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m68k.h revision 1.9
      1 /* Definitions of target machine for GCC for Motorola 680x0/ColdFire.
      2    Copyright (C) 1987-2018 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 /* We need to have MOTOROLA always defined (either 0 or 1) because we use
     21    if-statements and ?: on it.  This way we have compile-time error checking
     22    for both the MOTOROLA and MIT code paths.  We do rely on the host compiler
     23    to optimize away all constant tests.  */
     24 #if MOTOROLA  /* Use the Motorola assembly syntax.  */
     25 #else
     26 # define MOTOROLA 0  /* Use the MIT assembly syntax.  */
     27 #endif
     28 
     29 /* Handle --with-cpu default option from configure script.  */
     30 #define OPTION_DEFAULT_SPECS						\
     31   { "cpu",   "%{!m68020-40:%{!m68020-60:\
     32 %{!mcpu=*:%{!march=*:-%(VALUE)}}}}" },
     33 
     34 /* Pass flags to gas indicating which type of processor we have.  This
     35    can be simplified when we can rely on the assembler supporting .cpu
     36    and .arch directives.  */
     37 
     38 #define ASM_CPU_SPEC "\
     39 %{m68851}%{mno-68851} %{m68881}%{mno-68881} %{msoft-float:-mno-float} \
     40 %{m68020-40:-m68040}%{m68020-60:-m68040}\
     41 %{mcpu=*:-mcpu=%*}%{march=*:-march=%*}\
     42 "
     43 #define ASM_PCREL_SPEC "%{" FPIE_OR_FPIC_SPEC ":--pcrel} \
     44  %{mpcrel:%{" NO_FPIE_AND_FPIC_SPEC ":--pcrel}} \
     45  %{msep-data|mid-shared-library:--pcrel} \
     46 "
     47 
     48 #define ASM_SPEC "%(asm_cpu_spec) %(asm_pcrel_spec)"
     49 
     50 #define EXTRA_SPECS					\
     51   { "asm_cpu_spec", ASM_CPU_SPEC },			\
     52   { "asm_pcrel_spec", ASM_PCREL_SPEC },			\
     53   SUBTARGET_EXTRA_SPECS
     54 
     55 #define SUBTARGET_EXTRA_SPECS
     56 
     57 /* Note that some other tm.h files include this one and then override
     58    many of the definitions that relate to assembler syntax.  */
     59 
     60 #define TARGET_CPU_CPP_BUILTINS()					\
     61   do									\
     62     {									\
     63       builtin_define ("__m68k__");					\
     64       builtin_define_std ("mc68000");					\
     65       /* The other mc680x0 macros have traditionally been derived	\
     66 	 from the tuning setting.  For example, -m68020-60 defines	\
     67 	 m68060, even though it generates pure 68020 code.  */		\
     68       switch (m68k_tune)						\
     69 	{								\
     70 	case u68010:							\
     71 	  builtin_define_std ("mc68010");				\
     72 	  break;							\
     73 									\
     74 	case u68020:							\
     75 	  builtin_define_std ("mc68020");				\
     76 	  break;							\
     77 									\
     78 	case u68030:							\
     79 	  builtin_define_std ("mc68030");				\
     80 	  break;							\
     81 									\
     82 	case u68040:							\
     83 	  builtin_define_std ("mc68040");				\
     84 	  break;							\
     85 									\
     86 	case u68060:							\
     87 	  builtin_define_std ("mc68060");				\
     88 	  break;							\
     89 									\
     90 	case u68020_60:							\
     91 	  builtin_define_std ("mc68060");				\
     92 	  /* Fall through.  */						\
     93 	case u68020_40:							\
     94 	  builtin_define_std ("mc68040");				\
     95 	  builtin_define_std ("mc68030");				\
     96 	  builtin_define_std ("mc68020");				\
     97 	  break;							\
     98 									\
     99 	case ucpu32:							\
    100 	  builtin_define_std ("mc68332");				\
    101 	  builtin_define_std ("mcpu32");				\
    102 	  builtin_define_std ("mc68020");				\
    103 	  break;							\
    104 									\
    105 	case ucfv1:							\
    106 	  builtin_define ("__mcfv1__");					\
    107 	  break;							\
    108 									\
    109 	case ucfv2:							\
    110 	  builtin_define ("__mcfv2__");					\
    111 	  break;							\
    112 									\
    113     	case ucfv3:							\
    114 	  builtin_define ("__mcfv3__");					\
    115 	  break;							\
    116 									\
    117 	case ucfv4:							\
    118 	  builtin_define ("__mcfv4__");					\
    119 	  break;							\
    120 									\
    121 	case ucfv4e:							\
    122 	  builtin_define ("__mcfv4e__");				\
    123 	  break;							\
    124 									\
    125 	case ucfv5:							\
    126 	  builtin_define ("__mcfv5__");					\
    127 	  break;							\
    128 									\
    129 	default:							\
    130 	  break;							\
    131 	}								\
    132 									\
    133       if (TARGET_68881)							\
    134 	builtin_define ("__HAVE_68881__");				\
    135 									\
    136       if (TARGET_COLDFIRE)						\
    137 	{								\
    138 	  const char *tmp;						\
    139 	  								\
    140 	  tmp = m68k_cpp_cpu_ident ("cf");			   	\
    141 	  if (tmp)							\
    142 	    builtin_define (tmp);					\
    143 	  tmp = m68k_cpp_cpu_family ("cf");				\
    144 	  if (tmp)							\
    145 	    builtin_define (tmp);					\
    146 	  builtin_define ("__mcoldfire__");				\
    147 									\
    148 	  if (TARGET_ISAC)						\
    149 	    builtin_define ("__mcfisac__");				\
    150 	  else if (TARGET_ISAB)						\
    151 	    {								\
    152 	      builtin_define ("__mcfisab__");				\
