1 /* Definitions of target machine for GNU compiler, for DEC Alpha.
2    Copyright (C) 1992-2020 Free Software Foundation, Inc.
3    Contributed by Richard Kenner (kenner@vlsi1.ultra.nyu.edu)
4 
5 This file is part of GCC.
6 
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
10 any later version.
11 
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 GNU General Public License for more details.
16 
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3.  If not see
19 <http://www.gnu.org/licenses/>.  */
20 
21 /* Target CPU builtins.  */
22 #define TARGET_CPU_CPP_BUILTINS()			\
23   do							\
24     {							\
25 	builtin_define ("__alpha");			\
26 	builtin_define ("__alpha__");			\
27 	builtin_assert ("cpu=alpha");			\
28 	builtin_assert ("machine=alpha");		\
29 	if (TARGET_CIX)					\
30 	  {						\
31 	    builtin_define ("__alpha_cix__");		\
32 	    builtin_assert ("cpu=cix");			\
33 	  }						\
34 	if (TARGET_FIX)					\
35 	  {						\
36 	    builtin_define ("__alpha_fix__");		\
37 	    builtin_assert ("cpu=fix");			\
38 	  }						\
39 	if (TARGET_BWX)					\
40 	  {						\
41 	    builtin_define ("__alpha_bwx__");		\
42 	    builtin_assert ("cpu=bwx");			\
43 	  }						\
44 	if (TARGET_MAX)					\
45 	  {						\
46 	    builtin_define ("__alpha_max__");		\
47 	    builtin_assert ("cpu=max");			\
48 	  }						\
49 	if (alpha_cpu == PROCESSOR_EV6)			\
50 	  {						\
51 	    builtin_define ("__alpha_ev6__");		\
52 	    builtin_assert ("cpu=ev6");			\
53 	  }						\
54 	else if (alpha_cpu == PROCESSOR_EV5)		\
55 	  {						\
56 	    builtin_define ("__alpha_ev5__");		\
57 	    builtin_assert ("cpu=ev5");			\
58 	  }						\
59 	else	/* Presumably ev4.  */			\
60 	  {						\
61 	    builtin_define ("__alpha_ev4__");		\
62 	    builtin_assert ("cpu=ev4");			\
63 	  }						\
64 	if (TARGET_IEEE || TARGET_IEEE_WITH_INEXACT)	\
65 	  builtin_define ("_IEEE_FP");			\
66 	if (TARGET_IEEE_WITH_INEXACT)			\
67 	  builtin_define ("_IEEE_FP_INEXACT");		\
68 	if (TARGET_LONG_DOUBLE_128)			\
69 	  builtin_define ("__LONG_DOUBLE_128__");	\
70 							\
71 	/* Macros dependent on the C dialect.  */	\
72 	SUBTARGET_LANGUAGE_CPP_BUILTINS();		\
73 } while (0)
74 
75 #ifndef SUBTARGET_LANGUAGE_CPP_BUILTINS
76 #define SUBTARGET_LANGUAGE_CPP_BUILTINS()		\
77   do							\
78     {							\
79       if (preprocessing_asm_p ())			\
80 	builtin_define_std ("LANGUAGE_ASSEMBLY");	\
81       else if (c_dialect_cxx ())			\
82 	{						\
83 	  builtin_define ("__LANGUAGE_C_PLUS_PLUS");	\
84 	  builtin_define ("__LANGUAGE_C_PLUS_PLUS__");	\
85 	}						\
86       else						\
87 	builtin_define_std ("LANGUAGE_C");		\
88       if (c_dialect_objc ())				\
89 	{						\
90 	  builtin_define ("__LANGUAGE_OBJECTIVE_C");	\
91 	  builtin_define ("__LANGUAGE_OBJECTIVE_C__");	\
92 	}						\
93     }							\
94   while (0)
95 #endif
96 
97 /* Run-time compilation parameters selecting different hardware subsets.  */
98 
99 /* Which processor to schedule for. The cpu attribute defines a list that
100    mirrors this list, so changes to alpha.md must be made at the same time.  */
101 
102 enum processor_type
103 {
104   PROCESSOR_EV4,			/* 2106[46]{a,} */
105   PROCESSOR_EV5,			/* 21164{a,pc,} */
106   PROCESSOR_EV6,			/* 21264 */
107   PROCESSOR_MAX
108 };
109 
110 extern enum processor_type alpha_cpu;
111 extern enum processor_type alpha_tune;
112 
113 enum alpha_trap_precision
114 {
115   ALPHA_TP_PROG,	/* No precision (default).  */
116   ALPHA_TP_FUNC,      	/* Trap contained within originating function.  */
117   ALPHA_TP_INSN		/* Instruction accuracy and code is resumption safe.  */
118 };
119 
120 enum alpha_fp_rounding_mode
121 {
122   ALPHA_FPRM_NORM,	/* Normal rounding mode.  */
123   ALPHA_FPRM_MINF,	/* Round towards minus-infinity.  */
124   ALPHA_FPRM_CHOP,	/* Chopped rounding mode (towards 0).  */
125   ALPHA_FPRM_DYN	/* Dynamic rounding mode.  */
126 };
127 
128 enum alpha_fp_trap_mode
129 {
130   ALPHA_FPTM_N,		/* Normal trap mode.  */
131   ALPHA_FPTM_U,		/* Underflow traps enabled.  */
