Translation Buffer (TB) Fill Flows

Table 6–8 PALcode Exception Entry Locations (Continued)

Entry Name

Type

Offset16

Description

MCHK

Interrupt

500

Machine check.

ITB_MISS

Fault

580

Istream TB miss.

ARITH

Synch. Trap

600

Arithmetic exception or update to FPCR.

INTERRUPT

Interrupt

680

Interrupts: hardware, software, and AST.

MT_FPCR

Synch. Trap

700

Invoked when a MT_FPCR instruction is issued.

RESET/WAKEUP

Interrupt

780

Chip reset or wake-up from sleep mode.

 

 

 

 

6.9 Translation Buffer (TB) Fill Flows

This section shows the expected PALcode flows for DTB miss and ITB miss. Familiar- ity with 21264/EV67 IPRs is assumed.

6.9.1 DTB Fill

Figure 6–5shows single-miss DTB instructions flow.

Figure 6–5 Single-Miss DTB Instructions Flow Example

Figure 6–5shows single-miss DTB instructions flow.

hw_mfprp23, EV6__EXC_ADDR hw_mfprp4, EV6__VA_FORM hw_mfprp5, EV6__MM_STAT hw_mfpr p7, EV6__EXC_SUM

hw_mfpr p6, EV6__VA bicp7, #1, p7 xorp4, p6, p4 xorp4, p6, p4

trap__dtbm_single_vpte: hw_ldq/v p4, (p4) bltp_misc, trap__d1to1 blbcp4, trap__invalid_dpte

andp4, #^x80, p7 xorp7, #^x80, p7

;(0L) get exception address

;(4-7,1L) get vpte address

;(0L) get miss info

;(0L) get exc_sum for ra

;(4-7,1L) get original va

;clear double miss flag

;interlock p4 and p6

;restore p4

;(1L) get vpte

;(xU) <63>=1 => 1-to-1

;(xU) invalid => branch

;isolate mb bit

;flip mb bit

ALIGN_FETCH_BLOCK <^x47FF041F>

 

PVC_VIOLATE <2>

; ignore scoreboard violation

hw_mtprp6, EV6__DTB_TAG0

; (2&6,0L) write tag0

hw_mtpr p6, EV6__DTB_TAG1

; (1&5,1L) write tag1

6–14Privileged Architecture Library Code

Alpha 21264/EV67 Hardware Reference Manual

Page 198
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Compaq EV67, 21264 specifications Translation Buffer TB Fill Flows, DTB Fill, 14Privileged Architecture Library Code