Subversion Repositories eco32

%{

/*

 * eco32.md -- ECO32 back-end specification

 *

 * register usage:

 *   $0   always zero

 *   $1   reserved for assembler

 *   $2   func return value

 *   $3   func return value

 *   $4   proc/func argument

 *   $5   proc/func argument

 *   $6   proc/func argument

 *   $7   proc/func argument

 *   $8   temporary register (caller-save)

 *   $9   temporary register (caller-save)

 *   $10  temporary register (caller-save)

 *   $11  temporary register (caller-save)

 *   $12  temporary register (caller-save)

 *   $13  temporary register (caller-save)

 *   $14  temporary register (caller-save)

 *   $15  temporary register (caller-save)

 *   $16  register variable  (callee-save)

 *   $17  register variable  (callee-save)

 *   $18  register variable  (callee-save)

 *   $19  register variable  (callee-save)

 *   $20  register variable  (callee-save)

 *   $21  register variable  (callee-save)

 *   $22  register variable  (callee-save)

 *   $23  register variable  (callee-save)

 *   $24  temporary register (caller-save)

 *   $25  temporary register (caller-save)

 *   $26  reserved for OS kernel

 *   $27  reserved for OS kernel

 *   $28  reserved for OS kernel

 *   $29  stack pointer

 *   $30  interrupt return address

 *   $31  proc/func return address

 * caller-save registers are not preserved across procedure calls

 * callee-save registers are preserved across procedure calls

 *

 * tree grammar terminals produced by:

 *   ops c=1 s=2 i=4 l=4 h=4 f=4 d=8 x=8 p=4

 */

#include "c.h"

#define NODEPTR_TYPE    Node

#define OP_LABEL(p)     ((p)->op)

#define LEFT_CHILD(p)   ((p)->kids[0])

#define RIGHT_CHILD(p)  ((p)->kids[1])

#define STATE_LABEL(p)  ((p)->x.state)

static void address(Symbol, Symbol, long);

static void defaddress(Symbol);

static void defconst(int, int, Value);

static void defstring(int, char *);

static void defsymbol(Symbol);

static void export(Symbol);

static void function(Symbol, Symbol [], Symbol [], int);

static void global(Symbol);

static void import(Symbol);

static void local(Symbol);

static void progbeg(int, char * []);

static void progend(void);

static void segment(int);

static void space(int);

static Symbol rmap(int);

static void blkfetch(int, int, int, int);

static void blkstore(int, int, int, int);

static void blkloop(int, int, int, int, int, int []);

static void emit2(Node);

static void doarg(Node);

static void target(Node);

static void clobber(Node);

#define INTTMP  0x0100FF00

#define INTVAR  0x00FF0000

#define INTRET  0x00000004

#define FLTTMP  0x000F0FF0

#define FLTVAR  0xFFF00000

#define FLTRET  0x00000003

static Symbol ireg[32];

static Symbol iregw;

static Symbol freg2[32];

static Symbol freg2w;

static Symbol blkreg;

static int tmpregs[] = { 3, 9, 10 };

