1 /* Target machine description for generic Motorola 88000, for GDB.
2 Copyright 1986, 1987, 1988, 1989, 1990, 1991 Free Software Foundation, Inc.
4 This file is part of GDB.
6 This program 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 2 of the License, or
9 (at your option) any later version.
11 This program 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.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
20 /* g++ support is not yet included. */
22 #define TARGET_BYTE_ORDER BIG_ENDIAN
24 /* We cache information about saved registers in the frame structure,
25 to save us from having to re-scan function prologues every time
26 a register in a non-current frame is accessed. */
28 #define EXTRA_FRAME_INFO \
29 struct frame_saved_regs *fsr; \
30 CORE_ADDR locals_pointer; \
31 CORE_ADDR args_pointer;
33 /* Zero the frame_saved_regs pointer when the frame is initialized,
34 so that FRAME_FIND_SAVED_REGS () will know to allocate and
35 initialize a frame_saved_regs struct the first time it is called.
36 Set the arg_pointer to -1, which is not valid; 0 and other values
37 indicate real, cached values. */
39 #define INIT_EXTRA_FRAME_INFO(fromleaf, fi) \
40 init_extra_frame_info (fromleaf, fi)
41 extern void init_extra_frame_info ();
45 /* Define this if the C compiler puts an underscore at the front
46 of external names before giving them to the linker. */
48 #define NAMES_HAVE_UNDERSCORE
50 /* Offset from address of function to start of its code.
51 Zero on most machines. */
53 #define FUNCTION_START_OFFSET 0
55 /* Advance PC across any function entry prologue instructions
56 to reach some "real" code. */
58 #define SKIP_PROLOGUE(frompc) \
59 skip_prologue (frompc)
60 extern CORE_ADDR skip_prologue ();
62 /* The m88k kernel aligns all instructions on 4-byte boundaries. The
63 kernel also uses the least significant two bits for its own hocus
64 pocus. When gdb receives an address from the kernel, it needs to
65 preserve those right-most two bits, but gdb also needs to be careful
66 to realize that those two bits are not really a part of the address
67 of an instruction. Shrug. */
69 #define ADDR_BITS_REMOVE(addr) ((addr) & ~3)
70 #define ADDR_BITS_SET(addr) (((addr) | 0x00000002) - 4)
72 /* Immediately after a function call, return the saved pc.
73 Can't always go through the frames for this because on some machines
74 the new frame is not set up until the new function executes
77 #define SAVED_PC_AFTER_CALL(frame) \
78 (ADDR_BITS_REMOVE (read_register (SRP_REGNUM)))
80 /* Stack grows downward. */
84 /* Sequence of bytes for breakpoint instruction. */
86 /* instruction 0xF000D1FF is 'tb0 0,r0,511'
87 If Bit bit 0 of r0 is clear (always true),
88 initiate exception processing (trap).
90 #define BREAKPOINT {0xF0, 0x00, 0xD1, 0xFF}
92 /* Amount PC must be decremented by after a breakpoint.
93 This is often the number of bytes in BREAKPOINT
96 #define DECR_PC_AFTER_BREAK 0
98 /* Nonzero if instruction at PC is a return instruction. */
99 /* 'jmp r1' or 'jmp.n r1' is used to return from a subroutine. */
101 #define ABOUT_TO_RETURN(pc) (read_memory_integer (pc, 2) == 0xF800)
103 /* Return 1 if P points to an invalid floating point value.
104 LEN is the length in bytes. */
106 #define INVALID_FLOAT(p, len) IEEE_isNAN(p,len)
108 /* Say how long (ordinary) registers are. */
110 #define REGISTER_TYPE long
112 /* Number of machine registers */
116 /* Initializer for an array of names of registers.
117 There should be NUM_REGS strings in this initializer. */
119 #define REGISTER_NAMES {\
186 /* Register numbers of various important registers.
