Fujitsu MB91F109 FR30 Hardware Manual page 65

[bit 8] T: Step-trace-trap flag
This flag specifies whether to enable step-trace-trap.
0: Disables step-trace-trap.
1: Enables step-trace-trap.
Setting the bit to 1 inhibits all user NMIs and user interrupts.
The flag is cleared to 0 by resetting.
The step-trace-trap function is used by an emulator. It cannot be used in user programs
while it is used by the emulator.
Interrupt level mask register (ILM)
The configuration of the interrupt level mask register (ILM) is as follows:
20
ILM4
The ILM register holds an interrupt level mask value. The value held by the ILM register is used
for level masking.
Of the interrupt requests input to the CPU, only those with higher interrupt levels than the level
indicated by the ILM are accepted.
The level values range in descending order of highness from 0 (00000
The values that can be set from a program are limited. When the original value is in the range
from 16 to 31, a new value that can be set must be in the same range, i.e., from 16 to 31. If an
instruction that sets a value from 0 to 15 is executed, the "specified value + 16" is returned.
When the original value is in the range from 0 to 15, a desired value from 0 to 31 can be set.
The register is cleared to 15 (01111
19 18 17
ILM3 ILM2 ILM1 ILM0
) by resetting.
B
16 [Initial value]
01111
B
2.3 Programming Model
) to 31 (11111 ).
B B
41