- unsigned long res, shift;
- int rm = bits (inst, 0, 3);
- unsigned long shifttype = bits (inst, 5, 6);
-
- if (bit (inst, 4))
- {
- int rs = bits (inst, 8, 11);
- shift = (rs == 15 ? pc_val + 8
- : regcache_raw_get_unsigned (regcache, rs)) & 0xFF;
- }
- else
- shift = bits (inst, 7, 11);
-
- res = (rm == ARM_PC_REGNUM
- ? (pc_val + (bit (inst, 4) ? 12 : 8))
- : regcache_raw_get_unsigned (regcache, rm));
-
- switch (shifttype)
- {
- case 0: /* LSL */
- res = shift >= 32 ? 0 : res << shift;
- break;
-
- case 1: /* LSR */
- res = shift >= 32 ? 0 : res >> shift;
- break;
-
- case 2: /* ASR */
- if (shift >= 32)
- shift = 31;
- res = ((res & 0x80000000L)
- ? ~((~res) >> shift) : res >> shift);
- break;
-
- case 3: /* ROR/RRX */
- shift &= 31;
- if (shift == 0)
- res = (res >> 1) | (carry ? 0x80000000L : 0);
- else
- res = (res >> shift) | (res << (32 - shift));
- break;
- }
-
- return res & 0xffffffff;
-}
-
-static int
-thumb_advance_itstate (unsigned int itstate)
-{
- /* Preserve IT[7:5], the first three bits of the condition. Shift
- the upcoming condition flags left by one bit. */
- itstate = (itstate & 0xe0) | ((itstate << 1) & 0x1f);
-
- /* If we have finished the IT block, clear the state. */
- if ((itstate & 0x0f) == 0)
- itstate = 0;
-
- return itstate;
-}
-
-/* Find the next PC after the current instruction executes. In some
- cases we can not statically determine the answer (see the IT state
- handling in this function); in that case, a breakpoint may be
- inserted in addition to the returned PC, which will be used to set
- another breakpoint by our caller. */
-
-static CORE_ADDR
-thumb_get_next_pc_raw (struct regcache *regcache, CORE_ADDR pc)
-{
- struct gdbarch *gdbarch = get_regcache_arch (regcache);
- struct address_space *aspace = get_regcache_aspace (regcache);
- enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
- enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
- unsigned long pc_val = ((unsigned long) pc) + 4; /* PC after prefetch */
- unsigned short inst1;
- CORE_ADDR nextpc = pc + 2; /* Default is next instruction. */
- unsigned long offset;
- ULONGEST status, itstate;
-
- nextpc = MAKE_THUMB_ADDR (nextpc);
- pc_val = MAKE_THUMB_ADDR (pc_val);
-
- inst1 = read_memory_unsigned_integer (pc, 2, byte_order_for_code);
-
- /* Thumb-2 conditional execution support. There are eight bits in
- the CPSR which describe conditional execution state. Once
- reconstructed (they're in a funny order), the low five bits
- describe the low bit of the condition for each instruction and
- how many instructions remain. The high three bits describe the
- base condition. One of the low four bits will be set if an IT
- block is active. These bits read as zero on earlier
- processors. */
- status = regcache_raw_get_unsigned (regcache, ARM_PS_REGNUM);
- itstate = ((status >> 8) & 0xfc) | ((status >> 25) & 0x3);
-
- /* If-Then handling. On GNU/Linux, where this routine is used, we
- use an undefined instruction as a breakpoint. Unlike BKPT, IT
- can disable execution of the undefined instruction. So we might
- miss the breakpoint if we set it on a skipped conditional
- instruction. Because conditional instructions can change the
- flags, affecting the execution of further instructions, we may
- need to set two breakpoints. */
-
- if (gdbarch_tdep (gdbarch)->thumb2_breakpoint != NULL)
- {
- if ((inst1 & 0xff00) == 0xbf00 && (inst1 & 0x000f) != 0)
- {
- /* An IT instruction. Because this instruction does not
- modify the flags, we can accurately predict the next
- executed instruction. */
- itstate = inst1 & 0x00ff;
- pc += thumb_insn_size (inst1);
-
- while (itstate != 0 && ! condition_true (itstate >> 4, status))
- {
- inst1 = read_memory_unsigned_integer (pc, 2,
- byte_order_for_code);
- pc += thumb_insn_size (inst1);
- itstate = thumb_advance_itstate (itstate);
- }
-
- return MAKE_THUMB_ADDR (pc);
- }
- else if (itstate != 0)
- {
- /* We are in a conditional block. Check the condition. */
- if (! condition_true (itstate >> 4, status))
- {
- /* Advance to the next executed instruction. */
- pc += thumb_insn_size (inst1);
- itstate = thumb_advance_itstate (itstate);
-
- while (itstate != 0 && ! condition_true (itstate >> 4, status))
- {
- inst1 = read_memory_unsigned_integer (pc, 2,
- byte_order_for_code);
- pc += thumb_insn_size (inst1);
- itstate = thumb_advance_itstate (itstate);
- }
-
- return MAKE_THUMB_ADDR (pc);
- }
- else if ((itstate & 0x0f) == 0x08)
- {
- /* This is the last instruction of the conditional
- block, and it is executed. We can handle it normally
- because the following instruction is not conditional,
- and we must handle it normally because it is
- permitted to branch. Fall through. */
- }
- else
- {
- int cond_negated;
-
- /* There are conditional instructions after this one.
