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OS_SerialOp 8
Programmer's Reference Manuals
» Part 15 – SWI Calls
» OS
» OS_SerialOp
» OS_SerialOp 8
OS_SerialOp 8
(SWI &57)
| Entry | |
|---|---|
| R0 | 8 |
| R1 | -1 to read, or new threshold |
| Exit | |
|---|---|
| R0 | Preserved |
| R1 | Old threshold |
Use
The purpose of this call is to read or write the input buffer threshold value.
Notes
OS_SerialOp 0 can be used to examine or change the handshaking method.
The default value on RISC OS 3.5 is 17 characters, but this is subject to change and should not be relied upon.
The serial input routine attempts to halt input when the amount of free space left in the input buffer falls below a certain level. This call allows the value at which input is halted to be read or changed.