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OS_Byte 247
Programmer's Reference Manuals
» Part 15 – SWI Calls
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» OS_Byte 247
OS_Byte 247
(SWI &06)
| Entry | |
|---|---|
| R0 | 247 (&F7) |
| R1 | EOR value |
| R2 | AND value |
| Exit | |
|---|---|
| R0 | Preserved |
| R1 | Value before being overwritten |
| R2 | Corrupted |
Use
The purpose of this call is to read and change the result of pressing Break.
Notes
The value byte alters Break and modifiers of it as follows:
| Bits | Key combination |
|---|---|
| 0,1 | Break |
| 2,3 | Shift Break |
| 4,5 | Ctrl Break |
| 6,7 | Ctrl Shift Break |
Each two bit numbers can mean one of these:
| Value | Meaning |
|---|---|
| 00 | Act as reset |
| 01 | Act as escape key |
| 10 | No effect |
| 11 | Undefined |
The default is %00000001, so Break causes an escape condition, together with Shift and/or Ctrl it acts like the reset button.
Please note that this SWI also alters the CMOS when writing a new status.