Exceptions Related To Primitive Processing - Motorola MC68020 User Manual

Table 7-6. Exceptions Related to Primitive Processing
Busy
Null
*
Supervisory Check
Other: Privilege Violation if S-Bit in the SR = 0
Transfer Operation Word
Transfer from Instruction Stream
Protocol: If Length Field Is Odd (Zero Length Legal)
Evaluate and Transfer Effective Address
Protocol: If Used with Conditional Instruction
F-Line: If EA in Opword I s NOT Control Alterable
Evaluate Effective Address and Transfer Data
Protocol:
1. If Used with Conditional Instructions
2. Length I s 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
Write to Previously Evaluated Effective Address
Protocol: If Used with Conditional Instruction
Take Address and Transfer Data
Transfer to/from Top of Stack
Protocol: Length Field Other Than 1, 2, or 4
Transfer Single Main Processor Register
Transfer Main Processor Control Register
Protocol: Invalid Control Register Select Code
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
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
Take Preinstruction, Midinstruction, or Postinstruction Exception
Exception Depends on Vector Supplies in Primitive
*
Use of this primitive with CA = 0 will cause protocol violation on conditional instructions.
Abbreviations:
EA—Effective Address
CP—Coprocessor
7-54
Primitive
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M68020 USER'S MANUAL
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