132   ALPHA_FPTM_SU,	/* Software completion, w/underflow traps */
133   ALPHA_FPTM_SUI	/* Software completion, w/underflow & inexact traps */
134 };
135 
136 extern enum alpha_trap_precision alpha_tp;
137 extern enum alpha_fp_rounding_mode alpha_fprm;
138 extern enum alpha_fp_trap_mode alpha_fptm;
139 
140 /* Invert the easy way to make options work.  */
141 #define TARGET_FP	(!TARGET_SOFT_FP)
142 
143 /* These are for target os support and cannot be changed at runtime.  */
144 #define TARGET_ABI_OPEN_VMS	0
145 #define TARGET_ABI_OSF		(!TARGET_ABI_OPEN_VMS)
146 
147 #ifndef TARGET_CAN_FAULT_IN_PROLOGUE
148 #define TARGET_CAN_FAULT_IN_PROLOGUE 0
149 #endif
150 #ifndef TARGET_HAS_XFLOATING_LIBS
151 #define TARGET_HAS_XFLOATING_LIBS TARGET_LONG_DOUBLE_128
152 #endif
153 #ifndef TARGET_PROFILING_NEEDS_GP
154 #define TARGET_PROFILING_NEEDS_GP 0
155 #endif
156 #ifndef TARGET_FIXUP_EV5_PREFETCH
157 #define TARGET_FIXUP_EV5_PREFETCH 0
158 #endif
159 #ifndef HAVE_AS_TLS
160 #define HAVE_AS_TLS 0
161 #endif
162 
163 #define TARGET_DEFAULT MASK_FPREGS
164 
165 #ifndef TARGET_CPU_DEFAULT
166 #define TARGET_CPU_DEFAULT 0
167 #endif
168 
169 #ifndef TARGET_DEFAULT_EXPLICIT_RELOCS
170 #ifdef HAVE_AS_EXPLICIT_RELOCS
171 #define TARGET_DEFAULT_EXPLICIT_RELOCS MASK_EXPLICIT_RELOCS
172 #define TARGET_SUPPORT_ARCH 1
173 #else
174 #define TARGET_DEFAULT_EXPLICIT_RELOCS 0
175 #endif
176 #endif
177 
178 #ifndef TARGET_SUPPORT_ARCH
179 #define TARGET_SUPPORT_ARCH 0
180 #endif
181 
182 /* Support for a compile-time default CPU, et cetera.  The rules are:
183    --with-cpu is ignored if -mcpu is specified.
184    --with-tune is ignored if -mtune is specified.  */
185 #define OPTION_DEFAULT_SPECS \
186   {"cpu", "%{!mcpu=*:-mcpu=%(VALUE)}" }, \
187   {"tune", "%{!mtune=*:-mtune=%(VALUE)}" }
188 
189 
190 /* target machine storage layout */
191 
192 /* Define the size of `int'.  The default is the same as the word size.  */
193 #define INT_TYPE_SIZE 32
194 
195 /* Define the size of `long long'.  The default is the twice the word size.  */
196 #define LONG_LONG_TYPE_SIZE 64
197 
198 /* The two floating-point formats we support are S-floating, which is
199    4 bytes, and T-floating, which is 8 bytes.  `float' is S and `double'
200    and `long double' are T.  */
201 
202 #define FLOAT_TYPE_SIZE 32
203 #define DOUBLE_TYPE_SIZE 64
204 #define LONG_DOUBLE_TYPE_SIZE (TARGET_LONG_DOUBLE_128 ? 128 : 64)
205 
206 /* Work around target_flags dependency in ada/targtyps.c.  */
207 #define WIDEST_HARDWARE_FP_SIZE 64
208 
209 #define	WCHAR_TYPE "unsigned int"
210 #define	WCHAR_TYPE_SIZE 32
211 
212 /* Define this macro if it is advisable to hold scalars in registers
213    in a wider mode than that declared by the program.  In such cases,
214    the value is constrained to be within the bounds of the declared
215    type, but kept valid in the wider mode.  The signedness of the
216    extension may differ from that of the type.
217 
218    For Alpha, we always store objects in a full register.  32-bit integers
219    are always sign-extended, but smaller objects retain their signedness.
220 
221    Note that small vector types can get mapped onto integer modes at the
222    whim of not appearing in alpha-modes.def.  We never promoted these
223    values before; don't do so now that we've trimmed the set of modes to
224    those actually implemented in the backend.  */
225 
226 #define PROMOTE_MODE(MODE,UNSIGNEDP,TYPE)			\
227   if (GET_MODE_CLASS (MODE) == MODE_INT				\
228       && (TYPE == NULL || TREE_CODE (TYPE) != VECTOR_TYPE)	\
229       && GET_MODE_SIZE (MODE) < UNITS_PER_WORD)			\
230     {								\
231       if ((MODE) == SImode)					\
232 	(UNSIGNEDP) = 0;					\
233       (MODE) = DImode;						\
234     }
235 
236 /* Define this if most significant bit is lowest numbered
237    in instructions that operate on numbered bit-fields.
238 
239    There are no such instructions on the Alpha, but the documentation
240    is little endian.  */
241 #define BITS_BIG_ENDIAN 0
242 
243 /* Define this if most significant byte of a word is the lowest numbered.
