Fujitsu MB90480 Series Hardware Manual page 64

CHAPTER 2 CPU
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Interrupt suppress instruction
No interrupt requests are sampled on ten types of instruction as follows.
MOV ILM, #imm8/PCB/SPB/OR CCR, #imm8/NCC
AND CCR, #imm8/ADB/CMR/POPW PS/DTB
If an effective interrupt request is issued when any of above instructions is executed, an
interrupt may be processed only if instructions other than the above are executed. For more
information, see Figure 2.4-1.
Interrupt request
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Restrictions on interrupt suppress instruction and prefix instruction
If a prefix code is inserted before an interrupt is suppressed, the prefix code affects up to the
first instruction that appears after any code other than interrupt suppress instructions, as shown
in Figure 2.4-2.
MOV A, FFH
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Continuous prefix codes
If continuous prefix codes conflict, the latest ones are valid, as shown in Figure 2.4-3.
Such conflicting prefix codes mean PCB, ADB, DTB, and SPB, as shown in Figure 2.4-3.
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Figure 2.4-1 Interrupt suppress instruction
Interrupt suppress instruction
Figure 2.4-2 Interrupt suppress instruction and prefix code
Interrupt suppress instruction
NCC MOV ILM,#imm8
Figure 2.4-3 Continuous prefix codes
Prefix code
ADB DTB
(a)
Interrupt accept
No CCR changes are caused by NCC.
PCB ADD A,01H
PCB is valid as
a prefix code.
(a) Normal instruction
ADD A,01H
CCR:XXX10XX