DI
Operation | Resets both interrupt flip-flops, thus preventing maskable interrupts from triggering. |
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Op Code | 11110011 |
T States | 4 |
EI
Operation | Sets both interrupt flip-flops, thus allowing maskable interrupts to occur. An interrupt will not occur until after the immediatedly following instruction. |
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Op Code | 11111011 |
T States | 4 |
HALT
Operation | Suspends CPU operation until an interrupt or reset occurs. |
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Op Code | 01110110 |
T States | 4 |
IM 0
Operation | Sets interrupt mode 0. |
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Op Code | 11101101 : 01000110 |
T States | 8 |
IM 1
Operation | Sets interrupt mode 1. |
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Op Code | 11101101 : 01010110 |
T States | 8 |
IM 2
Operation | Sets interrupt mode 2. |
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Op Code | 11101101 : 01011110 |
T States | 4 |
IN A,(imm8)
Operation | A byte from port imm8 is written to A. |
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Op Code | 11011011 : [imm8] |
T States | 11 |
IN reg8,(C)
Operation | A byte from port C is written to reg8. | ||||||||||||||||
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Op Code | 11101011 : 01[reg8]000
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Flags | S Z are affected as defined H N are reset P/V is parity C is not affected |
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T States | 12 |
IND
Operation | A byte from port C is written to the memory location pointed to by HL. HL and B are then decremented. |
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Op Code | 11101101 : 10101010 |
Flags | S H P/V are scrambled Z is set if B becomes zero N is set C is not affected |
T States | 16 |
INDR
Operation | A byte from port C is written to the memory location pointed to by HL. HL and B are then decremented. If B is not zero, this operation is repeated. |
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Op Code | 11101101 : 10111010 |
Flags | S H P/V are scrambled Z N are set C is not affected |
T States | If B != 0: 21 If B == 0: 16 |
INI
Operation | A byte from port C is written to the memory location pointed to by HL. HL is incremented and B is decremented. |
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Op Code | 11101101 : 10100010 |
Flags | S H P/V are scrambled Z is set if B becomes zero N is set C is not affected |
T States | 16 |
INIR
Operation | A byte from port C is written to the memory location pointed to by HL. HL is incremented and B is decremented. If B is not zero, this operation is repeated. |
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Op Code | 11101101 : 10110010 |
Flags | S H P/V are scrambled Z N are set C is not affected |
T States | If B != 0: 21 If B == 0: 16 |
OTDR
Operation | A byte from the memory location pointed to by HL is written to port C. HL and B are then decremented. If B is not zero, this operation is repeated. |
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Op Code | 11101101 : 10111011 |
Flags | S H P/V are scrambled Z N are set C is not affected |
T States | If B != 0: 21 If B == 0: 16 |
OTIR
Operation | A byte from the memory location pointed to by HL is written to port C. HL is incremented and B is decremented. If B is not zero, this operation is repeated. |
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Op Code | 11101101 : 10110011 |
Flags | S H P/V are scrambled Z N are set C is not affected |
T States | If B != 0: 21 If B == 0: 16 |
OUT (imm8),A
Operation | The value of A is written to port imm8. |
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Op Code | 11010011 : [imm8] |
T States | 11 |
OUT (C),reg8
Operation | The value of reg8 is written to port C. | ||||||||||||||||
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Op Code | 11101011 : 01[reg8]001
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T States | 12 |
OUTD
Operation | A byte from the memory location pointed to by HL is written to port C. HL and B are then decremented. |
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Op Code | 11101101 : 10101011 |
Flags | S H P/V are scrambled Z is set if B becomes zero N is set C is not affected |
T States | 16 |
OUTI
Operation | A byte from the memory location pointed to by HL is written to port C. HL is incremented and B is decremented. |
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Op Code | 11101101 : 10100011 |
Flags | S H P/V are scrambled Z is set if B becomes zero N is set C is not affected |
T States | 16 |