Cray CRAY-1 - Page 160

Execution timE
For 176:
Instruction issue except for 034-037, 100-137, 176, 177: 1 CP
Instruction issue for above exceptions: (VL) + 4 CPs
Vi ready 14 CPs if (VL) ~ 5
Vi ready (VL) + 9 CPs if (VL) > 5
For 177:
Instructi on issue except for 034-037, 100-137, 176, 177: 1 CP
Instruction issue for above exceptions: (VL) + 5 CPs
Vj ready 5 CPs if (VL) ~ 5
V j ready
(VL) CPs if (VL·) > c=
Special cases
T~e increment, (A
o
), = 1 if k = 0
Chain slot issue is 9 CPs if full speed for 176, blocked for 177
Block I/O references
Block 034 - 037, 100 - 137, 176, 177
(Ak) determines speed control. There are 16 memory banks;
successive addresses are located in successive banks. References
to the
samp bank can be made every 4 CPs or more. Incrementing
(Ak) by 16
t
places successive
memory references in the same bank,
so a word is transferred every 4 CPs. If (Ak) is incremented
by 8,tt every other reference is to the same bank and words can
transfer every 2 CPs. With any address incrementing that allows
4
CPs before addressing the same bank, the words can transfer
each CPo
Memory reference out of limits will allow 6 CPs + 2 parcels to issue.
For 176, a parity error will allow a minimum of 16 CPs + 2 parcels
to issue
and a maximum of (VL) + 15 CPs + 2 parcels to issue.
t 8 places for 8-bank
memory option. Refer to section 5.
tt 4 places for 8-bank memory option. Refer to section 5.
2240004
4-74
E
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