INSTRUCTION SET DESCRIPTIONS
MOTOROLA INSTRUCTION SET DETAILS A - 251
Instruction Format:
REP X:ea
REP Y:ea
Opcode:
Instruction Fields:
ea=6-bit Effective Address=MMMRRR,
Effective
Addressing Mode M M M R R R Memory Space s
(Rn)-Nn 0 0 0 r r r X Memory 0
(Rn)+Nn 0 0 1 r r r Y Memory 1
(Rn)- 0 1 0 r r r
(Rn)+ 0 1 1 r r r
(Rn) 1 0 0 r r r
(Rn+Nn) 1 0 1 r r r
-(Rn) 1 1 1 r r r
where “rrr” refers to an address register R0-R7
Timing: 4+mv oscillator clock cycles
Memory: 1 program word
REP Repeat Next Instruction REP
23 16 15 8 7 0
0000011001MMMRRR0 s 10 0000