[PATCH] [binutils][arm] Fix disassembly of conditional VDUPs

[Fredrik Strupe]

VDUP (neon) instructions can be conditional, but this is not taken into
account in the current master. This commit fixes that by i) fixing the
VDUP instruction masks and ii) adding logic for disassembling
conditional neon instructions.

Before patch:
$ objdump -b binary -m arm -D vdups.bin
...
00000000 <.data>:
    0:   0e800b10        vdup.32 d0, r0
    4:   1e800b10                ; <UNDEFINED> instruction: 0x1e800b10
    8:   2e800b10        vdup.32 d0, r0
    c:   3e800b10                ; <UNDEFINED> instruction: 0x3e800b10
   10:   4e800b10        vdup.32 d0, r0
   14:   5e800b10                ; <UNDEFINED> instruction: 0x5e800b10
   18:   6e800b10        vdup.32 d0, r0
   1c:   7e800b10                ; <UNDEFINED> instruction: 0x7e800b10
   20:   8e800b10        vdup.32 d0, r0
   24:   9e800b10                ; <UNDEFINED> instruction: 0x9e800b10
   28:   ae800b10        vdup.32 d0, r0
   2c:   be800b10                ; <UNDEFINED> instruction: 0xbe800b10
   30:   ce800b10        vdup.32 d0, r0
   34:   de800b10                ; <UNDEFINED> instruction: 0xde800b10
   38:   ee800b10        vdup.32 d0, r0

After patch:

00000000 <.data>:
    0:   0e800b10        vdupeq.32       d0, r0
    4:   1e800b10        vdupne.32       d0, r0
    8:   2e800b10        vdupcs.32       d0, r0
    c:   3e800b10        vdupcc.32       d0, r0
   10:   4e800b10        vdupmi.32       d0, r0
   14:   5e800b10        vduppl.32       d0, r0
   18:   6e800b10        vdupvs.32       d0, r0
   1c:   7e800b10        vdupvc.32       d0, r0
   20:   8e800b10        vduphi.32       d0, r0
   24:   9e800b10        vdupls.32       d0, r0
   28:   ae800b10        vdupge.32       d0, r0
   2c:   be800b10        vduplt.32       d0, r0
   30:   ce800b10        vdupgt.32       d0, r0
   34:   de800b10        vduple.32       d0, r0
   38:   ee800b10        vdup.32 d0, r0

opcodes/ChangeLog:
2020-03-08  Fredrik Strupe  <fredrik@strupe.net>

     * arm-dis.c (neon_opcodes): Fix VDUP instruction masks.
     (print_insn_neon): Support disassembly of conditional
instructions.
---
  opcodes/arm-dis.c | 46 ++++++++++++++++++++++++++++++++++++----------
  1 file changed, 36 insertions(+), 10 deletions(-)

diff --git a/opcodes/arm-dis.c b/opcodes/arm-dis.c
index b926b65d6a..709443fcf5 100644
--- a/opcodes/arm-dis.c
+++ b/opcodes/arm-dis.c
@@ -1494,17 +1494,17 @@ static const struct opcode32 neon_opcodes[] =

    /* Data transfer between ARM and NEON registers.  */
    {ARM_FEATURE_COPROC (FPU_NEON_EXT_V1),
-    0x0e800b10, 0x1ff00f70, "vdup%c.32\t%16-19,7D, %12-15r"},
+    0x0e800b10, 0x0ff00f70, "vdup%c.32\t%16-19,7D, %12-15r"},
    {ARM_FEATURE_COPROC (FPU_NEON_EXT_V1),
-    0x0e800b30, 0x1ff00f70, "vdup%c.16\t%16-19,7D, %12-15r"},
+    0x0e800b30, 0x0ff00f70, "vdup%c.16\t%16-19,7D, %12-15r"},
    {ARM_FEATURE_COPROC (FPU_NEON_EXT_V1),
-    0x0ea00b10, 0x1ff00f70, "vdup%c.32\t%16-19,7Q, %12-15r"},
+    0x0ea00b10, 0x0ff00f70, "vdup%c.32\t%16-19,7Q, %12-15r"},
    {ARM_FEATURE_COPROC (FPU_NEON_EXT_V1),
-    0x0ea00b30, 0x1ff00f70, "vdup%c.16\t%16-19,7Q, %12-15r"},
+    0x0ea00b30, 0x0ff00f70, "vdup%c.16\t%16-19,7Q, %12-15r"},
    {ARM_FEATURE_COPROC (FPU_NEON_EXT_V1),
-    0x0ec00b10, 0x1ff00f70, "vdup%c.8\t%16-19,7D, %12-15r"},
+    0x0ec00b10, 0x0ff00f70, "vdup%c.8\t%16-19,7D, %12-15r"},
    {ARM_FEATURE_COPROC (FPU_NEON_EXT_V1),
-    0x0ee00b10, 0x1ff00f70, "vdup%c.8\t%16-19,7Q, %12-15r"},
+    0x0ee00b10, 0x0ff00f70, "vdup%c.8\t%16-19,7Q, %12-15r"},

    /* Move data element to all lanes.  */
    {ARM_FEATURE_COPROC (FPU_NEON_EXT_V1),
@@ -9038,12 +9038,39 @@ print_insn_neon (struct disassemble_info *info, 
long given, bfd_boolean thumb)

    for (insn = neon_opcodes; insn->assembler; insn++)
      {
-      if ((given & insn->mask) == insn->value)
+      unsigned long cond_mask = insn->mask;
+      unsigned long cond_value = insn->value;
+      int cond;
+
+      if (thumb)
+        {
+          cond_mask |= 0xf0000000;
+          cond_value |= 0xe0000000;
+          if (ifthen_state)
+            cond = IFTHEN_COND;
+          else
+            cond = COND_UNCOND;
+        }
+      else
+        {
+          if ((given & 0xf0000000) == 0xf0000000)
+            {
+              cond_mask |= 0xf0000000;
+              cond = COND_UNCOND;
+            }
+          else
+            {
+              cond = (given >> 28) & 0xf;
+              if (cond == 0xe)
+                cond = COND_UNCOND;
+            }
+        }
+
+      if ((given & cond_mask) == cond_value)
      {
        signed long value_in_comment = 0;
        bfd_boolean is_unpredictable = FALSE;
        const char *c;
-
        for (c = insn->assembler; *c; c++)
          {
            if (*c == '%')
@@ -9060,8 +9087,7 @@ print_insn_neon (struct disassemble_info *info, 
long given, bfd_boolean thumb)

                /* Fall through.  */
              case 'c':
-              if (thumb && ifthen_state)
-            func (stream, "%s", arm_conditional[IFTHEN_COND]);
+              func (stream, "%s", arm_conditional[cond]);
                break;

              case 'A':
-- 
2.20.1