gcc/config/sh/sh-mem.cc

   1 /* Helper routines for memory move and comparison insns.
   2    Copyright (C) 2013-2014 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 3, or (at your option)
   9 any later version.
  10
  11 GCC is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #include "config.h"
  21 #include "system.h"
  22 #include "coretypes.h"
  23 #include "tm.h"
  24 #include "machmode.h"
  25 #include "rtl.h"
  26 #include "tree.h"
  27 #include "expr.h"
  28 #include "tm_p.h"
  29 #include "basic-block.h"
  30
  31 /* Like force_operand, but guarantees that VALUE ends up in TARGET.  */
  32 static void
  33 force_into (rtx value, rtx target)
  34 {
  35   value = force_operand (value, target);
  36   if (! rtx_equal_p (value, target))
  37     emit_insn (gen_move_insn (target, value));
  38 }
  39
  40 /* Emit code to perform a block move.  Choose the best method.
  41
  42    OPERANDS[0] is the destination.
  43    OPERANDS[1] is the source.
  44    OPERANDS[2] is the size.
  45    OPERANDS[3] is the alignment safe to use.  */
  46 bool
  47 expand_block_move (rtx *operands)
  48 {
  49   int align = INTVAL (operands[3]);
  50   int constp = (CONST_INT_P (operands[2]));
  51   int bytes = (constp ? INTVAL (operands[2]) : 0);
  52
  53   if (! constp)
  54     return false;
  55
  56   /* If we could use mov.l to move words and dest is word-aligned, we
  57      can use movua.l for loads and still generate a relatively short
  58      and efficient sequence.  */
  59   if (TARGET_SH4A_ARCH && align < 4
  60       && MEM_ALIGN (operands[0]) >= 32
  61       && can_move_by_pieces (bytes, 32))
  62     {
  63       rtx dest = copy_rtx (operands[0]);
  64       rtx src = copy_rtx (operands[1]);
  65       /* We could use different pseudos for each copied word, but
  66          since movua can only load into r0, it's kind of
  67          pointless.  */
  68       rtx temp = gen_reg_rtx (SImode);
  69       rtx src_addr = copy_addr_to_reg (XEXP (src, 0));
  70       int copied = 0;
  71
  72       while (copied + 4 <= bytes)
  73         {
  74           rtx to = adjust_address (dest, SImode, copied);
  75           rtx from = adjust_automodify_address (src, BLKmode,
  76                                                 src_addr, copied);
  77
  78           set_mem_size (from, 4);
  79           emit_insn (gen_movua (temp, from));
  80           emit_move_insn (src_addr, plus_constant (Pmode, src_addr, 4));
  81           emit_move_insn (to, temp);
  82           copied += 4;
  83         }
  84
  85       if (copied < bytes)
  86         move_by_pieces (adjust_address (dest, BLKmode, copied),
  87                         adjust_automodify_address (src, BLKmode,
  88                                                    src_addr, copied),
  89                         bytes - copied, align, 0);
  90
  91       return true;
  92     }
  93
  94   /* If it isn't a constant number of bytes, or if it doesn't have 4 byte
  95      alignment, or if it isn't a multiple of 4 bytes, then fail.  */
  96   if (align < 4 || (bytes % 4 != 0))
  97     return false;
  98
  99   if (TARGET_HARD_SH4)
 100     {
 101       if (bytes < 12)
 102         return false;
 103       else if (bytes == 12)
 104         {
 105           rtx func_addr_rtx = gen_reg_rtx (Pmode);