    153 	      /* ISA_B: Legacy 5407 defines.  */			\
    154 	      builtin_define ("__mcf5400__");				\
    155 	      builtin_define ("__mcf5407__");				\
    156 	    }								\
    157 	  else if (TARGET_ISAAPLUS)					\
    158 	    {								\
    159 	      builtin_define ("__mcfisaaplus__");			\
    160 	      /* ISA_A+: legacy defines.  */				\
    161 	      builtin_define ("__mcf528x__");				\
    162 	      builtin_define ("__mcf5200__");				\
    163 	    }								\
    164 	  else 								\
    165 	    {								\
    166 	      builtin_define ("__mcfisaa__");				\
    167 	      /* ISA_A: legacy defines.  */				\
    168 	      switch (m68k_tune)					\
    169 		{							\
    170 		case ucfv2:						\
    171 		  builtin_define ("__mcf5200__");			\
    172 		  break;						\
    173 									\
    174 		case ucfv3:						\
    175 		  builtin_define ("__mcf5307__");			\
    176 		  builtin_define ("__mcf5300__");			\
    177 		  break;						\
    178 									\
    179 		default:						\
    180 		  break;						\
    181 		}							\
    182     	    }								\
    183 	}								\
    184 									\
    185       if (TARGET_COLDFIRE_FPU)						\
    186 	builtin_define ("__mcffpu__");					\
    187 									\
    188       if (TARGET_CF_HWDIV)						\
    189 	builtin_define ("__mcfhwdiv__");				\
    190 									\
    191       if (TARGET_FIDOA)							\
    192 	builtin_define ("__mfido__");					\
    193 									\
    194       builtin_assert ("cpu=m68k");					\
    195       builtin_assert ("machine=m68k");					\
    196     }									\
    197   while (0)
    198 
    199 /* Classify the groups of pseudo-ops used to assemble QI, HI and SI
    200    quantities.  */
    201 #define INT_OP_STANDARD	0	/* .byte, .short, .long */
    202 #define INT_OP_DOT_WORD	1	/* .byte, .word, .long */
    203 #define INT_OP_NO_DOT   2	/* byte, short, long */
    204 #define INT_OP_DC	3	/* dc.b, dc.w, dc.l */
    205 
    206 /* Set the default.  */
    207 #define INT_OP_GROUP INT_OP_DOT_WORD
    208 
    209 /* Bit values used by m68k-devices.def to identify processor capabilities.  */
    210 #define FL_BITFIELD  (1 << 0)    /* Support bitfield instructions.  */
    211 #define FL_68881     (1 << 1)    /* (Default) support for 68881/2.  */
    212 #define FL_COLDFIRE  (1 << 2)    /* ColdFire processor.  */
    213 #define FL_CF_HWDIV  (1 << 3)    /* ColdFire hardware divide supported.  */
    214 #define FL_CF_MAC    (1 << 4)    /* ColdFire MAC unit supported.  */
    215 #define FL_CF_EMAC   (1 << 5)    /* ColdFire eMAC unit supported.  */
    216 #define FL_CF_EMAC_B (1 << 6)    /* ColdFire eMAC-B unit supported.  */
    217 #define FL_CF_USP    (1 << 7)    /* ColdFire User Stack Pointer supported.  */
    218 #define FL_CF_FPU    (1 << 8)    /* ColdFire FPU supported.  */
    219 #define FL_ISA_68000 (1 << 9)
    220 #define FL_ISA_68010 (1 << 10)
    221 #define FL_ISA_68020 (1 << 11)
    222 #define FL_ISA_68040 (1 << 12)
    223 #define FL_ISA_A     (1 << 13)
    224 #define FL_ISA_APLUS (1 << 14)
    225 #define FL_ISA_B     (1 << 15)
    226 #define FL_ISA_C     (1 << 16)
    227 #define FL_FIDOA     (1 << 17)
    228 #define FL_CAS	     (1 << 18)	/* Support cas insn.  */
    229 #define FL_MMU 	     0   /* Used by multilib machinery.  */
    230 #define FL_UCLINUX   0   /* Used by multilib machinery.  */
    231 
    232 #define TARGET_68010		((m68k_cpu_flags & FL_ISA_68010) != 0)
    233 #define TARGET_68020		((m68k_cpu_flags & FL_ISA_68020) != 0)
    234 #define TARGET_68040		((m68k_cpu_flags & FL_ISA_68040) != 0)
    235 #define TARGET_COLDFIRE		((m68k_cpu_flags & FL_COLDFIRE) != 0)
    236 #define TARGET_COLDFIRE_FPU	(m68k_fpu == FPUTYPE_COLDFIRE)
    237 #define TARGET_68881		(m68k_fpu == FPUTYPE_68881)
    238 #define TARGET_FIDOA		((m68k_cpu_flags & FL_FIDOA) != 0)
    239 #define TARGET_CAS		((m68k_cpu_flags & FL_CAS) != 0)
    240 
    241 /* Size (in bytes) of FPU registers.  */
    242 #define TARGET_FP_REG_SIZE	(TARGET_COLDFIRE ? 8 : 12)
    243 
    244 #define TARGET_ISAAPLUS		((m68k_cpu_flags & FL_ISA_APLUS) != 0)
    245 #define TARGET_ISAB		((m68k_cpu_flags & FL_ISA_B) != 0)
    246 #define TARGET_ISAC		((m68k_cpu_flags & FL_ISA_C) != 0)
    247 
    248 /* Some instructions are common to more than one ISA.  */
    249 #define ISA_HAS_MVS_MVZ	(TARGET_ISAB || TARGET_ISAC)
    250 #define ISA_HAS_FF1	(TARGET_ISAAPLUS || TARGET_ISAC)
    251 #define ISA_HAS_TAS	(!TARGET_COLDFIRE || TARGET_ISAB || TARGET_ISAC)
    252 
    253 #define TUNE_68000	(m68k_tune == u68000)
    254 #define TUNE_68010	(m68k_tune == u68010)
    255 #define TUNE_68000_10	(TUNE_68000 || TUNE_68010)
    256 #define TUNE_68030	(m68k_tune == u68030 \
    257 			 || m68k_tune == u68020_40 \
    258 			 || m68k_tune == u68020_60)
    259 #define TUNE_68040	(m68k_tune == u68040 \
    260 			 || m68k_tune == u68020_40 \
    261 			 || m68k_tune == u68020_60)
    262 #define TUNE_68060	(m68k_tune == u68060 || m68k_tune == u68020_60)
    263 #define TUNE_68040_60	(TUNE_68040 || TUNE_68060)
    264 #define TUNE_CPU32	(m68k_tune == ucpu32)
    265 #define TUNE_CFV1       (m68k_tune == ucfv1)
