Cleanup some ancient Ultrix / Alpha code in main() that is intended to

modify how unaligned memory accesses are dealt with. Document that this
is really what is going on, and merge the NOFIXADE and NOPRINTADE code
paths.

diff --git a/src/backend/main/main.c b/src/backend/main/main.c
index df9c776b602b89719d02b1bbe97655726f38195a..bcab85cbc57e4b29a0afdcb761256835bde9012e 100644 (file)
--- a/src/backend/main/main.c
+++ b/src/backend/main/main.c
@@ -13,7 +13,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/main/main.c,v 1.89 2004/08/29 05:06:43 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/main/main.c,v 1.90 2004/09/24 06:29:07 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -71,18 +71,23 @@ main(int argc, char *argv[])
 
 #if defined(__alpha)                   /* no __alpha__ ? */
 #ifdef NOFIXADE
-       int                     buffer[] = {SSIN_UACPROC, UAC_SIGBUS};
-#endif   /* NOFIXADE */
-#ifdef NOPRINTADE
-       int                     buffer[] = {SSIN_UACPROC, UAC_NOPRINT};
-#endif   /* NOPRINTADE */
+       int                     buffer[] = {SSIN_UACPROC, UAC_SIGBUS | UAC_NOPRINT};
+#endif
 #endif   /* __alpha */
 
 #ifdef WIN32
        char       *env_locale;
 #endif
 
-#if defined(NOFIXADE) || defined(NOPRINTADE)
+       /*
+        * On some platforms, unaligned memory accesses result in a kernel
+        * trap; the default kernel behavior is to emulate the memory
+        * access, but this results in a significant performance
+        * penalty. We ought to fix PG not to make such unaligned memory
+        * accesses, so this code disables the kernel emulation: unaligned
+        * accesses will result in SIGBUS instead.
+        */
+#ifdef NOFIXADE
 
 #if defined(ultrix4)
        syscall(SYS_sysmips, MIPS_FIXADE, 0, NULL, NULL, NULL);
@@ -94,7 +99,7 @@ main(int argc, char *argv[])
                write_stderr("%s: setsysinfo failed: %s\n",
                                         argv[0], strerror(errno));
 #endif
-#endif   /* NOFIXADE || NOPRINTADE */
+#endif   /* NOFIXADE */
 
 #if defined(WIN32)
        {