MOTOROLA
Chapter 9. Memory Management Unit (MMU)
9-33
Part II. PowerPC Microprocessor Module
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The TLB entry is written by loading the tablewalk level-two entry value to Mx_RPN.
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A scratch register, M_TW, is provided in addition to the architecture-deÞned
SPRG0ÐSPRG3, so miss code need not corrupt existing GPRs.
9.10.1.1 Translation Reload Examples
The following examples reload a TLB entry using a two-level tree page table structure. In
both examples, M_TWB holds the base pointer to the Þrst-level table and data and
instruction address translation are turned off. Figure 9-23 performs a DTLB reload.
Figure 9-23. DTLB Reload Code Example
Figure 9-24 performs an ITLB reload
Figure 9-24. ITLB Reload Code Example
9.10.2 Locking TLB Entries
Four entries in each TLB can be made unavailable to the replacement algorithm, thus
enabling the user to lock translation entries into them by specially conÞguring the TLB
replacement counters.
dtlb_swtw
mtspr
M_TW, R1
# Save R1
mfspr
R1, M_TWB
# Load R1 with level-1 pointer
lwz
R1, (R1)
# Load level-1 page entry
mtspr
MD_TWC,R1
# Save level-2 base pointer and level-1 attributes
mfspr
R1, MD_TWC
# Load R1 with level-2 pointer while taking page
# size into account
lwz
R1, (R1)
# Load level-2 page entry
mtspr
MD_RPN, R1
# Write TLB entry
mfspr
R1, M_TW
# Restore R1
rfi
itlb_swtw
mtspr
M_TW, R1
# Save R1
mfspr
R1, SRR0
# Load R1 with instruction miss EA (the same data
# may be taken from MI_EPN)
mtspr
MD_EPN, R1
# Save instruction miss EA in MD_EPN
mfspr
R1, M_TWB
# Load R1 with level-1 pointer
lwz
R1, (R1)
# Load level-1 page entry
mtspr
MI_TWC,R1
# Save level-1 attributes
mtspr
MD_TWC,R1
# Save level-2 base pointer
mfspr
R1, MD_TWC
# Load R1 with level-2 pointer while taking page
# size into account
lwz
R1, (R1)
# Load level-2 page entry
mtspr
MI_RPN, R1
# Write TLB entry
mfspr
R1, M_TW
# Restore R1
rfi
Summary of Contents for MPC860 PowerQUICC
Page 3: ...MPC860UM AD 07 98 REV 1 MPC860 PowerQUICC ª UserÕs Manual ...
Page 36: ...xxxvi MPC860 PowerQUICC UserÕs Manual MOTOROLA CONTENTS Paragraph Number Title Page Number ...
Page 78: ...I iv MPC860 PowerQUICC UserÕs Manual MOTOROLA Part I Overview ...
Page 88: ...1 10 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part I Overview ...
Page 114: ...3 16 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part I Overview ...
Page 226: ...8 32 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part II PowerPC Microprocessor Module ...
Page 262: ...9 36 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part II PowerPC Microprocessor Module ...
Page 274: ...III iv MPC860 PowerQUICC UserÕs Manual MOTOROLA Part III Configuration ...
Page 320: ...12 12 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part III Configuration ...
Page 325: ...MOTOROLA Part IV Hardware Interface IV v Part IV Hardware Interface ...
Page 326: ...IV vi MPC860 PowerQUICC UserÕs Manual MOTOROLA Part IV Hardware Interface ...
Page 352: ...13 26 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part IV Hardware Interface ...
Page 394: ...14 42 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part IV Hardware Interface ...
Page 426: ...15 32 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part IV Hardware Interface ...
Page 530: ...17 26 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part IV Hardware Interface ...
Page 632: ...21 44 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 660: ...22 28 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 708: ...24 24 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 748: ...27 20 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 846: ...31 20 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 914: ...35 12 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 948: ...36 34 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part V The Communications Processor Module ...
Page 998: ...37 48 MPC860 PowerQUICC UserÕs Manual MOTOROLA Part VI Debug and Test ...
Page 1016: ...A 10 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
Page 1024: ...B 8 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
Page 1030: ...C 6 MPC860 PowerQUICC UserÕs Manual MOTOROLA Appendixes ...
Page 1086: ...Glossary 12 MPC860 PowerQUICC UserÕs Manual MOTOROLA ...
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