    266 #define TUNE_CFV2	(m68k_tune == ucfv2)
    267 #define TUNE_CFV3       (m68k_tune == ucfv3)
    268 #define TUNE_CFV4       (m68k_tune == ucfv4 || m68k_tune == ucfv4e)
    269 
    270 #define TUNE_MAC	((m68k_tune_flags & FL_CF_MAC) != 0)
    271 #define TUNE_EMAC	((m68k_tune_flags & FL_CF_EMAC) != 0)
    272 
    273 /* These are meant to be redefined in the host dependent files */
    274 #define SUBTARGET_OVERRIDE_OPTIONS
    275 
    276 /* target machine storage layout */
    278 
    279 /* "long double" is the same as "double" on ColdFire and fido
    280    targets.  */
    281 
    282 #define LONG_DOUBLE_TYPE_SIZE			\
    283   ((TARGET_COLDFIRE || TARGET_FIDOA) ? 64 : 80)
    284 
    285 #define BITS_BIG_ENDIAN 1
    286 #define BYTES_BIG_ENDIAN 1
    287 #define WORDS_BIG_ENDIAN 1
    288 
    289 #define UNITS_PER_WORD 4
    290 
    291 #define PARM_BOUNDARY (TARGET_SHORT ? 16 : 32)
    292 #define STACK_BOUNDARY 16
    293 #define FUNCTION_BOUNDARY 16
    294 #define EMPTY_FIELD_BOUNDARY 16
    295 /* ColdFire and fido strongly prefer a 32-bit aligned stack.  */
    296 #define PREFERRED_STACK_BOUNDARY \
    297   ((TARGET_COLDFIRE || TARGET_FIDOA) ? 32 : 16)
    298 
    299 /* No data type wants to be aligned rounder than this.
    300    Most published ABIs say that ints should be aligned on 16-bit
    301    boundaries, but CPUs with 32-bit busses get better performance
    302    aligned on 32-bit boundaries.  */
    303 #define BIGGEST_ALIGNMENT (TARGET_ALIGN_INT ? 32 : 16)
    304 
    305 #define STRICT_ALIGNMENT (TARGET_STRICT_ALIGNMENT)
    306 #define M68K_HONOR_TARGET_STRICT_ALIGNMENT 1
    307 
    308 #define DWARF_CIE_DATA_ALIGNMENT -2
    309 
    310 #define INT_TYPE_SIZE (TARGET_SHORT ? 16 : 32)
    311 
    312 /* Define these to avoid dependence on meaning of `int'.  */
    313 #define WCHAR_TYPE "long int"
    314 #define WCHAR_TYPE_SIZE 32
    315 
    316 /* Maximum number of library IDs we permit with -mid-shared-library.  */
    317 #define MAX_LIBRARY_ID 255
    318 
    319 
    320 /* Standard register usage.  */
    322 
    323 /* For the m68k, we give the data registers numbers 0-7,
    324    the address registers numbers 010-017 (8-15),
    325    and the 68881 floating point registers numbers 020-027 (16-23).
    326    We also have a fake `arg-pointer' register 030 (24) used for
    327    register elimination.  */
    328 #define FIRST_PSEUDO_REGISTER 25
    329 
    330 /* All m68k targets (except AmigaOS) use %a5 as the PIC register  */
    331 #define PIC_OFFSET_TABLE_REGNUM				\
    332   (!flag_pic ? INVALID_REGNUM				\
    333    : reload_completed ? REGNO (pic_offset_table_rtx)	\
    334    : PIC_REG)
    335 
    336 /* 1 for registers that have pervasive standard uses
    337    and are not available for the register allocator.
    338    On the m68k, only the stack pointer is such.
    339    Our fake arg-pointer is obviously fixed as well.  */
    340 #define FIXED_REGISTERS        \
    341  {/* Data registers.  */       \
    342   0, 0, 0, 0, 0, 0, 0, 0,      \
    343                                \
    344   /* Address registers.  */    \
    345   0, 0, 0, 0, 0, 0, 0, 1,      \
    346                                \
    347   /* Floating point registers  \
    348      (if available).  */       \
    349   0, 0, 0, 0, 0, 0, 0, 0,      \
    350                                \
    351   /* Arg pointer.  */          \
    352   1 }
    353 
    354 /* 1 for registers not available across function calls.
    355    These must include the FIXED_REGISTERS and also any
    356    registers that can be used without being saved.
    357    The latter must include the registers where values are returned
    358    and the register where structure-value addresses are passed.
    359    Aside from that, you can include as many other registers as you like.  */
    360 #define CALL_USED_REGISTERS     \
    361  {/* Data registers.  */        \
    362   1, 1, 0, 0, 0, 0, 0, 0,       \
    363                                 \
    364   /* Address registers.  */     \
    365   1, 1, 0, 0, 0, 0, 0, 1,       \
    366                                 \
    367   /* Floating point registers   \
    368      (if available).  */        \
    369   1, 1, 0, 0, 0, 0, 0, 0,       \
    370                                 \
    371   /* Arg pointer.  */           \
    372   1 }
    373 
    374 #define REG_ALLOC_ORDER		\
    375 { /* d0/d1/a0/a1 */		\
    376   0, 1, 8, 9,			\
    377   /* d2-d7 */			\
    378   2, 3, 4, 5, 6, 7,		\
    379   /* a2-a7/arg */		\
    380   10, 11, 12, 13, 14, 15, 24,	\
    381   /* fp0-fp7 */			\
    382   16, 17, 18, 19, 20, 21, 22, 23\
    383 }
    384 
    385 
    386 /* A C expression that is nonzero if hard register NEW_REG can be
    387    considered for use as a rename register for OLD_REG register.  */
    388 
    389 #define HARD_REGNO_RENAME_OK(OLD_REG, NEW_REG) \
    390   m68k_hard_regno_rename_ok (OLD_REG, NEW_REG)
    391 
    392 #define SECONDARY_RELOAD_CLASS(CLASS, MODE, X) \
    393   m68k_secondary_reload_class (CLASS, MODE, X)
    394 
    395 /* Specify the registers used for certain standard purposes.
