MPC5553/MPC5554 Microcontroller Reference Manual, Rev. 5
3-16 Freescale Semiconductor
3.3.1.5 MMU Assist Registers (MAS0–MAS4, MAS6)
The e200z6 uses six special purpose registers (MAS0, MAS1, MAS2, MAS3, MAS4 and MAS6) to
facilitate reading, writing, and searching the TLBs. The MAS registers can be read or written using the
mfspr and mtspr instructions. The e200z6 does not implement the MAS5 register, present in other
Freescale EIS designs, because the tlbsx instruction only searches based on a single SPID value.
Additional information on the MASn registers is available in the e200z6 PowerPC
TM
Core Reference
Manual. The MAS0 register is shown in Figure 3-7.
MAS0 fields are defined in Table 3-3.
The MAS1 register is shown in Figure 3-8.
MAS1 fields are defined in Table 3-4.
01 2 3 4 1011 1516 2627 31
Field — TLBSEL — ESEL — NV
Reset Undefined on Power Up Unchanged on Reset
R/W R/W
SPR SPR 624
Figure 3-7. MAS Register 0 (MAS0) Format
Table 3-3. MAS0—MMU Read/Write and Replacement Control
Bits Name Description
0–1 — Reserved, should be cleared.
2–3 TLBSEL Selects TLB for access
01 TLB1 (ignored by the e200z6, should be written to 01 for future compatibility)
4–10 — Reserved, should be cleared.
11–15 ESEL Entry select for TLB1
16–26 — Reserved, should be cleared.
27–31 NV Next replacement victim for TLB1 (software managed). Software updates this field; it is copied to
the ESEL field on a TLB error.
0 1 2 7 8 1516 181920 2324 31
Field VALID IPROT — TID — TS TSIZE —
Reset Undefined on Power Up Unchanged on Reset
R/W R/W
SPR SPR 625
Figure 3-8. MMU Assist Register 1 (MAS1)
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