%}

%start stmt

%term CNSTF4=4113 CNSTF8=8209

%term CNSTI1=1045 CNSTI2=2069 CNSTI4=4117

%term CNSTP4=4119

%term CNSTU1=1046 CNSTU2=2070 CNSTU4=4118

%term ARGB=41

%term ARGF4=4129 ARGF8=8225

%term ARGI4=4133

%term ARGP4=4135

%term ARGU4=4134

%term ASGNB=57

%term ASGNF4=4145 ASGNF8=8241

%term ASGNI1=1077 ASGNI2=2101 ASGNI4=4149

%term ASGNP4=4151

%term ASGNU1=1078 ASGNU2=2102 ASGNU4=4150

%term INDIRB=73

%term INDIRF4=4161 INDIRF8=8257

%term INDIRI1=1093 INDIRI2=2117 INDIRI4=4165

%term INDIRP4=4167

%term INDIRU1=1094 INDIRU2=2118 INDIRU4=4166

%term CVFF4=4209 CVFF8=8305

%term CVFI4=4213

%term CVIF4=4225 CVIF8=8321

%term CVII1=1157 CVII2=2181 CVII4=4229

%term CVIU1=1158 CVIU2=2182 CVIU4=4230

%term CVPU4=4246

%term CVUI1=1205 CVUI2=2229 CVUI4=4277

%term CVUP4=4279

%term CVUU1=1206 CVUU2=2230 CVUU4=4278

%term NEGF4=4289 NEGF8=8385

%term NEGI4=4293

%term CALLB=217

%term CALLF4=4305 CALLF8=8401

%term CALLI4=4309

%term CALLP4=4311

%term CALLU4=4310

%term CALLV=216

%term RETF4=4337 RETF8=8433

%term RETI4=4341

%term RETP4=4343

%term RETU4=4342

%term RETV=248

%term ADDRGP4=4359

%term ADDRFP4=4375

%term ADDRLP4=4391

%term ADDF4=4401 ADDF8=8497

%term ADDI4=4405

%term ADDP4=4407

%term ADDU4=4406

%term SUBF4=4417 SUBF8=8513

%term SUBI4=4421

%term SUBP4=4423

%term SUBU4=4422

%term LSHI4=4437

%term LSHU4=4438

%term MODI4=4453

%term MODU4=4454

%term RSHI4=4469

%term RSHU4=4470

%term BANDI4=4485

%term BANDU4=4486

%term BCOMI4=4501

%term BCOMU4=4502

%term BORI4=4517

%term BORU4=4518

%term BXORI4=4533

%term BXORU4=4534

%term DIVF4=4545 DIVF8=8641

%term DIVI4=4549

%term DIVU4=4550

%term MULF4=4561 MULF8=8657

%term MULI4=4565

%term MULU4=4566

%term EQF4=4577 EQF8=8673

%term EQI4=4581

%term EQU4=4582

%term GEF4=4593 GEF8=8689

%term GEI4=4597

%term GEU4=4598

%term GTF4=4609 GTF8=8705

%term GTI4=4613

%term GTU4=4614

%term LEF4=4625 LEF8=8721

%term LEI4=4629

%term LEU4=4630

%term LTF4=4641 LTF8=8737

%term LTI4=4645

%term LTU4=4646

%term NEF4=4657 NEF8=8753

%term NEI4=4661

%term NEU4=4662

%term JUMPV=584

%term LABELV=600

%term LOADB=233

%term LOADF4=4321 LOADF8=8417

%term LOADI1=1253 LOADI2=2277 LOADI4=4325

%term LOADP4=4327

%term LOADU1=1254 LOADU2=2278 LOADU4=4326

%term VREGP=711

%%

reg:    INDIRI1(VREGP)          "# read register\n"

reg:    INDIRI2(VREGP)          "# read register\n"

reg:    INDIRI4(VREGP)          "# read register\n"

reg:    INDIRP4(VREGP)          "# read register\n"

reg:    INDIRU1(VREGP)          "# read register\n"

reg:    INDIRU2(VREGP)          "# read register\n"

reg:    INDIRU4(VREGP)          "# read register\n"

stmt:   ASGNI1(VREGP,reg)       "# write register\n"

stmt:   ASGNI2(VREGP,reg)       "# write register\n"

stmt:   ASGNI4(VREGP,reg)       "# write register\n"

stmt:   ASGNP4(VREGP,reg)       "# write register\n"

stmt:   ASGNU1(VREGP,reg)       "# write register\n"

stmt:   ASGNU2(VREGP,reg)       "# write register\n"

stmt:   ASGNU4(VREGP,reg)       "# write register\n"

con:    CNSTI1                  "%a"

con:    CNSTI2                  "%a"

con:    CNSTI4                  "%a"

con:    CNSTP4                  "%a"

con:    CNSTU1                  "%a"

con:    CNSTU2                  "%a"

con:    CNSTU4                  "%a"

stmt:   reg                     ""

acon:   con                     "%0"

acon:   ADDRGP4                 "%a"

addr:   ADDI4(reg,acon)         "$%0,%1"

addr:   ADDP4(reg,acon)         "$%0,%1"

addr:   ADDU4(reg,acon)         "$%0,%1"

addr:   acon                    "$0,%0"

addr:   reg                     "$%0,0"

addr:   ADDRFP4                 "$29,%a+%F"

addr:   ADDRLP4                 "$29,%a+%F"

reg:    addr                    "\tadd\t$%c,%0\n"       1

reg:    CNSTI1                  "# reg\n"               range(a, 0, 0)

reg:    CNSTI2                  "# reg\n"               range(a, 0, 0)

reg:    CNSTI4                  "# reg\n"               range(a, 0, 0)

reg:    CNSTP4                  "# reg\n"               range(a, 0, 0)

reg:    CNSTU1                  "# reg\n"               range(a, 0, 0)

reg:    CNSTU2                  "# reg\n"               range(a, 0, 0)

reg:    CNSTU4                  "# reg\n"               range(a, 0, 0)

