Powerpc VLE operand extract

[Alan Modra]

Fixes a couple of occurrences of 64-bit unclean code.

	* ppc-opc.c (extract_vlesi): Properly sign extend.
	(extract_vlensi): Likewise.  Comment reason for setting invalid.

Index: opcodes/ppc-opc.c
===================================================================
RCS file: /cvs/src/src/opcodes/ppc-opc.c,v
retrieving revision 1.158
diff -u -p -r1.158 ppc-opc.c
--- opcodes/ppc-opc.c	11 Jan 2013 02:25:36 -0000	1.158
+++ opcodes/ppc-opc.c	9 May 2013 03:50:10 -0000
@@ -2022,11 +2022,8 @@ extract_vlesi (unsigned long insn,
              ppc_cpu_t dialect ATTRIBUTE_UNUSED,
              int *invalid ATTRIBUTE_UNUSED)
 {
-  /* RWRW Because I don't know how to make int be 16 and long be 32 */
-  /* I can't rely on casting an int to long to get sign extension. */
   long value = ((insn >> 10) & 0xf800) | (insn & 0x7ff);
-  if (value & 0x8000)
-    value |= 0xffff0000;
+  value = (value ^ 0x8000) - 0x8000;
   return value;
 }
 
@@ -2045,8 +2042,8 @@ extract_vlensi (unsigned long insn,
              int *invalid ATTRIBUTE_UNUSED)
 {
   long value = ((insn >> 10) & 0xf800) | (insn & 0x7ff);
-  if (value & 0x8000)
-    value |= 0xffff0000;
+  value = (value ^ 0x8000) - 0x8000;
+  /* Don't use for disassembly.  */
   *invalid = 1;
   return -value;
 }

-- 
Alan Modra
Australia Development Lab, IBM