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* rs6000-tdep.c (ppc_displaced_step_fixup): New function.

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(deal_with_atomic_sequence): Update BC masks.
	(rs6000_gdbarch_init): Init displaced stepping infra-structure.
	Define BRANCH_MASK, B_INSN, BC_INSN, BXL_INSN, BP_MASK and BP_INSN.
This commit is contained in:
Luis Machado 2008-06-30 14:11:48 +00:00
parent 395f2fc22d
commit f74c6cad4e
2 changed files with 118 additions and 3 deletions
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7
gdb/ChangeLog
View File

@ -1,3 +1,10 @@
2008-06-30 Luis Machado <luisgpm@br.ibm.com>
* rs6000-tdep.c (ppc_displaced_step_fixup): New function.
(deal_with_atomic_sequence): Update BC masks.
(rs6000_gdbarch_init): Init displaced stepping infra-structure.
Define BRANCH_MASK, B_INSN, BC_INSN, BXL_INSN, BP_MASK and BP_INSN.
2008-06-30 Daniel Jacobowitz <dan@codesourcery.com>
* cris-tdep.c (crisv32_single_step_through_delay): Get this frame's

114
gdb/rs6000-tdep.c
View File

@ -841,6 +841,105 @@ rs6000_breakpoint_from_pc (struct gdbarch *gdbarch, CORE_ADDR *bp_addr,
return little_breakpoint;
}
/* Instruction masks for displaced stepping. */
#define BRANCH_MASK 0xfc000000
#define BP_MASK 0xFC0007FE
#define B_INSN 0x48000000
#define BC_INSN 0x40000000
#define BXL_INSN 0x4c000000
#define BP_INSN 0x7C000008
/* Fix up the state of registers and memory after having single-stepped
a displaced instruction. */
void
ppc_displaced_step_fixup (struct gdbarch *gdbarch,
struct displaced_step_closure *closure,
CORE_ADDR from, CORE_ADDR to,
struct regcache *regs)
{
/* Since we use simple_displaced_step_copy_insn, our closure is a
copy of the instruction. */
ULONGEST insn = extract_unsigned_integer ((gdb_byte *) closure,
PPC_INSN_SIZE);
ULONGEST opcode = 0;
/* Offset for non PC-relative instructions. */
LONGEST offset = PPC_INSN_SIZE;
opcode = insn & BRANCH_MASK;
if (debug_displaced)
fprintf_unfiltered (gdb_stdlog,
"displaced: (ppc) fixup (0x%s, 0x%s)\n",
paddr_nz (from), paddr_nz (to));
/* Handle PC-relative branch instructions. */
if (opcode == B_INSN || opcode == BC_INSN || opcode == BXL_INSN)
{
CORE_ADDR current_pc;
/* Read the current PC value after the instruction has been executed
in a displaced location. Calculate the offset to be applied to the
original PC value before the displaced stepping. */
regcache_cooked_read_unsigned (regs, gdbarch_pc_regnum (gdbarch),
&current_pc);
offset = current_pc - to;
if (opcode != BXL_INSN)
{
/* Check for AA bit indicating whether this is an absolute
addressing or PC-relative (1: absolute, 0: relative). */
if (!(insn & 0x2))
{
/* PC-relative addressing is being used in the branch. */
if (debug_displaced)
fprintf_unfiltered
(gdb_stdlog,
"displaced: (ppc) branch instruction: 0x%s\n"
"displaced: (ppc) adjusted PC from 0x%s to 0x%s\n",
paddr_nz (insn), paddr_nz (current_pc),
paddr_nz (from + offset));
regcache_cooked_write_unsigned (regs, gdbarch_pc_regnum (gdbarch),
from + offset);
}
}
else
{
/* If we're here, it means we have a branch to LR or CTR. If the
branch was taken, the offset is probably greater than 4 (the next
instruction), so it's safe to assume that an offset of 4 means we
did not take the branch. */
if (offset == PPC_INSN_SIZE)
regcache_cooked_write_unsigned (regs, gdbarch_pc_regnum (gdbarch),
from + PPC_INSN_SIZE);
}
/* Check for LK bit indicating whether we should set the link
register to point to the next instruction
(1: Set, 0: Don't set). */
if (insn & 0x1)
{
/* Link register needs to be set to the next instruction's PC. */
regcache_cooked_write_unsigned (regs,
gdbarch_tdep (gdbarch)->ppc_lr_regnum,
from + PPC_INSN_SIZE);
if (debug_displaced)
fprintf_unfiltered (gdb_stdlog,
"displaced: (ppc) adjusted LR to 0x%s\n",
paddr_nz (from + PPC_INSN_SIZE));
}
}
/* Check for breakpoints in the inferior. If we've found one, place the PC
right at the breakpoint instruction. */
else if ((insn & BP_MASK) == BP_INSN)
regcache_cooked_write_unsigned (regs, gdbarch_pc_regnum (gdbarch), from);
else
/* Handle any other instructions that do not fit in the categories above. */
regcache_cooked_write_unsigned (regs, gdbarch_pc_regnum (gdbarch),
from + offset);
}
/* Instruction masks used during single-stepping of atomic sequences. */
#define LWARX_MASK 0xfc0007fe
@ -849,8 +948,6 @@ rs6000_breakpoint_from_pc (struct gdbarch *gdbarch, CORE_ADDR *bp_addr,
#define STWCX_MASK 0xfc0007ff
#define STWCX_INSTRUCTION 0x7c00012d
#define STDCX_INSTRUCTION 0x7c0001ad
#define BC_MASK 0xfc000000
#define BC_INSTRUCTION 0x40000000
/* Checks for an atomic sequence of instructions beginning with a LWARX/LDARX
instruction and ending with a STWCX/STDCX instruction. If such a sequence
@ -887,7 +984,7 @@ ppc_deal_with_atomic_sequence (struct frame_info *frame)
/* 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 ((insn & BC_MASK) == BC_INSTRUCTION)
if ((insn & BRANCH_MASK) == BC_INSN)
{
int immediate = ((insn & ~3) << 16) >> 16;
int absolute = ((insn >> 1) & 1);
@ -3214,6 +3311,17 @@ rs6000_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
/* Put the _Decimal128 pseudo-registers after the SPE registers. */
tdep->ppc_dl0_regnum += 32;
/* Setup displaced stepping. */
set_gdbarch_displaced_step_copy_insn (gdbarch,
simple_displaced_step_copy_insn);
set_gdbarch_displaced_step_fixup (gdbarch, ppc_displaced_step_fixup);
set_gdbarch_displaced_step_free_closure (gdbarch,
simple_displaced_step_free_closure);
set_gdbarch_displaced_step_location (gdbarch,
displaced_step_at_entry_point);
set_gdbarch_max_insn_length (gdbarch, PPC_INSN_SIZE);
return gdbarch;
}