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IDET     Interrupt Detection     Rabbit 3000A/4000 Instruction
Opcode
Instruction
Clocks
Operation

5B

IDET

2

Performs "LD E,E"
But if (EDMR && SU[0])
then the System Violation interrupt flag is set.


Flags ALTD IOI/IOE
S
Z
L/V
C
F
R
SP
S
D
-
-
-
-

Description

The IDET instruction asserts a System Mode Violation interrupt if System/User mode is enabled (which is done by writing to the Enable Dual Mode Register, EDMR) and the processor is currently in user mode.

Note that IDET has the same opcode value as the instruction "LD E,E" and actually executes that opcode as well as the behavior described above. If IDET is prefixed by ALTD, the instruction LD E',E is executed and the special System/User mode behavior does not occur.


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