    396    The values of these macros are register numbers.  */
    397 
    398 #define STACK_POINTER_REGNUM SP_REG
    399 
    400 /* Most m68k targets use %a6 as a frame pointer.  The AmigaOS
    401    ABI uses %a6 for shared library calls, therefore the frame
    402    pointer is shifted to %a5 on this target.  */
    403 #define FRAME_POINTER_REGNUM A6_REG
    404 
    405 /* Base register for access to arguments of the function.
    406  * This isn't a hardware register. It will be eliminated to the
    407  * stack pointer or frame pointer.
    408  */
    409 #define ARG_POINTER_REGNUM 24
    410 
    411 #define STATIC_CHAIN_REGNUM A0_REG
    412 #define M68K_STATIC_CHAIN_REG_NAME REGISTER_PREFIX "a0"
    413 
    414 /* Register in which address to store a structure value
    415    is passed to a function.  */
    416 #define M68K_STRUCT_VALUE_REGNUM A1_REG
    417 
    418 
    419 
    421 /* The m68k has three kinds of registers, so eight classes would be
    422    a complete set.  One of them is not needed.  */
    423 enum reg_class {
    424   NO_REGS, DATA_REGS,
    425   ADDR_REGS, FP_REGS,
    426   GENERAL_REGS, DATA_OR_FP_REGS,
    427   ADDR_OR_FP_REGS, ALL_REGS,
    428   LIM_REG_CLASSES };
    429 
    430 #define N_REG_CLASSES (int) LIM_REG_CLASSES
    431 
    432 #define REG_CLASS_NAMES \
    433  { "NO_REGS", "DATA_REGS",              \
    434    "ADDR_REGS", "FP_REGS",              \
    435    "GENERAL_REGS", "DATA_OR_FP_REGS",   \
    436    "ADDR_OR_FP_REGS", "ALL_REGS" }
    437 
    438 #define REG_CLASS_CONTENTS \
    439 {					\
    440   {0x00000000},  /* NO_REGS */		\
    441   {0x000000ff},  /* DATA_REGS */	\
    442   {0x0100ff00},  /* ADDR_REGS */	\
    443   {0x00ff0000},  /* FP_REGS */		\
    444   {0x0100ffff},  /* GENERAL_REGS */	\
    445   {0x00ff00ff},  /* DATA_OR_FP_REGS */	\
    446   {0x01ffff00},  /* ADDR_OR_FP_REGS */	\
    447   {0x01ffffff},  /* ALL_REGS */		\
    448 }
    449 
    450 extern enum reg_class regno_reg_class[];
    451 #define REGNO_REG_CLASS(REGNO) (regno_reg_class[(REGNO)])
    452 #define INDEX_REG_CLASS GENERAL_REGS
    453 #define BASE_REG_CLASS ADDR_REGS
    454 
    455 #define PREFERRED_RELOAD_CLASS(X,CLASS) \
    456   m68k_preferred_reload_class (X, CLASS)
    457 
    458 /* On the m68k, this is the size of MODE in words,
    459    except in the FP regs, where a single reg is always enough.  */
    460 #define CLASS_MAX_NREGS(CLASS, MODE)	\
    461  ((CLASS) == FP_REGS ? 1 \
    462   : ((GET_MODE_SIZE (MODE) + UNITS_PER_WORD - 1) / UNITS_PER_WORD))
    463 
    464 /* Moves between fp regs and other regs are two insns.  */
    465 #define REGISTER_MOVE_COST(MODE, CLASS1, CLASS2)	\
    466   ((((CLASS1) == FP_REGS) != ((CLASS2) == FP_REGS)) ? 4 : 2)
    467 
    468 
    469 /* Stack layout; function entry, exit and calling.  */
    471 
    472 #define STACK_GROWS_DOWNWARD 1
    473 #define FRAME_GROWS_DOWNWARD 1
    474 
    475 #define PUSH_ROUNDING(BYTES) m68k_push_rounding (BYTES)
    476 
    477 #define FIRST_PARM_OFFSET(FNDECL) 8
    478 
    479 /* On the m68k the return value defaults to D0.  */
    480 #define FUNCTION_VALUE(VALTYPE, FUNC)  \
    481   gen_rtx_REG (TYPE_MODE (VALTYPE), D0_REG)
    482 
    483 /* On the m68k the return value defaults to D0.  */
    484 #define LIBCALL_VALUE(MODE)  gen_rtx_REG (MODE, D0_REG)
    485 
    486 /* On the m68k, D0 is usually the only register used.  */
    487 #define FUNCTION_VALUE_REGNO_P(N) ((N) == D0_REG)
    488 
    489 /* Define this to be true when FUNCTION_VALUE_REGNO_P is true for
    490    more than one register.
    491    XXX This macro is m68k specific and used only for m68kemb.h.  */
    492 #define NEEDS_UNTYPED_CALL 0
    493 
    494 /* On the m68k, all arguments are usually pushed on the stack.  */
    495 #define FUNCTION_ARG_REGNO_P(N) 0
    496 
    497 /* On the m68k, this is a single integer, which is a number of bytes
    499    of arguments scanned so far.  */
    500 #define CUMULATIVE_ARGS int
    501 
    502 /* On the m68k, the offset starts at 0.  */
    503 #define INIT_CUMULATIVE_ARGS(CUM, FNTYPE, LIBNAME, INDIRECT, N_NAMED_ARGS) \
    504  ((CUM) = 0)
    505 
    506 #define FUNCTION_PROFILER(FILE, LABELNO)  \
    507   asm_fprintf (FILE, "\tlea %LLP%d,%Ra0\n\tjsr mcount\n", (LABELNO))
    508 
    509 #define EXIT_IGNORE_STACK 1
    510 
    511 /* Output assembler code for a block containing the constant parts
    512    of a trampoline, leaving space for the variable parts.
