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pjht 2016-10-20 13:18:20 -05:00
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KT8/KT8 opcodes v3-.txt
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Proposed Op codes for KT8 processor
Created - CAK 2-11-2014
KT8 (Krauter/Terpstra 8-bit) is a super simple processor that works with just 8-bit instructions.
KT8 Has:
@ -9,44 +6,36 @@ KT8 Has:
A = input 1
B = input 2
R = result
- 14 bytes of RAM memory[0-13].
- A keyboard at address 14
- A screen at address 15
- 32 bytes of RAM memory[0-31]. Some of these memory locations could do special things.
Op Codes:
Bits OP Name Description
0000 aaaa - LOADA aaaa : copy from RAM address to register A
0001 aaaa - LOADB aaaa : copy from RAM address to register B
0010 aaaa - SAVE aaaa : copy from register R to RAM address
000 aaaaa - LOADA aaaaa : copy from RAM address to register A
001 aaaaa - LOADB aaaaa : copy from RAM address to register B
010 aaaaa - SAVE aaaaa : copy from register R to RAM address
0011 xxxx - LOWBITS xxxx : B = 0000xxxx
0100 0000 - ADD : R = A + B
0100 0001 - SUB : R = A - B
0100 0010 - AND : R = A AND B
0100 0011 - OR : R = A OR B
0100 0100 - XOR : R = A XOR B
0100 0101 - INVA : R = bit inverse A
0100 0110 - INVB : R = bit inverse B
0100 0111 - PASSA : R = A
0100 1000 - PASSB : R = B
0100 1001 - LSHIFT : R = A << 1
0100 1010 - RSHIFT : R = A >> 1
0100 1011 - CLEAR : R = 0
0100 1100 - INC : R = A + 1
0100 1101 - DEC : R = A - 1
0101 xxxx - FJMP xxxx : move program counter forward by xxxx instructions
0110 xxxx - BJMP xxxx : move program counter back by xxxx instructions
0110 xxxx - LOWBITS xxxx : save 4bits=xxxx to low bits[0-3] of B
0111 xxxx - HIGHBITS xxxx : save 4bits=xxxx to high bits[7-4] of B
1000 0000 - ADD : R = A + B
1000 0001 - SUB : R = A - B
1000 0010 - AND : R = A AND B
1000 0011 - OR : R = A OR B
1000 0100 - XOR : R = A XOR B
1000 0101 - INVA : R = bit inverse A
1000 0110 - INVB : R = bit inverse B
1000 0111 - SWAPA : swap values between R and A
1000 1000 - SWAPB : swap values between R and B
1000 1001 - LSHIFT : shift bits in R to the left
1000 1010 - RSHIFT : shift bits in R to the right
1000 1011 - CLEAR : set R to zero
1000 1100 - INC : add 1 to R
1000 1101 - DEC : subtract 1 from R
0111 xxxx - FJMPZ : if R is zero move program counter forward by xxxx instructions
1000 xxxx - BJMPZ : if R is not zero move program counter forward by xxxx instructions
1100 xxxx - FJMP xxxx : move program counter forward by xxxx instructions
1101 xxxx - BJMP xxxx : move program counter back by xxxx instructions
1110 0000 - SKIPZ : if R is zero move program counter forward 2 instead of 1
1110 0001 - SKIPNZ : if R is not zero move program counter forward 2 instead of 1
1001 xxxx - FJMPNZ : if R is zero move program counter forward by xxxx instructions
1010 xxxx - BJMPNZ : if R is not zero move program counter forward by xxxx instructions
1011 0000 - RESET : R = 0
1011 0001 - HALT : stop KT8
1100 0000 - RKD : clear keyboard/display.
1111 0000 - RESET : put program counter back to zero.