244    This is false on the Alpha.  */
245 #define BYTES_BIG_ENDIAN 0
246 
247 /* Define this if most significant word of a multiword number is lowest
248    numbered.
249 
250    For Alpha we can decide arbitrarily since there are no machine instructions
251    for them.  Might as well be consistent with bytes.  */
252 #define WORDS_BIG_ENDIAN 0
253 
254 /* Width of a word, in units (bytes).  */
255 #define UNITS_PER_WORD 8
256 
257 /* Width in bits of a pointer.
258    See also the macro `Pmode' defined below.  */
259 #define POINTER_SIZE 64
260 
261 /* Allocation boundary (in *bits*) for storing arguments in argument list.  */
262 #define PARM_BOUNDARY 64
263 
264 /* Boundary (in *bits*) on which stack pointer should be aligned.  */
265 #define STACK_BOUNDARY 128
266 
267 /* Allocation boundary (in *bits*) for the code of a function.  */
268 #define FUNCTION_BOUNDARY 32
269 
270 /* Alignment of field after `int : 0' in a structure.  */
271 #define EMPTY_FIELD_BOUNDARY 64
272 
273 /* Every structure's size must be a multiple of this.  */
274 #define STRUCTURE_SIZE_BOUNDARY 8
275 
276 /* A bit-field declared as `int' forces `int' alignment for the struct.  */
277 #undef PCC_BITFILED_TYPE_MATTERS
278 #define PCC_BITFIELD_TYPE_MATTERS 1
279 
280 /* No data type wants to be aligned rounder than this.  */
281 #define BIGGEST_ALIGNMENT 128
282 
283 /* For atomic access to objects, must have at least 32-bit alignment
284    unless the machine has byte operations.  */
285 #define MINIMUM_ATOMIC_ALIGNMENT ((unsigned int) (TARGET_BWX ? 8 : 32))
286 
287 /* Align all constants and variables to at least a word boundary so
288    we can pick up pieces of them faster.  */
289 /* ??? Only if block-move stuff knows about different source/destination
290    alignment.  */
291 #if 0
292 #define DATA_ALIGNMENT(EXP, ALIGN) MAX ((ALIGN), BITS_PER_WORD)
293 #endif
294 
295 /* Set this nonzero if move instructions will actually fail to work
296    when given unaligned data.
297 
298    Since we get an error message when we do one, call them invalid.  */
299 
300 #define STRICT_ALIGNMENT 1
301 
302 /* Standard register usage.  */
303 
304 /* Number of actual hardware registers.
305    The hardware registers are assigned numbers for the compiler
306    from 0 to just below FIRST_PSEUDO_REGISTER.
307    All registers that the compiler knows about must be given numbers,
308    even those that are not normally considered general registers.
309 
310    We define all 32 integer registers, even though $31 is always zero,
311    and all 32 floating-point registers, even though $f31 is also
312    always zero.  We do not bother defining the FP status register and
313    there are no other registers.
314 
315    Since $31 is always zero, we will use register number 31 as the
316    argument pointer.  It will never appear in the generated code
317    because we will always be eliminating it in favor of the stack
318    pointer or hardware frame pointer.
319 
320    Likewise, we use $f31 for the frame pointer, which will always
321    be eliminated in favor of the hardware frame pointer or the
322    stack pointer.  */
323 
324 #define FIRST_PSEUDO_REGISTER 64
325 
326 /* 1 for registers that have pervasive standard uses
327    and are not available for the register allocator.  */
328 
329 #define FIXED_REGISTERS  \
330  {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
331   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, \
332   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
333   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 }
334 
335 /* 1 for registers not available across function calls.
336    These must include the FIXED_REGISTERS and also any
337    registers that can be used without being saved.
338    The latter must include the registers where values are returned
339    and the register where structure-value addresses are passed.
340    Aside from that, you can include as many other registers as you like.  */
341 #define CALL_USED_REGISTERS  \
342  {1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, \
343   1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, \
344   1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, \
345   1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 }
346 
347 /* List the order in which to allocate registers.  Each register must be
348    listed once, even those in FIXED_REGISTERS.  */
349 
350 #define REG_ALLOC_ORDER { \
351    1, 2, 3, 4, 5, 6, 7, 8,	/* nonsaved integer registers */	\
352    22, 23, 24, 25, 28,		/* likewise */				\
353    0,				/* likewise, but return value */	\
354    21, 20, 19, 18, 17, 16,	/* likewise, but input args */		\
355    27,				/* likewise, but OSF procedure value */	\
356 									\
357    42, 43, 44, 45, 46, 47,	/* nonsaved floating-point registers */	\
358    54, 55, 56, 57, 58, 59,	/* likewise */				\
359    60, 61, 62,			/* likewise */				\
360    32, 33,			/* likewise, but return values */	\
361    53, 52, 51, 50, 49, 48,	/* likewise, but input args */		\
362 									\
363    9, 10, 11, 12, 13, 14,	/* saved integer registers */		\
364    26,				/* return address */			\
365    15,				/* hard frame pointer */		\
366 									\
367    34, 35, 36, 37, 38, 39,	/* saved floating-point registers */	\
368    40, 41,			/* likewise */				\
369 									\
370    29, 30, 31, 63		/* gp, sp, ap, sfp */			\
371 }
372 
373 /* Specify the registers used for certain standard purposes.
