Motorola M68060 User Manual page 11

6.1.3.4 Accrued Exception Byte ........................................................................... 6-6
6.1.4 Floating-Point Instruction Address Register (FPIAR) ................................. 6-7
6.2 Floating-Point Data Formats and Data Types............................................... 6-7
6.3 Computational Accuracy ............................................................................. 6-11
6.3.1 Intermediate Result................................................................................... 6-12
6.3.2 Rounding the Result ................................................................................. 6-13
6.4 Postprocessing Operation........................................................................... 6-15
6.4.1 Underflow, Round, and Overflow.............................................................. 6-15
6.4.2 Conditional Testing ................................................................................... 6-16
6.5 Floating-Point Exceptions ........................................................................... 6-19
6.5.1 Unimplemented Floating-Point Instructions .............................................. 6-19
6.5.2 Unsupported Floating-Point Data Types................................................... 6-21
6.5.3 Unimplemented Effective Address Exception........................................... 6-22
6.6 Floating-Point Arithmetic Exceptions .......................................................... 6-22
6.6.1 Branch/Set on Unordered (BSUN)............................................................ 6-24
6.6.1.1 Trap Disabled Results (FPCR BSUN Bit Cleared) ................................. 6-24
6.6.1.2 Trap Enabled Results (FPCR BSUN Bit Set) ......................................... 6-24
6.6.2 Signaling Not-a-Number (SNAN) .............................................................. 6-25
6.6.2.1 Trap Disabled Results (FPCR SNAN Bit Cleared) ................................. 6-25
6.6.2.2 Trap Enabled Results (FPCR SNAN Bit Set) ......................................... 6-26
6.6.3 Operand Error ........................................................................................... 6-26
6.6.3.1 Trap Disabled Results (FPCR OPERR Bit Cleared)............................... 6-27
6.6.3.2 Trap Enabled Results (FPCR OPERR Bit Set)....................................... 6-27
6.6.4 Overflow.................................................................................................... 6-28
6.6.4.1 Trap Disabled Results (FPCR OVFL Bit Cleared) .................................. 6-29
6.6.4.2 Trap Enabled Results (FPCR OVFL Bit Set) .......................................... 6-29
6.6.5 Underflow.................................................................................................. 6-30
6.6.5.1 Trap Disabled Results (FPCR UNFL Bit Cleared) .................................. 6-31
6.6.5.2 Trap Enabled Results (FPCR UNFL Bit Set) .......................................... 6-31
6.6.6 Divide-by-Zero .......................................................................................... 6-32
6.6.6.1 Trap Disabled Results (FPCR DZ Bit Cleared)....................................... 6-33
6.6.6.2 Trap Enabled Results (FPCR DZ Bit Set)............................................... 6-33
6.6.7 Inexact Result ........................................................................................... 6-33
6.6.7.1 Trap Disabled Results (FPCR INEX1 Bit and INEX2 Bit Cleared........... 6-34
6.6.7.2 Trap Enabled Results (Either FPCR INEX1 Bit or INEX2 Bit Set).......... 6-34
6.7 Floating-Point State Frames ....................................................................... 6-35
7.1 Bus Characteristics ....................................................................................... 7-1
7.2 Full-, Half-, and Quarter-Speed Bus Operation and BCLK ........................... 7-3
7.3 Acknowledge Termination Ignore State Capability ....................................... 7-4
7.4 Bus Control Register..................................................................................... 7-4
7.5 Data Transfer Mechanism............................................................................. 7-5
7.6 Misaligned Operands .................................................................................... 7-9
MOTOROLA
Section 7
Bus Operation
M68060 USER'S MANUAL
Table of Contents
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