- If this instruction modifies the flags, then we can
- not predict what the next executed instruction will
- be. Fortunately, this instruction is architecturally
- forbidden to branch; we know it will fall through.
- Start by skipping past it. */
- pc += thumb_insn_size (inst1);
- itstate = thumb_advance_itstate (itstate);
-
- /* Set a breakpoint on the following instruction. */
- gdb_assert ((itstate & 0x0f) != 0);
- arm_insert_single_step_breakpoint (gdbarch, aspace,
- MAKE_THUMB_ADDR (pc));
- cond_negated = (itstate >> 4) & 1;
-
- /* Skip all following instructions with the same
- condition. If there is a later instruction in the IT
- block with the opposite condition, set the other
- breakpoint there. If not, then set a breakpoint on
- the instruction after the IT block. */
- do
- {
- inst1 = read_memory_unsigned_integer (pc, 2,
- byte_order_for_code);
- pc += thumb_insn_size (inst1);
- itstate = thumb_advance_itstate (itstate);
- }
- while (itstate != 0 && ((itstate >> 4) & 1) == cond_negated);
-
- return MAKE_THUMB_ADDR (pc);
- }
- }
- }
- else if (itstate & 0x0f)
- {
- /* We are in a conditional block. Check the condition. */
- int cond = itstate >> 4;
-
- if (! condition_true (cond, status))
- /* Advance to the next instruction. All the 32-bit
- instructions share a common prefix. */
- return MAKE_THUMB_ADDR (pc + thumb_insn_size (inst1));
-
- /* Otherwise, handle the instruction normally. */
- }
-
- if ((inst1 & 0xff00) == 0xbd00) /* pop {rlist, pc} */
- {
- CORE_ADDR sp;
-
- /* Fetch the saved PC from the stack. It's stored above
- all of the other registers. */
- offset = bitcount (bits (inst1, 0, 7)) * INT_REGISTER_SIZE;
- sp = regcache_raw_get_unsigned (regcache, ARM_SP_REGNUM);
- nextpc = read_memory_unsigned_integer (sp + offset, 4, byte_order);
- }
- else if ((inst1 & 0xf000) == 0xd000) /* conditional branch */
- {
- unsigned long cond = bits (inst1, 8, 11);
- if (cond == 0x0f) /* 0x0f = SWI */
- {
- struct gdbarch_tdep *tdep;
- tdep = gdbarch_tdep (gdbarch);
-
- if (tdep->syscall_next_pc != NULL)
- nextpc = tdep->syscall_next_pc (regcache);
-
- }
- else if (cond != 0x0f && condition_true (cond, status))
- nextpc = pc_val + (sbits (inst1, 0, 7) << 1);
- }
- else if ((inst1 & 0xf800) == 0xe000) /* unconditional branch */
- {
- nextpc = pc_val + (sbits (inst1, 0, 10) << 1);
- }
- else if (thumb_insn_size (inst1) == 4) /* 32-bit instruction */
- {
- unsigned short inst2;
- inst2 = read_memory_unsigned_integer (pc + 2, 2, byte_order_for_code);
-
- /* Default to the next instruction. */