 106           rtx r4 = gen_rtx_REG (SImode, 4);
 107           rtx r5 = gen_rtx_REG (SImode, 5);
 108
 109           function_symbol (func_addr_rtx, "__movmemSI12_i4", SFUNC_STATIC);
 110           force_into (XEXP (operands[0], 0), r4);
 111           force_into (XEXP (operands[1], 0), r5);
 112           emit_insn (gen_block_move_real_i4 (func_addr_rtx));
 113           return true;
 114         }
 115       else if (! optimize_size)
 116         {
 117           const char *entry_name;
 118           rtx func_addr_rtx = gen_reg_rtx (Pmode);
 119           int dwords;
 120           rtx r4 = gen_rtx_REG (SImode, 4);
 121           rtx r5 = gen_rtx_REG (SImode, 5);
 122           rtx r6 = gen_rtx_REG (SImode, 6);
 123
 124           entry_name = (bytes & 4 ? "__movmem_i4_odd" : "__movmem_i4_even");
 125           function_symbol (func_addr_rtx, entry_name, SFUNC_STATIC);
 126           force_into (XEXP (operands[0], 0), r4);
 127           force_into (XEXP (operands[1], 0), r5);
 128
 129           dwords = bytes >> 3;
 130           emit_insn (gen_move_insn (r6, GEN_INT (dwords - 1)));
 131           emit_insn (gen_block_lump_real_i4 (func_addr_rtx));
 132           return true;
 133         }
 134       else
 135         return false;
 136     }
 137   if (bytes < 64)
 138     {
 139       char entry[30];
 140       rtx func_addr_rtx = gen_reg_rtx (Pmode);
 141       rtx r4 = gen_rtx_REG (SImode, 4);
 142       rtx r5 = gen_rtx_REG (SImode, 5);
 143
 144       sprintf (entry, "__movmemSI%d", bytes);
 145       function_symbol (func_addr_rtx, entry, SFUNC_STATIC);
 146       force_into (XEXP (operands[0], 0), r4);
 147       force_into (XEXP (operands[1], 0), r5);
 148       emit_insn (gen_block_move_real (func_addr_rtx));
 149       return true;
 150     }
 151
 152   /* This is the same number of bytes as a memcpy call, but to a different
 153      less common function name, so this will occasionally use more space.  */
 154   if (! optimize_size)
 155     {
 156       rtx func_addr_rtx = gen_reg_rtx (Pmode);
 157       int final_switch, while_loop;
 158       rtx r4 = gen_rtx_REG (SImode, 4);
 159       rtx r5 = gen_rtx_REG (SImode, 5);
 160       rtx r6 = gen_rtx_REG (SImode, 6);
 161
 162       function_symbol (func_addr_rtx, "__movmem", SFUNC_STATIC);
 163       force_into (XEXP (operands[0], 0), r4);
 164       force_into (XEXP (operands[1], 0), r5);
 165
 166       /* r6 controls the size of the move.  16 is decremented from it
 167          for each 64 bytes moved.  Then the negative bit left over is used
 168          as an index into a list of move instructions.  e.g., a 72 byte move
 169          would be set up with size(r6) = 14, for one iteration through the
 170          big while loop, and a switch of -2 for the last part.  */
 171
 172       final_switch = 16 - ((bytes / 4) % 16);
 173       while_loop = ((bytes / 4) / 16 - 1) * 16;
 174       emit_insn (gen_move_insn (r6, GEN_INT (while_loop + final_switch)));
 175       emit_insn (gen_block_lump_real (func_addr_rtx));
 176       return true;
 177     }
 178
 179   return false;
 180 }
 181
 182 static int prob_unlikely = REG_BR_PROB_BASE / 10;
 183 static int prob_likely = REG_BR_PROB_BASE / 4;
 184
 185 /* Emit code to perform a strcmp.
