13.7.6. SYS_WRITE (0x05)

Writes the contents of a buffer to a specified file at the current file position. The file position is specified either:

The file position is at the start of the file when the file is opened, and is lost when the file is closed.

The file operation should be performed as a single action whenever possible. That is, a write of 16KB should not be split into four 4KB chunks unless there is no alternative.


On entry, r1 contains a pointer to a three word data block:

word 1

contains a handle for a file previously opened with SYS_OPEN.

word 2

points to the memory containing the data to be written.

word 3

contains the number of bytes to be written from the buffer to the file.


On exit, r0 contains:

  • 0 if the call is successful

  • the number of byte that are not written, if there is an error.

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