It is the reference of the instructions supported by the brainterpreter VM A full list of supported instructions is available in Supported operations can be split into a few groups based on their functions The groups are Placing constant values on stack Arithmetic and logical operations Jump to different instructions Loading and storing global variables Loading and storing local variables Accessing and storing array elements Calling functions Those operations place either immediate values or elements of constants array on the stack Mnemonics Parameters Effect code CONST_NIL type InlinedCode text None type SimpleText text Pushes type SimpleText code nil type InlinedCode text on stack type SimpleText code CONST_B <b> type InlinedCode code b type InlinedCode text immediate bolean value type SimpleText text Places boolean constant on stack type SimpleText code CONST_F <f> type InlinedCode code f type InlinedCode text immediate numeric value type SimpleText text Places a numeric constant on stack type SimpleText code CONST <n> type InlinedCode code n type InlinedCode text index of constant in the chunk constants type SimpleText text Copies chunk constant to the stack type SimpleText Placing values on stack makes them available for other manipulations like arithmetic or logical operations src vm opcodes rs

Arithmetic and logic operations manipulates topmost values of the stack The result of the operation is pushed back on the stack Operations aren t applicable to all data types E g division of strings does not make sense The virtual machine will stop with the error when the operation is not applicable to operands on the stack Unary operations Unary operations picks the last value from the stack performs the operation and places the result on stack It may seem as just replacing the value on the top of the stack Mnemonics Type Effect code NEG type InlinedCode text Boolean type SimpleText text Logical type SimpleText code not type InlinedCode text operation type SimpleText code NEG type InlinedCode text Number type SimpleText text Negates the value on top of the stack type SimpleText Binary operations Binary operations takes two operans from the stack performs the operation and places the result back on stack The first operand of the binary operation should be placed on top of the stack The second operand is on the position E g for the operation the stack layout should be like that Mnemonics Type Effect code ADD type InlinedCode text Number Number type SimpleText text Adds two numbers type SimpleText code ADD type InlinedCode text String String type SimpleText text Concatenates strings type SimpleText code SUB type InlinedCode text Number Number type SimpleText text Subtract second number from the first type SimpleText code MUL type InlinedCode text Number Number type SimpleText text Multiplies two numbers type SimpleText code DIV type InlinedCode text Number Number type SimpleText text Divides first number with second type SimpleText code CMP type InlinedCode text Number Number type SimpleText text Compares two numbers Places type SimpleText code true type InlinedCode text or type SimpleText code false type InlinedCode text on stack type SimpleText code CMP type InlinedCode text Boolean Boolean type SimpleText text Compares two booleans type SimpleText code CMP type InlinedCode text String String type SimpleText text Compares two strings type SimpleText code LE type InlinedCode text Number Number type SimpleText text Pushes type SimpleText code true type InlinedCode text if the first number is less or equal comparing to the second type SimpleText code GE type InlinedCode text Number Number type SimpleText text Pushes type SimpleText code true type InlinedCode text if the first number is greater or equal comparing to the second type SimpleText top 1 x y

There are currently two jump calls allowing VM to change the execution flow Each jump operation accepts the value When applied jump changes the instruction pointer by adding the offset to the current value Note that the offset can be negative Mnemonics Effect code JMP <offset> type InlinedCode text Unconditionally changes the instruction pointer by adding the offset type SimpleText code JZ <offset> type InlinedCode text Changes the instruction pointer only if the value on the top of the stack is type SimpleText code falze type InlinedCode text If not the execution proceeds to next operation type SimpleText offset

Global variable instructions access global variables by the name Compiler places the variable name into constants pool of bytecode chunk Loading the variable places the value on stack Storing the variable replaces the value in globals map via the topmost value on the stack Mnemonics Parameters Effect code LD_G <idx> type InlinedCode text idx constant index containing variable name type SimpleText text Copies the value of the global variable onto the stack type SimpleText code ST_G <idx> type InlinedCode text idx constant index containing variable name type SimpleText text Copies the value from the top of the stack to the globals map type SimpleText

Local variables are not resolved by the name Instead of that the compiler places values on the fixed positions of the stack Thus instructions operating on local variables takes the offset from the base of the stack to address the variable Mnemonics Parameters Effect code LD_L <idx> type InlinedCode text idx offset of the variable from the stack base type SimpleText text Copies stack value representing the local variable onto the stack top type SimpleText code ST_L <idx> type InlinedCode text idx offset of the variable from the stack base type SimpleText text Copies the value from the top of the stack to a stack position representing the local variable type SimpleText

Array operations access elements of arrays and strings by index Array operations does not have parameters Instead they need all parameters to be correctly placed on the stack Mnemonics Stack Top Top 1 Top 2 Effect code ARR type InlinedCode text initial value type SimpleText text size type SimpleText text None type SimpleText text Allocates an array of specified size filled with initial value Places the reference on the stack type SimpleText code LD_IDX type InlinedCode text array reference type SimpleText text index type SimpleText text none type SimpleText text Copies the value with specified index from array to the stack type SimpleText code ST_IDX type InlinedCode text value type SimpleText text array reference type SimpleText text index type SimpleText text Replaces value in array with the value from the top of the stack type SimpleText Array access operation will fail on attempt to access values by index outside of the array

Mnemonics Parameters Effect code CALL <arity> type InlinedCode code arity type InlinedCode text number of function parameters type SimpleText text Calls the function The function reference must be present at the type SimpleText code stack top arity 1 type InlinedCode text stack element Call operation creates a call frame for the function and starts processing the function chunk type SimpleText code RET type InlinedCode text None type SimpleText text Finishes the function Removes all arguments from the stack Places the return value or type SimpleText code nil type InlinedCode text on the stack type SimpleText

Mnemonics Parameters Effect code POP type InlinedCode text None type SimpleText text Pop the value off the stack Useful for cleaning up after finishing block statements or expression statements type SimpleText code PRN type InlinedCode text None type SimpleText text Prints the value from the top of the stack to the linked output Removes top value from the stack type SimpleText