Instructions That Disable Interrupts; Interrupts During Execution Of Eepmov Instruction; When Nmi Is Disabled - Renesas Hitachi H8S/2194 Series Hardware Manual

6.5.2

Instructions that Disable Interrupts

Instructions that disable interrupts are LDC, ANDC, ORC, and XORC. After any of these
instructions is executed, all interrupts except NMI are disabled and the next instruction is always
executed. When the I bit or UI bit is set by one of these instructions, the new value becomes
valid two states after execution of the instruction ends.
6.5.3

Interrupts during Execution of EEPMOV Instruction

Interrupt operation differs between the EEPMOV.B instruction and the EEPMOV.W instruction.
With the EEPMOV.B instruction, an interrupt request (including NMI) issued during the transfer
is not accepted until the move is completed.
With the EEPMOV.W instruction, if an interrupt request is issued during the transfer, interrupt
exception handling starts at a break in the transfer cycle. The PC value saved on the stack in this
case is the address of the next instruction.
Therefore, if an interrupt is generated during execution of an EEPMOV.W instruction, the
following coding should be used.
L1: EEPMOV.W
MOV.W R4,R4
BNE L1
6.5.4

When NMI is Disabled

When NMI is disabled, the input level to the
recommended that the NMI interrupt exception handling address be set to the NMI vector
address (H'00001C to H'00001F) and that the RTE instruction also be set to the NMI exception
handling address.
<Program Example>
.ORG
.DATA.L
.
.
.
.
NMI:RTE
H'00001C
NMI
pin must be fixed high or low. It is
10,
Rev. 2.0, 11/00, page 121 of 1037