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OS_CRC
Programmer's Reference Manuals
» Part 15 – SWI Calls
» OS
» OS_CRC
OS_CRC
(SWI &5B)
| Entry | |
|---|---|
| R0 | CRC continuation value, or 0 |
| R1 | Pointer to start of block |
| R2 | Pointer to end of block |
| R3 | Increment |
| Exit | |
|---|---|
| R0 | CRC value |
| R1 | Preserved |
| R2 | Preserved |
| R3 | Preserved |
Use
The purpose of this call is to calculate the cyclic-redundancy check for a block of data.
Notes
The value calculated is only 16 bit.
The SWI adds R3 to R1 until it equals R2, ie if R1 never equals R2 you have an infinite loop
The byte at R2 is not included in the CRC value.