 186
 187    OPERANDS[0] is the destination.
 188    OPERANDS[1] is the first string.
 189    OPERANDS[2] is the second string.
 190    OPERANDS[3] is the known alignment.  */
 191 bool
 192 sh_expand_cmpstr (rtx *operands)
 193 {
 194   rtx addr1 = operands[1];
 195   rtx addr2 = operands[2];
 196   rtx s1_addr = copy_addr_to_reg (XEXP (addr1, 0));
 197   rtx s2_addr = copy_addr_to_reg (XEXP (addr2, 0));
 198   rtx tmp0 = gen_reg_rtx (SImode);
 199   rtx tmp1 = gen_reg_rtx (SImode);
 200   rtx tmp2 = gen_reg_rtx (SImode);
 201   rtx tmp3 = gen_reg_rtx (SImode);
 202
 203   rtx jump;
 204   rtx L_return = gen_label_rtx ();
 205   rtx L_loop_byte = gen_label_rtx ();
 206   rtx L_end_loop_byte = gen_label_rtx ();
 207   rtx L_loop_long = gen_label_rtx ();
 208   rtx L_end_loop_long = gen_label_rtx ();
 209
 210   int align = INTVAL (operands[3]);
 211
 212   emit_move_insn (tmp0, const0_rtx);
 213
 214   if (align < 4)
 215     {
 216       emit_insn (gen_iorsi3 (tmp1, s1_addr, s2_addr));
 217       emit_insn (gen_tstsi_t (GEN_INT (3), tmp1));
 218       jump = emit_jump_insn (gen_branch_false (L_loop_byte));
 219       add_int_reg_note (jump, REG_BR_PROB, prob_likely);
 220     }
 221
 222   addr1 = adjust_automodify_address (addr1, SImode, s1_addr, 0);
 223   addr2 = adjust_automodify_address (addr2, SImode, s2_addr, 0);
 224
 225   /* tmp2 is aligned, OK to load.  */
 226   emit_move_insn (tmp3, addr2);
 227   emit_move_insn (s2_addr, plus_constant (Pmode, s2_addr, 4));
 228
 229   /*start long loop.  */
 230   emit_label (L_loop_long);
 231
 232   emit_move_insn (tmp2, tmp3);
 233
 234   /* tmp1 is aligned, OK to load.  */
 235   emit_move_insn (tmp1, addr1);
 236   emit_move_insn (s1_addr, plus_constant (Pmode, s1_addr, 4));
 237
 238   /* Is there a 0 byte ?  */
 239   emit_insn (gen_andsi3 (tmp3, tmp3, tmp1));
 240
 241   emit_insn (gen_cmpstr_t (tmp0, tmp3));
 242   jump = emit_jump_insn (gen_branch_true (L_end_loop_long));
 243   add_int_reg_note (jump, REG_BR_PROB, prob_unlikely);
 244
 245   emit_insn (gen_cmpeqsi_t (tmp1, tmp2));
 246
 247   /* tmp2 is aligned, OK to load.  */
 248   emit_move_insn (tmp3, addr2);
 249   emit_move_insn (s2_addr, plus_constant (Pmode, s2_addr, 4));
 250
 251   jump = emit_jump_insn (gen_branch_true (L_loop_long));
 252   add_int_reg_note (jump, REG_BR_PROB, prob_likely);
 253   /* end loop.  */
 254
 255   /* Fallthu, substract words.  */
 256   if (TARGET_LITTLE_ENDIAN)
 257     {
 258       rtx low_1 = gen_lowpart (HImode, tmp1);
 259       rtx low_2 = gen_lowpart (HImode, tmp2);
 260
 261       emit_insn (gen_rotlhi3_8 (low_1, low_1));
 262       emit_insn (gen_rotlhi3_8 (low_2, low_2));
 263       emit_insn (gen_rotlsi3_16 (tmp1, tmp1));
 264       emit_insn (gen_rotlsi3_16 (tmp2, tmp2));
 265       emit_insn (gen_rotlhi3_8 (low_1, low_1));
 266       emit_insn (gen_rotlhi3_8 (low_2, low_2));
 267     }
 268
 269   jump = emit_jump_insn (gen_jump_compact (L_return));
 270   emit_barrier_after (jump);
 271
 272   emit_label (L_end_loop_long);
 273
 274   emit_move_insn (s1_addr, plus_constant (Pmode, s1_addr, -4));
 275   emit_move_insn (s2_addr, plus_constant (Pmode, s2_addr, -4));
 276
 277   /* start byte loop.  */
 278   addr1 = adjust_address (addr1, QImode, 0);
 279   addr2 = adjust_address (addr2, QImode, 0);
