
  if(f==1.0)
    return r|1;
  if(f==2.0)
    return r|2;
  if(f==3.0)
    return r|3;
  if(f==4.0)
    return r|4;
  if(f==5.0)
    return r|5;
  if(f==0.5)
    return r|6;
  if(f==10.0)
    return r|7;
  return 0;
}

/* generate a floating point operation 'v = t1 op t2' instruction. The
   two operands are guaranted to have the same floating point type */
void gen_opf(int op)
{
  unsigned long x;
  int r,r2,c1,c2;
  //fputs("gen_opf\n",stderr);
  vswap();
  c1 = is_fconst();
  vswap();
  c2 = is_fconst();
  x=0xEE000100;
#if LDOUBLE_SIZE == 8
  if ((vtop->type.t & VT_BTYPE) != VT_FLOAT)
    x|=0x80;
#else
  if ((vtop->type.t & VT_BTYPE) == VT_DOUBLE)
    x|=0x80;
  else if ((vtop->type.t & VT_BTYPE) == VT_LDOUBLE)
    x|=0x80000;
#endif
  switch(op)
  {
    case '+':
      if(!c2) {
      vswap();
      c2=c1;
      }
      vswap();
      r=fpr(gv(RC_FLOAT));
      vswap();
      if(c2) {
      if(c2>0xf)
        x|=0x200000; // suf
      r2=c2&0xf;
      } else {
      r2=fpr(gv(RC_FLOAT));
      }
      break;
    case '-':
      if(c2) {
      if(c2<=0xf)
        x|=0x200000; // suf
      r2=c2&0xf;
      vswap();
      r=fpr(gv(RC_FLOAT));
      vswap();
      } else if(c1 && c1<=0xf) {
      x|=0x300000; // rsf
      r2=c1;
      r=fpr(gv(RC_FLOAT));
      vswap();
      } else {
      x|=0x200000; // suf
      vswap();
      r=fpr(gv(RC_FLOAT));
      vswap();
      r2=fpr(gv(RC_FLOAT));
      }
      break;
    case '*':
      if(!c2 || c2>0xf) {
      vswap();
      c2=c1;
      }
      vswap();
      r=fpr(gv(RC_FLOAT));
      vswap();
      if(c2 && c2<=0xf)
      r2=c2;
      else
      r2=fpr(gv(RC_FLOAT));
      x|=0x100000; // muf
      break;
    case '/':
      if(c2 && c2<=0xf) {
      x|=0x400000; // dvf
      r2=c2;
      vswap();
      r=fpr(gv(RC_FLOAT));
      vswap();
      } else if(c1 && c1<=0xf) {
      x|=0x500000; // rdf
      r2=c1;
      r=fpr(gv(RC_FLOAT));
      vswap();
      } else {
      x|=0x400000; // dvf
      vswap();
      r=fpr(gv(RC_FLOAT));
      vswap();
      r2=fpr(gv(RC_FLOAT));
      }     
      break;
    default:
      if(op >= TOK_ULT && op <= TOK_GT) {
      x|=0xd0f110; // cmfe
      switch(op) {
        case TOK_ULT:
        case TOK_UGE:
        case TOK_ULE:
        case TOK_UGT:
          fputs("unsigned comparision on floats?\n",stderr);
          break;
        case TOK_LT:
          op=TOK_ULT;
          break;
        case TOK_GE:
          op=TOK_UGE;
          break;
        case TOK_LE:
          op=TOK_ULE;
          break;
        case TOK_GT:
          op=TOK_UGT;
          break;
        case TOK_EQ:
        case TOK_NE:
          x&=~0x400000; // cmfe -> cmf
          break;
      }
      if(c1 && !c2) {
        c2=c1;
        vswap();
        switch(op) {
          case TOK_ULT:
            op=TOK_UGT;
            break;
          case TOK_UGE:
            op=TOK_ULE;
            break;
          case TOK_ULE:
            op=TOK_UGE;
            break;
          case TOK_UGT:
            op=TOK_ULT;
            break;
        }
      }
// bug (intention?) in Linux FPU emulator
// doesn't set carry if equal
      if(op==TOK_ULT)
        op=TOK_LT;
      else if(op==TOK_UGE)
        op=TOK_GE;
      vswap();
      r=fpr(gv(RC_FLOAT));
      vswap();
      if(c2) {
        if(c2>0xf)
          x|=0x200000;
        r2=c2&0xf;
      } else {
        r2=fpr(gv(RC_FLOAT));
      }
      vtop[-1].r = VT_CMP;
      vtop[-1].c.i = op;
      } else {
      error("unknown fp op %x!\n",op);
      return;
      }
  }
  if(vtop[-1].r == VT_CMP)
    c1=15;
  else {
    c1=vtop->r;
    if(r2&0x8)
      c1=vtop[-1].r;
    vtop[-1].r=get_reg_ex(RC_FLOAT,two2mask(vtop[-1].r,c1));
    c1=fpr(vtop[-1].r);
  }
  vtop--;
  o(x|(r<<16)|(c1<<12)|r2);
}

