IBM PowerPC 750GX User Manual page 73

Bits Field Name
6 DISCOUNT
7:8 RTCSELECT
9 INTONBITTRANS
10:15 THRESHOLD
16 PMC1INTCONTROL
17 PMCINTCONTROL
18 PMCTRIGGER
19:25 PMC1SELECT
26:31 PMC2SELECT
User Monitor Mode Control Register 0 (UMMCR0)
The contents of MMCR0 are reflected to UMMCR0, which can be read by user-level software. MMCR0 can
be accessed with mfspr using SPR 936.
gx_02.fm.(1.2)
March 27, 2006
IBM PowerPC 750GX and 750GL RISC Microprocessor
Disables counting of PMCn when a performance-monitor interrupt is signaled (that is,
((PMCnINTCONTROL = '1') & (PMCn[0] = '1') & (ENINT = '1')) or when an enabled time-
base transition occurs with ((INTONBITTRANS = '1') & (ENINT = '1')).
0 Signaling a performance-monitor interrupt does not affect the counting status of
PMCn.
1 Signaling a performance-monitor interrupt prevents changing of the PMC1
counter. The PMCn counter does not change if PMC2COUNTCTL = '0'.
Because a time-base signal could have occurred along with an enabled counter overflow
condition, software should always reset INTONBITTRANS to zero, if the value in INTON-
BITTRANS was a one.
64-bit time base, bit selection enable.
00 Pick bit 63 to count.
01 Pick bit 55 to count.
10 Pick bit 51 to count.
11 Pick bit 47 to count.
Cause interrupt signaling when the bit identified in RTCSELECT transitions from off to on.
0 Do not allow interrupt signal if chosen bit transitions.
1 Signal interrupt if chosen bit transitions.
Software is responsible for setting and clearing INTONBITTRANS.
Threshold value. The 750GX supports all six bits, allowing threshold values from 0–63.
The intent of the THRESHOLD support is to characterize L1 data-cache misses.
Enables interrupt signaling due to PMC1 counter overflow.
0 Disable PMC1 interrupt signaling due to PMC1 counter overflow.
1 Enable PMC1 interrupt signaling due to PMC1 counter overflow.
Enable interrupt signaling due to any PMC2–PMC4 counter overflow. Overrides the set-
ting of DISCOUNT.
0 Disable PMC2–PMC4 interrupt signaling due to PMC2–PMC4 counter overflow.
1 Enable PMC2–PMC4 interrupt signaling due to PMC2–PMC4 counter overflow.
Can be used to trigger counting of PMC2–PMC4 after PMC1 has overflowed or after a
performance-monitor interrupt is signaled.
0 Enable PMC2–PMC4 counting.
1 Disable PMC2–PMC4 counting until either PMC1[0] = 1 or a performance-moni-
tor interrupt is signaled.
PMC1 input selector; 128 events selectable.
PMC2 input selector; 64 events selectable.
Description
User's Manual
Programming Model
Page 73 of 377