NEC uPD72257, Preliminary User'S Manual

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8.8 Performance Counters
The Drawing Engine features two independent 32-bit performance counter
register DRWPERFCOUNTk (k = 1, 2) to count the number of occurrences of a
certain event.
The events to count can be set up independently for each performance counter
register via the performance counter control register
DRWPERFTRIGGER.PERFTRIGGER2 for DRWPERFCOUNT2 respectively
DRWPERFTRIGGER.PERFTRIGGER1 for DRWPERFCOUNT1.
The performance counter trigger event can be chosen from below list:
Table 8-2 Performance counter trigger events
DRWPERFTRIGGER.
PERFTRIGGERk
Event
0 disable performance counter
1 Drawing Engine active cycles
2 framebuffer read access
3 framebuffer write access
4 texture read access
5 invisible pixels (enumerated but selected with alpha 0%)
6 invisible pixels while internal FIFO is empty (lost cycles)
7 display list reader active cycles
8 framebuffer read hits
9 framebuffer read misses
10 framebuffer write hits
11 framebuffer write misses
12 texture read hits
13 texture read misses
31 every clock cycle (for use as timer)
Chapter 8 Drawing Engine
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Preliminary User's Manual S19203EE1V3UM00