e200z1 Core (Z1)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
10-18
Freescale Semiconductor
Preliminary
10.4.3
MMU Assist Registers (MAS)
e200 uses six special purpose registers (MAS0, MAS1, MAS2, MAS3, MAS4 and MAS6) to facilitate
reading, writing, and searching the TLB. The MAS registers can be read or written using the
mfspr
and
mtspr
instructions. e200 does not implement the MAS5 register, present in other EIS Book E designs,
because the
tlbsx
instruction only searches based on a single SPID value.
NOTE
e200z1 is a 32-bit implementation of the Power Architecture Book E
specification. In this document, register bits are sometimes numbered from
bit 0 (Most Significant Bit) to 31 (Least Significant Bit), rather than the
Book E numbering scheme of 32:63, thus register bit numbers for some
registers in Book E are 32 higher. Where appropriate, the Book E defined
bit numbers are shown in parentheses.
The MAS0 register is shown in Figure 10-8. Fields are defined in
.
Table 10-4. TLB Entry Bit Definitions
Field
Comments
V
Valid bit for entry
TS
Translation address space (compared against AS bit)
TID[0:7]
Translation ID (compared against PID0 or ‘0’)
EPN[0:19]
Effective page number (compared against effective address)
RPN[0:19]
Real page number (translated address)
SIZE[0-3]
Page size (4K/16K/64K/256K/1M/4M/16M/64M/256M/1G/4G)
SX, SW, SR
Supervisor execute, write, and read permission bits
UX, UW, UR
User execute, write, and read permission bits
WIMGE
Translation attributes (write-through required, cache-inhibited, memory coherence required,
guarded, endian)
U0-U3
User bits -- used only by software
IPROT
Invalidation protect
VLE
VLE page indicator
0
TLBSEL (01)
0
ESELCAM
0
NVCAM
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
SPR - 624; Read/ Write; Reset - Unaffected
Figure 10-8. MMU Assist Register 0 (MAS0)