 280
 281   emit_label (L_loop_byte);
 282
 283   emit_insn (gen_extendqisi2 (tmp2, addr2));
 284   emit_move_insn (s2_addr, plus_constant (Pmode, s2_addr, 1));
 285
 286   emit_insn (gen_extendqisi2 (tmp1, addr1));
 287   emit_move_insn (s1_addr, plus_constant (Pmode, s1_addr, 1));
 288
 289   emit_insn (gen_cmpeqsi_t (tmp2, const0_rtx));
 290   jump = emit_jump_insn (gen_branch_true (L_end_loop_byte));
 291   add_int_reg_note (jump, REG_BR_PROB, prob_unlikely);
 292
 293   emit_insn (gen_cmpeqsi_t (tmp1, tmp2));
 294   if (flag_delayed_branch)
 295     emit_insn (gen_zero_extendqisi2 (tmp2, gen_lowpart (QImode, tmp2)));
 296   jump = emit_jump_insn (gen_branch_true (L_loop_byte));
 297   add_int_reg_note (jump, REG_BR_PROB, prob_likely);
 298   /* end loop.  */
 299
 300   emit_label (L_end_loop_byte);
 301
 302   if (! flag_delayed_branch)
 303     emit_insn (gen_zero_extendqisi2 (tmp2, gen_lowpart (QImode, tmp2)));
 304   emit_insn (gen_zero_extendqisi2 (tmp1, gen_lowpart (QImode, tmp1)));
 305
 306   emit_label (L_return);
 307
 308   emit_insn (gen_subsi3 (operands[0], tmp1, tmp2));
 309
 310   return true;
 311 }
 312
 313 /* Emit code to perform a strncmp.
 314
 315    OPERANDS[0] is the destination.
 316    OPERANDS[1] is the first string.
 317    OPERANDS[2] is the second string.
 318    OPERANDS[3] is the length.
 319    OPERANDS[4] is the known alignment.  */
 320 bool
 321 sh_expand_cmpnstr (rtx *operands)
 322 {
 323   rtx addr1 = operands[1];
 324   rtx addr2 = operands[2];
 325   rtx s1_addr = copy_addr_to_reg (XEXP (addr1, 0));
 326   rtx s2_addr = copy_addr_to_reg (XEXP (addr2, 0));
 327   rtx tmp1 = gen_reg_rtx (SImode);
 328   rtx tmp2 = gen_reg_rtx (SImode);
 329
 330   rtx jump;
 331   rtx L_return = gen_label_rtx ();
 332   rtx L_loop_byte = gen_label_rtx ();
 333   rtx L_end_loop_byte = gen_label_rtx ();
 334
 335   rtx len = force_reg (SImode, operands[3]);
 336   int constp = CONST_INT_P (operands[3]);
 337
 338   /* Loop on a register count. */
 339   if (constp)
 340     {
 341       rtx tmp0 = gen_reg_rtx (SImode);
 342       rtx tmp3 = gen_reg_rtx (SImode);
 343       rtx lenw = gen_reg_rtx (SImode);
 344
 345       rtx L_loop_long = gen_label_rtx ();
 346       rtx L_end_loop_long = gen_label_rtx ();
 347
 348       int align = INTVAL (operands[4]);
 349       int bytes = INTVAL (operands[3]);
 350       int witers = bytes / 4;
 351
 352       if (witers > 1)
 353         {
 354           addr1 = adjust_automodify_address (addr1, SImode, s1_addr, 0);
 355           addr2 = adjust_automodify_address (addr2, SImode, s2_addr, 0);
 356
 357           emit_move_insn (tmp0, const0_rtx);
 358
 359           if (align < 4)
 360             {
 361               emit_insn (gen_iorsi3 (tmp1, s1_addr, s2_addr));
 362               emit_insn (gen_tstsi_t (GEN_INT (3), tmp1));
 363               jump = emit_jump_insn (gen_branch_false (L_loop_byte));
 364               add_int_reg_note (jump, REG_BR_PROB, prob_likely);
 365             }
 366
 367           /* word count. Do we have iterations ? */
 368           emit_insn (gen_lshrsi3 (lenw, len, GEN_INT (2)));
 369
 370           /*start long loop.  */
 371           emit_label (L_loop_long);
 372
 373           /* tmp2 is aligned, OK to load.  */
