234 lines
9.7 KiB
C
234 lines
9.7 KiB
C
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/* Target machine description for VxWorks on the 29k, for GDB, the GNU debugger.
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Copyright 1994 Free Software Foundation, Inc.
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Contributed by Cygnus Support.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
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#include "a29k/tm-a29k.h"
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#define GDBINIT_FILENAME ".vxgdbinit"
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#define DEFAULT_PROMPT "(vxgdb) "
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/* Number of registers in a ptrace_getregs call. */
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#define VX_NUM_REGS (NUM_REGS)
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/* Number of registers in a ptrace_getfpregs call. */
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/* #define VX_SIZE_FPREGS */
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/* This is almost certainly the wrong place for this: */
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#define LR2_REGNUM 34
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/* Vxworks has its own CALL_DUMMY since it manages breakpoints in the kernel */
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#undef CALL_DUMMY
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/* Replace the breakpoint instruction in the CALL_DUMMY with a nop.
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For Vxworks, the breakpoint is set and deleted by calls to
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CALL_DUMMY_BREAK_SET and CALL_DUMMY_BREAK_DELETE. */
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#if TARGET_BYTE_ORDER == HOST_BYTE_ORDER
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#define CALL_DUMMY {0x0400870f,\
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0x36008200|(MSP_HW_REGNUM), \
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0x15000040|(MSP_HW_REGNUM<<8)|(MSP_HW_REGNUM<<16), \
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0x03ff80ff, 0x02ff80ff, 0xc8008080, 0x70400101, 0x70400101}
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#else /* Byte order differs. */
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#define CALL_DUMMY {0x0f870004,\
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0x00820036|(MSP_HW_REGNUM << 24), \
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0x40000015|(MSP_HW_REGNUM<<8)|(MSP_HW_REGNUM<<16), \
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0xff80ff03, 0xff80ff02, 0x808000c8, 0x01014070, 0x01014070}
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#endif /* Byte order differs. */
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/* For the basic CALL_DUMMY definitions, see "tm-29k.h." We use the
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same CALL_DUMMY code, but define FIX_CALL_DUMMY (and related macros)
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locally to handle remote debugging of VxWorks targets. The difference
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is in the setting and clearing of the breakpoint at the end of the
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CALL_DUMMY code fragment; under VxWorks, we can't simply insert a
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breakpoint instruction into the code, since that would interfere with
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the breakpoint management mechanism on the target.
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Note that CALL_DUMMY is a piece of code that is used to call any C function
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thru VxGDB */
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/* The offset of the instruction within the CALL_DUMMY code where we
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want the inferior to stop after the function call has completed.
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call_function_by_hand () sets a breakpoint here (via CALL_DUMMY_BREAK_SET),
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which POP_FRAME later deletes (via CALL_DUMMY_BREAK_DELETE). */
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#define CALL_DUMMY_STOP_OFFSET (7 * 4)
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/* The offset of the first instruction of the CALL_DUMMY code fragment
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relative to the frame pointer for a dummy frame. This is equal to
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the size of the CALL_DUMMY plus the arg_slop area size (see the diagram
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in "tm-29k.h"). */
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/* PAD : the arg_slop area size doesn't appear to me to be useful since, the
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call dummy code no longer modify the msp. See below. This must be checked. */
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#define CALL_DUMMY_OFFSET_IN_FRAME (CALL_DUMMY_LENGTH + 16 * 4)
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/* Insert the specified number of args and function address
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into a CALL_DUMMY sequence stored at DUMMYNAME, replace the third
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instruction (add msp, msp, 16*4) with a nop, and leave the final nop.
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We can't keep using a CALL_DUMMY that modify the msp since, for VxWorks,
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CALL_DUMMY is stored in the Memory Stack. Adding 16 words to the msp
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would then make possible for the inferior to overwrite the CALL_DUMMY code,
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thus creating a lot of trouble when exiting the inferior to come back in
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a CALL_DUMMY code that no longer exists... Furthermore, ESF are also stored
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from the msp in the memory stack. If msp is set higher than the dummy code,
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an ESF may clobber this code. */
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#if TARGET_BYTE_ORDER == BIG_ENDIAN
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#define NOP_INSTR 0x70400101
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#else /* Target is little endian */
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#define NOP_INSTR 0x01014070
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#endif
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#undef FIX_CALL_DUMMY
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#define FIX_CALL_DUMMY(dummyname, pc, fun, nargs, args, type, gcc_p) \
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{ \
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*(int *)((char *)dummyname + 8) = NOP_INSTR; \
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STUFF_I16((char *)dummyname + CONST_INSN, fun); \
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STUFF_I16((char *)dummyname + CONST_INSN + 4, fun >> 16); \
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}
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/* For VxWorks, CALL_DUMMY must be stored in the stack of the task that is
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being debugged and executed "in the context of" this task */
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#undef CALL_DUMMY_LOCATION
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#define CALL_DUMMY_LOCATION ON_STACK
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/* Set or delete a breakpoint at the location within a CALL_DUMMY code
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fragment where we want the target program to stop after the function
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call is complete. CALL_DUMMY_ADDR is the address of the first
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instruction in the CALL_DUMMY. DUMMY_FRAME_ADDR is the value of the
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frame pointer in the dummy frame.
