Section 5 Exception Handling
Rev.1.00 Dec. 13, 2005 Page 106 of 1286
REJ09B0158-0100
5.5.2 Exception
Source
Acceptance
A priority ranking is provided for all exceptions for use in determining which of two or more
simultaneously generated exceptions should be accepted. Five of the general exceptions—general
illegal instruction exception, slot illegal instruction exception, general FPU disable exception, slot
FPU disable exception, and unconditional trap exception—are detected in the process of
instruction decoding, and do not occur simultaneously in the instruction pipeline. These
exceptions therefore all have the same priority. General exceptions are detected in the order of
instruction execution. However, exception handling is performed in the order of instruction flow
(program order). Thus, an exception for an earlier instruction is accepted before that for a later
instruction. An example of the order of acceptance for general exceptions is shown in figure 5.2.
I1
I1
ID
ID
E3
WB
WB
TLB miss (data access)
Pipeline flow:
Order of detection:
Instruction n
Instruction n + 1
General illegal instruction exception (instruction n + 1) and
TLB miss (instruction n + 2) are detected simultaneously
Order of exception handling:
TLB miss (instruction n)
Program order
1
Instruction n + 2
General illegal instruction exception
I1
ID
WB
I2
ID
WB
TLB miss (instruction access)
2
3
4
I1, I2 : Instruction fetch
ID :
Instruction decode
E1, E2, E3 : Instruction execution
(E2, E3: Memory access)
WB : Write-back
Instruction n + 3
TLB miss (instruction n)
Re-execution of instruction n
General illegal instruction exception
(instruction n + 1)
Re-execution of instruction n + 1
TLB miss (instruction n + 2)
Re-execution of instruction n + 2
Execution of instruction n + 3
[Legend]
E3
E3
E2
E2
E1
E1
I2
I2
E1
E1
E2
E2
E3
I2
I1
Figure 5.2 Example of General Exception Acceptance Order
Summary of Contents for SH7780 Series
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Page 82: ...Section 1 Overview Rev 1 00 Dec 13 2005 Page 32 of 1286 REJ09B0158 0100 ...
Page 122: ...Section 3 Instruction Set Rev 1 00 Dec 13 2005 Page 72 of 1286 REJ09B0158 0100 ...
Page 146: ...Section 4 Pipelining Rev 1 00 Dec 13 2005 Page 96 of 1286 REJ09B0158 0100 ...
Page 196: ...Section 6 Floating Point Unit FPU Rev 1 00 Dec 13 2005 Page 146 of 1286 REJ09B0158 0100 ...
Page 292: ...Section 9 L Memory Rev 1 00 Dec 13 2005 Page 242 of 1286 REJ09B0158 0100 ...
Page 492: ...Section 12 DDR SDRAM Interface DDRIF Rev 1 00 Dec 13 2005 Page 442 of 1286 REJ09B0158 0100 ...
Page 674: ...Section 15 Clock Pulse Generator CPG Rev 1 00 Dec 13 2005 Page 624 of 1286 REJ09B0158 0100 ...
Page 692: ...Section 16 Watchdog Timer and Reset Rev 1 00 Dec 13 2005 Page 642 of 1286 REJ09B0158 0100 ...
Page 726: ...Section 18 Timer Unit TMU Rev 1 00 Dec 13 2005 Page 676 of 1286 REJ09B0158 0100 ...
Page 1032: ...Section 25 Audio Codec Interface HAC Rev 1 00 Dec 13 2005 Page 982 of 1286 REJ09B0158 0100 ...
Page 1150: ...Section 28 General Purpose I O GPIO Rev 1 00 Dec 13 2005 Page 1100 of 1286 REJ09B0158 0100 ...
Page 1184: ...Section 29 User Break Controller UBC Rev 1 00 Dec 13 2005 Page 1134 of 1286 REJ09B0158 0100 ...
Page 1266: ...Section 31 Electrical Characteristics Rev 1 00 Dec 13 2005 Page 1216 of 1286 REJ09B0158 0100 ...
Page 1328: ...Appendix Rev 1 00 Dec 13 2005 Page 1278 of 1286 REJ09B0158 0100 ...
Page 1336: ...Rev 1 00 Dec 13 2005 Page 1286 of 1286 REJ09B0158 0100 ...
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