stmt:   ASGNI1(addr,reg)        "\tstb\t$%1,%0\n"       1

stmt:   ASGNI2(addr,reg)        "\tsth\t$%1,%0\n"       1

stmt:   ASGNI4(addr,reg)        "\tstw\t$%1,%0\n"       1

stmt:   ASGNP4(addr,reg)        "\tstw\t$%1,%0\n"       1

stmt:   ASGNU1(addr,reg)        "\tstb\t$%1,%0\n"       1

stmt:   ASGNU2(addr,reg)        "\tsth\t$%1,%0\n"       1

stmt:   ASGNU4(addr,reg)        "\tstw\t$%1,%0\n"       1

reg:    INDIRI1(addr)           "\tldb\t$%c,%0\n"       1

reg:    INDIRI2(addr)           "\tldh\t$%c,%0\n"       1

reg:    INDIRI4(addr)           "\tldw\t$%c,%0\n"       1

reg:    INDIRP4(addr)           "\tldw\t$%c,%0\n"       1

reg:    INDIRU1(addr)           "\tldbu\t$%c,%0\n"      1

reg:    INDIRU2(addr)           "\tldhu\t$%c,%0\n"      1

reg:    INDIRU4(addr)           "\tldw\t$%c,%0\n"       1

reg:    CVII4(INDIRI1(addr))    "\tldb\t$%c,%0\n"       1

reg:    CVII4(INDIRI2(addr))    "\tldh\t$%c,%0\n"       1

reg:    CVUU4(INDIRU1(addr))    "\tldbu\t$%c,%0\n"      1

reg:    CVUU4(INDIRU2(addr))    "\tldhu\t$%c,%0\n"      1

reg:    CVUI4(INDIRU1(addr))    "\tldbu\t$%c,%0\n"      1

reg:    CVUI4(INDIRU2(addr))    "\tldhu\t$%c,%0\n"      1

rc:     con                     "%0"

rc:     reg                     "$%0"

reg:    ADDI4(reg,rc)           "\tadd\t$%c,$%0,%1\n"   1

reg:    ADDP4(reg,rc)           "\tadd\t$%c,$%0,%1\n"   1

reg:    ADDU4(reg,rc)           "\tadd\t$%c,$%0,%1\n"   1

reg:    SUBI4(reg,rc)           "\tsub\t$%c,$%0,%1\n"   1

reg:    SUBP4(reg,rc)           "\tsub\t$%c,$%0,%1\n"   1

reg:    SUBU4(reg,rc)           "\tsub\t$%c,$%0,%1\n"   1

reg:    NEGI4(reg)              "\tsub\t$%c,$0,$%0\n"   1

reg:    MULI4(reg,rc)           "\tmul\t$%c,$%0,%1\n"   1

reg:    MULU4(reg,rc)           "\tmulu\t$%c,$%0,%1\n"  1

reg:    DIVI4(reg,rc)           "\tdiv\t$%c,$%0,%1\n"   1

reg:    DIVU4(reg,rc)           "\tdivu\t$%c,$%0,%1\n"  1

reg:    MODI4(reg,rc)           "\trem\t$%c,$%0,%1\n"   1

reg:    MODU4(reg,rc)           "\tremu\t$%c,$%0,%1\n"  1

reg:    BANDI4(reg,rc)          "\tand\t$%c,$%0,%1\n"   1

reg:    BANDU4(reg,rc)          "\tand\t$%c,$%0,%1\n"   1

reg:    BORI4(reg,rc)           "\tor\t$%c,$%0,%1\n"    1

reg:    BORU4(reg,rc)           "\tor\t$%c,$%0,%1\n"    1

reg:    BXORI4(reg,rc)          "\txor\t$%c,$%0,%1\n"   1

reg:    BXORU4(reg,rc)          "\txor\t$%c,$%0,%1\n"   1

reg:    BCOMI4(reg)             "\txnor\t$%c,$0,$%0\n"  1

reg:    BCOMU4(reg)             "\txnor\t$%c,$0,$%0\n"  1

rc5:    CNSTI4                  "%a"                    range(a, 0, 31)

rc5:    reg                     "$%0"

reg:    LSHI4(reg,rc5)          "\tsll\t$%c,$%0,%1\n"   1

reg:    LSHU4(reg,rc5)          "\tsll\t$%c,$%0,%1\n"   1

reg:    RSHI4(reg,rc5)          "\tsar\t$%c,$%0,%1\n"   1

reg:    RSHU4(reg,rc5)          "\tslr\t$%c,$%0,%1\n"   1

reg:    LOADI1(reg)             "\tadd\t$%c,$0,$%0\n"   move(a)

