|
version 1.1, 2012/09/24 20:05:43
|
version 1.2, 2013/01/24 06:41:12
|
|
|
|
| the following function is taken directly from chapter 2 of Kernighan and Ritchie | the following function is taken directly from chapter 2 of Kernighan and Ritchie |
| getbits: get n bits from position p | getbits: get n bits from position p |
| */ | */ |
| unsigned getbits(unsigned x, int p, int n) |
unsigned long long getbits(unsigned long long x, int p, int n) |
| { | { |
| return (x >> (p+1-n)) & ~(~0 << n); |
return (x >> (p+1-n)) & ~(~0ull << n); |
| } | } |
| | |
| /* | /* |
| Richard Heathfield's solution to exercise 2-6 of K&R | Richard Heathfield's solution to exercise 2-6 of K&R |
| */ | */ |
| unsigned setbits(unsigned x, int p, int n, unsigned y) |
unsigned long long setbits(unsigned long long x, int p, int n, unsigned long long y) |
| { | { |
| return (x & ((~0 << (p + 1)) | (~(~0 << (p + 1 - n))))) | ((y & ~(~0 << n)) << (p + 1 - n)); |
return (x & ((~0ull << (p + 1)) | (~(~0ull << (p + 1 - n))))) | ((y & ~(~0ull << n)) << (p + 1 - n)); |
| // another solution (unchecked): |
// another solution (untested): |
| //return (x & ~(~(~0<<n)<<p) | (y&~(~0<<n)) << p); |
//return (x & ~(~(~0<<n)<<(p+1)) | (y&~(~0<<n)) << (p+1)); |
| } | } |
| | |
| unsigned long long fixcalver64(unsigned long long x) | unsigned long long fixcalver64(unsigned long long x) |
Return to
calversfunctions.c
CVS log
Up to [Development] / JSOC / proj / globalhs / apps