536 lines
12 KiB
C
536 lines
12 KiB
C
/* C6X ABI compliant unwinding routines
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Copyright (C) 2011-2015 Free Software Foundation, Inc.
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This file is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 3, or (at your option) any
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later version.
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This file is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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#include "unwind.h"
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/* We add a prototype for abort here to avoid creating a dependency on
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target headers. */
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extern void abort (void);
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typedef struct _ZSt9type_info type_info; /* This names C++ type_info type */
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/* Misc constants. */
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#define R_A0 0
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#define R_A1 1
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#define R_A2 2
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#define R_A3 3
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#define R_A4 4
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#define R_A5 5
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#define R_A6 6
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#define R_A7 7
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#define R_A8 8
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#define R_A9 9
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#define R_A10 10
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#define R_A11 11
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#define R_A12 12
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#define R_A13 13
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#define R_A14 14
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#define R_A15 15
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#define R_B0 16
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#define R_B1 17
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#define R_B2 18
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#define R_B3 19
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#define R_B4 20
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#define R_B5 21
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#define R_B6 22
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#define R_B7 23
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#define R_B8 24
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#define R_B9 25
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#define R_B10 26
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#define R_B11 27
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#define R_B12 28
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#define R_B13 29
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#define R_B14 30
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#define R_B15 31
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#define R_SP R_B15
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#define R_PC 33
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#define uint32_highbit (((_uw) 1) << 31)
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void __attribute__((weak)) __cxa_call_unexpected(_Unwind_Control_Block *ucbp);
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/* Unwind descriptors. */
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typedef struct
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{
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_uw16 length;
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_uw16 offset;
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} EHT16;
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typedef struct
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{
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_uw length;
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_uw offset;
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} EHT32;
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/* Calculate the address encoded by a 31-bit self-relative offset at address
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P. Copy of routine in unwind-arm.c. */
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static inline _uw
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selfrel_offset31 (const _uw *p)
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{
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_uw offset;
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offset = *p;
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/* Sign extend to 32 bits. */
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if (offset & (1 << 30))
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offset |= 1u << 31;
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return offset + (_uw) p;
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}
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/* Personality routine helper functions. */
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#define CODE_FINISH (0xe7)
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/* Return the next byte of unwinding information, or CODE_FINISH if there is
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no data remaining. */
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static inline _uw8
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next_unwind_byte (__gnu_unwind_state * uws)
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{
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_uw8 b;
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if (uws->bytes_left == 0)
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{
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/* Load another word */
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if (uws->words_left == 0)
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return CODE_FINISH; /* Nothing left. */
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uws->words_left--;
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uws->data = *(uws->next++);
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uws->bytes_left = 3;
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}
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else
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uws->bytes_left--;
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/* Extract the most significant byte. */
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b = (uws->data >> 24) & 0xff;
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uws->data <<= 8;
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return b;
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}
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static void
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unwind_restore_pair (_Unwind_Context * context, int reg, _uw *ptr)
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{
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#ifdef _BIG_ENDIAN
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_Unwind_VRS_Set (context, _UVRSC_CORE, reg, _UVRSD_UINT32, ptr + 1);
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_Unwind_VRS_Set (context, _UVRSC_CORE, reg + 1, _UVRSD_UINT32, ptr);
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#else
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_Unwind_VRS_Set (context, _UVRSC_CORE, reg, _UVRSD_UINT32, ptr);
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_Unwind_VRS_Set (context, _UVRSC_CORE, reg + 1, _UVRSD_UINT32, ptr + 1);
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#endif
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}
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static const int
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unwind_frame_regs[13] =
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{
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R_A15, R_B15, R_B14, R_B13, R_B12, R_B11, R_B10, R_B3,
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R_A14, R_A13, R_A12, R_A11, R_A10
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};
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static void
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pop_compact_frame (_Unwind_Context * context, _uw mask, _uw *ptr, int inc_sp)
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{
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int size;
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_uw test;
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int i, regno, nregs;
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size = 0;
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nregs = __builtin_popcount (mask);
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for (i = 0; i < 13; i++)
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{
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test = 1 << i;
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if ((mask & test) == 0)
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continue;
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regno = unwind_frame_regs[12 - i];
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if (i < 12 && nregs > 2
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&& (mask & (test << 1)) != 0
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&& unwind_frame_regs[11 - i] == regno + 1
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&& (regno & 1) == 0)
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{
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i++;
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nregs--;
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}
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nregs--;
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size += 2;
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}
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if (!inc_sp)
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ptr -= size;
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/* SP points just past the end of the stack. */
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ptr += 2;
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nregs = __builtin_popcount (mask);
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for (i = 0; i < 13; i++)
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{
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test = 1 << i;
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if ((mask & test) == 0)
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continue;
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regno = unwind_frame_regs[12 - i];
