Table of Contents
xii
M68060 USER’S MANUAL
MOTOROLA
4.6.2
Effect of MDIS on Address Translation .................................................... 4-30
4.7
MMU Instructions........................................................................................ 4-30
4.7.1
MOVEC .................................................................................................... 4-30
4.7.2
PFLUSH ................................................................................................... 4-30
4.7.3
PLPA ........................................................................................................ 4-30
Section 5
Caches
5.1
Cache Operation........................................................................................... 5-1
5.2
Cache Control Register ................................................................................ 5-5
5.3
Cache Management ..................................................................................... 5-6
5.4
Caching Modes............................................................................................. 5-7
5.4.1
Cachable Accesses .................................................................................... 5-7
5.4.1.1
Writethrough Mode ................................................................................... 5-7
5.4.1.2
Copyback Mode ....................................................................................... 5-8
5.4.2
Cache-Inhibited Accesses .......................................................................... 5-8
5.4.3
Special Accesses ....................................................................................... 5-9
5.5
Cache Protocol ............................................................................................. 5-9
5.5.1
Read Miss................................................................................................... 5-9
5.5.2
Write Miss ................................................................................................... 5-9
5.5.3
Read Hit...................................................................................................... 5-9
5.5.4
Write Hit .................................................................................................... 5-10
5.6
Cache Coherency ....................................................................................... 5-10
5.7
Memory Accesses for Cache Maintenance ................................................ 5-11
5.7.1
Cache Filling ............................................................................................. 5-11
5.7.2
Cache Pushes .......................................................................................... 5-13
5.8
Push Buffer ................................................................................................. 5-13
5.9
Store Buffer................................................................................................. 5-13
5.10
Push Buffer and Store Buffer Bus Operation.............................................. 5-14
5.11
Branch Cache ............................................................................................. 5-14
5.12
Cache Operation Summary ........................................................................ 5-15
5.12.1
Instruction Cache...................................................................................... 5-15
5.12.2
Data Cache............................................................................................... 5-16
Section 6
Floating-Point Unit
6.1
Floating-Point User Programming Model...................................................... 6-2
6.1.1
Floating-Point Data Registers (FP7–FP0) .................................................. 6-3
6.1.2
Floating-Point Control Register (FPCR) ..................................................... 6-3
6.1.2.1
Exception Enable Byte ............................................................................. 6-3
6.1.2.2
Mode Control Byte.................................................................................... 6-3
6.1.3
Floating-Point Status Register (FPSR) ....................................................... 6-4
6.1.3.1
Floating-Point Condition Code Byte ......................................................... 6-5
6.1.3.2
Quotient Byte............................................................................................ 6-5
6.1.3.3
Exception Status Byte .............................................................................. 6-5