E-18
MPC8240 Integrated Processor User’s Manual
PowerPC Register Set
E.1.3.5 Segment Registers
The segment registers, shown in Figure E-15, contain the segment descriptors.
Figure E-15. Segment Register Format (T = 0)
Segment register bit settings when T = 0 are described in Table E-13.
E.1.3.6 SPRG0–SPRG3
The format of SPRG0–SPRG3 is shown in Figure E-16.
Figure E-16. SPRG0–SPRG3
Table E-14 provides a description of conventional uses of SPRG0 through SPRG3.
Table E-13. Segment Register Bit Settings (T = 0)
Bits
Name
Description
0
T
T = 0 selects this format
1
Ks
Supervisor-state protection key
2
Kp
User-state protection key
3
N
No-execute protection
4–7
—
Reserved
8–31
VSID
Virtual segment ID
Table E-14. Conventional Uses of SPRG0–SPRG3
Register
Description
SPRG0
Software may load a unique physical address in this register to identify an area of memory
reserved for use by the first-level exception handler. This area must be unique for each processor
in the system.
SPRG1
This register may be used as a scratch register by the first-level exception handler to save the
content of a GPR. That GPR then can be loaded from SPRG0 and used as a base register to save
other GPRs to memory.
SPRG2
This register may be used by the operating system as needed.
SPRG3
This register may be used by the operating system as needed.
0
1
2
3
4
7 8
31
T Ks Kp N
0000
VSID
Reserved
SPRG0
SPRG1
SPRG2
SPRG3
0
31
Summary of Contents for MPC8240
Page 1: ...MPC8240UM D Rev 1 1 2001 MPC8240 Integrated Processor User s Manual ...
Page 38: ...xviii MPC8240 Integrated Processor User s Manual TABLES Table Number Title Page Number ...
Page 48: ...xlviii MPC8240 Integrated Processor User s Manual Acronyms and Abbreviations ...
Page 312: ...6 94 MPC8240 Integrated Processor User s Manual ROM Flash Interface Operation ...
Page 348: ...7 36 MPC8240 Integrated Processor User s Manual PCI Host and Agent Modes ...
Page 372: ...8 24 MPC8240 Integrated Processor User s Manual DMA Register Descriptions ...
Page 394: ...9 22 MPC8240 Integrated Processor User s Manual I2O Interface ...
Page 412: ...10 18 MPC8240 Integrated Processor User s Manual Programming Guidelines ...
Page 454: ...12 14 MPC8240 Integrated Processor User s Manual Internal Arbitration ...
Page 466: ...13 12 MPC8240 Integrated Processor User s Manual Exception Latencies ...
Page 516: ...16 14 Watchpoint Trigger Applications ...
Page 538: ...B 16 MPC8240 Integrated Processor User s Manual Setting the Endian Mode of Operation ...
Page 546: ...C 8 MPC8240 Integrated Processor User s Manual ...
Page 640: ...INDEX Index 16 MPC8240 Integrated Processor User s Manual ...