187 Note that some of these values are "real" register numbers,
188 and correspond to the general registers of the machine,
189 and some are "phony" register numbers which are too large
190 to be actual register numbers as far as the user is concerned
191 but do serve to get the desired values when passed to read_register. */
193 #define SRP_REGNUM 1 /* Contains subroutine return pointer */
194 #define RV_REGNUM 2 /* Contains simple return values */
195 #define SRA_REGNUM 12 /* Contains address of struct return values */
196 #define FP_REGNUM 31 /* Reg fetched to locate frame when pgm stops */
197 #define SP_REGNUM 31 /* Contains address of top of stack */
198 #define SXIP_REGNUM 35 /* Contains Shadow Execute Instruction Pointer */
199 #define SNIP_REGNUM 36 /* Contains Shadow Next Instruction Pointer */
200 #define PC_REGNUM SXIP_REGNUM /* Program Counter */
201 #define NPC_REGNUM SNIP_REGNUM /* Next Program Counter */
202 #define PSR_REGNUM 32 /* Processor Status Register */
203 #define FPSR_REGNUM 33 /* Floating Point Status Register */
204 #define FPCR_REGNUM 34 /* Floating Point Control Register */
205 #define SFIP_REGNUM 37 /* Contains Shadow Fetched Intruction pointer */
206 #define NNPC_REGNUM SFIP_REGNUM /* Next Next Program Counter */
208 /* PSR status bit definitions. */
210 #define PSR_MODE 0x80000000
211 #define PSR_BYTE_ORDER 0x40000000
212 #define PSR_SERIAL_MODE 0x20000000
213 #define PSR_CARRY 0x10000000
214 #define PSR_SFU_DISABLE 0x000003f0
215 #define PSR_SFU1_DISABLE 0x00000008
216 #define PSR_MXM 0x00000004
217 #define PSR_IND 0x00000002
218 #define PSR_SFRZ 0x00000001
220 /* BCS requires that the SXIP_REGNUM (or PC_REGNUM) contain the address
221 of the next instr to be executed when a breakpoint occurs. Because
222 the kernel gets the next instr (SNIP_REGNUM), the instr in SNIP needs
223 to be put back into SFIP, and the instr in SXIP should be shifted
226 /* Are you sitting down? It turns out that the 88K BCS (binary compatibility
227 standard) folks originally felt that the debugger should be responsible
228 for backing up the IPs, not the kernel (as is usually done). Well, they
229 have reversed their decision, and in future releases our kernel will be
230 handling the backing up of the IPs. So, eventually, we won't need to
231 do the SHIFT_INST_REGS stuff. But, for now, since there are 88K systems out
232 there that do need the debugger to do the IP shifting, and since there
233 will be systems where the kernel does the shifting, the code is a little
234 more complex than perhaps it needs to be (we still go inside SHIFT_INST_REGS,
235 and if the shifting hasn't occurred then gdb goes ahead and shifts). */
237 #define SHIFT_INST_REGS
239 /* Number of bytes of storage in the actual machine representation
242 #define REGISTER_RAW_SIZE(N) 4
244 /* Total amount of space needed to store our copies of the machine's
245 register state, the array `registers'. */
247 #define REGISTER_BYTES (NUM_REGS * REGISTER_RAW_SIZE(0))
249 /* Index within `registers' of the first byte of the space for
252 #define REGISTER_BYTE(N) ((N)*REGISTER_RAW_SIZE(0))
254 /* Number of bytes of storage in the program's representation
257 #define REGISTER_VIRTUAL_SIZE(N) (REGISTER_RAW_SIZE(N))
259 /* Largest value REGISTER_RAW_SIZE can have. */
261 #define MAX_REGISTER_RAW_SIZE (REGISTER_RAW_SIZE(0))
263 /* Largest value REGISTER_VIRTUAL_SIZE can have.
264 /* Are FPS1, FPS2, FPR "virtual" regisers? */
266 #define MAX_REGISTER_VIRTUAL_SIZE (REGISTER_RAW_SIZE(0))
268 /* Nonzero if register N requires conversion
269 from raw format to virtual format. */
271 #define REGISTER_CONVERTIBLE(N) (0)
273 /* Convert data from raw format for register REGNUM
274 to virtual format for register REGNUM. */
276 #define REGISTER_CONVERT_TO_VIRTUAL(REGNUM,FROM,TO) \
277 {bcopy ((FROM), (TO), REGISTER_RAW_SIZE (REGNUM));}
279 /* Convert data from virtual format for register REGNUM
280 to raw format for register REGNUM. */
282 #define REGISTER_CONVERT_TO_RAW(REGNUM,FROM,TO)
283 {bcopy ((FROM), (TO), REGISTER_RAW_SIZE (REGNUM));}
285 /* Return the GDB type object for the "standard" data type
286 of data in register N. */
288 #define REGISTER_VIRTUAL_TYPE(N) (builtin_type_int)
290 /* The 88k call/return conventions call for "small" values to be returned
291 into consecutive registers starting from r2. */
293 #define EXTRACT_RETURN_VALUE(TYPE,REGBUF,VALBUF) \
294 bcopy (&(((char *)REGBUF)[REGISTER_BYTE(RV_REGNUM)]), (VALBUF), TYPE_LENGTH (TYPE))
296 #define EXTRACT_STRUCT_VALUE_ADDRESS(REGBUF) (*(int *)(REGBUF))
298 /* Write into appropriate registers a function return value
299 of type TYPE, given in virtual format. */
301 #define STORE_RETURN_VALUE(TYPE,VALBUF) \
302 write_register_bytes (2*REGISTER_RAW_SIZE(0), (VALBUF), TYPE_LENGTH (TYPE))
304 /* In COFF, if PCC says a parameter is a short or a char, do not
305 change it to int (it seems the convention is to change it). */
307 #define BELIEVE_PCC_PROMOTION 1
309 /* Describe the pointer in each stack frame to the previous stack frame
312 /* FRAME_CHAIN takes a frame's nominal address
313 and produces the frame's chain-pointer.
