A java implementation of the FML machine which i have designed.
Run the VFml class. Press Ctrl+Alt+A to Assemble and load a file. Press Ctrl+Alt+S to start the VM. Hold Ctrl+Alt+D to see debug information. Hold Ctrl+Alt+Q to pause the machine.
Each instruction is a 16-bit word.
An instruction may have at most two arguments.
An instruction may carry up to two non registry arguments.
These will be placed after the instruction in memory.
In the case of only one non register argument this will be placed immediately after
the instruction. In the case of two non registry arguments the first address after
the instruction will be the first argument and the next will be the second.
####Instruction encoding bits: 0-3. These specify the second argument(a2) 4-7. These specify the first argument (a1) 8-11. These specify the operation to be done 12-15. These specify the action to be taken.
####Argument encodings: bits 0-1: 00. The stack 01. The X register 10. The Y register 11. a non-registry argument
bit 2:
0. Use argument as value
1. Use argument as address
bit 3:
0. Use argument
1. Don't use argument *
####Operations:
| Operation Bits | Description |
|---|---|
| 0 | NOP |
| 1 | INC |
| 2 | DEC |
| 3 | ADD |
| 4 | SUB |
| 5 | MUL |
| 6 | DIV |
| 7 | MOD |
| 8 | EQL |
| 9 | GRT |
| 10 | LES |
| 11 | AND |
| 12 | OOR |
| 13 | XOR |
| 14 | NOT |
| 15 | SFT |
####Actions:
| Action Bits | Description |
|---|---|
| 0 | NOP |
| 1 | JMP |
| 2 | JSR |
| 3 | RET |
| 4 | SEQ |
| 5 | SGR |
| 6 | SLE |
| 7 | JOO |
| 8 | JOZ |
| 9 | SOO |
| 10 | SOZ |
| 11 | HLT |
| 12 | MOV |
| 13 | SNE |
| #####Explanations: |
| Menonic | Description |
|---|---|
| NOP | No Operation |
| MOV | Move a1 to a2 (a2 != n or $n) |
| INC | Increment a1 |
| DEC | Decrement a1 |
| ADD | s := a1 |
| SUB | s := a1 - a2 |
| MUL | s := a1 * a2 |
| DIV | s := a1 / a2 |
| MOD | s := a1 % a2 |
| EQL | s := a1 = a2 |
| GRT | s := a1 > a2 |
| LES | s := a1 < a2 |
| AND | s := a1 and a2 |
| OOR | s := a1 or a2 |
| XOR | s := a1 xor a2 |
| NOT | s := not a1 |
| NOT | (s := a1 << a2) if a2 < 0 otherwise (s := a1 >> -a2) |
| JMP | Jump to a1 |
| JSR | Jump to subroutine at a1 |
| RET | Return from subroutine |
| SEQ | Skip on a1 = a2 |
| SNE | Skip on a1 != a2 |
| SGR | Skip on a1 > a2 |
| SLE | Skip on a1 < a2 |
| JOO | Jump to a1 if s = 1 |
| JOZ | Jump to a1 if s = 0 |
| SOO | Jump to subroutine a1 if s = 1 |
| SOZ | Jump to subroutine a1 if s = 0 |
| HLT | Halt |
Special charcters:
\ Are considered comments and everything after this character will be ignored
: This is raw data entry. Its address will correspond to where in the code they appear
< Includes the file specified. Into the place where it was found.
_ Are blanks and will be ignored. (not the same as spaces)
References:
@ Are pointers and they will be assigned an arbitrary address
# Are labels and their address will correspond to where in the code they are
! These are constants. The place where they are declared will not appear in the output
Pointer declarations can be augmented with a + and then a number. This reserves that many addresses after the address given to the pointer.
So @array+100 will allocate 99 addresses after the address given to the array pointer. This is used for handling arrays.