    513 
    514    On the m68k, the trampoline looks like this:
    515      movl #STATIC,a0
    516      jmp  FUNCTION
    517 
    518    WARNING: Targets that may run on 68040+ cpus must arrange for
    519    the instruction cache to be flushed.  Previous incarnations of
    520    the m68k trampoline code attempted to get around this by either
    521    using an out-of-line transfer function or pc-relative data, but
    522    the fact remains that the code to jump to the transfer function
    523    or the code to load the pc-relative data needs to be flushed
    524    just as much as the "variable" portion of the trampoline.
    525    Recognizing that a cache flush is going to be required anyway,
    526    dispense with such notions and build a smaller trampoline.
    527 
    528    Since more instructions are required to move a template into
    529    place than to create it on the spot, don't use a template.  */
    530 
    531 #define TRAMPOLINE_SIZE 12
    532 #define TRAMPOLINE_ALIGNMENT 16
    533 
    534 /* Targets redefine this to invoke code to either flush the cache,
    535    or enable stack execution (or both).  */
    536 #ifndef FINALIZE_TRAMPOLINE
    537 #define FINALIZE_TRAMPOLINE(TRAMP)
    538 #endif
    539 
    540 /* This is the library routine that is used to transfer control from the
    541    trampoline to the actual nested function.  It is defined for backward
    542    compatibility, for linking with object code that used the old trampoline
    543    definition.
    544 
    545    A colon is used with no explicit operands to cause the template string
    546    to be scanned for %-constructs.
    547 
    548    The function name __transfer_from_trampoline is not actually used.
    549    The function definition just permits use of "asm with operands"
    550    (though the operand list is empty).  */
    551 #define TRANSFER_FROM_TRAMPOLINE				\
    552 void								\
    553 __transfer_from_trampoline ()					\
    554 {								\
    555   register char *a0 asm (M68K_STATIC_CHAIN_REG_NAME);		\
    556   asm (GLOBAL_ASM_OP "___trampoline");				\
    557   asm ("___trampoline:");					\
    558   asm volatile ("move%.l %0,%@" : : "m" (a0[22]));		\
    559   asm volatile ("move%.l %1,%0" : "=a" (a0) : "m" (a0[18]));	\
    560   asm ("rts":);							\
    561 }
    562 
    563 /* There are two registers that can always be eliminated on the m68k.
    565    The frame pointer and the arg pointer can be replaced by either the
    566    hard frame pointer or to the stack pointer, depending upon the
    567    circumstances.  The hard frame pointer is not used before reload and
    568    so it is not eligible for elimination.  */
    569 #define ELIMINABLE_REGS					\
    570 {{ ARG_POINTER_REGNUM, STACK_POINTER_REGNUM },		\
    571  { ARG_POINTER_REGNUM, FRAME_POINTER_REGNUM },		\
    572  { FRAME_POINTER_REGNUM, STACK_POINTER_REGNUM }}
    573 
    574 #define INITIAL_ELIMINATION_OFFSET(FROM, TO, OFFSET)			\
    575   (OFFSET) = m68k_initial_elimination_offset(FROM, TO)
    576 
    577 /* Addressing modes, and classification of registers for them.  */
    579 
    580 #define HAVE_POST_INCREMENT 1
    581 #define HAVE_PRE_DECREMENT 1
    582 
    583 /* Macros to check register numbers against specific register classes.  */
    584 
    585 /* True for data registers, D0 through D7.  */
    586 #define DATA_REGNO_P(REGNO)	IN_RANGE (REGNO, 0, 7)
    587 
    588 /* True for address registers, A0 through A7.  */
    589 #define ADDRESS_REGNO_P(REGNO)	IN_RANGE (REGNO, 8, 15)
    590 
    591 /* True for integer registers, D0 through D7 and A0 through A7.  */
    592 #define INT_REGNO_P(REGNO)	IN_RANGE (REGNO, 0, 15)
    593 
    594 /* True for floating point registers, FP0 through FP7.  */
    595 #define FP_REGNO_P(REGNO)	IN_RANGE (REGNO, 16, 23)
    596 
    597 #define REGNO_OK_FOR_INDEX_P(REGNO)			\
    598   (INT_REGNO_P (REGNO)					\
    599    || INT_REGNO_P (reg_renumber[REGNO]))
    600 
    601 #define REGNO_OK_FOR_BASE_P(REGNO)			\
    602   (ADDRESS_REGNO_P (REGNO)				\
    603    || ADDRESS_REGNO_P (reg_renumber[REGNO]))
    604 
    605 #define REGNO_OK_FOR_INDEX_NONSTRICT_P(REGNO)		\
    606   (INT_REGNO_P (REGNO)					\
    607    || REGNO == ARG_POINTER_REGNUM			\
    608    || REGNO >= FIRST_PSEUDO_REGISTER)
    609 
    610 #define REGNO_OK_FOR_BASE_NONSTRICT_P(REGNO)		\
    611   (ADDRESS_REGNO_P (REGNO)				\
    612    || REGNO == ARG_POINTER_REGNUM			\
    613    || REGNO >= FIRST_PSEUDO_REGISTER)
    614 
    615 /* Now macros that check whether X is a register and also,
    616    strictly, whether it is in a specified class.
