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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/mpvecsub.c | |
parent | 498bb22174aa2c76493e8c67b92949271131ebfb (diff) | |
download | plan9port-b3f61791f1e9095ce8ae9c6d6415b4ee94e2f7eb.tar.gz plan9port-b3f61791f1e9095ce8ae9c6d6415b4ee94e2f7eb.tar.bz2 plan9port-b3f61791f1e9095ce8ae9c6d6415b4ee94e2f7eb.zip |
Add libmp.
Diffstat (limited to 'src/libmp/port/mpvecsub.c')
-rw-r--r-- | src/libmp/port/mpvecsub.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/src/libmp/port/mpvecsub.c b/src/libmp/port/mpvecsub.c new file mode 100644 index 00000000..db93b65b --- /dev/null +++ b/src/libmp/port/mpvecsub.c @@ -0,0 +1,34 @@ +#include "os.h" +#include <mp.h> +#include "dat.h" + +// prereq: a >= b, alen >= blen, diff has at least alen digits +void +mpvecsub(mpdigit *a, int alen, mpdigit *b, int blen, mpdigit *diff) +{ + int i, borrow; + mpdigit x, y; + + borrow = 0; + for(i = 0; i < blen; i++){ + x = *a++; + y = *b++; + y += borrow; + if(y < borrow) + borrow = 1; + else + borrow = 0; + if(x < y) + borrow++; + *diff++ = x - y; + } + for(; i < alen; i++){ + x = *a++; + y = x - borrow; + if(y > x) + borrow = 1; + else + borrow = 0; + *diff++ = y; + } +} |