D-22 Compaq AlphaServer ES40 Service Guide
Table D–8 I_CTL Register Fields (Continued)
Name Extent Type Description
SPE[2:0] [5:3] RW,0 Super Page Mode Enable.
Identical to the SPE bits in the Mbox
M_CTL SPE[2:0].
IC_EN[1:0] [2:1] RW,3
Icache Set Enable.
At least one set must be enabled. The entire
cache may be enabled by setting both bits.
Zero, one, or two Icache sets can be enabled.
This bit does not clear the Icache, but only
disables fills to the affected set.
SPCE [0] RW,0 System Performance Counting Enable.
Enables performance counting for the entire
system if individual counters (PCTR0 or
PCTR1) are enabled by setting PCT0_EN or
PCT1_EN, respectively.
Performance counting for individual
processes can be enabled by setting
PCTX[PPCE].