    617 
    618    These macros are specific to the m68k, and may be used only
    619    in code for printing assembler insns and in conditions for
    620    define_optimization.  */
    621 
    622 /* 1 if X is a data register.  */
    623 #define DATA_REG_P(X)	(REG_P (X) && DATA_REGNO_P (REGNO (X)))
    624 
    625 /* 1 if X is an fp register.  */
    626 #define FP_REG_P(X)	(REG_P (X) && FP_REGNO_P (REGNO (X)))
    627 
    628 /* 1 if X is an address register  */
    629 #define ADDRESS_REG_P(X) (REG_P (X) && ADDRESS_REGNO_P (REGNO (X)))
    630 
    631 /* True if SYMBOL + OFFSET constants must refer to something within
    633    SYMBOL's section.  */
    634 #ifndef M68K_OFFSETS_MUST_BE_WITHIN_SECTIONS_P
    635 #define M68K_OFFSETS_MUST_BE_WITHIN_SECTIONS_P 0
    636 #endif
    637 
    638 #define MAX_REGS_PER_ADDRESS 2
    639 
    640 #define CONSTANT_ADDRESS_P(X)						\
    641   ((GET_CODE (X) == LABEL_REF || GET_CODE (X) == SYMBOL_REF		\
    642     || GET_CODE (X) == CONST_INT || GET_CODE (X) == CONST		\
    643     || GET_CODE (X) == HIGH)						\
    644    && m68k_legitimate_constant_p (Pmode, X))
    645 
    646 #ifndef REG_OK_STRICT
    647 #define REG_STRICT_P 0
    648 #else
    649 #define REG_STRICT_P 1
    650 #endif
    651 
    652 #define LEGITIMATE_PIC_OPERAND_P(X)				\
    653   (!symbolic_operand (X, VOIDmode)				\
    654    || (TARGET_PCREL && REG_STRICT_P)				\
    655    || m68k_tls_reference_p (X, true))
    656 
    657 #define REG_OK_FOR_BASE_P(X) \
    658   m68k_legitimate_base_reg_p (X, REG_STRICT_P)
    659 
    660 #define REG_OK_FOR_INDEX_P(X) \
    661   m68k_legitimate_index_reg_p (X, REG_STRICT_P)
    662 
    663 
    664 /* This address is OK as it stands.  */
    666 #define PIC_CASE_VECTOR_ADDRESS(index) index
    667 #define CASE_VECTOR_MODE (TARGET_LONG_JUMP_TABLE_OFFSETS ? SImode : HImode)
    668 #define CASE_VECTOR_PC_RELATIVE 1
    669 
    670 #define DEFAULT_SIGNED_CHAR 1
    671 #define MOVE_MAX 4
    672 #define SLOW_BYTE_ACCESS 0
    673 
    674 /* The 68020 BFFFO and ColdFire FF1 instructions return 32 for zero. */
    675 #define CLZ_DEFINED_VALUE_AT_ZERO(MODE, VALUE) ((VALUE) = 32, 1)
    676 
    677 #define STORE_FLAG_VALUE (-1)
    678 
    679 #define Pmode SImode
    680 #define FUNCTION_MODE QImode
    681 
    682 
    683 /* Tell final.c how to eliminate redundant test instructions.  */
    685 
    686 /* Here we define machine-dependent flags and fields in cc_status
    687    (see `conditions.h').  */
    688 
    689 /* Set if the cc value is actually in the 68881, so a floating point
    690    conditional branch must be output.  */
    691 #define CC_IN_68881 04000
    692 
    693 /* On the 68000, all the insns to store in an address register fail to
    694    set the cc's.  However, in some cases these instructions can make it
    695    possibly invalid to use the saved cc's.  In those cases we clear out
    696    some or all of the saved cc's so they won't be used.  */
    697 #define NOTICE_UPDATE_CC(EXP,INSN) notice_update_cc (EXP, INSN)
    698 
    699 /* The shift instructions always clear the overflow bit.  */
    700 #define CC_OVERFLOW_UNUSABLE 01000
    701 
    702 /* The shift instructions use the carry bit in a way not compatible with
    703    conditional branches.  conditions.h uses CC_NO_OVERFLOW for this purpose.
    704    Rename it to something more understandable.  */
    705 #define CC_NO_CARRY CC_NO_OVERFLOW
    706 
    707 #define OUTPUT_JUMP(NORMAL, FLOAT, NO_OV)  \
    708 do { if (cc_prev_status.flags & CC_IN_68881)			\
    709     return FLOAT;						\
    710   if (cc_prev_status.flags & CC_NO_OVERFLOW)			\
    711     return NO_OV;						\
    712   return NORMAL; } while (0)
    713 
    714 /* Control the assembler format that we output.  */
    716 
    717 #define ASM_APP_ON "#APP\n"
    718 #define ASM_APP_OFF "#NO_APP\n"
    719 #define TEXT_SECTION_ASM_OP "\t.text"
    720 #define DATA_SECTION_ASM_OP "\t.data"
    721 #define GLOBAL_ASM_OP "\t.globl\t"
    722 #define REGISTER_PREFIX ""
    723 #define LOCAL_LABEL_PREFIX ""
    724 #define USER_LABEL_PREFIX "_"
    725 #define IMMEDIATE_PREFIX "#"
    726 
    727 #define REGISTER_NAMES \
    728 {REGISTER_PREFIX"d0", REGISTER_PREFIX"d1", REGISTER_PREFIX"d2",	\
    729  REGISTER_PREFIX"d3", REGISTER_PREFIX"d4", REGISTER_PREFIX"d5",	\
    730  REGISTER_PREFIX"d6", REGISTER_PREFIX"d7",			\
    731  REGISTER_PREFIX"a0", REGISTER_PREFIX"a1", REGISTER_PREFIX"a2", \
    732  REGISTER_PREFIX"a3", REGISTER_PREFIX"a4", REGISTER_PREFIX"a5", \
    733  REGISTER_PREFIX"a6", REGISTER_PREFIX"sp",			\
    734  REGISTER_PREFIX"fp0", REGISTER_PREFIX"fp1", REGISTER_PREFIX"fp2", \
    735  REGISTER_PREFIX"fp3", REGISTER_PREFIX"fp4", REGISTER_PREFIX"fp5", \
    736  REGISTER_PREFIX"fp6", REGISTER_PREFIX"fp7", REGISTER_PREFIX"argptr" }
    737 
    738 #define M68K_FP_REG_NAME REGISTER_PREFIX"fp"
    739 
    740 /* Return a register name by index, handling %fp nicely.