374    The values of these macros are register numbers.  */
375 
376 /* Alpha pc isn't overloaded on a register that the compiler knows about.  */
377 /* #define PC_REGNUM  */
378 
379 /* Register to use for pushing function arguments.  */
380 #define STACK_POINTER_REGNUM 30
381 
382 /* Base register for access to local variables of the function.  */
383 #define HARD_FRAME_POINTER_REGNUM 15
384 
385 /* Base register for access to arguments of the function.  */
386 #define ARG_POINTER_REGNUM 31
387 
388 /* Base register for access to local variables of function.  */
389 #define FRAME_POINTER_REGNUM 63
390 
391 /* Register in which static-chain is passed to a function.
392 
393    For the Alpha, this is based on an example; the calling sequence
394    doesn't seem to specify this.  */
395 #define STATIC_CHAIN_REGNUM 1
396 
397 /* The register number of the register used to address a table of
398    static data addresses in memory.  */
399 #define PIC_OFFSET_TABLE_REGNUM 29
400 
401 /* Define this macro if the register defined by `PIC_OFFSET_TABLE_REGNUM'
402    is clobbered by calls.  */
403 /* ??? It is and it isn't.  It's required to be valid for a given
404    function when the function returns.  It isn't clobbered by
405    current_file functions.  Moreover, we do not expose the ldgp
406    until after reload, so we're probably safe.  */
407 /* #define PIC_OFFSET_TABLE_REG_CALL_CLOBBERED */
408 
409 /* Define the classes of registers for register constraints in the
410    machine description.  Also define ranges of constants.
411 
412    One of the classes must always be named ALL_REGS and include all hard regs.
413    If there is more than one class, another class must be named NO_REGS
414    and contain no registers.
415 
416    The name GENERAL_REGS must be the name of a class (or an alias for
417    another name such as ALL_REGS).  This is the class of registers
418    that is allowed by "g" or "r" in a register constraint.
419    Also, registers outside this class are allocated only when
420    instructions express preferences for them.
421 
422    The classes must be numbered in nondecreasing order; that is,
423    a larger-numbered class must never be contained completely
424    in a smaller-numbered class.
425 
426    For any two classes, it is very desirable that there be another
427    class that represents their union.  */
428 
429 enum reg_class {
430   NO_REGS, R0_REG, R24_REG, R25_REG, R27_REG,
431   GENERAL_REGS, FLOAT_REGS, ALL_REGS,
432   LIM_REG_CLASSES
433 };
434 
435 #define N_REG_CLASSES (int) LIM_REG_CLASSES
436 
437 /* Give names of register classes as strings for dump file.  */
438 
439 #define REG_CLASS_NAMES					\
440  {"NO_REGS", "R0_REG", "R24_REG", "R25_REG", "R27_REG",	\
441   "GENERAL_REGS", "FLOAT_REGS", "ALL_REGS" }
442 
443 /* Define which registers fit in which classes.
444    This is an initializer for a vector of HARD_REG_SET
445    of length N_REG_CLASSES.  */
446 
447 #define REG_CLASS_CONTENTS				\
448 { {0x00000000, 0x00000000},	/* NO_REGS */		\
449   {0x00000001, 0x00000000},	/* R0_REG */		\
450   {0x01000000, 0x00000000},	/* R24_REG */		\
451   {0x02000000, 0x00000000},	/* R25_REG */		\
452   {0x08000000, 0x00000000},	/* R27_REG */		\
453   {0xffffffff, 0x80000000},	/* GENERAL_REGS */	\
454   {0x00000000, 0x7fffffff},	/* FLOAT_REGS */	\
455   {0xffffffff, 0xffffffff} }
456 
457 /* The same information, inverted:
458    Return the class number of the smallest class containing
459    reg number REGNO.  This could be a conditional expression
460    or could index an array.  */
461 
462 #define REGNO_REG_CLASS(REGNO)			\
463  ((REGNO) == 0 ? R0_REG				\
464   : (REGNO) == 24 ? R24_REG			\
465   : (REGNO) == 25 ? R25_REG			\
466   : (REGNO) == 27 ? R27_REG			\
467   : IN_RANGE ((REGNO), 32, 62) ? FLOAT_REGS	\
468   : GENERAL_REGS)
469 
470 /* The class value for index registers, and the one for base regs.  */
471 #define INDEX_REG_CLASS NO_REGS
472 #define BASE_REG_CLASS GENERAL_REGS
473 
474 /* Given an rtx X being reloaded into a reg required to be
475    in class CLASS, return the class of reg to actually use.
476    In general this is just CLASS; but on some machines
477    in some cases it is preferable to use a more restrictive class.  */
478 
479 #define PREFERRED_RELOAD_CLASS  alpha_preferred_reload_class
480 
481 /* Provide the cost of a branch.  Exact meaning under development.  */
482 #define BRANCH_COST(speed_p, predictable_p) 5
483 
484 /* Stack layout; function entry, exit and calling.  */
485 
486 /* Define this if pushing a word on the stack
487    makes the stack pointer a smaller address.  */
488 #define STACK_GROWS_DOWNWARD 1
489 
490 /* Define this to nonzero if the nominal address of the stack frame
491    is at the high-address end of the local variables;
492    that is, each additional local variable allocated
493    goes at a more negative offset in the frame.  */
494 /* #define FRAME_GROWS_DOWNWARD 0 */
495 
496 /* If we generate an insn to push BYTES bytes,
497    this says how many the stack pointer really advances by.
