brokkr

Bytecode virtual machine for Valhalla.
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BYTECODE.md (6626B)

Brokkr Bytecode Specification

Sizes are as follows:

Type Size
Operator 1 Byte (8 Bits, u8)
Operand 2 Bytes (16 Bits, u16)

Bytecodes

Byte Name Operands Description
0x00
(0)		 EOI
N/A
 End Of Instructions! This is not a real opcode and only appears at the end of the instruction byte-stream to signal that there are no more instructions to be read. Essentially it’s just a null-terminator.
0xc8
(200)		 HALT 1 — Exit Code (Integer) Stops execution.
0x01
(1)		 PUSH_CONST 1 — Unsigned index to constants table Pushes a constant onto the stack. Constant is specified by a given index to the constant-table, containing all local constant.
0x02
(2)		 PUSH_LOCAL 1 — Local variable index (Unsigned) Pushes a local variable (e.g. a function param) onto the stack. The local variable is identified by an index operand, to where it is in the current symbol table.
0x03
(3)		 PUSH_SUPER 1 — Name of super-scoped variable (String) When a variable is out of the local scope, load it onto the stack by searching up the super-scope by its name, (much slower than PUSH_LOCAL).
0x04
(4)		 POP
N/A
 Pops the top element off of the stack.
0x05
(5)		 STORE_LOCAL 1 — Index to store local variable in table (Unsigned) Pops the top value and stores it in the local symbol table at a given index.
0x06
(6)		 DUP
N/A
 Duplicates what was on the top of the stack, by popping it off and then pushing two copies.
0x07
(7)		 DUP_N 1 — The number of duplicates Duplicates the top value on the stack N times.
0x08
(8)		 SWAP
N/A
 Swaps the position of the top two stack elements.
0x09
(9)		 CALL_1
N/A
 Calls function at top of stack with argument at second from top of stack.
0x0a
(10)		 CHECK_TYPE
N/A
 Checks if second from top of stack value is a member of the set/type loaded from the top of the stack.
0x0b
(11)		 CAST 1 — One byte, specifies the origin type.
2 — One byte, specifies the destination type.		 Changes the top-of-stack value to have a different primitive type.
0x0c
(12)		 MAKE_FUNC
N/A
 Takes the top-of-stack value, referencing a code block, and makes it a function, with all the special properties that come with that.
0x0d
(13)		 YIELD
N/A
 Causes the current function to yield a value (i.e. return).
0x0e
(14)		 RAW_PRINT
N/A
 Native debug print of TOS. Should not be used unless working on the compiler.
0x28
(40)		 N_ADD
N/A
 Addition between two pointer-sized unsigned integers. Pops top two elements from the stacks and adds them together, pushing the result.
0x29
(41)		 I_ADD
N/A
 Addition between two pointer-sized signed integers. Pops top two elements from the stacks and adds them together, pushing the result.
0x2a
(42)		 R_ADD
N/A
 Addition between two 64-bit floating-point numbers. Pops top two elements from the stacks and adds them together, pushing the result.
0x2b
(43)		 U_ADD
N/A
 Addition between two values of unknown types, found out at runtime. Pops top two elements from the stacks and adds them together, pushing the result.
0x2c
(44)		 CONCAT
N/A
 Works like add, but concatenates strings.
0x2d
(45)		 N_SUB
N/A
 Subtraction between two pointer-sized unsigned integers. Pops top two elements from the stacks and subtracts them together, pushing the result.
0x2e
(46)		 I_SUB
N/A
 Subtraction between two pointer-sized signed integers. Pops top two elements from the stacks and subtracts them together, pushing the result.
0x2f
(47)		 R_SUB
N/A
 Subtraction between two 64-bit floating-point numbers. Pops top two elements from the stacks and subtracts them together, pushing the result.
0x30
(48)		 U_SUB
N/A
 Subtraction between two values of unknown types, found out at runtime. Pops top two elements from the stacks and subtracts one from the other, pushing the result.
0x31
(49)		 N_MUL
N/A
 Multiplication between two pointer-sized unsigned integers. Pops top two elements from the stacks and multiplies them together, pushing the result.
0x32
(50)		 I_MUL
N/A
 Multiplication between two pointer-sized signed integers. Pops top two elements from the stacks and multiplies them together, pushing the result.
0x33
(51)		 R_MUL
N/A
 Multiplication between two 64-bit floating-point numbers. Pops top two elements from the stacks and multiplies them together, pushing the result.
0x34
(52)		 U_MUL
N/A
 Multiplication between two values of unknown types, found out at runtime. Pops top two elements from the stacks and multiplies them together, pushing the result.
0x35
(53)		 N_DIV
N/A
 Division between two pointer-sized unsigned integers. Pops top two elements from the stacks and finds their quotient, pushing the result.
0x36
(54)		 I_DIV
N/A
 Division between two pointer-sized signed integers. Pops top two elements from the stacks and finds their quotient, pushing the result.
0x37
(55)		 R_DIV
N/A
 Division between two 64-bit floating-point numbers. Pops top two elements from the stacks and finds their quotient, pushing the result.
0x38
(56)		 U_DIV
N/A
 Division between two values of unknown types, found out at runtime. Pops top two elements from the stacks and finds their quotient, pushing the result.
0xfe
(254)		 SET_LINE 1 — Current line number, given directly as u16. Operand value is line number. Sets the current line number that the subsequent bytecode instructions correspond to in the code source file.
0xff
(255)		 NOP
N/A
 No Operation. Does nothing. You shouldn’t see this in the final compiled bytecode, it may only exists temporarily while the bytecode is being produced. 
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# Brokkr Bytecode Specification

