Download Errata Sheet

Errata Sheet
Functional Deviations
Workaround
None
CPU_TC.064 Co-incident FCU and CDO traps can cause system-lock
A problem exists in the interaction between Free Context Underflow (FCU) and
Call Depth Overflow (CDO) traps. An FCU trap occurs when a context save
operation is attempted and the free context list is empty, or when the context
operation encounters an error. A CDO trap occurs when a program attempts to
make a call with call depth counting enabled and the call depth counter was
already at its maximum value.
When an FCU trap occurs with call depth counting enabled (PSW.CDE = ’1’) and
the call depth counter at a value such that the next call will generate a CDO trap,
then the FCU trap causes a co-incident CDO trap. In this case the PC is
correctly set to the FCU trap handler but appears to freeze in this state as a
constant stream of FCU traps is generated.
A related problem occurs when call trace mode is enabled (PSW.CDC = 0x7E).
If in call trace mode a call or return operation encounters an FCU trap, either a
CDO (call) or Call Depth Underflow (CDU, return) trap is generated co-incident
with the FCU trap, either of which situations lead to a constant stream of FCU
traps and system lockup.
Note however that FCU traps are not expected during normal operation since
this trap is indicative of software errors.
Workaround
None
CPU_TC.065 Error when unconditional loop targets unconditional jump
An error in the program flow occurs when an unconditional loop (LOOPU)
instruction has as its target an unconditional jump instruction, i.e. as the first
instruction of the loop. Such unconditional jump instructions are J, JA, JI, JL,
JLA and JLI.
TC1796, EES-BE, ES-BE, BE
43/207
Rel. 1.3, 2011-08-29