Fujitsu FR20 Home Theater Server User Manual


 
53
Operation of Step Trace Trap
When the T flag of the SCR within the PS is set, and the step trace function is set to Enabled, a trap is
generated per command execution and creates a break.
Condition of step trace trap detection
•T Flag = 1
There is no delayed branch instruction.
While executing other than the INTE command and step trace trap processing routine.
When the above condition occurs, breaks at the command operation gap.
[Operation]
1. SSP-4 SSP
2. PS (SSP)
3. SSP-4 SSP
4. Address of the following instruction(SSP)
5. "00100" ILM
6. "0" S Flag
7. (TBR+3CCH) PC
When step trace traps are enabled by setting the T flag, NMI for users and user interruption are disabled.
Moreover, EIT by the INTE instruction is not generated.
Operation of Undefined Instruction Exception
If an undefined instruction is detected when decoding the command, an undefined instruction exception is
generated.
Detection condition of undefined instruction exception
1) It is detected that it is undefined instruction at the decoding of the instruction.
2) Placed outside the delay slot (not immediately after the delay branch command).
When the above condition occurs, an undefined instruction exception is generated, and a break is created.
[Operation]
1. SSP-4 SSP
2. PS (SSP)
3. SSP-4 SSP
4. PC (SSP)
5. "0" S Flag
6. (TBR+3C4H) PC
The address of the actual command that detected the undefined instruction exception is saved as the PC.