 374           emit_move_insn (tmp2, addr2);
 375           emit_move_insn (s2_addr, plus_constant (Pmode, s2_addr,
 376                                                   GET_MODE_SIZE (SImode)));
 377
 378           /* tmp1 is aligned, OK to load.  */
 379           emit_move_insn (tmp1, addr1);
 380           emit_move_insn (s1_addr, plus_constant (Pmode, s1_addr,
 381                                                   GET_MODE_SIZE (SImode)));
 382
 383           /* Is there a 0 byte ?  */
 384           emit_insn (gen_andsi3 (tmp3, tmp2, tmp1));
 385
 386           emit_insn (gen_cmpstr_t (tmp0, tmp3));
 387           jump = emit_jump_insn (gen_branch_true (L_end_loop_long));
 388           add_int_reg_note (jump, REG_BR_PROB, prob_unlikely);
 389
 390           emit_insn (gen_cmpeqsi_t (tmp1, tmp2));
 391           jump = emit_jump_insn (gen_branch_false (L_end_loop_long));
 392           add_int_reg_note (jump, REG_BR_PROB, prob_unlikely);
 393
 394           if (TARGET_SH2)
 395             emit_insn (gen_dect (lenw, lenw));
 396           else
 397             {
 398               emit_insn (gen_addsi3 (lenw, lenw, GEN_INT (-1)));
 399               emit_insn (gen_tstsi_t (lenw, lenw));
 400             }
 401
 402           jump = emit_jump_insn (gen_branch_false (L_loop_long));
 403           add_int_reg_note (jump, REG_BR_PROB, prob_likely);
 404
 405          int sbytes = bytes % 4;
 406
 407           /* end loop.  Reached max iterations.  */
 408           if (! sbytes)
 409             {
 410               jump = emit_jump_insn (gen_jump_compact (L_return));
 411               emit_barrier_after (jump);
 412             }
 413           else
 414             {
 415               /* Remaining bytes to check.  */
 416
 417               addr1 = adjust_automodify_address (addr1, QImode, s1_addr, 0);
 418               addr2 = adjust_automodify_address (addr2, QImode, s2_addr, 0);
 419
 420               while (sbytes--)
 421                 {
 422                   emit_insn (gen_extendqisi2 (tmp1, addr1));
 423                   emit_insn (gen_extendqisi2 (tmp2, addr2));
 424
 425                   emit_insn (gen_cmpeqsi_t (tmp2, const0_rtx));
 426                   jump = emit_jump_insn (gen_branch_true (L_end_loop_byte));
 427                   add_int_reg_note (jump, REG_BR_PROB, prob_unlikely);
 428
 429                   emit_insn (gen_cmpeqsi_t (tmp1, tmp2));
 430                   if (flag_delayed_branch)
 431                     emit_insn (gen_zero_extendqisi2 (tmp2,
 432                                                      gen_lowpart (QImode,
 433                                                                   tmp2)));
 434                   jump = emit_jump_insn (gen_branch_false (L_end_loop_byte));
 435                   add_int_reg_note (jump, REG_BR_PROB, prob_unlikely);
 436
 437                   addr1 = adjust_address (addr1, QImode,
 438                                           GET_MODE_SIZE (QImode));
 439                   addr2 = adjust_address (addr2, QImode,
 440                                           GET_MODE_SIZE (QImode));
 441                 }
 442
 443               jump = emit_jump_insn (gen_jump_compact( L_end_loop_byte));
 444               emit_barrier_after (jump);
 445             }
 446