reg:    LOADI2(reg)             "\tadd\t$%c,$0,$%0\n"   move(a)

reg:    LOADI4(reg)             "\tadd\t$%c,$0,$%0\n"   move(a)

reg:    LOADP4(reg)             "\tadd\t$%c,$0,$%0\n"   move(a)

reg:    LOADU1(reg)             "\tadd\t$%c,$0,$%0\n"   move(a)

reg:    LOADU2(reg)             "\tadd\t$%c,$0,$%0\n"   move(a)

reg:    LOADU4(reg)             "\tadd\t$%c,$0,$%0\n"   move(a)

reg:    CVII4(reg)  "\tsll\t$%c,$%0,8*(4-%a)\n\tsar\t$%c,$%c,8*(4-%a)\n"  2

reg:    CVUI4(reg)  "\tand\t$%c,$%0,(1<<(8*%a))-1\n"    1

reg:    CVUU4(reg)  "\tand\t$%c,$%0,(1<<(8*%a))-1\n"    1

stmt:   LABELV                  "%a:\n"

stmt:   JUMPV(acon)             "\tj\t%0\n"             1

stmt:   JUMPV(reg)              "\tjr\t$%0\n"           1

stmt:   EQI4(reg,reg)           "\tbeq\t$%0,$%1,%a\n"   1

stmt:   EQU4(reg,reg)           "\tbeq\t$%0,$%1,%a\n"   1

stmt:   NEI4(reg,reg)           "\tbne\t$%0,$%1,%a\n"   1

stmt:   NEU4(reg,reg)           "\tbne\t$%0,$%1,%a\n"   1

stmt:   LEI4(reg,reg)           "\tble\t$%0,$%1,%a\n"   1

stmt:   LEU4(reg,reg)           "\tbleu\t$%0,$%1,%a\n"  1

stmt:   LTI4(reg,reg)           "\tblt\t$%0,$%1,%a\n"   1

stmt:   LTU4(reg,reg)           "\tbltu\t$%0,$%1,%a\n"  1

stmt:   GEI4(reg,reg)           "\tbge\t$%0,$%1,%a\n"   1

stmt:   GEU4(reg,reg)           "\tbgeu\t$%0,$%1,%a\n"  1

stmt:   GTI4(reg,reg)           "\tbgt\t$%0,$%1,%a\n"   1

stmt:   GTU4(reg,reg)           "\tbgtu\t$%0,$%1,%a\n"  1

reg:    CALLI4(ar)              "\tjal\t%0\n"           1

reg:    CALLP4(ar)              "\tjal\t%0\n"           1

reg:    CALLU4(ar)              "\tjal\t%0\n"           1

stmt:   CALLV(ar)               "\tjal\t%0\n"           1

ar:     ADDRGP4                 "%a"

ar:     reg                     "$%0"

ar:     CNSTP4                  "%a"            range(a, 0, 0x03FFFFFF)

stmt:   RETI4(reg)              "# ret\n"               1

stmt:   RETP4(reg)              "# ret\n"               1

stmt:   RETU4(reg)              "# ret\n"               1

stmt:   RETV(reg)               "# ret\n"               1

stmt:   ARGI4(reg)              "# arg\n"               1

stmt:   ARGP4(reg)              "# arg\n"               1

stmt:   ARGU4(reg)              "# arg\n"               1

stmt:   ARGB(INDIRB(reg))       "# argb %0\n"           1

stmt:   ASGNB(reg,INDIRB(reg))  "# asgnb %0 %1\n"       1

reg:    INDIRF4(VREGP)          "# read register\n"

stmt:   ASGNF4(VREGP,reg)       "# write register\n"

reg:    INDIRF4(addr)           ";FP: l.s $f%c,%0\n"            1

stmt:   ASGNF4(addr,reg)        ";FP: s.s $f%1,%0\n"            1

reg:    ADDF4(reg,reg)          ";FP: add.s $f%c,$f%0,$f%1\n"   1

reg:    SUBF4(reg,reg)          ";FP: sub.s $f%c,$f%0,$f%1\n"   1

reg:    MULF4(reg,reg)          ";FP: mul.s $f%c,$f%0,$f%1\n"   1

reg:    DIVF4(reg,reg)          ";FP: div.s $f%c,$f%0,$f%1\n"   1

reg:    LOADF4(reg)             ";FP: mov.s $f%c,$f%0\n"        1

reg:    NEGF4(reg)              ";FP: neg.s $f%c,$f%0\n"        1

reg:    CVFF4(reg)              ";FP: cvt.s.d $f%c,$f%0\n"      1

reg:    CVIF4(reg)              ";FP: mtc1 $%0,$f%c; cvt.s.w $f%c,$f%c\n"      1

reg:    CVFI4(reg)              ";FP: trunc.w.s $f2,$f%0,$%c; mfc1 $%c,$f2\n"  (a->syms[0]->u.c.v.i == 4 ? 1 : LBURG_MAX)

