Instructions That Inhibit Interrupts; Interrupts During Eepmov Instruction Execution - Hitachi H8/3006 Hardware Manual

5.5.2

Instructions that Inhibit Interrupts

The LDC, ANDC, ORC, and XORC instructions inhibit interrupts. When an interrupt occurs, after
determining the interrupt priority, the interrupt controller requests a CPU interrupt. If the CPU is
currently executing one of these interrupt-inhibiting instructions, however, when the instruction is
completed the CPU always continues by executing the next instruction.
5.5.3

Interrupts during EEPMOV Instruction Execution

The EEPMOV.B and EEPMOV.W instructions differ in their reaction to interrupt requests.
When the EEPMOV.B instruction is executing a transfer, no interrupts are accepted until the
transfer is completed, not even NMI.
When the EEPMOV.W instruction is executing a transfer, interrupt requests other than NMI are
not accepted until the transfer is completed. If NMI is requested, NMI exception handling starts at
a transfer cycle boundary. The PC value saved on the stack is the address of the next instruction.
Programs should be coded as follows to allow for NMI interrupts during EEPMOV.W execution:
L1: EEPMOV.W
MOV.W R4,R4
BNE L1
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