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author | rsc <devnull@localhost> | 2004-03-21 14:06:38 +0000 |
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committer | rsc <devnull@localhost> | 2004-03-21 14:06:38 +0000 |
commit | b3f61791f1e9095ce8ae9c6d6415b4ee94e2f7eb (patch) | |
tree | deaa85427ae73a045ddef39395bd286f9d3dc2ff /src/libmp/port/betomp.c | |
parent | 498bb22174aa2c76493e8c67b92949271131ebfb (diff) | |
download | plan9port-b3f61791f1e9095ce8ae9c6d6415b4ee94e2f7eb.tar.gz plan9port-b3f61791f1e9095ce8ae9c6d6415b4ee94e2f7eb.tar.bz2 plan9port-b3f61791f1e9095ce8ae9c6d6415b4ee94e2f7eb.zip |
Add libmp.
Diffstat (limited to 'src/libmp/port/betomp.c')
-rw-r--r-- | src/libmp/port/betomp.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/src/libmp/port/betomp.c b/src/libmp/port/betomp.c new file mode 100644 index 00000000..95935fcd --- /dev/null +++ b/src/libmp/port/betomp.c @@ -0,0 +1,40 @@ +#include "os.h" +#include <mp.h> +#include "dat.h" + +// convert a big-endian byte array (most significant byte first) to an mpint +mpint* +betomp(uchar *p, uint n, mpint *b) +{ + int m, s; + mpdigit x; + + if(b == nil) + b = mpnew(0); + + // dump leading zeros + while(*p == 0 && n > 1){ + p++; + n--; + } + + // get the space + mpbits(b, n*8); + b->top = DIGITS(n*8); + m = b->top-1; + + // first digit might not be Dbytes long + s = ((n-1)*8)%Dbits; + x = 0; + for(; n > 0; n--){ + x |= ((mpdigit)(*p++)) << s; + s -= 8; + if(s < 0){ + b->p[m--] = x; + s = Dbits-8; + x = 0; + } + } + + return b; +} |