Opcode Table for the Stack VM¶
Below is a table describing the opcodes, their operands, and their functions in the Stack VM, based on the implemented codegen and VM code. Only opcodes with codegen support are included.
| Opcode (Hex) | Mnemonic | Operands | Description |
|---|---|---|---|
| Data Push Instructions | |||
| 0x01 | PUSH_CHAR | 1 byte | Push a literal 1-byte character onto the stack. |
| 0x03 | PUSH_INT | 8 bytes | Push a literal 8-byte integer (little-endian) onto the stack. |
| 0x05 | PUSH_FLOAT | 4 bytes | Push a literal 4-byte IEEE 754 float (little-endian) onto the stack. |
| 0x07 | PUSH_NONE | None | Push a value of 0 (VAL_INT type) onto the stack. |
| Stack Manipulation | |||
| 0x10 | POP | None | Pop the top value off the stack. |
| 0x11 | DUP | None | Duplicate the top value on the stack. |
| 0x12 | SWAP | None | Swap the top two values on the stack. |
| 0x13 | OVER | None | Copy the second value and push it onto the stack. |
| Identifier Manipulation | |||
| 0x15 | GET | 8 bytes (ID) | Push the value corresponding to the variable ID onto the stack. |
| 0x16 | SET | 8 bytes (ID) | Pop a value from the stack and assign it to the variable ID. |
| 0x98 | BIND | 8 bytes (ID) | Bind a popped value to a variable ID in the current scope, creating a new scope entry if needed. |
| Arithmetic Operations | |||
| 0x20 | ADD | None | Pop two values, add them, and push the result. Supports INT, FLOAT, and CHAR types. |
| 0x21 | SUB | None | Pop two values, subtract the top from the next, and push the result. Supports INT, FLOAT, and CHAR types. |
| 0x22 | MUL | None | Pop two values, multiply them, and push the result. Supports INT, FLOAT, and CHAR types. |
| 0x23 | DIV | None | Pop two values, divide the second by the top, and push the result. Supports INT and FLOAT types. |
| 0x24 | MOD | None | Pop two values, compute the modulus, and push the result. Supports INT types. |
| 0x25 | NEG | None | Negate the top value and push the result. Supports INT and FLOAT types. |
| Logical Operations | |||
| 0x34 | AND | None | Pop two INT values, perform logical AND, push 1 if true, else 0. |
| 0x35 | OR | None | Pop two INT values, perform logical OR, push 1 if true, else 0. |
| 0x36 | NOT | None | Pop an INT value, push 1 if it is 0, else push 0. |
| Comparison Operations | |||
| 0x40 | EQ | None | Pop two values; push 1 if equal, else 0. Supports INT, FLOAT, and CHAR types. |
| 0x41 | NEQ | None | Pop two values; push 1 if not equal, else 0. Supports INT, FLOAT, and CHAR types. |
| 0x42 | LT | None | Pop two values; push 1 if the second is less than the top, else 0. Supports INT and FLOAT types. |
| 0x43 | GT | None | Pop two values; push 1 if the second is greater than the top, else 0. Supports INT and FLOAT types. |
| 0x44 | LE | None | Pop two values; push 1 if the second is less than or equal to the top, else 0. Supports INT and FLOAT types. |
| 0x45 | GE | None | Pop two values; push 1 if the second is greater than or equal to the top, else 0. Supports INT and FLOAT types. |
| Control Flow | |||
| 0x50 | JUMP | 4 bytes (signed offset) | Unconditionally jump by the relative offset (added to PC). |
| 0x51 | JUMP_IF_ZERO | 4 bytes (signed offset) | Pop an INT; if zero, jump by the relative offset. |
| 0x53 | CALL | None | Pop a function object, increment call scope, set up closure objects, and jump to the function's entry point. |
| 0x54 | RETURN | None | Pop a return value and address, clean up scope, and jump to the return address. |
| 0x55 | HALT | None | Terminate program execution. |
| Type Conversion Operations | |||
| 0x60 | I2F | None | Convert the top INT value to a FLOAT. |
| 0x61 | F2I | None | Convert the top FLOAT value to an INT. |
| Heap Object Operations | |||
| 0x70 | NEW_OBJECT | 1 byte (field count) | Allocate a new object with the specified number of fields; push the object pointer onto the stack. |
| 0x71 | GET_FIELD | 1 byte (field index) | Pop an object and push the value from the specified field of the object. |
| 0x72 | SET_FIELD | 1 byte (field index) | Pop a value and then an object; set the object's specified field to the popped value. |
| I/O Operations | |||
| 0x90 | LOG | None | Pop a value and print it to STDOUT. Supports INT, FLOAT, and CHAR types. |
| Function Instructions | |||
| 0x91 | MAKE_FUNC | None | Pop entry and exit points, create a function object, and push it onto the stack. |
| 0x92 | MAKE_CLOSURE | None | Pop number of closed objects, their IDs, and a function object; create a closure and attach it to the function. |
| Array Instructions | |||
| 0x93 | MAKE_ARRAY | 2 bytes (size) | Pop the specified number of elements, create an array, and push it onto the stack. |
| 0x94 | ARRACC | None | Pop an array and index, push the value at the specified index. |
| 0x95 | STORE | None | Pop a location and value, store the value at the location. Supports INT, FLOAT, CHAR, BOOL, and ARR types. |
| 0x96 | LOAD | None | Pop a location, push the value stored at that location. |
| 0x97 | MAKE_ARRAY_DECL | 2 bytes (number of dimensions) | Pop dimension sizes, create a multi-dimensional array initialized to 0, and push it onto the stack. |