in
the "S1C88 Core Reference
Manual" | Name | #bits | Description |
| A | 8 | data register |
| B | 8 | data register |
| AB | 16 | combination of A and B |
| H | 8 | index (data) register |
| L | 8 | index (data) register |
| HL | 16 | combination of H and L |
| IX | 16 | index register |
| IY | 16 | index register |
| PC | 16 | program counter |
| SP | 16 | stack pointer |
| BR | 8 | base register |
| SC | 8 | system condition register |
| CC | 4 | custom condition flag |
| NB | 8 | new code bank register |
| CB | 8 | code bank register |
| EP | 8 | expand page register |
| XP | 8 | expand page register for IX |
| YP | 8 | expand page register for IY |
System Condition Flags (SC)
Mnemonic
Bit
Description
Z
0
zero flag
C
1
carry flag
V
2
overflow flag
N
3
negative flag
D
4
decimal flag
U
5
unpack flag
I0
6
interupt 0 flag
I1
7
interupt 1 flag
| Function | Mnemonic | Operation | Intel® 8088 Equivalent | Notes |
| Arithmetic and Logic | ADC | addition with carry | ||
| ADD | addition | |||
| AND | logical product (bitwise AND) | |||
| BIT | bit test | TEST | Use a mask to test a bit or bits in A, B, [HL] without affecting registers except for the flags. | |
| CP | comparision | CMP | Basically subtraction of second argument from first argument except that only the flags are changed (not other register contents as with SUB). So, if arguments are equal, the Z flag is set. | |
| CPL | 1's compliment (negation) | |||
| DEC | decrement | |||
| DIV | division | L=HL/A, H=remainder Only 8-bit :( | ||
| INC | increment | |||
| MLT | multiplication | MUL | HL=A*L, No arguments because always A*L! | |
| NEG | 2's compliment (negation) | |||
| OR | logical sum (bitwise OR) | |||
| SUB | subtraction | |||
| UPCK | unpack | |||
| XOR | exclusive OR | |||
| Transfer | EX | byte/word exchange | XCHG | |
| LD | load | MOV | ||
| SWAP | nibble exchange | |||
| Rotate/Shift Only 1 shift per instruction! |
RL | rotate left through carry | RCL | |
| RLC | rotate left | ROL | ||
| RR | rotate right through carry | RCR | Carry goes to LSB, MSB goes into carry | |
| RRC | rotate right | ROR | ||
| SLA | shift arithmetic left | SAL | MSB goes to carry, 0 goes to LSB | |
| SLL | shift logical left | SHL | ||
| SRA | shift arithmetic right | SAR | ||
| SRL | shift logical right | SHR | ||
| Auxilary Operation | PACK | pack | ||
| SEP | code extension | |||
| UPCK | unpack | |||
| Stack Control | POP | pop stack | ||
| PUSH | push stack | |||
| Branch | CALL | indirect call | ||
| CARL | relative long call | See note below | ||
| CARS | relative short call | See note below | ||
| DJR | loop | |||
| INT | software interrupt | |||
| JP | indirect jump | |||
| JRL | relative long jump | See not below | ||
| JRS | relative short jump | See not below | ||
| RET | return | |||
| RETE | exception processing return | |||
| RETS | return and skip | |||
| System Control | HALT | shift to HALT status | ||
| NOP | no operation | |||
| SLP | shift to SLEEP status |
Note: We seem to be using CAR for CARL and CARS and JR for JRS and
JRL. I think the assembler decides which to use automatically.