Sizes are as follows:

| Type     | Size                     |
|----------|--------------------------|
| Operator | 1 Byte  (8  Bits,  `u8`)  |
| Operand  | 2 Bytes (16 Bits, `u16`) |

## Bytecodes
| Byte | Name | Operands | Description |
|:---:|:---:|---|---|
| `0x00`<br />(0) | `EOI` | <center>N/A</center> | End Of Instructions! This is not a real opcode and only appears at the end of the instruction byte-stream to signal that there are no more instructions to be read. Essentially it's just a null-terminator. |
| `0xc8`<br />(200) | `HALT` | 1 — Exit Code (Integer) | Stops execution. |
| `0x01`<br />(1) | `PUSH_CONST` | 1 — Unsigned index to constants table | Pushes a constant onto the stack. Constant is specified by a given index to the constant-table, containing all local constant. |
| `0x02`<br />(2) | `PUSH_LOCAL` | 1 — Local variable index (Unsigned) | Pushes a local variable (e.g. a function param) onto the stack. The local variable is identified by an index operand, to where it is in the current symbol table. |
| `0x03`<br />(3) | `PUSH_SUPER` | 1 — Name of super-scoped variable (String) | When a variable is out of the local scope, load it onto the stack by searching up the super-scope by its name, (much slower than `PUSH_LOCAL`). |
| `0x04`<br />(4) | `POP` | <center>N/A</center> | Pops the top element off of the stack. |
| `0x05`<br />(5) | `STORE_LOCAL` | 1 — Index to store local variable in table (Unsigned) | Pops the top value and stores it in the local symbol table at a given index. |
| `0x06`<br />(6) | `DUP` | <center>N/A</center> | Duplicates what was on the top of the stack, by popping it off and then pushing two copies. |
| `0x07`<br />(7) | `DUP_N` | 1 — The number of duplicates | Duplicates the top value on the stack N times. |
| `0x08`<br />(8) | `SWAP` | <center>N/A</center> | Swaps the position of the top two stack elements. |
| `0x09`<br />(9) | `CALL_1` | <center>N/A</center> | Calls function at top of stack with argument at second from top of stack. |
| `0x0a`<br />(10) | `CHECK_TYPE` | <center>N/A</center> | Checks if second from top of stack value is a member of the set/type loaded from the top of the stack. |
| `0x0b`<br />(11) | `CAST` | 1 — One byte, specifies the origin type.<br />2 — One byte, specifies the destination type. | Changes the top-of-stack value to have a different primitive type. |
| `0x0c`<br />(12) | `MAKE_FUNC` | <center>N/A</center> | Takes the top-of-stack value, referencing a code block, and makes it a function, with all the special properties that come with that. |
| `0x0d`<br />(13) | `YIELD` | <center>N/A</center> | Causes the current function to yield a value (i.e. return). |
| `0x0e`<br />(14) | `RAW_PRINT` | <center>N/A</center> | Native debug print of `TOS`. Should not be used unless working on the compiler. |
| `0x28`<br />(40) | `N_ADD` | <center>N/A</center> | Addition between two pointer-sized unsigned integers. Pops top two elements from the stacks and adds them together, pushing the result. |
| `0x29`<br />(41) | `I_ADD` | <center>N/A</center> | Addition between two pointer-sized signed integers. Pops top two elements from the stacks and adds them together, pushing the result. |
