Datasheet

Semihosting
ARM DUI0058D Copyright © 1999-2001 ARM Limited. All rights reserved. 5-15
5.4.5 SYS_WRITE (0x05)
Writes the contents of a buffer to a specified file at the current file position. The file
position is specified either:
• explicitly, by a SYS_SEEK
• implicitly as one byte beyond the previous SYS_READ or SYS_WRITE request.
The file position is at the start of the file when the file is opened, and is lost when the
file is closed.
Perform the file operation as a single action whenever possible. For example, do not
split a write of 16KB into four 4KB chunks unless there is no alternative.
Entry
On entry, r1 contains a pointer to a three-word data block:
word 1 This contains a handle for a file previously opened with SYS_OPEN
word 2 This points to the memory containing the data to be written
word 3 This contains the number of bytes to be written from the buffer to the file.
Return
On exit, r0 contains:
• 0 if the call is successful
• the number of bytes that are not written, if there is an error.