 447           emit_label (L_end_loop_long);
 448
 449           /* Found last word.  Restart it byte per byte. */
 450
 451           emit_move_insn (s1_addr, plus_constant (Pmode, s1_addr,
 452                                                   -GET_MODE_SIZE (SImode)));
 453           emit_move_insn (s2_addr, plus_constant (Pmode, s2_addr,
 454                                                   -GET_MODE_SIZE (SImode)));
 455
 456           /* fall thru.  */
 457         }
 458
 459       addr1 = adjust_automodify_address (addr1, QImode, s1_addr, 0);
 460       addr2 = adjust_automodify_address (addr2, QImode, s2_addr, 0);
 461
 462       while (bytes--)
 463         {
 464           emit_insn (gen_extendqisi2 (tmp1, addr1));
 465           emit_insn (gen_extendqisi2 (tmp2, addr2));
 466
 467           emit_insn (gen_cmpeqsi_t (tmp2, const0_rtx));
 468           jump = emit_jump_insn (gen_branch_true (L_end_loop_byte));
 469           add_int_reg_note (jump, REG_BR_PROB, prob_unlikely);
 470
 471           emit_insn (gen_cmpeqsi_t (tmp1, tmp2));
 472           if (flag_delayed_branch)
 473             emit_insn (gen_zero_extendqisi2 (tmp2,
 474                                              gen_lowpart (QImode, tmp2)));
 475           jump = emit_jump_insn (gen_branch_false (L_end_loop_byte));
 476           add_int_reg_note (jump, REG_BR_PROB, prob_unlikely);
 477
 478           addr1 = adjust_address (addr1, QImode, GET_MODE_SIZE (QImode));
 479           addr2 = adjust_address (addr2, QImode, GET_MODE_SIZE (QImode));
 480         }
 481
 482       jump = emit_jump_insn (gen_jump_compact( L_end_loop_byte));
 483       emit_barrier_after (jump);
 484     }
 485
 486   addr1 = adjust_automodify_address (addr1, QImode, s1_addr, 0);
 487   addr2 = adjust_automodify_address (addr2, QImode, s2_addr, 0);
 488
 489   emit_label (L_loop_byte);
 490
 491   emit_insn (gen_extendqisi2 (tmp2, addr2));
 492   emit_move_insn (s2_addr, plus_constant (Pmode, s2_addr, 1));
 493
 494   emit_insn (gen_extendqisi2 (tmp1, addr1));
 495   emit_move_insn (s1_addr, plus_constant (Pmode, s1_addr, 1));
 496
 497   emit_insn (gen_cmpeqsi_t (tmp2, const0_rtx));
 498   jump = emit_jump_insn (gen_branch_true (L_end_loop_byte));
 499   add_int_reg_note (jump, REG_BR_PROB, prob_unlikely);
 500
 501   emit_insn (gen_cmpeqsi_t (tmp1, tmp2));
 502   if (flag_delayed_branch)
 503     emit_insn (gen_zero_extendqisi2 (tmp2, gen_lowpart (QImode, tmp2)));
 504   jump = emit_jump_insn (gen_branch_false (L_end_loop_byte));
 505   add_int_reg_note (jump, REG_BR_PROB, prob_unlikely);
 506
 507   if (TARGET_SH2)
 508     emit_insn (gen_dect (len, len));
 509   else
 510     {
 511       emit_insn (gen_addsi3 (len, len, GEN_INT (-1)));
 512       emit_insn (gen_tstsi_t (len, len));
 513     }
 514
 515   jump = emit_jump_insn (gen_branch_false (L_loop_byte));
 516   add_int_reg_note (jump, REG_BR_PROB, prob_likely);
 517   /* end byte loop.  */
 518
 519   emit_label (L_end_loop_byte);
 520
 521   if (! flag_delayed_branch)
 522     emit_insn (gen_zero_extendqisi2 (tmp2, gen_lowpart (QImode, tmp2)));
 523   emit_insn (gen_zero_extendqisi2 (tmp1, gen_lowpart (QImode, tmp1)));
 524
 525   emit_label (L_return);
 526
 527   emit_insn (gen_subsi3 (operands[0], tmp1, tmp2));
 528
 529   return true;