| `0x2a`<br />(42) | `R_ADD` | <center>N/A</center> | Addition between two 64-bit floating-point numbers. Pops top two elements from the stacks and adds them together, pushing the result. |
| `0x2b`<br />(43) | `U_ADD` | <center>N/A</center> | Addition between two values of unknown types, found out at runtime. Pops top two elements from the stacks and adds them together, pushing the result. |
| `0x2c`<br />(44) | `CONCAT` | <center>N/A</center> | Works like add, but concatenates strings. |
| `0x2d`<br />(45) | `N_SUB` | <center>N/A</center> | Subtraction between two pointer-sized unsigned integers. Pops top two elements from the stacks and subtracts them together, pushing the result. |
| `0x2e`<br />(46) | `I_SUB` | <center>N/A</center> | Subtraction between two pointer-sized signed integers. Pops top two elements from the stacks and subtracts them together, pushing the result. |
| `0x2f`<br />(47) | `R_SUB` | <center>N/A</center> | Subtraction between two 64-bit floating-point numbers. Pops top two elements from the stacks and subtracts them together, pushing the result. |
| `0x30`<br />(48) | `U_SUB` | <center>N/A</center> | Subtraction between two values of unknown types, found out at runtime. Pops top two elements from the stacks and subtracts one from the other, pushing the result. |
| `0x31`<br />(49) | `N_MUL` | <center>N/A</center> | Multiplication between two pointer-sized unsigned integers. Pops top two elements from the stacks and multiplies them together, pushing the result. |
| `0x32`<br />(50) | `I_MUL` | <center>N/A</center> | Multiplication between two pointer-sized signed integers. Pops top two elements from the stacks and multiplies them together, pushing the result. |
| `0x33`<br />(51) | `R_MUL` | <center>N/A</center> | Multiplication between two 64-bit floating-point numbers. Pops top two elements from the stacks and multiplies them together, pushing the result. |
| `0x34`<br />(52) | `U_MUL` | <center>N/A</center> | Multiplication between two values of unknown types, found out at runtime. Pops top two elements from the stacks and multiplies them together, pushing the result. |
| `0x35`<br />(53) | `N_DIV` | <center>N/A</center> | Division between two pointer-sized unsigned integers. Pops top two elements from the stacks and finds their quotient, pushing the result. |
| `0x36`<br />(54) | `I_DIV` | <center>N/A</center> | Division between two pointer-sized signed integers. Pops top two elements from the stacks and finds their quotient, pushing the result. |
| `0x37`<br />(55) | `R_DIV` | <center>N/A</center> | Division between two 64-bit floating-point numbers. Pops top two elements from the stacks and finds their quotient, pushing the result. |
| `0x38`<br />(56) | `U_DIV` | <center>N/A</center> | Division between two values of unknown types, found out at runtime. Pops top two elements from the stacks and finds their quotient, pushing the result. |
| `0xfe`<br />(254) | `SET_LINE` | 1 — Current line number, given directly as `u16`. Operand value is line number. | Sets the current line number that the subsequent bytecode instructions correspond to in the code source file. |
| `0xff`<br />(255) | `NOP` | <center>N/A</center> | <u>N</u>o <u>Op</u>eration. Does nothing. You shouldn't see this in the final compiled bytecode, it may only exists temporarily while the bytecode is being produced. |