- nextpc = pc + 4;
- nextpc = MAKE_THUMB_ADDR (nextpc);
-
- if ((inst1 & 0xf800) == 0xf000 && (inst2 & 0x8000) == 0x8000)
- {
- /* Branches and miscellaneous control instructions. */
-
- if ((inst2 & 0x1000) != 0 || (inst2 & 0xd001) == 0xc000)
- {
- /* B, BL, BLX. */
- int j1, j2, imm1, imm2;
-
- imm1 = sbits (inst1, 0, 10);
- imm2 = bits (inst2, 0, 10);
- j1 = bit (inst2, 13);
- j2 = bit (inst2, 11);
-
- offset = ((imm1 << 12) + (imm2 << 1));
- offset ^= ((!j2) << 22) | ((!j1) << 23);
-
- nextpc = pc_val + offset;
- /* For BLX make sure to clear the low bits. */
- if (bit (inst2, 12) == 0)
- nextpc = nextpc & 0xfffffffc;
- }
- else if (inst1 == 0xf3de && (inst2 & 0xff00) == 0x3f00)
- {
- /* SUBS PC, LR, #imm8. */
- nextpc = regcache_raw_get_unsigned (regcache, ARM_LR_REGNUM);
- nextpc -= inst2 & 0x00ff;
- }
- else if ((inst2 & 0xd000) == 0x8000 && (inst1 & 0x0380) != 0x0380)
- {
- /* Conditional branch. */
- if (condition_true (bits (inst1, 6, 9), status))
- {
- int sign, j1, j2, imm1, imm2;
-
- sign = sbits (inst1, 10, 10);
- imm1 = bits (inst1, 0, 5);
- imm2 = bits (inst2, 0, 10);
- j1 = bit (inst2, 13);
- j2 = bit (inst2, 11);
-
- offset = (sign << 20) + (j2 << 19) + (j1 << 18);
- offset += (imm1 << 12) + (imm2 << 1);
-
- nextpc = pc_val + offset;
- }
- }
- }
- else if ((inst1 & 0xfe50) == 0xe810)
- {
- /* Load multiple or RFE. */
- int rn, offset, load_pc = 1;
-
- rn = bits (inst1, 0, 3);
- if (bit (inst1, 7) && !bit (inst1, 8))
- {
- /* LDMIA or POP */
- if (!bit (inst2, 15))
- load_pc = 0;
- offset = bitcount (inst2) * 4 - 4;
- }
- else if (!bit (inst1, 7) && bit (inst1, 8))
- {
- /* LDMDB */
- if (!bit (inst2, 15))
- load_pc = 0;
- offset = -4;
- }
- else if (bit (inst1, 7) && bit (inst1, 8))
- {
- /* RFEIA */
- offset = 0;
- }
- else if (!bit (inst1, 7) && !bit (inst1, 8))
- {
- /* RFEDB */
- offset = -8;
- }
- else
- load_pc = 0;
-
- if (load_pc)
- {
- CORE_ADDR addr = regcache_raw_get_unsigned (regcache, rn);
- nextpc = read_memory_unsigned_integer (addr + offset, 4,
- byte_order);
- }
- }
- else if ((inst1 & 0xffef) == 0xea4f && (inst2 & 0xfff0) == 0x0f00)
- {
- /* MOV PC or MOVS PC. */
- nextpc = regcache_raw_get_unsigned (regcache, bits (inst2, 0, 3));
- nextpc = MAKE_THUMB_ADDR (nextpc);
- }
- else if ((inst1 & 0xff70) == 0xf850 && (inst2 & 0xf000) == 0xf000)
- {
- /* LDR PC. */
- CORE_ADDR base;
- int rn, load_pc = 1;
-
- rn = bits (inst1, 0, 3);
- base = regcache_raw_get_unsigned (regcache, rn);
- if (rn == ARM_PC_REGNUM)
- {
- base = (base + 4) & ~(CORE_ADDR) 0x3;