/* convert integers to fp 't' type. Must handle 'int', 'unsigned int'
   and 'long long' cases. */
void gen_cvt_itof(int t)
{
  int r,r2,bt;
  bt=vtop->type.t & VT_BTYPE;
  if(bt == VT_INT || bt == VT_SHORT || bt == VT_BYTE) {
    r=intr(gv(RC_INT));
    r2=fpr(vtop->r=get_reg(RC_FLOAT));
    o(0xEE000190|(r2<<16)|(r<<12));
    if((vtop->type.t & (VT_UNSIGNED|VT_BTYPE)) == (VT_UNSIGNED|VT_INT)) {
      unsigned int off=0;
      o(0xE3500000|(r<<12));
      r=fpr(get_reg(RC_FLOAT));
      if(last_itod_magic) {
      off=ind+8-last_itod_magic;
      off/=4;
      if(off>255)
        off=0;
      }
      o(0xBD1F8100|(r<<12)|off);
      if(!off) {
        o(0xEA000001);
        last_itod_magic=ind;
        o(0x41F00000);
        o(0);
      }
      o(0xBE000180|(r2<<16)|(r2<<12)|r);
    }
    return;
  } else if(bt == VT_LLONG) {
    int func;
    if(vtop->type.t & VT_UNSIGNED)
      func=TOK___ulltold;
    else
      func=TOK___slltold;
    vpush_global_sym(&func_old_type, func);
    vswap();
    gfunc_call(1);
    vpushi(0);
    vtop->r=TREG_F0;
    return;
  }
  error("unimplemented gen_cvt_itof %x!",vtop->type.t);
}

/* convert fp to int 't' type */
void gen_cvt_ftoi(int t)
{
  int r,r2,u,func=0;
  u=t&VT_UNSIGNED;
  t&=VT_BTYPE;
  r2=vtop->type.t & VT_BTYPE;
  if(t==VT_INT) {
    if(u) {
      if(r2 == VT_FLOAT)
        func=TOK___fixunssfsi;
      else if(r2 == VT_DOUBLE)
      func=TOK___fixunsdfsi;
      else if(r2 == VT_LDOUBLE)
#if LDOUBLE_SIZE == 8
      func=TOK___fixunsdfsi;
#else
      func=TOK___fixunsxfsi;
#endif
    } else {
      r=fpr(gv(RC_FLOAT));
      r2=intr(vtop->r=get_reg(RC_INT));
      o(0xEE100170|(r2<<12)|r);
    return;
    }
  } else if(t == VT_LLONG) { // unsigned handled in gen_cvt_ftoi1
    if(r2 == VT_FLOAT)
      func=TOK___fixsfdi;
    else if(r2 == VT_DOUBLE)
      func=TOK___fixdfdi;
    else if(r2 == VT_LDOUBLE)
#if LDOUBLE_SIZE == 8
      func=TOK___fixdfdi;
#else
      func=TOK___fixxfdi;
#endif
    }
  if(func) {
    vpush_global_sym(&func_old_type, func);
    vswap();
    gfunc_call(1);
    vpushi(0);
    if(t == VT_LLONG)
      vtop->r2 = REG_LRET;
    vtop->r = REG_IRET;
    return;
  }
  error("unimplemented gen_cvt_ftoi!");
}

/* convert from one floating point type to another */
void gen_cvt_ftof(int t)
{
  /* all we have to do on i386 and ARM is to put the float in a register */
  gv(RC_FLOAT);
}

/* computed goto support */
void ggoto(void)
{
  gcall_or_jmp(1);
  vtop--;
}

/* end of ARM code generator */
/*************************************************************/


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