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Chapter 3 Functions
3.2 Functions
UNDefined instruction
Interrupt for undefined instruction
[ Syntax ]
UND
[ Flag Change ]
[ Description Example ]
UND UND
[ Operation ]
SP SP – 2
M(SP) (PC + 1)H, FLG
SP SP – 2
M(SP) (PC + 1)ML
PC M(FFFDC16)
*1 The flags are saved to the stack area before the UND
instruction is executed. After the interrupt, the flag status
becomes as shown on the left.
UIOBSZDC
Conditions
U : The flag is cleared.
I : The flag is cleared.
D : The flag is cleared.
UND
[ Instruction Code/Number of Cycles ]
Page=
243
Flag
Change
• This instruction generates an undefined instruction interrupt.
• The undefined instruction interrupt is a nonmaskable interrupt.
[ Function ]
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