- if (bit (inst1, 7))
- base += bits (inst2, 0, 11);
- else
- base -= bits (inst2, 0, 11);
- }
- else if (bit (inst1, 7))
- base += bits (inst2, 0, 11);
- else if (bit (inst2, 11))
- {
- if (bit (inst2, 10))
- {
- if (bit (inst2, 9))
- base += bits (inst2, 0, 7);
- else
- base -= bits (inst2, 0, 7);
- }
- }
- else if ((inst2 & 0x0fc0) == 0x0000)
- {
- int shift = bits (inst2, 4, 5), rm = bits (inst2, 0, 3);
- base += regcache_raw_get_unsigned (regcache, rm) << shift;
- }
- else
- /* Reserved. */
- load_pc = 0;
-
- if (load_pc)
- nextpc = read_memory_unsigned_integer (base, 4, byte_order);
- }
- else if ((inst1 & 0xfff0) == 0xe8d0 && (inst2 & 0xfff0) == 0xf000)
- {
- /* TBB. */
- CORE_ADDR tbl_reg, table, offset, length;
-
- tbl_reg = bits (inst1, 0, 3);
- if (tbl_reg == 0x0f)
- table = pc + 4; /* Regcache copy of PC isn't right yet. */
- else
- table = regcache_raw_get_unsigned (regcache, tbl_reg);
-
- offset = regcache_raw_get_unsigned (regcache, bits (inst2, 0, 3));
- length = 2 * read_memory_unsigned_integer (table + offset, 1,
- byte_order);
- nextpc = pc_val + length;
- }
- else if ((inst1 & 0xfff0) == 0xe8d0 && (inst2 & 0xfff0) == 0xf010)
- {
- /* TBH. */
- CORE_ADDR tbl_reg, table, offset, length;
-
- tbl_reg = bits (inst1, 0, 3);
- if (tbl_reg == 0x0f)
- table = pc + 4; /* Regcache copy of PC isn't right yet. */
- else
- table = regcache_raw_get_unsigned (regcache, tbl_reg);
-
- offset = 2 * regcache_raw_get_unsigned (regcache, bits (inst2, 0, 3));
- length = 2 * read_memory_unsigned_integer (table + offset, 2,
- byte_order);
- nextpc = pc_val + length;
- }
- }
- else if ((inst1 & 0xff00) == 0x4700) /* bx REG, blx REG */
- {
- if (bits (inst1, 3, 6) == 0x0f)
- nextpc = UNMAKE_THUMB_ADDR (pc_val);
- else
- nextpc = regcache_raw_get_unsigned (regcache, bits (inst1, 3, 6));
- }
- else if ((inst1 & 0xff87) == 0x4687) /* mov pc, REG */
- {
- if (bits (inst1, 3, 6) == 0x0f)
- nextpc = pc_val;
- else
- nextpc = regcache_raw_get_unsigned (regcache, bits (inst1, 3, 6));
-
- nextpc = MAKE_THUMB_ADDR (nextpc);
- }
- else if ((inst1 & 0xf500) == 0xb100)
- {
- /* CBNZ or CBZ. */
- int imm = (bit (inst1, 9) << 6) + (bits (inst1, 3, 7) << 1);
- ULONGEST reg = regcache_raw_get_unsigned (regcache, bits (inst1, 0, 2));
-
- if (bit (inst1, 11) && reg != 0)
- nextpc = pc_val + imm;
- else if (!bit (inst1, 11) && reg == 0)
- nextpc = pc_val + imm;
- }
- return nextpc;
-}
-
-/* Get the raw next address. PC is the current program counter, in
- FRAME, which is assumed to be executing in ARM mode.
