+2013-05-24 Adhemerval Zanella <azanella@linux.vnet.ibm.com>
+
+ * manual/platform.texi: Add PowerPC PPR function set documentation.
+ * sysdeps/powerpc/sys/platform/ppc.h: Add PowerPC PPR set function
+ implementation.
+
2013-05-24 Carlos O'Donell <carlos@redhat.com>
* math/libm-test.inc (MAX_EXP): Define.
dedicated to the executing processor are released until all outstanding storage
accesses to cacheable storage for which the data is not in the cache have been
completed.
+
+@deftypefun {void} __ppc_set_ppr_med (void)
+Set the Program Priority Register to medium value (default).
+
+The @dfn{Program Priority Register} (PPR) is a 64-bit register that controls
+the program's priority. By adjusting the PPR value the programmer may
+improve system throughput by causing the system resources to be used
+more efficiently, especially in contention situations.
+The three unprivileged states available are covered by the functions
+@code{__ppc_set_ppr_med} (medium -- default), @code{__ppc_set_ppc_low} (low)
+and @code{__ppc_set_ppc_med_low} (medium low). More information
+available in @cite{Power ISA 2.06b - Book II - Section 3.1}.
+@end deftypefun
+
+@deftypefun {void} __ppc_set_ppr_low (void)
+Set the Program Priority Register to low value.
+@end deftypefun
+
+@deftypefun {void} __ppc_set_ppr_med_low (void)
+Set the Program Priority Register to medium low value.
@end deftypefun
__asm__ volatile ("or 30,30,30");
}
+
+/* ISA 2.05 and beyond support the Program Priority Register (PPR) to adjust
+ thread priorities based on lock acquisition, wait and release. The ISA
+ defines the use of form 'or Rx,Rx,Rx' as the way to modify the PRI field.
+ The unprivileged priorities are:
+ Rx = 1 (low)
+ Rx = 2 (medium)
+ Rx = 6 (medium-low/normal)
+ The 'or' instruction form is a nop in previous hardware, so it is safe to
+ use unguarded. The default value is 'medium'.
+ */
+
+static inline void
+__ppc_set_ppr_med (void)
+{
+ __asm__ volatile ("or 2,2,2");
+}
+
+static inline void
+__ppc_set_ppr_med_low (void)
+{
+ __asm__ volatile ("or 6,6,6");
+}
+
+static inline void
+__ppc_set_ppr_low (void)
+{
+ __asm__ volatile ("or 1,1,1");
+}
+
#endif /* sys/platform/ppc.h */