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Chapter 3 Functions
3.2 Functions
Interrupt by INT instruction
INTerrupt
[ Related Instructions ] BRK,INTO
[ Flag Change ]
INT INT
[ Syntax ]
INT src
[ Description Example ]
INT #0
[ Operation ]
SP SP – 2
M(SP) (PC + 2)H, FLG
SP SP – 2
M(SP) (PC + 2)ML
PC M(IntBase + src 4)
src
#IMM
*1*2
*1 #IMM denotes a software interrupt number.
*2 The range of values that can be taken on is 0 < #IMM < 63.
[ Selectable src ]
*3 The flags are saved to the stack area before the INT in-
struction is executed. After the interrupt, the flags
change state as shown on the left.
UIOBSZDC
Flag
Conditions
U : The flag is cleared if the software interrupt number is 31 or smaller. The flag does not change if
the software interrupt number is 32 or larger.
I : The flag is cleared.
D : The flag is cleared.
Change
[ Instruction Code/Number of Cycles ]
Page=
183
[ Function ]
• This instruction generates a software interrupt specified by
src
.
src
represents a software interrupt
number.
• If
src
is 31 or smaller, the U flag is cleared to 0 and the interrupt stack pointer (ISP) is used.
• If
src
is 32 or larger, the stack pointer indicated by the U flag is used.
• The interrupts generated by the INT instruction are nonmaskable interrupts.
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