pep9 opcode Flashcards
(12 cards)
1
Q
0000
A
Stop execution
2
Q
1100
A
Load word into the A register
3
Q
1101
A
Load byte into the A register
4
Q
1110
A
Store word from tthe A register
5
Q
1111
A
Store byte from the A register
6
Q
0110
A
Add number to the A register
7
Q
0111
A
Subtract number from the A register
8
Q
Program counter
A
Contains address of the next instruction to be executed. 16 bits
9
Q
Instruction register
A
Contains a copy of the instruction being executed, Instruction 8 bits, operand 16 bits
10
Q
Accumulator
A
Used to hold data and results of operations. 16 bits
11
Q
Immediate Addressing mode
A
000, operand used as data
12
Q
Direct addressing mode
A
001, operand used as address, addressed memory ussed as data