    741    We don't replace %fp for targets that don't map it to %a6
    742    since it may confuse GAS.  */
    743 #define M68K_REGNAME(r) ( \
    744   ((FRAME_POINTER_REGNUM == A6_REG) \
    745     && ((r) == FRAME_POINTER_REGNUM) \
    746     && frame_pointer_needed) ? \
    747     M68K_FP_REG_NAME : reg_names[(r)])
    748 
    749 /* On the Sun-3, the floating point registers have numbers
    750    18 to 25, not 16 to 23 as they do in the compiler.  */
    751 #define DBX_REGISTER_NUMBER(REGNO) ((REGNO) < 16 ? (REGNO) : (REGNO) + 2)
    752 
    753 /* Before the prologue, RA is at 0(%sp).  */
    754 #define INCOMING_RETURN_ADDR_RTX \
    755   gen_rtx_MEM (Pmode, gen_rtx_REG (Pmode, STACK_POINTER_REGNUM))
    756 
    757 /* After the prologue, RA is at 4(AP) in the current frame.  */
    758 #define RETURN_ADDR_RTX(COUNT, FRAME)					   \
    759   ((COUNT) == 0								   \
    760    ? gen_rtx_MEM (Pmode, plus_constant (Pmode, arg_pointer_rtx,	   \
    761 					UNITS_PER_WORD))		   \
    762    : gen_rtx_MEM (Pmode, plus_constant (Pmode, FRAME, UNITS_PER_WORD)))
    763 
    764 /* We must not use the DBX register numbers for the DWARF 2 CFA column
    765    numbers because that maps to numbers beyond FIRST_PSEUDO_REGISTER.
    766    Instead use the identity mapping.  */
    767 #define DWARF_FRAME_REGNUM(REG) \
    768   (INT_REGNO_P (REG) || FP_REGNO_P (REG) ? (REG) : INVALID_REGNUM)
    769 
    770 /* The return column was originally 24, but gcc used 25 for a while too.
    771    Define both registers 24 and 25 as Pmode ones and use 24 in our own
    772    unwind information.  */
    773 #define DWARF_FRAME_REGISTERS 25
    774 #define DWARF_FRAME_RETURN_COLUMN 24
    775 #define DWARF_ALT_FRAME_RETURN_COLUMN 25
    776 
    777 /* Before the prologue, the top of the frame is at 4(%sp).  */
    778 #define INCOMING_FRAME_SP_OFFSET 4
    779 
    780 #define EPILOGUE_USES(REGNO) m68k_epilogue_uses (REGNO)
    781 
    782 /* Describe how we implement __builtin_eh_return.  */
    783 #define EH_RETURN_DATA_REGNO(N) \
    784   ((N) < 2 ? (N) : INVALID_REGNUM)
    785 #define EH_RETURN_STACKADJ_RTX	gen_rtx_REG (Pmode, A0_REG)
    786 #define EH_RETURN_HANDLER_RTX					    \
    787   gen_rtx_MEM (Pmode,						    \
    788 	       gen_rtx_PLUS (Pmode, arg_pointer_rtx,		    \
    789 			     plus_constant (Pmode, EH_RETURN_STACKADJ_RTX, \
    790 					    UNITS_PER_WORD)))
    791 
    792 /* Select a format to encode pointers in exception handling data.  CODE
    793    is 0 for data, 1 for code labels, 2 for function pointers.  GLOBAL is
    794    true if the symbol may be affected by dynamic relocations.
    795 
    796    TARGET_ID_SHARED_LIBRARY and TARGET_SEP_DATA are designed to support
    797    a read-only text segment without imposing a fixed gap between the
    798    text and data segments.  As a result, the text segment cannot refer
    799    to anything in the data segment, even in PC-relative form.  Because
    800    .eh_frame refers to both code and data, it follows that .eh_frame
    801    must be in the data segment itself, and that the offset between
    802    .eh_frame and code will not be a link-time constant.
    803 
    804    In theory, we could create a read-only .eh_frame by using DW_EH_PE_pcrel
    805    | DW_EH_PE_indirect for all code references.  However, gcc currently
    806    handles indirect references using a per-TU constant pool.  This means
    807    that if a function and its eh_frame are removed by the linker, the
    808    eh_frame's indirect references to the removed function will not be
    809    removed, leading to an unresolved symbol error.
    810 
    811    It isn't clear that any -msep-data or -mid-shared-library target
    812    would benefit from a read-only .eh_frame anyway.  In particular,
    813    no known target that supports these options has a feature like
    814    PT_GNU_RELRO.  Without any such feature to motivate them, indirect
    815    references would be unnecessary bloat, so we simply use an absolute
    816    pointer for code and global references.  We still use pc-relative
    817    references to data, as this avoids a relocation.  */
    818 #define ASM_PREFERRED_EH_DATA_FORMAT(CODE, GLOBAL)			   \
    819   (flag_pic								   \
    820    && !((TARGET_ID_SHARED_LIBRARY || TARGET_SEP_DATA)			   \
    821 	&& ((GLOBAL) || (CODE)))					   \
    822    ? ((GLOBAL) ? DW_EH_PE_indirect : 0) | DW_EH_PE_pcrel | DW_EH_PE_sdata4 \
    823    : DW_EH_PE_absptr)
    824 
    825 #define ASM_OUTPUT_LABELREF(FILE,NAME)	\
    826   asm_fprintf (FILE, "%U%s", NAME)
    827 
    828 #define ASM_GENERATE_INTERNAL_LABEL(LABEL,PREFIX,NUM)	\
    829   sprintf (LABEL, "*%s%s%ld", LOCAL_LABEL_PREFIX, PREFIX, (long)(NUM))
    830 
    831 #define ASM_OUTPUT_REG_PUSH(FILE,REGNO)			\
    832   asm_fprintf (FILE, (MOTOROLA				\
    833 		      ? "\tmove.l %s,-(%Rsp)\n"		\
    834 		      : "\tmovel %s,%Rsp@-\n"),		\
    835 	       reg_names[REGNO])
    836 
    837 #define ASM_OUTPUT_REG_POP(FILE,REGNO)			\
    838   asm_fprintf (FILE, (MOTOROLA				\
    839 		      ? "\tmove.l (%Rsp)+,%s\n"		\