498    On Alpha, don't define this because there are no push insns.  */
499 /*  #define PUSH_ROUNDING(BYTES) */
500 
501 /* Define this to be nonzero if stack checking is built into the ABI.  */
502 #define STACK_CHECK_BUILTIN 1
503 
504 /* Define this if the maximum size of all the outgoing args is to be
505    accumulated and pushed during the prologue.  The amount can be
506    found in the variable crtl->outgoing_args_size.  */
507 #define ACCUMULATE_OUTGOING_ARGS 1
508 
509 /* Offset of first parameter from the argument pointer register value.  */
510 
511 #define FIRST_PARM_OFFSET(FNDECL) 0
512 
513 /* Definitions for register eliminations.
514 
515    We have two registers that can be eliminated on the Alpha.  First, the
516    frame pointer register can often be eliminated in favor of the stack
517    pointer register.  Secondly, the argument pointer register can always be
518    eliminated; it is replaced with either the stack or frame pointer.  */
519 
520 /* This is an array of structures.  Each structure initializes one pair
521    of eliminable registers.  The "from" register number is given first,
522    followed by "to".  Eliminations of the same "from" register are listed
523    in order of preference.  */
524 
525 #define ELIMINABLE_REGS				     \
526 {{ ARG_POINTER_REGNUM, STACK_POINTER_REGNUM},	     \
527  { ARG_POINTER_REGNUM, HARD_FRAME_POINTER_REGNUM},   \
528  { FRAME_POINTER_REGNUM, STACK_POINTER_REGNUM},	     \
529  { FRAME_POINTER_REGNUM, HARD_FRAME_POINTER_REGNUM}}
530 
531 /* Round up to a multiple of 16 bytes.  */
532 #define ALPHA_ROUND(X) ROUND_UP ((X), 16)
533 
534 /* Define the offset between two registers, one to be eliminated, and the other
535    its replacement, at the start of a routine.  */
536 #define INITIAL_ELIMINATION_OFFSET(FROM, TO, OFFSET) \
537   ((OFFSET) = alpha_initial_elimination_offset(FROM, TO))
538 
539 /* Define this if stack space is still allocated for a parameter passed
540    in a register.  */
541 /* #define REG_PARM_STACK_SPACE */
542 
543 /* 1 if N is a possible register number for function argument passing.
544    On Alpha, these are $16-$21 and $f16-$f21.  */
545 
546 #define FUNCTION_ARG_REGNO_P(N) \
547   (IN_RANGE ((N), 16, 21) || ((N) >= 16 + 32 && (N) <= 21 + 32))
548 
549 /* Define a data type for recording info about an argument list
550    during the scan of that argument list.  This data type should
551    hold all necessary information about the function itself
552    and about the args processed so far, enough to enable macros
553    such as FUNCTION_ARG to determine where the next arg should go.
554 
555    On Alpha, this is a single integer, which is a number of words
556    of arguments scanned so far.
557    Thus 6 or more means all following args should go on the stack.  */
558 
559 #define CUMULATIVE_ARGS int
560 
561 /* Initialize a variable CUM of type CUMULATIVE_ARGS
562    for a call to a function whose data type is FNTYPE.
563    For a library call, FNTYPE is 0.  */
564 
565 #define INIT_CUMULATIVE_ARGS(CUM, FNTYPE, LIBNAME, INDIRECT, N_NAMED_ARGS) \
566   (CUM) = 0
567 
568 /* Define intermediate macro to compute
569    the size (in registers) of an argument.  */
570 
571 #define ALPHA_ARG_SIZE(MODE, TYPE)					\
572   ((MODE) == TFmode || (MODE) == TCmode ? 1				\
573    : CEIL (((MODE) == BLKmode						\
574 	    ? int_size_in_bytes (TYPE)					\
575 	    : GET_MODE_SIZE (MODE)),					\
576 	   UNITS_PER_WORD))
577 
578 /* Make (or fake) .linkage entry for function call.
579    IS_LOCAL is 0 if name is used in call, 1 if name is used in definition.  */
580 
581 /* This macro defines the start of an assembly comment.  */
582 
583 #define ASM_COMMENT_START " #"
584 
585 /* This macro produces the initial definition of a function.  */
586 
587 #undef ASM_DECLARE_FUNCTION_NAME
588 #define ASM_DECLARE_FUNCTION_NAME(FILE,NAME,DECL) \
589   alpha_start_function(FILE,NAME,DECL);
590 
591 /* This macro closes up a function definition for the assembler.  */
592 
593 #undef ASM_DECLARE_FUNCTION_SIZE
594 #define ASM_DECLARE_FUNCTION_SIZE(FILE,NAME,DECL) \
595   alpha_end_function(FILE,NAME,DECL)
596 
597 /* Output any profiling code before the prologue.  */
598 
599 #define PROFILE_BEFORE_PROLOGUE 1
600 
601 /* Never use profile counters.  */
602 
603 #define NO_PROFILE_COUNTERS 1
604 
605 /* Output assembler code to FILE to increment profiler label # LABELNO
606    for profiling a function entry.  Under OSF/1, profiling is enabled
607    by simply passing -pg to the assembler and linker.  */
608 
609 #define FUNCTION_PROFILER(FILE, LABELNO)
610 
611 /* EXIT_IGNORE_STACK should be nonzero if, when returning from a function,
612    the stack pointer does not matter.  The value is tested only in
613    functions that have frame pointers.