-
- The value returned has the execution state of the next instruction
- encoded in it. Use IS_THUMB_ADDR () to see whether the instruction is
- in Thumb-State, and gdbarch_addr_bits_remove () to get the plain memory
- address. */
-
-static CORE_ADDR
-arm_get_next_pc_raw (struct regcache *regcache, CORE_ADDR pc)
-{
- struct gdbarch *gdbarch = get_regcache_arch (regcache);
- enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
- enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
- unsigned long pc_val;
- unsigned long this_instr;
- unsigned long status;
- CORE_ADDR nextpc;
-
- pc_val = (unsigned long) pc;
- this_instr = read_memory_unsigned_integer (pc, 4, byte_order_for_code);
-
- status = regcache_raw_get_unsigned (regcache, ARM_PS_REGNUM);
- nextpc = (CORE_ADDR) (pc_val + 4); /* Default case */
-
- if (bits (this_instr, 28, 31) == INST_NV)
- switch (bits (this_instr, 24, 27))
- {
- case 0xa:
- case 0xb:
- {
- /* Branch with Link and change to Thumb. */
- nextpc = BranchDest (pc, this_instr);
- nextpc |= bit (this_instr, 24) << 1;
- nextpc = MAKE_THUMB_ADDR (nextpc);
- break;
- }
- case 0xc:
- case 0xd:
- case 0xe:
- /* Coprocessor register transfer. */
- if (bits (this_instr, 12, 15) == 15)
- error (_("Invalid update to pc in instruction"));
- break;
- }
- else if (condition_true (bits (this_instr, 28, 31), status))
- {
- switch (bits (this_instr, 24, 27))
- {
- case 0x0:
- case 0x1: /* data processing */
- case 0x2:
- case 0x3:
- {
- unsigned long operand1, operand2, result = 0;
- unsigned long rn;
- int c;
-
- if (bits (this_instr, 12, 15) != 15)
- break;
-
- if (bits (this_instr, 22, 25) == 0
- && bits (this_instr, 4, 7) == 9) /* multiply */
- error (_("Invalid update to pc in instruction"));
-
- /* BX <reg>, BLX <reg> */
- if (bits (this_instr, 4, 27) == 0x12fff1
- || bits (this_instr, 4, 27) == 0x12fff3)
- {
- rn = bits (this_instr, 0, 3);
- nextpc = ((rn == ARM_PC_REGNUM)
- ? (pc_val + 8)
- : regcache_raw_get_unsigned (regcache, rn));
-
- return nextpc;
- }
-
- /* Multiply into PC. */
- c = (status & FLAG_C) ? 1 : 0;
- rn = bits (this_instr, 16, 19);
- operand1 = ((rn == ARM_PC_REGNUM)
- ? (pc_val + 8)
- : regcache_raw_get_unsigned (regcache, rn));
-
- if (bit (this_instr, 25))
- {
- unsigned long immval = bits (this_instr, 0, 7);
- unsigned long rotate = 2 * bits (this_instr, 8, 11);
- operand2 = ((immval >> rotate) | (immval << (32 - rotate)))
- & 0xffffffff;
- }
- else /* operand 2 is a shifted register. */
- operand2 = shifted_reg_val (regcache, this_instr, c,
- pc_val, status);
-
- switch (bits (this_instr, 21, 24))
- {
- case 0x0: /*and */
- result = operand1 & operand2;
- break;
-
- case 0x1: /*eor */
- result = operand1 ^ operand2;
- break;
-
- case 0x2: /*sub */
- result = operand1 - operand2;
- break;
-
- case 0x3: /*rsb */
- result = operand2 - operand1;
- break;
-
- case 0x4: /*add */
- result = operand1 + operand2;
- break;
-
- case 0x5: /*adc */
- result = operand1 + operand2 + c;
- break;
-
- case 0x6: /*sbc */
- result = operand1 - operand2 + c;
- break;
-
- case 0x7: /*rsc */
- result = operand2 - operand1 + c;
- break;
-
- case 0x8:
- case 0x9:
- case 0xa:
- case 0xb: /* tst, teq, cmp, cmn */
- result = (unsigned long) nextpc;
- break;
-
- case 0xc: /*orr */
- result = operand1 | operand2;
- break;
-
- case 0xd: /*mov */
- /* Always step into a function. */
- result = operand2;
- break;
-
- case 0xe: /*bic */
- result = operand1 & ~operand2;
- break;
-
- case 0xf: /*mvn */
- result = ~operand2;
- break;
- }
-
- /* In 26-bit APCS the bottom two bits of the result are
- ignored, and we always end up in ARM state. */
- if (!arm_apcs_32)
- nextpc = arm_addr_bits_remove (gdbarch, result);
- else
- nextpc = result;
-
- break;
- }
-
- case 0x4:
- case 0x5: /* data transfer */
- case 0x6:
- case 0x7:
- if (bits (this_instr, 25, 27) == 0x3 && bit (this_instr, 4) == 1)
- {
- /* Media instructions and architecturally undefined
- instructions. */
- break;
- }
-
- if (bit (this_instr, 20))
- {
