! "cas" only works on sparcv9 chips, and requies a compiler
! that is targeting sparcv9. It will fail on a compiler
! targeting sparcv8, and of course will not be understood
- ! by a sparcv8 CPU. If this fails on existing Solaris
- ! systems, we need to use a !defined(__sparcv9) test
- ! to fall back to the old "ldstub" call for sparcv8 compiles.
- ! gcc continues to use "ldstub" because there is no indication
- ! which sparc version it is targeting.
+ ! by a sparcv8 CPU. gcc continues to use "ldstub" because
+ ! there is no indication which sparc version it is targeting.
!
! There actually is a trick for embedding "cas" for a compiler
! that is targeting sparcv8:
!
! http://cvs.opensolaris.org/source/xref/on/usr/src/lib/libc/sparc/threads/sparc.il
- !
- ! This might work for sparc8:
- ! ldstub [%o0],%o1 ! moves only a byte
+#ifdef __sparcv9
cas [%o0],%o2,%o1
+#else
+ ldstub [%o0],%o1
+#endif
mov %o1,%o0
retl
nop