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if (i < 12 && nregs > 2
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&& (mask & (test << 1)) != 0
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&& unwind_frame_regs[11 - i] == regno + 1
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&& (regno & 1) == 0)
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{
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/* Register pair. */
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unwind_restore_pair (context, regno, ptr);
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i++;
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nregs--;
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}
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else
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{
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/* Single register with padding. */
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_Unwind_VRS_Set (context, _UVRSC_CORE, regno, _UVRSD_UINT32, ptr);
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}
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nregs--;
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ptr += 2;
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}
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ptr -= 2;
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if ((mask & (1 << 11)) == 0)
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_Unwind_VRS_Set (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, &ptr);
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}
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static void
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pop_frame (_Unwind_Context * context, _uw mask, _uw *ptr, int inc_sp)
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{
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int i;
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int regno;
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int nregs;
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nregs = __builtin_popcount (mask);
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if (!inc_sp)
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ptr -= nregs;
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else if (nregs & 1)
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ptr++;
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ptr++;
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for (i = 0; i < 13; i++)
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{
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if ((mask & (1 << i)) == 0)
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continue;
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regno = unwind_frame_regs[12 - i];
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if (i < 12 && unwind_frame_regs[11 - i] == (regno + 1)
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&& (mask & (1 << (i + 1))) != 0
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&& (((_uw)ptr) & 4) == 0
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&& (regno & 1) == 0)
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{
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unwind_restore_pair (context, regno, ptr);
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i++;
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ptr += 2;
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}
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else
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{
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_Unwind_VRS_Set (context, _UVRSC_CORE, regno, _UVRSD_UINT32,
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ptr);
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ptr++;
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}
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}
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ptr--;
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if ((mask & (1 << 11)) == 0)
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_Unwind_VRS_Set (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, &ptr);
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}
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/* Unwind a 24-bit encoded frame. */
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_Unwind_Reason_Code
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__gnu_unwind_24bit (_Unwind_Context * context, _uw data, int compact)
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{
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_uw offset;
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_uw mask;
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_uw *ptr;
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_uw tmp;
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int ret_reg = unwind_frame_regs[data & 0xf];
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if (ret_reg != R_B3)
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{
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_Unwind_VRS_Get (context, _UVRSC_CORE, unwind_frame_regs[data & 0xf],
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_UVRSD_UINT32, &tmp);
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_Unwind_VRS_Set (context, _UVRSC_CORE, R_B3, _UVRSD_UINT32, &tmp);
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}
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mask = (data >> 4) & 0x1fff;
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offset = (data >> 17) & 0x7f;
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if (offset == 0x7f)
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_Unwind_VRS_Get (context, _UVRSC_CORE, R_A15, _UVRSD_UINT32, &ptr);
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else
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{
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_Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, &ptr);
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ptr += offset * 2;
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}
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if (compact)
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pop_compact_frame (context, mask, ptr, offset != 0x7f);
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else
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pop_frame (context, mask, ptr, offset != 0x7f);
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_Unwind_VRS_Get (context, _UVRSC_CORE, R_B3, _UVRSD_UINT32, &tmp);
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_Unwind_VRS_Set (context, _UVRSC_CORE, R_PC, _UVRSD_UINT32, &tmp);
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return _URC_OK;
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}
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static void
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unwind_pop_rts (_Unwind_Context * context)
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{
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_uw *ptr;
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_Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, &ptr);
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#ifdef _BIG_ENDIAN
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_Unwind_VRS_Set (context, _UVRSC_CORE, R_B3, _UVRSD_UINT32, ptr + 1);
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#else
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_Unwind_VRS_Set (context, _UVRSC_CORE, R_B3, _UVRSD_UINT32, ptr + 2);
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#endif
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ptr += 3;
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unwind_restore_pair (context, R_A10, ptr);
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ptr += 2;
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unwind_restore_pair (context, R_B10, ptr);
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ptr += 2;
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unwind_restore_pair (context, R_A12, ptr);
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ptr += 2;
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unwind_restore_pair (context, R_B12, ptr);
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ptr += 2;
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unwind_restore_pair (context, R_A14, ptr);
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ptr += 2;
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_Unwind_VRS_Set (context, _UVRSC_CORE, R_B14, _UVRSD_UINT32, ptr);
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_Unwind_VRS_Set (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, &ptr);
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/* PC will be set by implicit RETURN opcode. */
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}
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/* Execute the unwinding instructions described by UWS. */
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_Unwind_Reason_Code
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__gnu_unwind_execute (_Unwind_Context * context, __gnu_unwind_state * uws)
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{
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_uw op;
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int inc_sp;
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_uw reg;
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_uw *ptr;
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inc_sp = 1;
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for (;;)
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{
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op = next_unwind_byte (uws);
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if (op == CODE_FINISH)
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{
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/* Drop out of the loop. */
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break;
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}
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if ((op & 0xc0) == 0)
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{
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/* sp += (imm6 << 3) + 8. */
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_uw offset;
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offset = ((op & 0x3f) << 3) + 8;
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_Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, ®);
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reg += offset;
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_Unwind_VRS_Set (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, ®);
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continue;
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}
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if (op == 0xd2)
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{
