Guest Processor Identification Register (Gpir); Thread Run State; Thread Stop I/O Pin; Thread Control And Status Register (Thrctl) - IBM A2 User Manual

Bits Field Name
62:63 TID

2.3.1.3 Guest Processor Identification Register (GPIR)

The GPIR is a register that identifies a specific instance of a processor thread for the guest operating system.
The GPIR is used to filter incoming processor messages. See Processor Messages on page 357.
Register Short Name:
Decimal SPR Number:
Initial Value:
Slow SPR:
Guest Supervisor Mapping:
Bits Field Name
32:49 VPTAG
50:63 DBTAG

2.3.2 Thread Run State

The A2 core provides several methods for controlling a thread's run state. For a thread to fetch instructions,
all methods outlined below must be properly configured. If any one I/O or register is configured to stop a
thread, the affected thread will not fetch instructions.

2.3.2.1 Thread Stop I/O Pin

The I/O pin, an_ac_pm_thread_stop, can be used to stop the A2 core from fetching instructions. Stopping a
thread causes all instructions that have begun executing to be completed and all prefetched instructions to be
discarded.

2.3.2.2 Thread Control and Status Register (THRCTL)

The SCOM accessible THRCTL register can control the thread run state to allow an external debugger
control of the processor. See Direct Access to I-Cache and D-Cache Directories on page 437. Stopping a
thread via THRCTRL causes all instructions that have begun executing to be completed and all prefetched
instructions to be discarded.
Version 1.3
October 23, 2012
Initial
Value
0b00 Processor Thread ID
This field can be used to distinguish the thread from other threads on the processor.
Threads are numbered sequentially, with valid values ranging from 0 to 3.
GPIR
382
0x0000000000000000
N
Y
Initial
Value
0x0 Virtual Processor Tag
Storage used by the guest operating system to identify the virtual processor on which the
operating system is running.
0x0 Doorbell Tag
Used to match guest doorbell messages that are sent to all the processors and virtual pro-
cessors in a coherence domain. If a sent guest doorbell message tag matches the DBTAG
field, a guest doorbell is said to be accepted on the (virtual) processor.
Description
Read Access:
Write Access:
Duplicated for Multithread:
Notes:
Scan Ring:
Description
User's Manual
A2 Processor
Priv
Hypv
Y
HM
func
CPU Programming Model
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