7- 54 M68020 USER’S MANUAL MOTOROLA
Table 7-6. Exceptions Related to Primitive Processing
Primitive Protocol F-Line Other
Busy
Null
Supervisory Check*
Other: Privilege Violation if S-Bit in the SR = 0 X
Transfer Operation Word*
Transfer from Instruction Stream*
Protocol: If Length Field Is Odd (Zero Length Legal) X
Evaluate and Transfer Effective Address
Protocol: If Used with Conditional Instruction
F-Line: If EA in Opword Is NOT Control Alterable
X
X
Evaluate Effective Address and Transfer Data
Protocol:
1. If Used with Conditional Instructions
2. Length Is Not 1, 2, or 4 and EA = Register Direct
3. If EA = Immediate and Length Odd and Greater Than 1
4. Attempt to Write to Unalterable Address
Even if Address Declared Legal in Primitive
F-Line: Valid EA Field Does Not Match EA in Opword
X
X
Write to Previously Evaluated Effective Address
Protocol: If Used with Conditional Instruction X
Take Address and Transfer Data*
Transfer to/from Top of Stack*
Protocol: Length Field Other Than 1, 2, or 4 X
Transfer Single Main Processor Register*
Transfer Main Processor Control Register
Protocol: Invalid Control Register Select Code X
Transfer Multiple Main Processor Registers*
Transfer Multiple Coprocessor Registers
Protocol:
1. If Used with Conditional Instructions
2. Odd Length Value
F-Line:
1. EA Not Control Alterable or (An)+ for CP to Memory Transfer
2. EA Not Control Alterable or –(An) for Memory to CP Transfer
X
X
Transfer Status and ScanPC
Protocol: If Used with Conditional Instruction
Other:
1. Trace—Trace Made Pending if MC68020/EC020 in “Trace on Change of
Flow” Mode and DR = 1
2. Address Error—If Odd Value Written to ScanPC
X
X
Take Preinstruction, Midinstruction, or Postinstruction Exception
Exception Depends on Vector Supplies in Primitive
X X X
*Use of this primitive with CA = 0 will cause protocol violation on conditional instructions.
Abbreviations:
EA—Effective Address
CP—Coprocessor
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