614    No definition is equivalent to always zero.  */
615 
616 #define EXIT_IGNORE_STACK 1
617 
618 /* Define registers used by the epilogue and return instruction.  */
619 
620 #define EPILOGUE_USES(REGNO)	((REGNO) == 26)
621 
622 /* Length in units of the trampoline for entering a nested function.  */
623 
624 #define TRAMPOLINE_SIZE    32
625 
626 /* The alignment of a trampoline, in bits.  */
627 
628 #define TRAMPOLINE_ALIGNMENT  64
629 
630 /* A C expression whose value is RTL representing the value of the return
631    address for the frame COUNT steps up from the current frame.
632    FRAMEADDR is the frame pointer of the COUNT frame, or the frame pointer of
633    the COUNT-1 frame if RETURN_ADDR_IN_PREVIOUS_FRAME is defined.  */
634 
635 #define RETURN_ADDR_RTX  alpha_return_addr
636 
637 /* Provide a definition of DWARF_FRAME_REGNUM here so that fallback unwinders
638    can use DWARF_ALT_FRAME_RETURN_COLUMN defined below.  This is just the same
639    as the default definition in dwarf2out.c.  */
640 #undef DWARF_FRAME_REGNUM
641 #define DWARF_FRAME_REGNUM(REG) DBX_REGISTER_NUMBER (REG)
642 
643 /* Before the prologue, RA lives in $26.  */
644 #define INCOMING_RETURN_ADDR_RTX  gen_rtx_REG (Pmode, 26)
645 #define DWARF_FRAME_RETURN_COLUMN DWARF_FRAME_REGNUM (26)
646 #define DWARF_ALT_FRAME_RETURN_COLUMN DWARF_FRAME_REGNUM (64)
647 #define DWARF_ZERO_REG 31
648 
649 /* Describe how we implement __builtin_eh_return.  */
650 #define EH_RETURN_DATA_REGNO(N)	((N) < 4 ? (N) + 16 : INVALID_REGNUM)
651 #define EH_RETURN_STACKADJ_RTX	gen_rtx_REG (Pmode, 28)
652 #define EH_RETURN_HANDLER_RTX \
653   gen_rtx_MEM (Pmode, plus_constant (Pmode, stack_pointer_rtx, \
654 				     crtl->outgoing_args_size))
655 
656 /* Addressing modes, and classification of registers for them.  */
657 
658 /* Macros to check register numbers against specific register classes.  */
659 
660 /* These assume that REGNO is a hard or pseudo reg number.
661    They give nonzero only if REGNO is a hard reg of the suitable class
662    or a pseudo reg currently allocated to a suitable hard reg.
663    Since they use reg_renumber, they are safe only once reg_renumber
664    has been allocated, which happens in reginfo.c during register
665    allocation.  */
666 
667 #define REGNO_OK_FOR_INDEX_P(REGNO) 0
668 #define REGNO_OK_FOR_BASE_P(REGNO) \
669 ((REGNO) < 32 || (unsigned) reg_renumber[REGNO] < 32  \
670  || (REGNO) == 63 || reg_renumber[REGNO] == 63)
671 
672 /* Maximum number of registers that can appear in a valid memory address.  */
673 #define MAX_REGS_PER_ADDRESS 1
674 
675 /* Recognize any constant value that is a valid address.  For the Alpha,
676    there are only constants none since we want to use LDA to load any
677    symbolic addresses into registers.  */
678 
679 #define CONSTANT_ADDRESS_P(X)   \
680   (CONST_INT_P (X)		\
681    && (UINTVAL (X) + 0x8000) < 0x10000)
682 
683 /* The macros REG_OK_FOR..._P assume that the arg is a REG rtx
684    and check its validity for a certain class.
685    We have two alternate definitions for each of them.
686    The usual definition accepts all pseudo regs; the other rejects
687    them unless they have been allocated suitable hard regs.
688    The symbol REG_OK_STRICT causes the latter definition to be used.
689 
690    Most source files want to accept pseudo regs in the hope that
691    they will get allocated to the class that the insn wants them to be in.
