David CARLIER <devne...@gmail.com> writes:
> On 20 November 2017 at 18:49, Tom Lane <t...@sss.pgh.pa.us> wrote:
>> OTOH, we still have M68K
>> and VAX stanzas in that file, so I suppose it's silly to complain
>> about 88K. A bigger issue is that I wonder whether that code has
>> ever been tested: it does not look to me like the __asm__ call is
>> even syntactically correct. There should be colons in it.
> True :-) corrected. Thanks.
I still dare to doubt whether you've tested this, because AFAICS
the operand numbering is wrong. The "r"(lock) operand is number 3
given these operand declarations, not number 2.
Our practice elsewhere in s_lock.h is to use a "+" constraint instead of
duplicated operands, and I think that's better style because it avoids any
question of whether you're supposed to count duplicated operands.
Also, per the comment near s_lock.h line 115, it's important to specify
"+m"(*lock) as an output operand so that gcc knows that the asm
clobbers *lock. It's possible that "memory" makes that redundant,
but I'd just as soon maintain consistency with the well-tested
other parts of the file.
So I propose the attached patch instead. It would still be a good idea
to actually test this ;-)
regards, tom lane
diff --git a/src/backend/storage/lmgr/s_lock.c b/src/backend/storage/lmgr/s_lock.c
index 40d8156..247d7b8 100644
--- a/src/backend/storage/lmgr/s_lock.c
+++ b/src/backend/storage/lmgr/s_lock.c
@@ -251,7 +251,7 @@ static void
tas_dummy()
{
__asm__ __volatile__(
-#if defined(__NetBSD__) && defined(__ELF__)
+#if (defined(__NetBSD__) || defined(__OpenBSD__)) && defined(__ELF__)
/* no underscore for label and % for registers */
"\
.global tas \n\
@@ -276,7 +276,7 @@ _tas: \n\
_success: \n\
moveq #0,d0 \n\
rts \n"
-#endif /* __NetBSD__ && __ELF__ */
+#endif /* (__NetBSD__ || __OpenBSD__) && __ELF__ */
);
}
#endif /* __m68k__ && !__linux__ */
diff --git a/src/include/storage/s_lock.h b/src/include/storage/s_lock.h
index 99e1098..35088db 100644
--- a/src/include/storage/s_lock.h
+++ b/src/include/storage/s_lock.h
@@ -543,6 +543,30 @@ tas(volatile slock_t *lock)
#endif /* (__mc68000__ || __m68k__) && __linux__ */
+/* Motorola 88k */
+#if defined(__m88k__)
+#define HAS_TEST_AND_SET
+
+typedef unsigned int slock_t;
+
+#define TAS(lock) tas(lock)
+
+static __inline__ int
+tas(volatile slock_t *lock)
+{
+ register slock_t _res = 1;
+
+ __asm__ __volatile__(
+ " xmem %0, %2, %%r0 \n"
+: "+r"(_res), "+m"(*lock)
+: "r"(lock)
+: "memory");
+ return (int) _res;
+}
+
+#endif /* __m88k__ */
+
+
/*
* VAXen -- even multiprocessor ones
* (thanks to Tom Ivar Helbekkmo)