 530 }
 531
 532 /* Emit code to perform a strlen
 533
 534    OPERANDS[0] is the destination.
 535    OPERANDS[1] is the string.
 536    OPERANDS[2] is the char to search.
 537    OPERANDS[3] is the alignment.  */
 538 bool
 539 sh_expand_strlen (rtx *operands)
 540 {
 541   rtx addr1 = operands[1];
 542   rtx current_addr = copy_addr_to_reg (XEXP (addr1, 0));
 543   rtx start_addr = gen_reg_rtx (Pmode);
 544   rtx tmp0 = gen_reg_rtx (SImode);
 545   rtx tmp1 = gen_reg_rtx (SImode);
 546   rtx L_return = gen_label_rtx ();
 547   rtx L_loop_byte = gen_label_rtx ();
 548
 549   rtx jump;
 550   rtx L_loop_long = gen_label_rtx ();
 551   rtx L_end_loop_long = gen_label_rtx ();
 552
 553   int align = INTVAL (operands[3]);
 554
 555   emit_move_insn (operands[0], GEN_INT (-1));
 556
 557   /* remember start of string.  */
 558   emit_move_insn (start_addr, current_addr);
 559
 560   if (align < 4)
 561     {
 562       emit_insn (gen_tstsi_t (GEN_INT (3), current_addr));
 563       jump = emit_jump_insn (gen_branch_false (L_loop_byte));
 564       add_int_reg_note (jump, REG_BR_PROB, prob_likely);
 565     }
 566
 567   emit_move_insn (tmp0, operands[2]);
 568
 569   addr1 = adjust_automodify_address (addr1, SImode, current_addr, 0);
 570
 571   /*start long loop.  */
 572   emit_label (L_loop_long);
 573
 574   /* tmp1 is aligned, OK to load.  */
 575   emit_move_insn (tmp1, addr1);
 576   emit_move_insn (current_addr, plus_constant (Pmode, current_addr, 4));
 577
 578   /* Is there a 0 byte ?  */
 579   emit_insn (gen_cmpstr_t (tmp0, tmp1));
 580
 581   jump = emit_jump_insn (gen_branch_false (L_loop_long));
 582   add_int_reg_note (jump, REG_BR_PROB, prob_likely);
 583   /* end loop.  */
 584
 585   emit_label (L_end_loop_long);
 586
 587   emit_move_insn (current_addr, plus_constant (Pmode, current_addr, -4));
 588
 589   /* start byte loop.  */
 590   addr1 = adjust_address (addr1, QImode, 0);
 591
 592   emit_label (L_loop_byte);
 593
 594   emit_insn (gen_extendqisi2 (tmp1, addr1));
 595   emit_move_insn (current_addr, plus_constant (Pmode, current_addr, 1));
 596
 597   emit_insn (gen_cmpeqsi_t (tmp1, const0_rtx));
 598   jump = emit_jump_insn (gen_branch_false (L_loop_byte));
 599   add_int_reg_note (jump, REG_BR_PROB, prob_likely);
 600
 601   /* end loop.  */
 602
 603   emit_label (L_return);
 604
 605   emit_insn (gen_addsi3 (start_addr, start_addr, GEN_INT (1)));
 606
 607   emit_insn (gen_subsi3 (operands[0], current_addr, start_addr));
 608
 609   return true;
 610 }