692    Source files for reload pass need to be strict.
693    After reload, it makes no difference, since pseudo regs have
694    been eliminated by then.  */
695 
696 /* Nonzero if X is a hard reg that can be used as an index
697    or if it is a pseudo reg.  */
698 #define REG_OK_FOR_INDEX_P(X) 0
699 
700 /* Nonzero if X is a hard reg that can be used as a base reg
701    or if it is a pseudo reg.  */
702 #define NONSTRICT_REG_OK_FOR_BASE_P(X)  \
703   (REGNO (X) < 32 || REGNO (X) == 63 || REGNO (X) >= FIRST_PSEUDO_REGISTER)
704 
705 /* ??? Nonzero if X is the frame pointer, or some virtual register
706    that may eliminate to the frame pointer.  These will be allowed to
707    have offsets greater than 32K.  This is done because register
708    elimination offsets will change the hi/lo split, and if we split
709    before reload, we will require additional instructions.  */
710 #define NONSTRICT_REG_OK_FP_BASE_P(X)		\
711   (REGNO (X) == 31 || REGNO (X) == 63		\
712    || (REGNO (X) >= FIRST_PSEUDO_REGISTER	\
713        && REGNO (X) < LAST_VIRTUAL_POINTER_REGISTER))
714 
715 /* Nonzero if X is a hard reg that can be used as a base reg.  */
716 #define STRICT_REG_OK_FOR_BASE_P(X) REGNO_OK_FOR_BASE_P (REGNO (X))
717 
718 #ifdef REG_OK_STRICT
719 #define REG_OK_FOR_BASE_P(X)	STRICT_REG_OK_FOR_BASE_P (X)
720 #else
721 #define REG_OK_FOR_BASE_P(X)	NONSTRICT_REG_OK_FOR_BASE_P (X)
722 #endif
723 
724 /* Try a machine-dependent way of reloading an illegitimate address
725    operand.  If we find one, push the reload and jump to WIN.  This
726    macro is used in only one place: `find_reloads_address' in reload.c.  */
727 
728 #define LEGITIMIZE_RELOAD_ADDRESS(X,MODE,OPNUM,TYPE,IND_L,WIN)		     \
729 do {									     \
730   rtx new_x = alpha_legitimize_reload_address (X, MODE, OPNUM, TYPE, IND_L); \
731   if (new_x)								     \
732     {									     \
733       X = new_x;							     \
734       goto WIN;								     \
735     }									     \
736 } while (0)
737 
738 
739 /* Specify the machine mode that this machine uses
740    for the index in the tablejump instruction.  */
741 #define CASE_VECTOR_MODE SImode
742 
743 /* Define as C expression which evaluates to nonzero if the tablejump
744    instruction expects the table to contain offsets from the address of the
745    table.
746 
747    Do not define this if the table should contain absolute addresses.
748    On the Alpha, the table is really GP-relative, not relative to the PC
749    of the table, but we pretend that it is PC-relative; this should be OK,
750    but we should try to find some better way sometime.  */
751 #define CASE_VECTOR_PC_RELATIVE 1
752 
753 /* Define this as 1 if `char' should by default be signed; else as 0.  */
754 #define DEFAULT_SIGNED_CHAR 1
755 
756 /* Max number of bytes we can move to or from memory
757    in one reasonably fast instruction.  */
758 
759 #define MOVE_MAX 8
760 
761 /* If a memory-to-memory move would take MOVE_RATIO or more simple
762    move-instruction pairs, we will do a cpymem or libcall instead.
763 
764    Without byte/word accesses, we want no more than four instructions;
765    with, several single byte accesses are better.  */
766 
767 #define MOVE_RATIO(speed)  (TARGET_BWX ? 7 : 2)
768 
769 /* Largest number of bytes of an object that can be placed in a register.
770    On the Alpha we have plenty of registers, so use TImode.  */
771 #define MAX_FIXED_MODE_SIZE	GET_MODE_BITSIZE (TImode)
772 
773 /* Nonzero if access to memory by bytes is no faster than for words.
774    Also nonzero if doing byte operations (specifically shifts) in registers
775    is undesirable.
776 
777    On the Alpha, we want to not use the byte operation and instead use
778    masking operations to access fields; these will save instructions.  */
779 
780 #define SLOW_BYTE_ACCESS	1
781 
782 /* Define if operations between registers always perform the operation
783    on the full register even if a narrower mode is specified.  */
784 #define WORD_REGISTER_OPERATIONS 1
785 
786 /* Define if loading in MODE, an integral mode narrower than BITS_PER_WORD
787    will either zero-extend or sign-extend.  The value of this macro should
788    be the code that says which one of the two operations is implicitly
789    done, UNKNOWN if none.  */
790 #define LOAD_EXTEND_OP(MODE) ((MODE) == SImode ? SIGN_EXTEND : ZERO_EXTEND)
791 
792 /* Define if loading short immediate values into registers sign extends.  */
793 #define SHORT_IMMEDIATES_SIGN_EXTEND 1
794 
795 /* The CIX ctlz and cttz instructions return 64 for zero.  */
796 #define CLZ_DEFINED_VALUE_AT_ZERO(MODE, VALUE)  ((VALUE) = 64, \
797   TARGET_CIX ? 1 : 0)
798 #define CTZ_DEFINED_VALUE_AT_ZERO(MODE, VALUE)  ((VALUE) = 64, \
799   TARGET_CIX ? 1 : 0)
800 
801 /* Define the value returned by a floating-point comparison instruction.  */
802 
803 #define FLOAT_STORE_FLAG_VALUE(MODE) \
804   REAL_VALUE_ATOF ((TARGET_FLOAT_VAX ? "0.5" : "2.0"), (MODE))
805 
806 /* Specify the machine mode that pointers have.
807    After generation of rtl, the compiler makes no further distinction
808    between pointers and any other objects of this machine mode.  */
809 #define Pmode DImode
810 
811 /* Mode of a function address in a call instruction (for indexing purposes).  */
812 
813 #define FUNCTION_MODE Pmode
814 
815 /* Define this if addresses of constant functions
816    shouldn't be put through pseudo regs where they can be cse'd.
817    Desirable on machines where ordinary constants are expensive
818    but a CALL with constant address is cheap.
