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| author | Maciej W. Rozycki <macro@codesourcery.com> | 2014-10-05 21:50:47 +0100 |
|---|---|---|
| committer | Maciej W. Rozycki <macro@codesourcery.com> | 2014-10-05 21:50:47 +0100 |
| commit | ae79065284d6250c27377b5ca1dce54da9b1d4ba (patch) | |
| tree | df4f921408584d2897ed09efac7ffa0c990357d3 /gdb/mips-tdep.c | |
| parent | 24340e81faf9d23de6456293954de73785e53d3f (diff) | |
| download | gdb-ae79065284d6250c27377b5ca1dce54da9b1d4ba.zip gdb-ae79065284d6250c27377b5ca1dce54da9b1d4ba.tar.gz gdb-ae79065284d6250c27377b5ca1dce54da9b1d4ba.tar.bz2 | |
MIPS: Correct MUSTBE32 interpretation in delay slot handling
This change addresses `micromips_instruction_has_delay_slot' and
`mips16_instruction_has_delay_slot' that both incorrectly interpret
their MUSTBE32 argument. Their callers assume that when the flag is
clear these functions will return 1 when any non-compact jump or branch
instruction is present at ADDR, while in fact they will only return 1
for 16-bit such instructions only. This change makes the implementation
match the expectations.
* mips-tdep.c (micromips_instruction_has_delay_slot): When
!mustbe32 also return 1 for 32-bit instructions.
(mips16_instruction_has_delay_slot): Likewise. Add an
explanatory comment.
Diffstat (limited to 'gdb/mips-tdep.c')
| -rw-r--r-- | gdb/mips-tdep.c | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/gdb/mips-tdep.c b/gdb/mips-tdep.c index 188580f..7e07673 100644 --- a/gdb/mips-tdep.c +++ b/gdb/mips-tdep.c @@ -7035,17 +7035,18 @@ micromips_instruction_has_delay_slot (struct gdbarch *gdbarch, if (status) return 0; - if (!mustbe32) /* 16-bit instructions. */ - return (micromips_op (insn) == 0x11 + /* 16-bit instructions. */ + if ((micromips_op (insn) == 0x11 /* POOL16C: bits 010001 */ - && (b5s5_op (insn) == 0xc + && (b5s5_op (insn) == 0xc /* JR16: bits 010001 01100 */ - || (b5s5_op (insn) & 0x1e) == 0xe)) + || (b5s5_op (insn) & 0x1e) == 0xe)) /* JALR16, JALRS16: bits 010001 0111x */ - || (micromips_op (insn) & 0x37) == 0x23 + || (micromips_op (insn) & 0x37) == 0x23 /* BEQZ16, BNEZ16: bits 10x011 */ - || micromips_op (insn) == 0x33; + || micromips_op (insn) == 0x33) /* B16: bits 110011 */ + return !mustbe32; /* 32-bit instructions. */ if (micromips_op (insn) == 0x0) @@ -7091,6 +7092,10 @@ micromips_instruction_has_delay_slot (struct gdbarch *gdbarch, /* JALX: bits 111100 */ } +/* Return non-zero if a MIPS16 instruction at ADDR has a branch delay + slot (i.e. it is a non-compact jump instruction). The instruction + must be 32-bit if MUSTBE32 is set or can be any instruction otherwise. */ + static int mips16_instruction_has_delay_slot (struct gdbarch *gdbarch, CORE_ADDR addr, int mustbe32) @@ -7102,8 +7107,8 @@ mips16_instruction_has_delay_slot (struct gdbarch *gdbarch, CORE_ADDR addr, if (status) return 0; - if (!mustbe32) - return (inst & 0xf89f) == 0xe800; /* JR/JALR (16-bit instruction) */ + if ((inst & 0xf89f) == 0xe800) /* JR/JALR (16-bit instruction) */ + return !mustbe32; return (inst & 0xf800) == 0x1800; /* JAL/JALX (32-bit instruction) */ } |