Compaq EV68A specifications Index-7

2–16

Integer execution unit. See Ebox

Integer issue queue, 2–6pipelined, 2–15

Internal processor registers, 5–1

accessing, 6–7explicitly written, 6–8implicitly written, 6–9ordering access, 6–9paired fetch order, 6–9scoreboard bits for, 6–8

INTERRUPT interrupt, 6–14

INVAL_TO_DIRTY Cbox CSR, 4–23

programming, 4–23

INVAL_TO_DIRTY_ENABLE Cbox CSR, 5–39 ,

7–12

InvalToDirty, 21264/EV68A command, 4–12 ,4–22 ,4–40

system probes, with, 4–41InvalToDirtyVic, 21264/EV68A command, 4–22 ,

4–40

IOWB. See I/O write buffer

IPRs. See Internal processor registers

IQ. See Integer issue queue

IRQ_H signal pins, 3–5

Istream, 2–5

Istream memory references

translation to external references, 4–5ISTREAM_BC_DBL error status in C_STAT, 5–42ISTREAM_BC_ERR error status in C_STAT, 5–42

ISTREAM_MEM_DBL error status in C_STAT, 5–42

ISTREAM_MEM_ERR error status in C_STAT, 5–42

ISUM interrupt summary register, 5–11at power-on reset state, 7–15

ITB, 2–5

ITB fill, 6–16

ITB miss, pipeline abort delay with, 2–16

ITB_IA invalidate-all register, 5–7at power-on reset state, 7–15

ITB_IAP invalidate-all (ASM=0) register, 5–7at power-on reset state, 7–15

ITB_IS invalidate single register, 5–7

at power-on reset state, 7–15ITB_MISS fault, 6–14

ITB_PTE array write register, 5–6at power-on reset state, 7–14

ITB_TAG array write register, 5–6at power-on reset state, 7–14

IVA_FORM instruction virtual address format register, 5–9

at power-on reset state, 7–15

J

JITTER_CMD Cbox CSR, defined, 5–38JMP misprediction, in PALcode, D–15

JSR misprediction

in PALcode, D–15

pipeline abort delay with, 2–16JSR_COR misprediction, in PALcode, D–15Junction temperature, 9–1

L

Late-write non-bursting SSRAM pin assignments, E–2

LDBU instruction, normal prefetch with, 2–23

LDF instruction, normal prefetch with, 2–23LDG instruction, normal prefetch with, 2–23

LDQ instruction, prefetch with evict next, 2–24LDS instruction, prefetch with modify intent, 2–23

LDT instruction, normal prefetch with, 2–23LDWU instruction, normal prefetch with, 2–23

LDx_L instructions

in-order processing for, 4–15locking mechanism for, 4–14

Load hit speculation, 2–24

Load instructions

ECC with, 8–3

I/O reference ordering, 2–31Mbox order traps, 2–31memory reference ordering, 2–30translation to external interface, 4–5

Load queue, described, 2–13Load-load order trap, 2–31

Local predictor, 2–4

Lock mechanism, 4–14

Logic symbol, the 21264/EV68A, 3–2

LQ. See Load queue

M

M_CTL Mbox control register, 5–29at power-on reset state, 7–16

MAF. See Miss address file

MB instruction processing, 2–33

21264/EV68A Hardware Reference Manual Index–7