stmt:   EQF4(reg,reg)           ";FP: c.eq.s $f%0,$f%1; bc1t %a\n"      1

stmt:   LEF4(reg,reg)           ";FP: c.ule.s $f%0,$f%1; bc1t %a\n"     1

stmt:   LTF4(reg,reg)           ";FP: c.ult.s $f%0,$f%1; bc1t %a\n"     1

stmt:   GEF4(reg,reg)           ";FP: c.lt.s $f%0,$f%1; bc1f %a\n"      1

stmt:   GTF4(reg,reg)           ";FP: c.le.s $f%0,$f%1; bc1f %a\n"      1

stmt:   NEF4(reg,reg)           ";FP: c.eq.s $f%0,$f%1; bc1f %a\n"      1

reg:    CALLF4(ar)              "\tjal\t%0\n"                   1

stmt:   RETF4(reg)              "# ret\n"                       1

stmt:   ARGF4(reg)              "# arg\n"                       1

reg:    INDIRF8(VREGP)          "# read register\n"

stmt:   ASGNF8(VREGP,reg)       "# write register\n"

reg:    INDIRF8(addr)           ";FP: l.d $f%c,%0\n"            1

stmt:   ASGNF8(addr,reg)        ";FP: s.d $f%1,%0\n"            1

reg:    ADDF8(reg,reg)          ";FP: add.d $f%c,$f%0,$f%1\n"   1

reg:    SUBF8(reg,reg)          ";FP: sub.d $f%c,$f%0,$f%1\n"   1

reg:    MULF8(reg,reg)          ";FP: mul.d $f%c,$f%0,$f%1\n"   1

reg:    DIVF8(reg,reg)          ";FP: div.d $f%c,$f%0,$f%1\n"   1

reg:    LOADF8(reg)             ";FP: mov.d $f%c,$f%0\n"        1

reg:    NEGF8(reg)              ";FP: neg.d $f%c,$f%0\n"        1

reg:    CVFF8(reg)              ";FP: cvt.d.s $f%c,$f%0\n"      1

reg:    CVIF8(reg)              ";FP: mtc1 $%0,$f%c; cvt.d.w $f%c,$f%c\n"      1

reg:    CVFI4(reg)              ";FP: trunc.w.d $f2,$f%0,$%c; mfc1 $%c,$f2\n"  (a->syms[0]->u.c.v.i == 8 ? 1 : LBURG_MAX)

stmt:   EQF8(reg,reg)           ";FP: c.eq.d $f%0,$f%1; bc1t %a\n"      1

stmt:   LEF8(reg,reg)           ";FP: c.ule.d $f%0,$f%1; bc1t %a\n"     1

stmt:   LTF8(reg,reg)           ";FP: c.ult.d $f%0,$f%1; bc1t %a\n"     1

stmt:   GEF8(reg,reg)           ";FP: c.lt.d $f%0,$f%1; bc1f %a\n"      1

stmt:   GTF8(reg,reg)           ";FP: c.le.d $f%0,$f%1; bc1f %a\n"      1

stmt:   NEF8(reg,reg)           ";FP: c.eq.d $f%0,$f%1; bc1f %a\n"      1

reg:    CALLF8(ar)              "\tjal\t%0\n"                   1

stmt:   RETF8(reg)              "# ret\n"                       1

stmt:   ARGF8(reg)              "# arg\n"                       1

%%

static void address(Symbol s1, Symbol s2, long n) {

  if (s2->scope == GLOBAL ||

      s2->sclass == STATIC ||

      s2->sclass == EXTERN) {

    s1->x.name = stringf("%s%s%D", s2->x.name, n >= 0 ? "+" : "", n);

  } else {

    assert(n >= INT_MIN && n <= INT_MAX);

    s1->x.offset = s2->x.offset + n;

    s1->x.name = stringd(s1->x.offset);

  }

}

static void defaddress(Symbol s) {

  print("\t.word\t%s\n", s->x.name);

}

static void defconst(int suffix, int size, Value v) {

  float f;

  double d;

  unsigned *p;

  if (suffix == F && size == 4) {

    f = v.d;

    print("\t.word\t0x%x\n", * (unsigned *) &f);

