copy: Wasm text instruction

The 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

;; 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-function
(memory.copy (i32.const 50) (i32.const 100) (i32.const 25))

Copy specified memory (if multi-memory supported)

;; Copy data in specific memory  [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)  ;; Copy memory within memory with index 2

;; Copy within memory referenced by its name
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 $memoryName) ;; Copy memory with memory named "$memoryName"

;; Copy same memory using an S function
(memory.copy (memory $memoryName) (i32.const 50) (i32.const 100) (i32.const 25))

Instructions and opcodes

Specifications

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Browser compatibility

[!NOTE] Memory support in Wasm modules matches the WebAssembly.Memory JavaScript API. The multiMemory key indicates versions in which copy can be used with a specified memory.

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