[PATCH v2] gdb/hppa-tdep.c: Fix logical working flow typo issue

[Chen Gang <gang.chen.5i5j@gmail.com>]

inst_saves_gr() wants to recognize 'st??' instruction, according to the
code we know it include 'stb' (for store byte), 'stw(m)' (for store
word), and 'std' (for store double word).

They should be in the same format, and have neighbour numbers:
especially, 'stw(m)' need be in the middle of 'stb' and 'std'.

 - for ((inst >> 26) != 0x3):

   stb: 0x18, or 0x19,
   stw: 0x1a, stwm: 0x1b,
   std: 0x1c.

 - else ((inst >> 26) == 0x3), need check:

   stb: 0x08, or 0x09,
   stw: 0x0a,
   std: 0x0b.

For clearer reason, not combine the logical comparation code together.

2014-10-22  Chen Gang  <gang.chen.5i5j@gmail.com>

        * hppa-tdep.c (inst_saves_gr): Fix logical working flow typo
        issue.

Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
---
 gdb/hppa-tdep.c | 33 ++++++++++++++++++++++++---------
 1 file changed, 24 insertions(+), 9 deletions(-)

diff --git a/gdb/hppa-tdep.c b/gdb/hppa-tdep.c
index 627f31a..4363ab4 100644
--- a/gdb/hppa-tdep.c
+++ b/gdb/hppa-tdep.c
@@ -1376,16 +1376,35 @@ is_branch (unsigned long inst)
 }
 
 /* Return the register number for a GR which is saved by INST or
-   zero it INST does not save a GR.  */
+   zero it INST does not save a GR.
+
+   inst_saves_gr() wants to recognize 'st??' instruction, it include 'stb' (for
+   store byte), 'stw(m)' (for store word), and 'std' (for store double word).
+
+   They should be in the same format, and have neighbour numbers: especially,
+   'stw(m)' need be in the middle of 'stb' and 'std'.
+
+    - for ((inst >> 26) != 0x3):
+
+      stb: 0x18, or 0x19,
+      stw: 0x1a, stwm: 0x1b,
+      std: 0x1c.
+
+    - else ((inst >> 26) == 0x3), need check :
+
+      stb: 0x08, or 0x09,
+      stw: 0x0a,
+      std: 0x0b.
+*/
 
 static int
 inst_saves_gr (unsigned long inst)
 {
-  /* Does it look like a stw?  */
+  /* Does it look like a stw(m)?  */
   if ((inst >> 26) == 0x1a || (inst >> 26) == 0x1b
       || (inst >> 26) == 0x1f
-      || ((inst >> 26) == 0x1f
-	  && ((inst >> 6) == 0xa)))
+      || ((inst >> 26) == 0x3
+	  && ((inst >> 6) & 0xf) == 0xa))
     return hppa_extract_5R_store (inst);
 
   /* Does it look like a std?  */
@@ -1394,16 +1413,12 @@ inst_saves_gr (unsigned long inst)
 	  && ((inst >> 6) & 0xf) == 0xb))
     return hppa_extract_5R_store (inst);
 
-  /* Does it look like a stwm?  GCC & HPC may use this in prologues.  */
-  if ((inst >> 26) == 0x1b)
-    return hppa_extract_5R_store (inst);
-
   /* Does it look like sth or stb?  HPC versions 9.0 and later use these
      too.  */
   if ((inst >> 26) == 0x19 || (inst >> 26) == 0x18
       || ((inst >> 26) == 0x3
 	  && (((inst >> 6) & 0xf) == 0x8
-	      || (inst >> 6) & 0xf) == 0x9))
+	      || ((inst >> 6) & 0xf) == 0x9)))
     return hppa_extract_5R_store (inst);
 
   return 0;
-- 
1.9.3