mirror of
https://github.com/hsoft/collapseos.git
synced 2024-11-05 20:30:56 +11:00
17 lines
423 B
Plaintext
17 lines
423 B
Plaintext
|
( c n -- c )
|
||
|
|
( Computes n into crc c with polynomial 0x09
|
||
|
|
Note that the result is "left aligned", that is, that 8th
|
||
|
|
bit to the "right" is insignificant (will be stop bit). )
|
||
|
|
: _crc7
|
||
|
|
XOR ( c )
|
||
|
|
8 0 DO
|
||
|
|
2 * ( <<1 )
|
||
|
|
DUP 255 > IF
|
||
|
|
( MSB was set, apply polynomial )
|
||
|
|
0xff AND
|
||
|
|
0x12 XOR ( 0x09 << 1, we apply CRC on high bits )
|
||
|
|
THEN
|
||
|
|
LOOP
|
||
|
|
;
|
||
|
|
|