diff options
Diffstat (limited to 'libgo/runtime/runtime.c')
| -rw-r--r-- | libgo/runtime/runtime.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/libgo/runtime/runtime.c b/libgo/runtime/runtime.c index abc1affcf74..496e77b75c5 100644 --- a/libgo/runtime/runtime.c +++ b/libgo/runtime/runtime.c @@ -195,12 +195,12 @@ runtime_cputicks(void) asm("rdtsc" : "=a" (low), "=d" (high)); return (int64)(((uint64)high << 32) | (uint64)low); #elif defined (__s390__) || defined (__s390x__) - uint64 clock; -#ifdef S390_HAVE_STCKF - asm("stckf\t%0" : "=Q" (clock) : : ); -#else - clock = 0; -#endif + uint64 clock = 0; + /* stckf may not write the return variable in case of a clock error, so make + it read-write to prevent that the initialisation is optimised out. + Note: Targets below z9-109 will crash when executing store clock fast, i.e. + we don't support Go for machines older than that. */ + asm volatile(".insn s,0xb27c0000,%0" /* stckf */ : "+Q" (clock) : : "cc" ); return (int64)clock; #else // FIXME: implement for other processors. |