]>
Commit | Line | Data |
---|---|---|
d9dc34cd TMQMF |
1 | @node Platform, Contributors, Maintenance, Top |
2 | @c %MENU% Describe all platform-specific facilities provided | |
3 | @appendix Platform-specific facilities | |
4 | ||
5 | @Theglibc{} can provide machine-specific functionality. | |
6 | ||
7 | @menu | |
8 | * PowerPC:: Facilities Specific to the PowerPC Architecture | |
9 | @end menu | |
10 | ||
11 | @node PowerPC | |
12 | @appendixsec PowerPC-specific Facilities | |
13 | ||
14 | Facilities specific to PowerPC that are not specific to a particular | |
15 | operating system are declared in @file{sys/platform/ppc.h}. | |
16 | ||
17 | @deftypefun {uint64_t} __ppc_get_timebase (void) | |
e2dfb7f4 | 18 | @safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}} |
d9dc34cd TMQMF |
19 | Read the current value of the Time Base Register. |
20 | ||
21 | The @dfn{Time Base Register} is a 64-bit register that stores a monotonically | |
22 | incremented value updated at a system-dependent frequency that may be | |
23 | different from the processor frequency. More information is available in | |
24 | @cite{Power ISA 2.06b - Book II - Section 5.2}. | |
25 | ||
26 | @code{__ppc_get_timebase} uses the processor's time base facility directly | |
27 | without requiring assistance from the operating system, so it is very | |
28 | efficient. | |
29 | @end deftypefun | |
8ad11b9a TMQMF |
30 | |
31 | @deftypefun {uint64_t} __ppc_get_timebase_freq (void) | |
e2dfb7f4 AO |
32 | @safety{@prelim{}@mtunsafe{@mtuinit{}}@asunsafe{@asucorrupt{:init}}@acunsafe{@acucorrupt{:init}}} |
33 | @c __ppc_get_timebase_freq=__get_timebase_freq @mtuinit @acsfd | |
34 | @c __get_clockfreq @mtuinit @asucorrupt:init @acucorrupt:init @acsfd | |
35 | @c the initialization of the static timebase_freq is not exactly | |
36 | @c safe, because hp_timing_t cannot be atomically set up. | |
37 | @c syscall:get_tbfreq ok | |
38 | @c open dup @acsfd | |
39 | @c read dup ok | |
40 | @c memcpy dup ok | |
41 | @c memmem dup ok | |
42 | @c close dup @acsfd | |
8ad11b9a TMQMF |
43 | Read the current frequency at which the Time Base Register is updated. |
44 | ||
45 | This frequency is not related to the processor clock or the bus clock. | |
46 | It is also possible that this frequency is not constant. More information is | |
47 | available in @cite{Power ISA 2.06b - Book II - Section 5.2}. | |
48 | @end deftypefun | |
9323d39b EM |
49 | |
50 | The following functions provide hints about the usage of resources that are | |
51 | shared with other processors. They can be used, for example, if a program | |
52 | waiting on a lock intends to divert the shared resources to be used by other | |
53 | processors. More information is available in @cite{Power ISA 2.06b - Book II - | |
54 | Section 3.2}. | |
55 | ||
56 | @deftypefun {void} __ppc_yield (void) | |
e2dfb7f4 | 57 | @safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}} |
9323d39b EM |
58 | Provide a hint that performance will probably be improved if shared resources |
59 | dedicated to the executing processor are released for use by other processors. | |
60 | @end deftypefun | |
61 | ||
62 | @deftypefun {void} __ppc_mdoio (void) | |
e2dfb7f4 | 63 | @safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}} |
9323d39b EM |
64 | Provide a hint that performance will probably be improved if shared resources |
65 | dedicated to the executing processor are released until all outstanding storage | |
66 | accesses to caching-inhibited storage have been completed. | |
67 | @end deftypefun | |
68 | ||
69 | @deftypefun {void} __ppc_mdoom (void) | |
e2dfb7f4 | 70 | @safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}} |
9323d39b EM |
71 | Provide a hint that performance will probably be improved if shared resources |
72 | dedicated to the executing processor are released until all outstanding storage | |
73 | accesses to cacheable storage for which the data is not in the cache have been | |
74 | completed. | |
2b66ef5d | 75 | @end deftypefun |
d116b7c4 AZ |
76 | |
77 | @deftypefun {void} __ppc_set_ppr_med (void) | |
e2dfb7f4 | 78 | @safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}} |
d116b7c4 AZ |
79 | Set the Program Priority Register to medium value (default). |
80 | ||
81 | The @dfn{Program Priority Register} (PPR) is a 64-bit register that controls | |
82 | the program's priority. By adjusting the PPR value the programmer may | |
83 | improve system throughput by causing the system resources to be used | |
84 | more efficiently, especially in contention situations. | |
85 | The three unprivileged states available are covered by the functions | |
86 | @code{__ppc_set_ppr_med} (medium -- default), @code{__ppc_set_ppc_low} (low) | |
87 | and @code{__ppc_set_ppc_med_low} (medium low). More information | |
88 | available in @cite{Power ISA 2.06b - Book II - Section 3.1}. | |
89 | @end deftypefun | |
90 | ||
91 | @deftypefun {void} __ppc_set_ppr_low (void) | |
e2dfb7f4 | 92 | @safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}} |
d116b7c4 AZ |
93 | Set the Program Priority Register to low value. |
94 | @end deftypefun | |
95 | ||
96 | @deftypefun {void} __ppc_set_ppr_med_low (void) | |
e2dfb7f4 | 97 | @safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}} |
d116b7c4 | 98 | Set the Program Priority Register to medium low value. |
9323d39b | 99 | @end deftypefun |
1747fcda GG |
100 | |
101 | Power ISA 2.07 extends the priorities that can be set to the Program Priority | |
102 | Register (PPR). The following functions implement the new priority levels: | |
103 | very low and medium high. | |
104 | ||
105 | @deftypefun {void} __ppc_set_ppr_very_low (void) | |
106 | @safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}} | |
107 | Set the Program Priority Register to very low value. | |
108 | @end deftypefun | |
109 | ||
110 | @deftypefun {void} __ppc_set_ppr_med_high (void) | |
111 | @safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}} | |
112 | Set the Program Priority Register to medium high value. The medium high | |
113 | priority is privileged and may only be set during certain time intervals by | |
114 | problem-state programs. If the program priority is medium high when the time | |
115 | interval expires or if an attempt is made to set the priority to medium high | |
116 | when it is not allowed, the priority is set to medium. | |
117 | @end deftypefun |