- /* load */
- if (bits (this_instr, 12, 15) == 15)
- {
- /* rd == pc */
- unsigned long rn;
- unsigned long base;
-
- if (bit (this_instr, 22))
- error (_("Invalid update to pc in instruction"));
-
- /* byte write to PC */
- rn = bits (this_instr, 16, 19);
- base = ((rn == ARM_PC_REGNUM)
- ? (pc_val + 8)
- : regcache_raw_get_unsigned (regcache, rn));
-
- if (bit (this_instr, 24))
- {
- /* pre-indexed */
- int c = (status & FLAG_C) ? 1 : 0;
- unsigned long offset =
- (bit (this_instr, 25)
- ? shifted_reg_val (regcache, this_instr, c, pc_val,
- status)
- : bits (this_instr, 0, 11));
-
- if (bit (this_instr, 23))
- base += offset;
- else
- base -= offset;
- }
- nextpc =
- (CORE_ADDR) read_memory_unsigned_integer ((CORE_ADDR) base,
- 4, byte_order);
- }
- }
- break;
-
- case 0x8:
- case 0x9: /* block transfer */
- if (bit (this_instr, 20))
- {
- /* LDM */
- if (bit (this_instr, 15))
- {
- /* loading pc */
- int offset = 0;
- unsigned long rn_val
- = regcache_raw_get_unsigned (regcache,
- bits (this_instr, 16, 19));
-
- if (bit (this_instr, 23))
- {
- /* up */
- unsigned long reglist = bits (this_instr, 0, 14);
- offset = bitcount (reglist) * 4;
- if (bit (this_instr, 24)) /* pre */
- offset += 4;
- }
- else if (bit (this_instr, 24))
- offset = -4;
-
- nextpc =
- (CORE_ADDR) read_memory_unsigned_integer ((CORE_ADDR)
- (rn_val + offset),
- 4, byte_order);
- }
- }
- break;
-
- case 0xb: /* branch & link */
- case 0xa: /* branch */
- {
- nextpc = BranchDest (pc, this_instr);
- break;
- }
-
- case 0xc:
- case 0xd:
- case 0xe: /* coproc ops */
- break;
- case 0xf: /* SWI */
- {
- struct gdbarch_tdep *tdep;
- tdep = gdbarch_tdep (gdbarch);
-
- if (tdep->syscall_next_pc != NULL)
- nextpc = tdep->syscall_next_pc (regcache);
-
- }
- break;
-
- default:
- fprintf_filtered (gdb_stderr, _("Bad bit-field extraction\n"));
- return (pc);
- }
- }
-
- return nextpc;
-}
-
-/* Determine next PC after current instruction executes. Will call either
- arm_get_next_pc_raw or thumb_get_next_pc_raw. Error out if infinite
- loop is detected. */
-
-CORE_ADDR
-arm_get_next_pc (struct regcache *regcache, CORE_ADDR pc)
-{
- CORE_ADDR nextpc;
-
- if (arm_is_thumb (regcache))
- nextpc = thumb_get_next_pc_raw (regcache, pc);
- else
- nextpc = arm_get_next_pc_raw (regcache, pc);
-
- return nextpc;
-}
-
-/* Like insert_single_step_breakpoint, but make sure we use a breakpoint
- of the appropriate mode (as encoded in the PC value), even if this
- differs from what would be expected according to the symbol tables. */
-
-void
-arm_insert_single_step_breakpoint (struct gdbarch *gdbarch,
- struct address_space *aspace,
- CORE_ADDR pc)
-{
- struct cleanup *old_chain
- = make_cleanup_restore_integer (&arm_override_mode);
-
- arm_override_mode = IS_THUMB_ADDR (pc);
- pc = gdbarch_addr_bits_remove (gdbarch, pc);
-
- insert_single_step_breakpoint (gdbarch, aspace, pc);
-
- do_cleanups (old_chain);
-}
-
-/* Checks for an atomic sequence of instructions beginning with a LDREX{,B,H,D}
- instruction and ending with a STREX{,B,H,D} instruction. If such a sequence
- is found, attempt to step through it. A breakpoint is placed at the end of
- the sequence. */
-
-static int
-thumb_deal_with_atomic_sequence_raw (struct regcache *regcache)
-{
- struct gdbarch *gdbarch = get_regcache_arch (regcache);
- struct address_space *aspace = get_regcache_aspace (regcache);
- enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
- CORE_ADDR pc = regcache_read_pc (regcache);
- CORE_ADDR breaks[2] = {-1, -1};
- CORE_ADDR loc = pc;
- unsigned short insn1, insn2;
- int insn_count;
- int index;
- int last_breakpoint = 0; /* Defaults to 0 (no breakpoints placed). */
- const int atomic_sequence_length = 16; /* Instruction sequence length. */
- ULONGEST status, itstate;
-
- /* We currently do not support atomic sequences within an IT block. */
- status = regcache_raw_get_unsigned (regcache, ARM_PS_REGNUM);
- itstate = ((status >> 8) & 0xfc) | ((status >> 25) & 0x3);
- if (itstate & 0x0f)