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NOTE: in the both of the following definitions, we take advantage of
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knowledge of the implementation of the target breakpoint operation,
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in that we pass a null pointer as the second argument. It seems
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reasonable to assume that any target requiring the use of
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CALL_DUMMY_BREAK_{SET,DELETE} will not store the breakpoint
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shadow contents in GDB; in any case, this assumption is vaild
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for all VxWorks-related targets. */
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#define CALL_DUMMY_BREAK_SET(call_dummy_addr) \
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target_insert_breakpoint ((call_dummy_addr) + CALL_DUMMY_STOP_OFFSET, \
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(char *) 0)
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#define CALL_DUMMY_BREAK_DELETE(dummy_frame_addr) \
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target_remove_breakpoint ((dummy_frame_addr) - (CALL_DUMMY_OFFSET_IN_FRAME \
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- CALL_DUMMY_STOP_OFFSET), \
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(char *) 0)
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/* Return nonzero if the pc is executing within a CALL_DUMMY frame. */
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#define PC_IN_CALL_DUMMY(pc, sp, frame_address) \
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((pc) >= (sp) \
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&& (pc) <= (sp) + CALL_DUMMY_OFFSET_IN_FRAME + CALL_DUMMY_LENGTH)
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/* Defining this prevents us from trying to pass a structure-valued argument
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to a function called via the CALL_DUMMY mechanism. This is not handled
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properly in call_function_by_hand (), and the fix might require re-writing
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the CALL_DUMMY handling for all targets (at least, a clean solution
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would probably require this). Arguably, this should go in "tm-29k.h"
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rather than here. */
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#define STRUCT_VAL_ARGS_UNSUPPORTED
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#define BKPT_OFFSET (7 * 4)
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#define BKPT_INSTR 0x72500101
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#undef FIX_CALL_DUMMY
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#define FIX_CALL_DUMMY(dummyname, pc, fun, nargs, args, type, gcc_p) \
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{\
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STUFF_I16((char *)dummyname + CONST_INSN, fun);\
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STUFF_I16((char *)dummyname + CONST_INSN + 4, fun >> 16);\
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*(int *)((char *)dummyname + BKPT_OFFSET) = BKPT_INSTR;\
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}
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/* Offsets into jmp_buf. They are derived from VxWorks' REG_SET struct
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(see VxWorks' setjmp.h). Note that Sun2, Sun3 and SunOS4 and VxWorks have
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different REG_SET structs, hence different layouts for the jmp_buf struct.
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Only JB_PC is needed for getting the saved PC value. */
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#define JB_ELEMENT_SIZE 4 /* size of each element in jmp_buf */
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#define JB_PC 3 /* offset of pc (pc1) in jmp_buf */
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/* Figure out where the longjmp will land. We expect that we have just entered
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longjmp and haven't yet setup the stack frame, so the args are still in the
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output regs. lr2 (LR2_REGNUM) points at the jmp_buf structure from which we
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extract the pc (JB_PC) that we will land at. The pc is copied into ADDR.
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This routine returns true on success */
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#define GET_LONGJMP_TARGET(ADDR) get_longjmp_target(ADDR)
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extern int get_longjmp_target PARAMS ((CORE_ADDR *));
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/* VxWorks adjusts the PC after a breakpoint has been hit. */
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#undef DECR_PC_AFTER_BREAK
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#define DECR_PC_AFTER_BREAK 0
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/* Do whatever promotions are appropriate on a value being returned
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from a function. VAL is the user-supplied value, and FUNC_TYPE
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is the return type of the function if known, else 0.
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For the Am29k, as far as I understand, if the function return type is known,
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cast the value to that type; otherwise, ensure that integer return values
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fill all of gr96.
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This definition really belongs in "tm-29k.h", since it applies
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to most Am29K-based systems; but once moved into that file, it might
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need to be redefined for all Am29K-based targets that also redefine
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STORE_RETURN_VALUE. For now, to be safe, we define it here. */
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#define PROMOTE_RETURN_VALUE(val, func_type) \
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do { \
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if (func_type) \
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val = value_cast (func_type, val); \
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if ((TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_INT \
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|| TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_ENUM) \
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&& TYPE_LENGTH (VALUE_TYPE (val)) < REGISTER_RAW_SIZE (0)) \
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val = value_cast (builtin_type_int, val); \
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} while (0)
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#define SPECIAL_FRAME_CHAIN_FP get_fp_contents
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#undef FRAME_CHAIN_VALID
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#define FRAME_CHAIN_VALID(chain, thisframe) \
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(SPECIAL_FRAME_CHAIN_FP (chain, thisframe))
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extern int SPECIAL_FRAME_CHAIN_FP ();
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extern CORE_ADDR frame_saved_call_site ();
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#undef PREPARE_TO_INIT_FRAME_INFO
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#define PREPARE_TO_INIT_FRAME_INFO(fci) do { \
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long current_msp = read_register (MSP_REGNUM); \
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if (PC_IN_CALL_DUMMY (fci->pc, current_msp, 0)) \
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{ \
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fci->rsize = DUMMY_FRAME_RSIZE; \
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fci->msize = 0; \
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fci->saved_msp = \
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read_register_stack_integer (fci->frame + DUMMY_FRAME_RSIZE - 4, 4); \
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fci->flags |= (TRANSPARENT|MFP_USED); \
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return; \
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} \
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} while (0)
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