819 
820    We define this on the Alpha so that gen_call and gen_call_value
821    get to see the SYMBOL_REF (for the hint field of the jsr).  It will
822    then copy it into a register, thus actually letting the address be
823    cse'ed.  */
824 
825 #define NO_FUNCTION_CSE 1
826 
827 /* Define this to be nonzero if shift instructions ignore all but the low-order
828    few bits.  */
829 #define SHIFT_COUNT_TRUNCATED 1
830 
831 /* Control the assembler format that we output.  */
832 
833 /* Output to assembler file text saying following lines
834    may contain character constants, extra white space, comments, etc.  */
835 #define ASM_APP_ON (TARGET_EXPLICIT_RELOCS ? "\t.set\tmacro\n" : "")
836 
837 /* Output to assembler file text saying following lines
838    no longer contain unusual constructs.  */
839 #define ASM_APP_OFF (TARGET_EXPLICIT_RELOCS ? "\t.set\tnomacro\n" : "")
840 
841 #define TEXT_SECTION_ASM_OP "\t.text"
842 
843 /* Output before writable data.  */
844 
845 #define DATA_SECTION_ASM_OP "\t.data"
846 
847 /* How to refer to registers in assembler output.
848    This sequence is indexed by compiler's hard-register-number (see above).  */
849 
850 #define REGISTER_NAMES						\
851 {"$0", "$1", "$2", "$3", "$4", "$5", "$6", "$7", "$8",		\
852  "$9", "$10", "$11", "$12", "$13", "$14", "$15",		\
853  "$16", "$17", "$18", "$19", "$20", "$21", "$22", "$23",	\
854  "$24", "$25", "$26", "$27", "$28", "$29", "$30", "AP",		\
855  "$f0", "$f1", "$f2", "$f3", "$f4", "$f5", "$f6", "$f7", "$f8",	\
856  "$f9", "$f10", "$f11", "$f12", "$f13", "$f14", "$f15",		\
857  "$f16", "$f17", "$f18", "$f19", "$f20", "$f21", "$f22", "$f23",\
858  "$f24", "$f25", "$f26", "$f27", "$f28", "$f29", "$f30", "FP"}
859 
860 /* Strip name encoding when emitting labels.  */
861 
862 #define ASM_OUTPUT_LABELREF(STREAM, NAME)	\
863 do {						\
864   const char *name_ = NAME;			\
865   if (*name_ == '@' || *name_ == '%')		\
866     name_ += 2;					\
867   if (*name_ == '*')				\
868     name_++;					\
869   else						\
870     fputs (user_label_prefix, STREAM);		\
871   fputs (name_, STREAM);			\
872 } while (0)
873 
874 /* Globalizing directive for a label.  */
875 #define GLOBAL_ASM_OP "\t.globl "
876 
877 /* Use dollar signs rather than periods in special g++ assembler names.  */
878 
879 #undef NO_DOLLAR_IN_LABEL
880 
881 /* This is how to store into the string LABEL
882    the symbol_ref name of an internal numbered label where
883    PREFIX is the class of label and NUM is the number within the class.
884    This is suitable for output with `assemble_name'.  */
885 
886 #undef ASM_GENERATE_INTERNAL_LABEL
887 #define ASM_GENERATE_INTERNAL_LABEL(LABEL,PREFIX,NUM)	\
888   sprintf ((LABEL), "*$%s%ld", (PREFIX), (long)(NUM))
889 
890 /* This is how to output an element of a case-vector that is relative.  */
891 
892 #define ASM_OUTPUT_ADDR_DIFF_ELT(FILE, BODY, VALUE, REL) \
893   fprintf (FILE, "\t.gprel32 $L%d\n", (VALUE))
894 
895 /* If we use NM, pass -g to it so it only lists globals.  */
896 #define NM_FLAGS "-pg"
897 
898 /* Definitions for debugging.  */
899 
900 /* Correct the offset of automatic variables and arguments.  Note that
901    the Alpha debug format wants all automatic variables and arguments
902    to be in terms of two different offsets from the virtual frame pointer,
903    which is the stack pointer before any adjustment in the function.
904    The offset for the argument pointer is fixed for the native compiler,
905    it is either zero (for the no arguments case) or large enough to hold
906    all argument registers.
907    The offset for the auto pointer is the fourth argument to the .frame
908    directive (local_offset).
909    To stay compatible with the native tools we use the same offsets
910    from the virtual frame pointer and adjust the debugger arg/auto offsets
911    accordingly. These debugger offsets are set up in output_prolog.  */
912 
913 extern long alpha_arg_offset;
914 extern long alpha_auto_offset;
915 #define DEBUGGER_AUTO_OFFSET(X) \
916   ((GET_CODE (X) == PLUS ? INTVAL (XEXP (X, 1)) : 0) + alpha_auto_offset)
917 #define DEBUGGER_ARG_OFFSET(OFFSET, X) (OFFSET + alpha_arg_offset)
918 
919 #define ASM_OUTPUT_SOURCE_FILENAME(STREAM, NAME)			\
920   alpha_output_filename (STREAM, NAME)
921 
922 /* By default, turn on GDB extensions.  */
923 #define DEFAULT_GDB_EXTENSIONS 1
924 
925 #define TARGET_SUPPORTS_WIDE_INT 1
926