- return 0;
-
- /* Assume all atomic sequences start with a ldrex{,b,h,d} instruction. */
- insn1 = read_memory_unsigned_integer (loc, 2, byte_order_for_code);
- loc += 2;
- if (thumb_insn_size (insn1) != 4)
- return 0;
-
- insn2 = read_memory_unsigned_integer (loc, 2, byte_order_for_code);
- loc += 2;
- if (!((insn1 & 0xfff0) == 0xe850
- || ((insn1 & 0xfff0) == 0xe8d0 && (insn2 & 0x00c0) == 0x0040)))
- return 0;
-
- /* Assume that no atomic sequence is longer than "atomic_sequence_length"
- instructions. */
- for (insn_count = 0; insn_count < atomic_sequence_length; ++insn_count)
- {
- insn1 = read_memory_unsigned_integer (loc, 2, byte_order_for_code);
- loc += 2;
-
- if (thumb_insn_size (insn1) != 4)
- {
- /* Assume that there is at most one conditional branch in the
- atomic sequence. If a conditional branch is found, put a
- breakpoint in its destination address. */
- if ((insn1 & 0xf000) == 0xd000 && bits (insn1, 8, 11) != 0x0f)
- {
- if (last_breakpoint > 0)
- return 0; /* More than one conditional branch found,
- fallback to the standard code. */
-
- breaks[1] = loc + 2 + (sbits (insn1, 0, 7) << 1);
- last_breakpoint++;
- }
-
- /* We do not support atomic sequences that use any *other*
- instructions but conditional branches to change the PC.
- Fall back to standard code to avoid losing control of
- execution. */
- else if (thumb_instruction_changes_pc (insn1))
- return 0;
- }
- else
- {
- insn2 = read_memory_unsigned_integer (loc, 2, byte_order_for_code);
- loc += 2;
-
- /* Assume that there is at most one conditional branch in the
- atomic sequence. If a conditional branch is found, put a
- breakpoint in its destination address. */
- if ((insn1 & 0xf800) == 0xf000
- && (insn2 & 0xd000) == 0x8000
- && (insn1 & 0x0380) != 0x0380)
- {
- int sign, j1, j2, imm1, imm2;
- unsigned int offset;
-
- sign = sbits (insn1, 10, 10);
- imm1 = bits (insn1, 0, 5);
- imm2 = bits (insn2, 0, 10);
- j1 = bit (insn2, 13);
- j2 = bit (insn2, 11);
-
- offset = (sign << 20) + (j2 << 19) + (j1 << 18);
- offset += (imm1 << 12) + (imm2 << 1);
-
- if (last_breakpoint > 0)
- return 0; /* More than one conditional branch found,
- fallback to the standard code. */
-
- breaks[1] = loc + offset;
- last_breakpoint++;
- }
-
- /* We do not support atomic sequences that use any *other*
- instructions but conditional branches to change the PC.
- Fall back to standard code to avoid losing control of
- execution. */
- else if (thumb2_instruction_changes_pc (insn1, insn2))
- return 0;
-
- /* If we find a strex{,b,h,d}, we're done. */
- if ((insn1 & 0xfff0) == 0xe840
- || ((insn1 & 0xfff0) == 0xe8c0 && (insn2 & 0x00c0) == 0x0040))
- break;
- }
- }
-
- /* If we didn't find the strex{,b,h,d}, we cannot handle the sequence. */
- if (insn_count == atomic_sequence_length)
- return 0;
-
- /* Insert a breakpoint right after the end of the atomic sequence. */
- breaks[0] = loc;
-
- /* Check for duplicated breakpoints. Check also for a breakpoint
- placed (branch instruction's destination) anywhere in sequence. */
- if (last_breakpoint
- && (breaks[1] == breaks[0]
- || (breaks[1] >= pc && breaks[1] < loc)))
- last_breakpoint = 0;
-
- /* Effectively inserts the breakpoints. */
- for (index = 0; index <= last_breakpoint; index++)
- arm_insert_single_step_breakpoint (gdbarch, aspace,
- MAKE_THUMB_ADDR (breaks[index]));
-
- return 1;
-}
-
-static int
-arm_deal_with_atomic_sequence_raw (struct regcache *regcache)
-{
- struct gdbarch *gdbarch = get_regcache_arch (regcache);
- struct address_space *aspace = get_regcache_aspace (regcache);
- enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
- CORE_ADDR pc = regcache_read_pc (regcache);
- CORE_ADDR breaks[2] = {-1, -1};
- CORE_ADDR loc = pc;
- unsigned int insn;
- int insn_count;
- int index;
- int last_breakpoint = 0; /* Defaults to 0 (no breakpoints placed). */
- const int atomic_sequence_length = 16; /* Instruction sequence length. */
-
- /* Assume all atomic sequences start with a ldrex{,b,h,d} instruction.
