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Waivers and Implementation-Dependent Functionality E–25
E.2.3.3 OpenVMS Alpha and DIGITAL UNIX Functions and Arguments
The functions execute only on a single (the current running) processor and are described in
Table E–20.
The OpenVMS Alpha MTPR_PERFMON instruction is called with a function code in R16, a
function-specific argument in R17, and any output is returned in R0.
The DIGITAL UNIX wrperfmon instruction is called with a function code in a0, a function-
specific argument in a1, and any output is returned in v0.
3–2 SL1 PCTR1 input selector. If SL0 value is 0:
1–0 Reserved
Table E–20: OpenVMS Alpha and DIGITAL UNIX Performance Monitoring
Functions
Function Register Usage Comments
Enable performance monitoring
DIGITAL UNIX
Input: a0 = 1 Function code value
a1 = arg Argument from Table E–21
OpenVMS Alpha
Input: R16 = 1 Function code value
R17 = arg Argument from Table E–21
Table E–19: Bit Summary of PCTR_CTL Register for Windows NT Alpha
Bits Name Meaning
Bit value Meaning
0000 Counter 1 counts cycles.
0001 Counter 1 counts retired conditional
branches.
0010 Counter 1 counts retired branch mispre-
dicts.
0011 Counter 1 counts retired DTB single
misses * 2.
0100 Counter 1 counts retired DTB double
double misses.
0101 Counter 1 counts retired ITB misses.
0110 Counter 1 counts retired unaligned traps.
0111 Counter 1 counts replay traps.