315 However, if FRAME_CHAIN_VALID returns zero,
316 it means the given frame is the outermost one and has no caller. */
318 extern CORE_ADDR frame_chain ();
319 extern int frame_chain_valid ();
320 extern int frameless_function_invocation ();
322 #define FRAME_CHAIN(thisframe) \
323 frame_chain (thisframe)
325 #define FRAME_CHAIN_VALID(chain, thisframe) \
326 frame_chain_valid (chain, thisframe)
328 #define FRAMELESS_FUNCTION_INVOCATION(frame, fromleaf) \
329 fromleaf = frameless_function_invocation (frame)
331 /* Define other aspects of the stack frame. */
333 #define FRAME_SAVED_PC(FRAME) \
334 frame_saved_pc (FRAME)
335 extern CORE_ADDR frame_saved_pc ();
337 #define FRAME_ARGS_ADDRESS(fi) \
338 frame_args_address (fi)
339 extern CORE_ADDR frame_args_address ();
341 #define FRAME_LOCALS_ADDRESS(fi) \
342 frame_locals_address (fi)
343 extern CORE_ADDR frame_locals_address ();
345 /* Return number of args passed to a frame.
346 Can return -1, meaning no way to tell. */
348 #define FRAME_NUM_ARGS(numargs, fi) ((numargs) = -1)
350 /* Return number of bytes at start of arglist that are not really args. */
352 #define FRAME_ARGS_SKIP 0
354 /* Put here the code to store, into a struct frame_saved_regs,
355 the addresses of the saved registers of frame described by FRAME_INFO.
356 This includes special registers such as pc and fp saved in special
357 ways in the stack frame. sp is even more special:
358 the address we return for it IS the sp for the next frame. */
360 /* On the 88k, parameter registers get stored into the so called "homing"
361 area. This *always* happens when you compiled with GCC and use -g.
362 Also, (with GCC and -g) the saving of the parameter register values
363 always happens right within the function prologue code, so these register
364 values can generally be relied upon to be already copied into their
365 respective homing slots by the time you will normally try to look at
368 Note that homing area stack slots are always at *positive* offsets from
369 the frame pointer. Thus, the homing area stack slots for the parameter
370 registers (passed values) for a given function are actually part of the
371 frame area of the caller. This is unusual, but it should not present
372 any special problems for GDB.
374 Note also that on the 88k, we are only interested in finding the
375 registers that might have been saved in memory. This is a subset of
376 the whole set of registers because the standard calling sequence allows
377 the called routine to clobber many registers.
379 We could manage to locate values for all of the so called "preserved"
380 registers (some of which may get saved within any particular frame) but
381 that would require decoding all of the tdesc information. Tht would be
382 nice information for GDB to have, but it is not strictly manditory if we
383 can live without the ability to look at values within (or backup to)
387 #define FRAME_FIND_SAVED_REGS(frame_info, frame_saved_regs) \
388 frame_find_saved_regs (frame_info, &frame_saved_regs)
391 /* There is not currently a functioning way to call functions in the
394 /* But if there was this is where we'd put the call dummy. */
395 /* #define CALL_DUMMY_LOCATION AFTER_TEXT_END */
397 /* When popping a frame on the 88k (say when doing a return command), the
398 calling function only expects to have the "preserved" registers restored.
399 Thus, those are the only ones that we even try to restore here. */
401 #define POP_FRAME pop_frame ()
402 extern void pop_frame ();