Changeset 316 for trunk

Timestamp:

Feb 15, 2012, 8:20:00 PM (14 years ago)

Author:

dmik

Message:

Narrow down the operand constraint for XCHGB instruction.

This is necessary to prevent GCC from selecting DIL (the low byte of EDI)
as the operand to XCHGB since DIL is not available in 32-bit CPU mode
(GAS would complain).

See ​http://gcc.gnu.org/bugzilla/show_bug.cgl?id=10153 for details of why
GCC can't do it on its own.

File:

• trunk/openjdk/hotspot/src/os_cpu/linux_x86/vm/orderAccess_linux_x86.inline.hpp (modified) (2 diffs)

trunk/openjdk/hotspot/src/os_cpu/linux_x86/vm/orderAccess_linux_x86.inline.hpp

@@ -94 +94 @@
 inline void     OrderAccess::store_fence(jbyte*  p, jbyte  v) {
   __asm__ volatile (  "xchgb (%2),%0"
-                    : "=r" (v)
+                    : "=q" (v)
                     : "0" (v), "r" (p)
                     : "memory");
@@ -156 +156 @@
 inline void     OrderAccess::release_store_fence(volatile jbyte*  p, jbyte  v) {
   __asm__ volatile (  "xchgb (%2),%0"
-                    : "=r" (v)
+                    : "=q" (v)
                     : "0" (v), "r" (p)
                     : "memory");