Query/feature bits are commonly tested via MSB bit numbers on
s390. Let's add test bit functions, so we don't need to copy code to
test query bits.
Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
---
lib/s390x/asm/bitops.h | 16 ++++++++++++++++
lib/s390x/asm/facility.h | 3 ++-
2 files changed, 18 insertions(+), 1 deletion(-)
diff --git a/lib/s390x/asm/bitops.h b/lib/s390x/asm/bitops.h
index e7cdda9..a272dd7 100644
--- a/lib/s390x/asm/bitops.h
+++ b/lib/s390x/asm/bitops.h
@@ -7,4 +7,20 @@
#define BITS_PER_LONG 64
+static inline bool test_bit(unsigned long nr,
+ const volatile unsigned long *ptr)
+{
+ const volatile unsigned char *addr;
+
+ addr = ((const volatile unsigned char *)ptr);
+ addr += (nr ^ (BITS_PER_LONG - 8)) >> 3;
+ return (*addr >> (nr & 7)) & 1;
+}
+
+static inline bool test_bit_inv(unsigned long nr,
+ const volatile unsigned long *ptr)
+{
+ return test_bit(nr ^ (BITS_PER_LONG - 1), ptr);
+}
+
#endif
diff --git a/lib/s390x/asm/facility.h b/lib/s390x/asm/facility.h
index def2705..5593c2d 100644
--- a/lib/s390x/asm/facility.h
+++ b/lib/s390x/asm/facility.h
@@ -13,13 +13,14 @@
#include <libcflat.h>
#include <asm/facility.h>
#include <asm/arch_def.h>
+#include <bitops.h>
#define NB_STFL_DOUBLEWORDS 32
extern uint64_t stfl_doublewords[];
static inline bool test_facility(int nr)
{
- return stfl_doublewords[nr / 64] & (0x8000000000000000UL >> (nr % 64));
+ return test_bit_inv(nr, stfl_doublewords);
}
static inline void stfl(void)
--
2.25.1
