copy: Wasm text instruction
The memory.copy memory instruction copies data from one region of a memory to another.
The instruction does not return a value. If either the source or destination range is out of bounds, the instruction traps.
Syntax
Copy within default memory
wat
;; Copy data in default memory from [100, 125] to [50, 75]
i32.const 50 ;; Destination address to copy to
i32.const 100 ;; Source address to copy from
i32.const 25 ;; Number of bytes to copy
memory.copy ;; Copy memory
;; Copy in default memory using an S-expression
(memory.copy (i32.const 50) (i32.const 100) (i32.const 25))
Copy specified memory (if multi-memory supported)
wat
;; Copy data within specific memory from [100, 125] to [50, 75]
i32.const 50 ;; Destination address to copy to
i32.const 100 ;; Source address to copy from
i32.const 25 ;; Number of bytes to copy
memory.copy (memory 2) (memory 2) ;; Copy memory within memory with index 2
;; Copy between memories referenced by their names
i32.const 50 ;; Destination address (in $destMem)
i32.const 100 ;; Source address (in $sourceMem)
i32.const 25 ;; Number of bytes to copy
memory.copy (memory $destMem) (memory $sourceMem) ;; Copy memory from "$sourceMem" to "$destMem"
;; Copy between memories using an S-expression
(memory.copy (memory $destMem) (memory $sourceMem) (i32.const 50) (i32.const 100) (i32.const 25))
Instructions and opcodes
| Instruction | Binary opcode |
|---|---|
memory.copy |
0xFC 0x0a |
Specifications
| Specification |
|---|
| Unknown specification # syntax-instr-memory |
Browser compatibility
webassembly.bulk-memory-operations
webassembly.multiMemory
Note:
The multiMemory compatibility table indicates versions in which copy can be used with a specified memory.