EPXA4 Datasheet, PDF (17/34 Pages) Altera Corporation – Excalibur Devices

Errata Sheet - Appendix A
Table 4 shows an example of incorrect trace caused by this erratum.
Table 5 shows an example where this erratum does not occur.
Table 4. Example of incorrect trace behavior on interrupt
Actual instructions executed
Correct behavior
Actual behavior
Address
Instruction
Trace generated
Trace generated
Decompressed
trace
0x00001000
0x00001004
(0x00001020)
0x00000018
.
.
.
0x00001020
Trace starts, address
Trace starts, address
0x00001000
0x00001000
ADD r1, r1, 1
Instruction executed
Instruction executed
B 0x00001020
Instruction executed, branch to Instruction executed, branch to
0x00001020
0x00000018
(Not executed due to Instruction executed, branch to
interrupt)
0x00000018^a
IRQ hander
.
.
SUBS pc, r14, #4
IRQ handler traced
.
.
Instruction executed, branch to
0x00001020
IRQ handler traced
.
.
Instruction executed, branch to
0x00001020
…
…
…
0x00001000
IRQ!
0x00000018
.
.
.
0x00001020
Note:
(a) Extra instruction traced to indicate interrupt
Table 5. Example of correct trace behavior on interrupt
Actual instructions executed
Actual behavior
Address
Instruction
Trace generated
Decompressed trace
0x00002000
0x00002004
(0x00002020)
0x00000018
.
.
.
0x00002020
Trace starts, address
0x00002000
ADD r1, r1, 1
Instruction executed
0x00002000
BNE 0x00002020
Failed its condition
codes
Instruction executed but failed 0x00002004
its condition codes
Failed its condition codes
(Not executed due to Instruction executed, branch to IRQ!
interrupt)
0x00000018^a
IRQ hander
IRQ handler traced
.
.
.
.
SUBS pc, r14, #4 Instruction executed, branch to
0x00002020
0x00000018
.
.
.
…
…
0x00002020
Note:
(a) Extra instruction traced to indicate interrupt
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