svn commit: r205363 - head/sys/mips/sibyte

[Neel Natu]

Author: neel
Date: Sat Mar 20 05:21:14 2010
New Revision: 205363
URL: http://svn.freebsd.org/changeset/base/205363

Log:
  Make sure that the registers 'v0' and 'v1' are properly sign-extended
  when sb_load64() returns.
  
  Some 32-bit arithmetic operations (e.g. subu) have unpredicatable results
  when operating on 64-bit registers that are not properly sign-extended.

Modified:
  head/sys/mips/sibyte/sb_asm.S

Modified: head/sys/mips/sibyte/sb_asm.S
==============================================================================
--- head/sys/mips/sibyte/sb_asm.S	Sat Mar 20 05:11:56 2010	(r205362)
+++ head/sys/mips/sibyte/sb_asm.S	Sat Mar 20 05:21:14 2010	(r205363)
@@ -53,14 +53,14 @@ LEAF(sb_load64)
 	move	v0, v1
 #if _BYTE_ORDER == _BIG_ENDIAN
 	dsll32	v1, v1, 0
-	dsrl32	v1, v1, 0	/* v1 = lower_uint32(result) */
+	dsra32	v1, v1, 0	/* v1 = lower_uint32(result) */
 	jr	ra
-	dsrl32	v0, v0, 0	/* v0 = upper_uint32(result) */
+	dsra32	v0, v0, 0	/* v0 = upper_uint32(result) */
 #else
 	dsll32	v0, v0, 0
-	dsrl32	v0, v0, 0	/* v0 = lower_uint32(result) */
+	dsra32	v0, v0, 0	/* v0 = lower_uint32(result) */
 	jr	ra
-	dsrl32	v1, v1, 0	/* v1 = upper_uint32(result) */
+	dsra32	v1, v1, 0	/* v1 = upper_uint32(result) */
 #endif
 END(sb_load64)