- Note that we do not currently support conditionally executed atomic
- instructions. */
- insn = read_memory_unsigned_integer (loc, 4, byte_order_for_code);
- loc += 4;
- if ((insn & 0xff9000f0) != 0xe1900090)
- return 0;
-
- /* Assume that no atomic sequence is longer than "atomic_sequence_length"
- instructions. */
- for (insn_count = 0; insn_count < atomic_sequence_length; ++insn_count)
- {
- insn = read_memory_unsigned_integer (loc, 4, byte_order_for_code);
- loc += 4;
-
- /* Assume that there is at most one conditional branch in the atomic
- sequence. If a conditional branch is found, put a breakpoint in
- its destination address. */
- if (bits (insn, 24, 27) == 0xa)
- {
- if (last_breakpoint > 0)
- return 0; /* More than one conditional branch found, fallback
- to the standard single-step code. */
-
- breaks[1] = BranchDest (loc - 4, insn);
- last_breakpoint++;
- }
-
- /* We do not support atomic sequences that use any *other* instructions
- but conditional branches to change the PC. Fall back to standard
- code to avoid losing control of execution. */
- else if (arm_instruction_changes_pc (insn))
- return 0;
-
- /* If we find a strex{,b,h,d}, we're done. */
- if ((insn & 0xff9000f0) == 0xe1800090)
- break;
- }
-
- /* If we didn't find the strex{,b,h,d}, we cannot handle the sequence. */
- if (insn_count == atomic_sequence_length)
- return 0;
-
- /* Insert a breakpoint right after the end of the atomic sequence. */
- breaks[0] = loc;
-
- /* Check for duplicated breakpoints. Check also for a breakpoint
- placed (branch instruction's destination) anywhere in sequence. */
- if (last_breakpoint
- && (breaks[1] == breaks[0]
- || (breaks[1] >= pc && breaks[1] < loc)))
- last_breakpoint = 0;
-
- /* Effectively inserts the breakpoints. */
- for (index = 0; index <= last_breakpoint; index++)
- arm_insert_single_step_breakpoint (gdbarch, aspace, breaks[index]);
-
- return 1;
-}
-
-int
-arm_deal_with_atomic_sequence (struct regcache *regcache)
-{
- if (arm_is_thumb (regcache))
- return thumb_deal_with_atomic_sequence_raw (regcache);
- else
- return arm_deal_with_atomic_sequence_raw (regcache);
-}
-
-/* single_step() is called just before we want to resume the inferior,
- if we want to single-step it but there is no hardware or kernel
- single-step support. We find the target of the coming instruction
- and breakpoint it. */
-
-int
-arm_software_single_step (struct frame_info *frame)
-{
- struct regcache *regcache = get_current_regcache ();
- struct gdbarch *gdbarch = get_regcache_arch (regcache);
- struct address_space *aspace = get_regcache_aspace (regcache);
- CORE_ADDR next_pc;
-
- if (arm_deal_with_atomic_sequence (regcache))
- return 1;
-
- next_pc = arm_get_next_pc (regcache, regcache_read_pc (regcache));
- arm_insert_single_step_breakpoint (gdbarch, aspace, next_pc);
-
- return 1;
-}
-
-/* Given BUF, which is OLD_LEN bytes ending at ENDADDR, expand
- the buffer to be NEW_LEN bytes ending at ENDADDR. Return
- NULL if an error occurs. BUF is freed. */
-
-static gdb_byte *
-extend_buffer_earlier (gdb_byte *buf, CORE_ADDR endaddr,
- int old_len, int new_len)
-{
- gdb_byte *new_buf;
- int bytes_to_read = new_len - old_len;