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/* vsp = vsp + 0x204 + (uleb128 << 2). */
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int shift;
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_Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, ®);
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op = next_unwind_byte (uws);
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shift = 3;
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while (op & 0x80)
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{
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reg += ((op & 0x7f) << shift);
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shift += 7;
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op = next_unwind_byte (uws);
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}
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reg += ((op & 0x7f) << shift) + 0x408;
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_Unwind_VRS_Set (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, ®);
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continue;
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}
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if ((op & 0xe0) == 0x80)
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{
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/* POP bitmask */
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_uw mask = ((op & 0x1f) << 8) | next_unwind_byte (uws);
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if (mask == 0)
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{
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/* CANTUNWIND */
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return _URC_FAILURE;
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}
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_Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, &ptr);
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pop_frame (context, mask, ptr, inc_sp);
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continue;
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}
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if ((op & 0xe0) == 0xa0)
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{
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/* POP bitmask (compact) */
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_uw mask = ((op & 0x1f) << 8) | next_unwind_byte (uws);
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_Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, &ptr);
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pop_compact_frame (context, mask, ptr, inc_sp);
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continue;
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}
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if ((op & 0xf0) == 0xc0)
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{
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/* POP registers */
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int nregs = op & 0xf;
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_Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, &ptr);
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while (nregs > 0)
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{
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op = next_unwind_byte (uws);
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if ((op >> 4) != 0xf)
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{
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reg = unwind_frame_regs[op >> 4];
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_Unwind_VRS_Set (context, _UVRSC_CORE, reg, _UVRSD_UINT32,
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ptr);
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nregs--;
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}
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ptr--;
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if ((op & 0xf) != 0xf)
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{
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reg = unwind_frame_regs[op & 0xf];
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_Unwind_VRS_Set (context, _UVRSC_CORE, reg, _UVRSD_UINT32,
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ptr);
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nregs--;
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}
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ptr--;
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}
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continue;
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}
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if (op == 0xd0)
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{
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/* MV FP, SP */
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inc_sp = 0;
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_Unwind_VRS_Get (context, _UVRSC_CORE, R_A15, _UVRSD_UINT32, ®);
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_Unwind_VRS_Set (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, ®);
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continue;
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}
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if (op == 0xd1)
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{
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/* __cx6abi_pop_rts */
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unwind_pop_rts (context);
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break;
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}
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if ((op & 0xf0) == 0xe0)
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{
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/* B3 = reg. RETURN case alreadh handled above. */
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int regno = unwind_frame_regs[op & 0xf];
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_Unwind_VRS_Get (context, _UVRSC_CORE, regno, _UVRSD_UINT32, ®);
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_Unwind_VRS_Set (context, _UVRSC_CORE, R_B3, _UVRSD_UINT32, ®);
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continue;
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}
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/* Reserved. */
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return _URC_FAILURE;
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}
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/* Implicit RETURN. */
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_Unwind_VRS_Get (context, _UVRSC_CORE, R_B3, _UVRSD_UINT32, ®);
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_Unwind_VRS_Set (context, _UVRSC_CORE, R_PC, _UVRSD_UINT32, ®);
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return _URC_OK;
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}
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/* Execute the unwinding instructions associated with a frame. UCBP and
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CONTEXT are the current exception object and virtual CPU state
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respectively. */
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_Unwind_Reason_Code
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__gnu_unwind_frame (_Unwind_Control_Block * ucbp, _Unwind_Context * context)
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{
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_uw *ptr;
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__gnu_unwind_state uws;
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ptr = (_uw *) ucbp->pr_cache.ehtp;
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/* Skip over the personality routine address. */
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ptr++;
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/* Setup the unwinder state. */
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uws.data = (*ptr) << 8;
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uws.next = ptr + 1;
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uws.bytes_left = 3;
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uws.words_left = ((*ptr) >> 24) & 0xff;
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return __gnu_unwind_execute (context, &uws);
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}
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/* Data segment base pointer corresponding to the function catching
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the exception. */
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_Unwind_Ptr
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_Unwind_GetDataRelBase (_Unwind_Context *context)
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{
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return _Unwind_GetGR (context, R_B14);
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}
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/* This should never be used. */
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_Unwind_Ptr
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_Unwind_GetTextRelBase (_Unwind_Context *context __attribute__ ((unused)))
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{
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abort ();
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}
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/* Only used by gcc personality routines, so can rely on a value they hid
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there earlier. */
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_Unwind_Ptr
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_Unwind_GetRegionStart (_Unwind_Context *context)
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{
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_Unwind_Control_Block *ucbp;
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ucbp = (_Unwind_Control_Block *) _Unwind_GetGR (context, UNWIND_POINTER_REG);
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return (_Unwind_Ptr) ucbp->pr_cache.fnstart;
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}
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void *
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_Unwind_GetLanguageSpecificData (_Unwind_Context *context)
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{
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_Unwind_Control_Block *ucbp;
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_uw *ptr;
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ucbp = (_Unwind_Control_Block *) _Unwind_GetGR (context, UNWIND_POINTER_REG);
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ptr = (_uw *) ucbp->pr_cache.ehtp;
|
|
/* Skip the personality routine address. */
|
|
ptr++;
|
|
/* Skip the unwind opcodes. */
|
|
ptr += (((*ptr) >> 24) & 0xff) + 1;
|
|
|
|
return ptr;
|
|
}
|