    840 		      : "\tmovel %Rsp@+,%s\n"),		\
    841 	       reg_names[REGNO])
    842 
    843 /* The m68k does not use absolute case-vectors, but we must define this macro
    844    anyway.  */
    845 #define ASM_OUTPUT_ADDR_VEC_ELT(FILE, VALUE)  \
    846   asm_fprintf (FILE, "\t.long %LL%d\n", VALUE)
    847 
    848 #define ASM_OUTPUT_ADDR_DIFF_ELT(FILE, BODY, VALUE, REL)  \
    849   asm_fprintf (FILE,						\
    850 	       TARGET_LONG_JUMP_TABLE_OFFSETS			\
    851 	       ? "\t.long %LL%d-%LL%d\n"			\
    852 	       : "\t.word %LL%d-%LL%d\n",			\
    853 	       VALUE, REL)
    854 
    855 /* We don't have a way to align to more than a two-byte boundary, so do the
    856    best we can and don't complain.  */
    857 #define ASM_OUTPUT_ALIGN(FILE,LOG)	\
    858   if ((LOG) >= 1)			\
    859     fprintf (FILE, "\t.even\n");
    860 
    861 #ifdef HAVE_GAS_BALIGN_AND_P2ALIGN
    862 /* Use "move.l %a4,%a4" to advance within code.  */
    863 #define ASM_OUTPUT_ALIGN_WITH_NOP(FILE,LOG)			\
    864   if ((LOG) > 0)						\
    865     fprintf ((FILE), "\t.balignw %u,0x284c\n", 1 << (LOG));
    866 #endif
    867 
    868 #define ASM_OUTPUT_SKIP(FILE,SIZE)  \
    869   fprintf (FILE, "\t.skip %u\n", (int)(SIZE))
    870 
    871 #define ASM_OUTPUT_COMMON(FILE, NAME, SIZE, ROUNDED)  \
    872 ( fputs (".comm ", (FILE)),			\
    873   assemble_name ((FILE), (NAME)),		\
    874   fprintf ((FILE), ",%u\n", (int)(ROUNDED)))
    875 
    876 #define ASM_OUTPUT_LOCAL(FILE, NAME, SIZE, ROUNDED)  \
    877 ( fputs (".lcomm ", (FILE)),			\
    878   assemble_name ((FILE), (NAME)),		\
    879   fprintf ((FILE), ",%u\n", (int)(ROUNDED)))
    880 
    881 #define FINAL_PRESCAN_INSN(INSN, OPVEC, NOPERANDS) \
    882   m68k_final_prescan_insn (INSN, OPVEC, NOPERANDS)
    883 
    884 /* On the 68000, we use several CODE characters:
    885    '.' for dot needed in Motorola-style opcode names.
    886    '-' for an operand pushing on the stack:
    887        sp@-, -(sp) or -(%sp) depending on the style of syntax.
    888    '+' for an operand pushing on the stack:
    889        sp@+, (sp)+ or (%sp)+ depending on the style of syntax.
    890    '@' for a reference to the top word on the stack:
    891        sp@, (sp) or (%sp) depending on the style of syntax.
    892    '#' for an immediate operand prefix (# in MIT and Motorola syntax
    893        but & in SGS syntax).
    894    '!' for the fpcr register (used in some float-to-fixed conversions).
    895    '$' for the letter `s' in an op code, but only on the 68040.
    896    '&' for the letter `d' in an op code, but only on the 68040.
    897    '/' for register prefix needed by longlong.h.
    898    '?' for m68k_library_id_string
    899 
    900    'b' for byte insn (no effect, on the Sun; this is for the ISI).
    901    'd' to force memory addressing to be absolute, not relative.
    902    'f' for float insn (print a CONST_DOUBLE as a float rather than in hex)
    903    'x' for float insn (print a CONST_DOUBLE as a float rather than in hex),
    904        or print pair of registers as rx:ry.  */
    905 
    906 #define PRINT_OPERAND_PUNCT_VALID_P(CODE)				\
    907   ((CODE) == '.' || (CODE) == '#' || (CODE) == '-'			\
    908    || (CODE) == '+' || (CODE) == '@' || (CODE) == '!'			\
    909    || (CODE) == '$' || (CODE) == '&' || (CODE) == '/' || (CODE) == '?')
    910 
    911 
    912 /* See m68k.c for the m68k specific codes.  */
    913 #define PRINT_OPERAND(FILE, X, CODE) print_operand (FILE, X, CODE)
    914 
    915 #define PRINT_OPERAND_ADDRESS(FILE, ADDR) print_operand_address (FILE, ADDR)
    916 
    917 #include "config/m68k/m68k-opts.h"
    918 
    919 enum fpu_type
    920 {
    921   FPUTYPE_NONE,
    922   FPUTYPE_68881,
    923   FPUTYPE_COLDFIRE
    924 };
    925 
    926 enum m68k_function_kind
    927 {
    928   m68k_fk_normal_function,
    929   m68k_fk_interrupt_handler,
    930   m68k_fk_interrupt_thread
    931 };
    932 
    933 /* Variables in m68k.c; see there for details.  */
    934 extern enum target_device m68k_cpu;
    935 extern enum uarch_type m68k_tune;
    936 extern enum fpu_type m68k_fpu;
    937 extern unsigned int m68k_cpu_flags;
    938 extern unsigned int m68k_tune_flags;
    939 extern const char *m68k_symbolic_call;
    940 extern const char *m68k_symbolic_jump;
    941 
    942 enum M68K_SYMBOLIC_CALL { M68K_SYMBOLIC_CALL_NONE, M68K_SYMBOLIC_CALL_JSR,
    943 			  M68K_SYMBOLIC_CALL_BSR_C, M68K_SYMBOLIC_CALL_BSR_P };
    944 
    945 extern enum M68K_SYMBOLIC_CALL m68k_symbolic_call_var;
    946 
    947 /* ??? HOST_WIDE_INT is not being defined for auto-generated files.
    948    Workaround that.  */
    949 #ifdef HOST_WIDE_INT
    950 typedef enum { MOVL, SWAP, NEGW, NOTW, NOTB, MOVQ, MVS, MVZ }
    951   M68K_CONST_METHOD;
    952 
    953 extern M68K_CONST_METHOD m68k_const_method (HOST_WIDE_INT);
    954 #endif
    955 
    956 extern void m68k_emit_move_double (rtx [2]);
    957 
    958 extern int m68k_sched_address_bypass_p (rtx_insn *, rtx_insn *);
    959 extern int m68k_sched_indexed_address_bypass_p (rtx_insn *, rtx_insn *);
    960 
    961 #define CPU_UNITS_QUERY 1
    962