44
BRK
BRK
FORCE
BR
EA
K
(B)
←
1
(PC)
←
(PC) + 2
(M(S))
←
(PC
H
)
(S)
←
(S) – 1
(M(S))
←
(PC
L
)
(S)
←
(S) – 1
(M(S))
←
(PS)
(S)
←
(S) – 1
(I)
←
1
(PC)
←
BADRS (Note 1)
When the BRK instruction is executed, the CPU pushes the
current PC contents onto the stack. The BADRS designated in
the interrupt vector table is stored into the PC.
No change
No change
No change
1
1
No change
No change
No change
Op e r a t io n :
F u n c t io n :
St a t u s fla g :
N :
V :
T :
B :
I :
D :
Z :
C :
Addressing mode
Implied
Statement
∆
BRK
∆
Machine codes
00
16
Byte number
1
Cycle number
7
Notes 1: “BADRS” means a break address.
2: The value of the PC pushed onto the stack by the execution of the
BRK instruction is the BRK instruction address plus two. Therefore,
the byte following the BRK will not be executed when the value of
the PC is returned from the BRK routine.
3: Both after the BRK instruction is executed and after INT is input, the
program is branched to the address where is specified by the inter-
rupt vector table. By testing the value of the B Flag in the PS
(pushed on the Stack) in the interrupt service routine, the user can
determine if the interrupt was caused by the BRK instruction.