  } else

  if (suffix == F && size == 8) {

    d = v.d;

    p = (unsigned *) &d;

    print("\t.word\t0x%x\n", p[swap]);

    print("\t.word\t0x%x\n", p[1 - swap]);

  } else

  if (suffix == P) {

    print("\t.word\t0x%lx\n", (unsigned long) v.p);

  } else

  if (size == 1) {

    print("\t.byte\t0x%x\n",

          (unsigned) ((unsigned char) (suffix == I ? v.i : v.u)));

  } else

  if (size == 2) {

    print("\t.half\t0x%x\n",

          (unsigned) ((unsigned short) (suffix == I ? v.i : v.u)));

  } else

  if (size == 4) {

    print("\t.word\t0x%x\n", (unsigned) (suffix == I ? v.i : v.u));

  }

}

static void defstring(int n, char *str) {

  char *s;

  for (s = str; s < str + n; s++) {

    print("\t.byte\t0x%x\n", (*s) & 0xFF);

  }

}

static void defsymbol(Symbol s) {

  if (s->scope >= LOCAL && s->sclass == STATIC) {

    s->x.name = stringf("L.%d", genlabel(1));

  } else

  if (s->generated) {

    s->x.name = stringf("L.%s", s->name);

  } else {

    assert(s->scope != CONSTANTS || isint(s->type) || isptr(s->type));

    s->x.name = s->name;

  }

}

static void export(Symbol s) {

  print("\t.export\t%s\n", s->name);

}

static int bitcount(unsigned mask) {

  unsigned i, n;

  n = 0;

  for (i = 1; i != 0; i <<= 1) {

    if (mask & i) {

      n++;

    }

  }

  return n;

}

static Symbol argreg(int argno, int offset, int ty, int sz, int ty0) {

  assert((offset & 3) == 0);

  if (offset > 12) {

    return NULL;

  }

  return ireg[(offset / 4) + 4];

}

static void function(Symbol f, Symbol caller[], Symbol callee[], int ncalls) {

  int i;

  Symbol p, q;

  Symbol r;

  int sizeisave;

  int saved;

  Symbol argregs[4];

  usedmask[0] = usedmask[1] = 0;

  freemask[0] = freemask[1] = ~((unsigned) 0);

  offset = 0;

  maxoffset = 0;

  maxargoffset = 0;

  for (i = 0; callee[i] != NULL; i++) {

    p = callee[i];

    q = caller[i];

    assert(q != NULL);

    offset = roundup(offset, q->type->align);

    p->x.offset = q->x.offset = offset;

    p->x.name = q->x.name = stringd(offset);

    r = argreg(i, offset, optype(ttob(q->type)),

               q->type->size, optype(ttob(caller[0]->type)));

    if (i < 4) {

      argregs[i] = r;

    }

    offset = roundup(offset + q->type->size, 4);

    if (variadic(f->type)) {

      p->sclass = AUTO;

    } else

    if (r != NULL && ncalls == 0 && !isstruct(q->type) &&

        !p->addressed && !(isfloat(q->type) && r->x.regnode->set == IREG)) {

      p->sclass = q->sclass = REGISTER;

      askregvar(p, r);

      assert(p->x.regnode && p->x.regnode->vbl == p);

      q->x = p->x;

      q->type = p->type;

    } else

    if (askregvar(p, rmap(ttob(p->type))) &&

        r != NULL && (isint(p->type) || p->type == q->type)) {

      assert(q->sclass != REGISTER);

      p->sclass = q->sclass = REGISTER;

      q->type = p->type;

    }

  }

  assert(caller[i] == NULL);

  offset = 0;

  gencode(caller, callee);

  if (ncalls != 0) {

    usedmask[IREG] |= ((unsigned) 1) << 31;

  }

  usedmask[IREG] &= 0x80FF0000;

  usedmask[FREG] &= 0xFFF00000;

  maxargoffset = roundup(maxargoffset, 4);

  if (ncalls != 0 && maxargoffset < 16) {

    maxargoffset = 16;

  }

  sizeisave = 4 * bitcount(usedmask[IREG]);

  framesize = roundup(maxargoffset + sizeisave + maxoffset, 16);

  segment(CODE);

  print("\t.align\t4\n");

  print("%s:\n", f->x.name);

  if (framesize > 0) {

    print("\tsub\t$29,$29,%d\n", framesize);

  }

  saved = maxargoffset;

  for (i = 16; i < 32; i++) {

    if (usedmask[IREG] & (1 << i)) {

      print("\tstw\t$%d,$29,%d\n", i, saved);

      saved += 4;

    }

  }

  for (i = 0; i < 4 && callee[i] != NULL; i++) {

    r = argregs[i];

    if (r && r->x.regnode != callee[i]->x.regnode) {

      Symbol out = callee[i];

