28 lines
1.3 KiB
Plaintext
28 lines
1.3 KiB
Plaintext
(module
|
|
;; Import the required fd_write WASI function which will write the given io vectors to stdout
|
|
;; The function signature for fd_write is:
|
|
;; (File Descriptor, *iovs, iovs_len, nwritten) -> Returns number of bytes written
|
|
(import "wasi_unstable" "fd_write" (func $fd_write (param i32 i32 i32 i32) (result i32)))
|
|
|
|
(memory 1)
|
|
(export "memory" (memory 0))
|
|
|
|
;; Write 'hello world\n' to memory at an offset of 8 bytes
|
|
;; Note the trailing newline which is required for the text to appear
|
|
(data (i32.const 8) "hello world\n")
|
|
|
|
(func $main (export "_start")
|
|
;; Creating a new io vector within linear memory
|
|
(i32.store (i32.const 0) (i32.const 8)) ;; iov.iov_base - This is a pointer to the start of the 'hello world\n' string
|
|
(i32.store (i32.const 4) (i32.const 12)) ;; iov.iov_len - The length of the 'hello world\n' string
|
|
|
|
(call $fd_write
|
|
(i32.const 1) ;; file_descriptor - 1 for stdout
|
|
(i32.const 0) ;; *iovs - The pointer to the iov array, which is stored at memory location 0
|
|
(i32.const 1) ;; iovs_len - We're printing 1 string stored in an iov - so one.
|
|
(i32.const 20) ;; nwritten - A place in memory to store the number of bytes written
|
|
)
|
|
drop ;; Discard the number of bytes written from the top of the stack
|
|
)
|
|
)
|