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authorMaciej W. Rozycki <macro@linux-mips.org>2011-12-08 18:55:48 +0000
committerMaciej W. Rozycki <macro@linux-mips.org>2011-12-08 18:55:48 +0000
commit4c2051c6c94ae19b0f2ded3a2244ecbd4bfb11e4 (patch)
treef5edf292dddd17c8f7e8316c325a7abde310a580 /gdb
parentff011ed785d6a9e25c853f8c69bb5d62bc080fec (diff)
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* mips-tdep.c (extended_offset): Correct calculation.
(unpack_mips16): Correct bitfield positions used for extraction of the immediate argument; fix sign-extension of same. (extended_mips16_next_pc): Correct B instruction's offset calculation. Correct register decoding of the BEQZ and BNEZ as well as jump-register instructions. Handle compact jumps.
Diffstat (limited to 'gdb')
-rw-r--r--gdb/ChangeLog9
-rw-r--r--gdb/mips-tdep.c64
2 files changed, 26 insertions, 47 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 5b1de64..2fb4758 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,12 @@
+2011-12-08 Maciej W. Rozycki <macro@codesourcery.com>
+
+ * mips-tdep.c (extended_offset): Correct calculation.
+ (unpack_mips16): Correct bitfield positions used for extraction
+ of the immediate argument; fix sign-extension of same.
+ (extended_mips16_next_pc): Correct B instruction's offset
+ calculation. Correct register decoding of the BEQZ and BNEZ
+ as well as jump-register instructions. Handle compact jumps.
+
2011-12-08 Tom Tromey <tromey@redhat.com>
* objfiles.h (struct objfile): Remove obsolete comment.
diff --git a/gdb/mips-tdep.c b/gdb/mips-tdep.c
index 64b7629..0f9a4ab 100644
--- a/gdb/mips-tdep.c
+++ b/gdb/mips-tdep.c
@@ -1319,9 +1319,9 @@ extended_offset (unsigned int extension)
{
CORE_ADDR value;
- value = (extension >> 21) & 0x3f; /* Extract 15:11. */
+ value = (extension >> 16) & 0x1f; /* Extract 15:11. */
value = value << 6;
- value |= (extension >> 16) & 0x1f; /* Extract 10:5. */
+ value |= (extension >> 21) & 0x3f; /* Extract 10:5. */
value = value << 5;
value |= extension & 0x1f; /* Extract 4:0. */
@@ -1361,14 +1361,13 @@ unpack_mips16 (struct gdbarch *gdbarch, CORE_ADDR pc,
CORE_ADDR value;
if (extension)
{
- value = extended_offset (extension);
- value = value << 11; /* rom for the original value */
- value |= inst & 0x7ff; /* eleven bits from instruction */
+ value = extended_offset ((extension << 16) | inst);
+ value = (value ^ 0x8000) - 0x8000; /* Sign-extend. */
}
else
{
value = inst & 0x7ff;
- /* FIXME : Consider sign extension. */
+ value = (value ^ 0x400) - 0x400; /* Sign-extend. */
}
offset = value;
regx = -1;
@@ -1383,28 +1382,16 @@ unpack_mips16 (struct gdbarch *gdbarch, CORE_ADDR pc,
CORE_ADDR value;
if (extension)
{
- value = extended_offset (extension);
- value = value << 8; /* from the original instruction */
- value |= inst & 0xff; /* eleven bits from instruction */
- regx = (extension >> 8) & 0x07; /* or i8 funct */
- if (value & 0x4000) /* Test the sign bit, bit 26. */
- {
- value &= ~0x3fff; /* Remove the sign bit. */
- value = -value;
- }
+ value = extended_offset ((extension << 16) | inst);
+ value = (value ^ 0x8000) - 0x8000; /* Sign-extend. */
}
else
{
- value = inst & 0xff; /* 8 bits */
- regx = (inst >> 8) & 0x07; /* or i8 funct */
- /* FIXME: Do sign extension, this format needs it. */
- if (value & 0x80) /* THIS CONFUSES ME. */
- {
- value &= 0xef; /* Remove the sign bit. */
- value = -value;
- }
+ value = inst & 0xff; /* 8 bits */
+ value = (value ^ 0x80) - 0x80; /* Sign-extend. */
}
offset = value;
+ regx = (inst >> 8) & 0x07; /* i8 funct */
regy = -1;
break;
}
@@ -1450,13 +1437,7 @@ extended_mips16_next_pc (struct frame_info *frame, CORE_ADDR pc,
CORE_ADDR offset;
struct upk_mips16 upk;
unpack_mips16 (gdbarch, pc, extension, insn, itype, &upk);
- offset = upk.offset;
- if (offset & 0x800)
- {
- offset &= 0xeff;
- offset = -offset;
- }
- pc += (offset << 1) + 2;
+ pc += (upk.offset << 1) + 2;
break;
}
case 3: /* JAL , JALX - Watch out, these are 32 bit
@@ -1476,7 +1457,7 @@ extended_mips16_next_pc (struct frame_info *frame, CORE_ADDR pc,
struct upk_mips16 upk;
int reg;
unpack_mips16 (gdbarch, pc, extension, insn, ritype, &upk);
- reg = get_frame_register_signed (frame, upk.regx);
+ reg = get_frame_register_signed (frame, mips16_to_32_reg[upk.regx]);
if (reg == 0)
pc += (upk.offset << 1) + 2;
else
@@ -1488,7 +1469,7 @@ extended_mips16_next_pc (struct frame_info *frame, CORE_ADDR pc,
struct upk_mips16 upk;
int reg;
unpack_mips16 (gdbarch, pc, extension, insn, ritype, &upk);
- reg = get_frame_register_signed (frame, upk.regx);
+ reg = get_frame_register_signed (frame, mips16_to_32_reg[upk.regx]);
if (reg != 0)
pc += (upk.offset << 1) + 2;
else
@@ -1520,21 +1501,10 @@ extended_mips16_next_pc (struct frame_info *frame, CORE_ADDR pc,
int reg;
upk.regx = (insn >> 8) & 0x07;
upk.regy = (insn >> 5) & 0x07;
- switch (upk.regy)
- {
- case 0:
- reg = upk.regx;
- break;
- case 1:
- reg = 31;
- break; /* Function return instruction. */
- case 2:
- reg = upk.regx;
- break;
- default:
- reg = 31;
- break; /* BOGUS Guess */
- }
+ if ((upk.regy & 1) == 0)
+ reg = mips16_to_32_reg[upk.regx];
+ else
+ reg = 31; /* Function return instruction. */
pc = get_frame_register_signed (frame, reg);
}
else