      Symbol in = caller[i];

      int rn = r->x.regnode->number;

      int rs = r->x.regnode->set;

      int tyin = ttob(in->type);

      assert(out && in && r && r->x.regnode);

      assert(out->sclass != REGISTER || out->x.regnode);

      if (out->sclass == REGISTER &&

          (isint(out->type) || out->type == in->type)) {

        int outn = out->x.regnode->number;

        print("\tadd\t$%d,$0,$%d\n", outn, rn);

      } else {

        int off = in->x.offset + framesize;

        int n = (in->type->size + 3) / 4;

        int i;

        for (i = rn; i < rn + n && i <= 7; i++) {

          print("\tstw\t$%d,$29,%d\n", i, off + (i - rn) * 4);

        }

      }

    }

  }

  if (variadic(f->type) && callee[i - 1] != NULL) {

    i = callee[i - 1]->x.offset + callee[i - 1]->type->size;

    for (i = roundup(i, 4)/4; i <= 3; i++) {

      print("\tstw\t$%d,$29,%d\n", i + 4, framesize + 4 * i);

    }

  }

  emitcode();

  saved = maxargoffset;

  for (i = 16; i < 32; i++) {

    if (usedmask[IREG] & (1 << i)) {

      print("\tldw\t$%d,$29,%d\n", i, saved);

      saved += 4;

    }

  }

  if (framesize > 0) {

    print("\tadd\t$29,$29,%d\n", framesize);

  }

  print("\tjr\t$31\n");

  print("\n");

}

static void global(Symbol s) {

  if (s->type->align != 0) {

    print("\t.align\t%d\n", s->type->align);

  } else {

    print("\t.align\t%d\n", 4);

  }

  print("%s:\n", s->x.name);

}

static void import(Symbol s) {

  print("\t.import\t%s\n", s->name);

}

static void local(Symbol s) {

  if (askregvar(s, rmap(ttob(s->type))) == 0) {

    mkauto(s);

  }

}

static void setSwap(void) {

  union {

    char c;

    int i;

  } u;

  u.i = 0;

  u.c = 1;

  swap = ((u.i == 1) != IR->little_endian);

}

static void progbeg(int argc, char *argv[]) {

  int i;

  setSwap();

  segment(CODE);

  parseflags(argc, argv);

  for (i = 0; i < 32; i++) {

    ireg[i] = mkreg("%d", i, 1, IREG);

  }

  iregw = mkwildcard(ireg);

  for (i = 0; i < 32; i += 2) {

    freg2[i] = mkreg("%d", i, 3, FREG);

  }

  freg2w = mkwildcard(freg2);

  tmask[IREG] = INTTMP;

  vmask[IREG] = INTVAR;

  tmask[FREG] = FLTTMP;

  vmask[FREG] = FLTVAR;

  blkreg = mkreg("8", 8, 7, IREG);

}

static void progend(void) {

}

static void segment(int n) {

  static int currSeg = -1;

  int newSeg;

  switch (n) {

    case CODE:

      newSeg = CODE;

      break;

    case BSS:

      newSeg = BSS;

      break;

    case DATA:

      newSeg = DATA;

      break;

    case LIT:

      newSeg = DATA;

      break;

  }

  if (currSeg == newSeg) {

    return;

  }

  switch (newSeg) {

    case CODE:

      print("\t.code\n");

      break;

    case BSS:

      print("\t.bss\n");

      break;

    case DATA:

      print("\t.data\n");

      break;

  }

  currSeg = newSeg;

}

static void space(int n) {

  print("\t.space\t%d\n", n);

}

static Symbol rmap(int opk) {

  switch (optype(opk)) {

    case I:

    case U:

    case P:

    case B:

      return iregw;

    case F:

      return freg2w;

    default:

      return 0;

  }

}

static void blkfetch(int size, int off, int reg, int tmp) {

  assert(size == 1 || size == 2 || size == 4);

  if (size == 1) {

    print("\tldbu\t$%d,$%d,%d\n", tmp, reg, off);

  } else

  if (size == 2) {

    print("\tldhu\t$%d,$%d,%d\n", tmp, reg, off);

  } else

  if (size == 4) {

    print("\tldw\t$%d,$%d,%d\n", tmp, reg, off);

  }

}

static void blkstore(int size, int off, int reg, int tmp) {

  assert(size == 1 || size == 2 || size == 4);

  if (size == 1) {

    print("\tstb\t$%d,$%d,%d\n", tmp, reg, off);

