xref: /plan9-contrib/sys/src/cmd/qi/timing (revision 7d9195a7bc3493d7fc3e1166ef25bf446be66b1a)
1*7d9195a7SDavid du Colombierunits
2*7d9195a7SDavid du Colombier	branch
3*7d9195a7SDavid du Colombier	integer
4*7d9195a7SDavid du Colombier	floating point
5*7d9195a7SDavid du Colombieron 601
6*7d9195a7SDavid du Colombier	issue at most one per unit per cycle
7*7d9195a7SDavid du Colombier	eight entry instruction queue
8*7d9195a7SDavid du Colombier	can fill queue from cache in one clock cycle
9*7d9195a7SDavid du Colombier		loads from requested address to end of cache block
10*7d9195a7SDavid du Colombierpipeline
11*7d9195a7SDavid du Colombier	prefetch
12*7d9195a7SDavid du Colombier		includes ins. cache access cycles
13*7d9195a7SDavid du Colombier	decode
14*7d9195a7SDavid du Colombier	execute
15*7d9195a7SDavid du Colombier	writeback
16*7d9195a7SDavid du Colombier
17*7d9195a7SDavid du Colombierfpu
18*7d9195a7SDavid du Colombier	IQ[3210] → fpu buffer/decode [≥1 cycle] → execute 1 → execute 2 → writeback
19*7d9195a7SDavid du Colombieriu
20*7d9195a7SDavid du Colombier	IQ0/decode → buffer [if exec busy] → execute [hold for dependency] →
21*7d9195a7SDavid du Colombier					circulate in load/store
22*7d9195a7SDavid du Colombier					writeback
23*7d9195a7SDavid du Colombierbpu
24*7d9195a7SDavid du Colombier	IQ[3210] → decode/execute → writeback
25*7d9195a7SDavid du Colombier
26*7d9195a7SDavid du Colombiernotes
27*7d9195a7SDavid du Colombier	address calculation must complete before stored value enters write buffer
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