[binutils-gdb] ppc: use "trap" ("tw, 31, 0, 0") as breakpoint instruction

[Jan Vrany <jv@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=44f3c3c212f9b568a6b3cff0444b6750e3d8680f

commit 44f3c3c212f9b568a6b3cff0444b6750e3d8680f
Author: Jan Vrany <jan.vrany@labware.com>
Date:   Wed Dec 8 10:46:49 2021 +0000

    ppc: use "trap" ("tw, 31, 0, 0") as breakpoint instruction
    
    Power ISA 3.0 B spec [1], sections 3.3.11 "Fixed-Point Trap Instructions"
    and section C.6 "Trap Mnemonics" specify "tw, 31, 0, 0" (encoded as
    0x7fe00008) as canonical unconditional trap instruction.
    
    This commit changes the breakpoint instruction used by GDB from
    "tw 12, r2, r2" to unconditional "trap".
    
    [1]: https://openpowerfoundation.org/?resource_lib=power-isa-version-3-0

Diff:
---
 gdb/rs6000-tdep.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/gdb/rs6000-tdep.c b/gdb/rs6000-tdep.c
index 87a494e0bb8..43880fa4426 100644
--- a/gdb/rs6000-tdep.c
+++ b/gdb/rs6000-tdep.c
@@ -824,8 +824,8 @@ rs6000_fetch_pointer_argument (struct frame_info *frame, int argi,
 
 /* Sequence of bytes for breakpoint instruction.  */
 
-constexpr gdb_byte big_breakpoint[] = { 0x7d, 0x82, 0x10, 0x08 };
-constexpr gdb_byte little_breakpoint[] = { 0x08, 0x10, 0x82, 0x7d };
+constexpr gdb_byte big_breakpoint[] = { 0x7f, 0xe0, 0x00, 0x08 };
+constexpr gdb_byte little_breakpoint[] = { 0x08, 0x00, 0xe0, 0x7f };
 
 typedef BP_MANIPULATION_ENDIAN (little_breakpoint, big_breakpoint)
   rs6000_breakpoint;