Opcodes

This page documents the current Phantasma VM opcode set used by the Carbon validator.

Gas Cost Model

The VM assigns a small base gas cost per opcode before any interop-side native work is considered.

The current base costs are:

• 0

  • NOP, RET

• 1

  • most ordinary opcodes

• 5

  • CALL, LOAD, PUT, GET

• 10

  • EXTCALL, CTX

• 100

  • SWITCH

Full Opcode Table

Opcode	Args	Purpose	Base Gas
NOP	-	Do nothing.	0
MOVE	src, dst	Move a register value by reference semantics.	1
COPY	src, dst	Copy a register value by value semantics.	1
PUSH	src	Push a register value onto the shared stack.	1
POP	dst	Pop the top stack value into a register.	1
SWAP	a, b	Swap two register values.	1
CALL	count, offset	Enter a new execution frame and jump to an offset.	5
EXTCALL	reg	Execute a native interop method named by the register value.	10
JMP	offset	Unconditional jump.	1
JMPIF	offset, reg	Jump if the register evaluates to true.	1
JMPNOT	offset, reg	Jump if the register evaluates to false.	1
RET	-	Return from the current frame or context.	0
THROW	reg	Abort execution with a VM exception.	1
LOAD	dst, type, data	Load an immediate typed value into a register.	5
CAST	src, dst, type	Convert a value into another VM type.	1
CAT	a, b, dst	Concatenate values into a result.	1
RANGE	src, dst, index, length	Extract a slice from a value.	1
LEFT	src, dst, length	Extract the left-most portion of a value.	1
RIGHT	src, dst, length	Extract the right-most portion of a value.	1
SIZE	src, dst	Return the serialized RAM size of a value.	1
COUNT	src, dst	Return the number of elements in a struct-like value.	1
NOT	src, dst	Boolean negation.	1
AND	a, b, dst	Boolean or bitwise AND depending on value shape.	1
OR	a, b, dst	Boolean or bitwise OR depending on value shape.	1
XOR	a, b, dst	Boolean or bitwise XOR depending on value shape.	1
EQUAL	a, b, dst	Equality comparison.	1
LT	a, b, dst	Less-than comparison.	1
GT	a, b, dst	Greater-than comparison.	1
LTE	a, b, dst	Less-than-or-equal comparison.	1
GTE	a, b, dst	Greater-than-or-equal comparison.	1
INC	reg	Increment a numeric value.	1
DEC	reg	Decrement a numeric value.	1
SIGN	src, dst	Return the sign of a numeric value.	1
NEGATE	src, dst	Negate a numeric value.	1
ABS	src, dst	Return absolute value.	1
ADD	a, b, dst	Addition.	1
SUB	a, b, dst	Subtraction.	1
MUL	a, b, dst	Multiplication.	1
DIV	a, b, dst	Division.	1
MOD	a, b, dst	Modulo.	1
SHL	a, b, dst	Shift left.	1
SHR	a, b, dst	Shift right.	1
MIN	a, b, dst	Return the smaller value.	1
MAX	a, b, dst	Return the larger value.	1
POW	a, b, dst	Exponentiation.	1
CTX	src, dst	Resolve a named execution context.	10
SWITCH	reg	Switch execution into a resolved context.	100
PUT	value, target, field	Write a field into a struct-like target.	5
GET	dst, target, field	Read a field from a struct-like target.	5
CLEAR	reg	Reset a register to None.	1
UNPACK	src, dst	Decode a serialized struct-like value.	1
PACK	-	Reserved; currently unused.	1
DEBUG	-	Debug breakpoint opcode. In code this is stored as DEBUG_.	1

Notes For Contract Authors

• EXTCALL is how VM code reaches native chain functionality such as token transfers, storage helpers, and contract lifecycle operations.

• CTX and SWITCH are what make cross-context contract calls and trigger execution possible.

• PACK is still effectively unused in the current implementation.

• The base opcode gas above is only part of the final transaction cost. Heavy interops can add much larger native gas charges.