  } else

  if (size == 2) {

    print("\tsth\t$%d,$%d,%d\n", tmp, reg, off);

  } else

  if (size == 4) {

    print("\tstw\t$%d,$%d,%d\n", tmp, reg, off);

  }

}

static void blkloop(int dreg, int doff,

                    int sreg, int soff,

                    int size, int tmps[]) {

  int label;

  label = genlabel(1);

  print("\tadd\t$%d,$%d,%d\n", sreg, sreg, size & ~7);

  print("\tadd\t$%d,$%d,%d\n", tmps[2], dreg, size & ~7);

  blkcopy(tmps[2], doff, sreg, soff, size & 7, tmps);

  print("L.%d:\n", label);

  print("\tsub\t$%d,$%d,%d\n", sreg, sreg, 8);

  print("\tsub\t$%d,$%d,%d\n", tmps[2], tmps[2], 8);

  blkcopy(tmps[2], doff, sreg, soff, 8, tmps);

  print("\tbltu\t$%d,$%d,L.%d\n", dreg, tmps[2], label);

}

static void emit2(Node p) {

  static int ty0;

  int ty, sz;

  Symbol q;

  int src;

  int dst, n;

  switch (specific(p->op)) {

    case ARG+I:

    case ARG+P:

    case ARG+U:

      ty = optype(p->op);

      sz = opsize(p->op);

      if (p->x.argno == 0) {

        ty0 = ty;

      }

      q = argreg(p->x.argno, p->syms[2]->u.c.v.i, ty, sz, ty0);

      src = getregnum(p->x.kids[0]);

      if (q == NULL) {

        print("\tstw\t$%d,$29,%d\n", src, p->syms[2]->u.c.v.i);

      }

      break;

    case ASGN+B:

      dalign = p->syms[1]->u.c.v.i;

      salign = p->syms[1]->u.c.v.i;

      blkcopy(getregnum(p->x.kids[0]), 0,

              getregnum(p->x.kids[1]), 0,

              p->syms[0]->u.c.v.i, tmpregs);

      break;

    case ARG+B:

      dalign = 4;

      salign = p->syms[1]->u.c.v.i;

      blkcopy(29, p->syms[2]->u.c.v.i,

              getregnum(p->x.kids[0]), 0,

              p->syms[0]->u.c.v.i, tmpregs);

      n = p->syms[2]->u.c.v.i + p->syms[0]->u.c.v.i;

      dst = p->syms[2]->u.c.v.i;

      for (; dst <= 12 && dst < n; dst += 4) {

        print("\tldw\t$%d,$29,%d\n", (dst / 4) + 4, dst);

      }

      break;

  }

}

static void doarg(Node p) {

  static int argno;

  int align;

  int size;

  int offset;

  if (argoffset == 0) {

    argno = 0;

  }

  p->x.argno = argno++;

  align = p->syms[1]->u.c.v.i;

  if (align < 4) {

    align = 4;

  }

  size = p->syms[0]->u.c.v.i;

  offset = mkactual(align, size);

  p->syms[2] = intconst(offset);

}

static void target(Node p) {

  static int ty0;

  int ty;

  Symbol q;

  assert(p);

  switch (specific(p->op)) {

    case CNST+I:

    case CNST+P:

    case CNST+U:

      if (range(p, 0, 0) == 0) {

        setreg(p, ireg[0]);

        p->x.registered = 1;

      }

      break;

    case CALL+I:

    case CALL+P:

    case CALL+U:

      rtarget(p, 0, ireg[25]);

      setreg(p, ireg[2]);

      break;

    case CALL+F:

      rtarget(p, 0, ireg[25]);

      setreg(p, freg2[0]);

      break;

    case CALL+V:

      rtarget(p, 0, ireg[25]);

      break;

    case RET+I:

    case RET+P:

    case RET+U:

      rtarget(p, 0, ireg[2]);

      break;

    case RET+F:

      rtarget(p, 0, freg2[0]);

      break;

    case ARG+I:

    case ARG+P:

    case ARG+U:

    case ARG+F:

      ty = optype(p->op);

      q = argreg(p->x.argno, p->syms[2]->u.c.v.i, ty, opsize(p->op), ty0);

      if (p->x.argno == 0) {

        ty0 = ty;

      }

      if (q && !(ty == F && q->x.regnode->set == IREG)) {

        rtarget(p, 0, q);

      }

      break;

    case ASGN+B:

      rtarget(p->kids[1], 0, blkreg);

      break;

    case ARG+B:

      rtarget(p->kids[0], 0, blkreg);

      break;

  }

}

static void clobber(Node p) {