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4
4.3 EIT Processing Procedure
EIT processing consists of two parts, one in which they are handled automatically by hardware, and
one in which they are handled by user-created programs (EIT handlers). The procedure for
processing EITs when accepted, except for a rest interrupt, is shown below.
Instruction
Instruction
A
PC
BPC
PSW (B)PSW
EIT vector
entry
Branch
instruc
-tion
(SBI)
Figure 4.3.1 Outline of EIT Processing Procedure
EIT request
generated
Program
Instruction
suspended
B
C
EIT request
accepted
Hardware
preprocessing
EIT handlers except for SBI
BPC, (B)PSW,
and general-purpose
registers saved to
stack
SBI
(System Break Interrupt
processing)
Note: (B)PSW denotes the BPSW field of the PSW register.
Program execution restarted
Instruction
C
Instruction
processing-
canceled type
(RIE, AE)
Hardware
postprocessing
User-created EIT handler
General-purpose
Processing
registers, (B)PSW,
by
and BPC restored
handler
from stack
Program terminated or
system is reset
4-4
4.3 EIT Processing Procedure
Instruction
••••
D
Instruction processing
-completed type
(EI, TRAP)
(B)PSW PSW
BPC PC
RTE
instruc-
tion
EIT
Ver.0.10
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