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)
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