Intel Embedded Intel486

EMBEDDED Intel486™ PROCESSOR HARDWARE REFERENCE MANUAL
4-60
Figure 4-41. Snoop to the Line that is Being Replaced
If the replacement write-back cycle is burst and there is a snoop hit to the same line as the line
that is being replaced, the on-going replacement cycle runs to completion. HITM# is asserted un-
til the line is written back and the snoop write-back is not initiated. In this case, the replacement
write-back is converted to the snoop write-back, and HITM# is asserted and de-asserted without
a specific ADS# to initiate the write-back cycle.
If there is a snoop hit to a different line from the line being replaced, and if the replacement write-
back cycle is burst, the replacement cycle goes to completion. Only then is the snoop write-back
cycle initiated.
If the replacement write-back cycle is a non-burst cycle, and if there is a snoop hit to the same
line as the line being replaced, it fractures the replacement write-back cycle after RDY# is assert-
ed for the current non-burst transfer. The snoop write-back cycle is reordered in front of the frac-
242202-153
CLK
AHOLD
EADS#
INV
HITM#
A31–A4
A3–A2
ADS#
1234567891011
W/R#
To Processor
BRDY#
CACHE#
BLAST#
0 8 C
Replace
048C
Replace
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