X-Git-Url: https://pd.if.org/git/?a=blobdiff_plain;f=tomsfastmath%2Fsrc%2Faddsub%2Ffp_add.c;fp=tomsfastmath%2Fsrc%2Faddsub%2Ffp_add.c;h=9d1cf45827d9402989251de16fa83b98e56d0e08;hb=66bc25938679f1d6a1d1200f329093d82a5e99b4;hp=0000000000000000000000000000000000000000;hpb=a52ee0733f420ca20224049260d6fc5cf7d8f621;p=zpackage

diff --git a/tomsfastmath/src/addsub/fp_add.c b/tomsfastmath/src/addsub/fp_add.c
new file mode 100644
index 0000000..9d1cf45
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+++ b/tomsfastmath/src/addsub/fp_add.c
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+/* TomsFastMath, a fast ISO C bignum library.
+ * 
+ * This project is meant to fill in where LibTomMath
+ * falls short.  That is speed ;-)
+ *
+ * This project is public domain and free for all purposes.
+ * 
+ * Tom St Denis, tomstdenis@gmail.com
+ */
+#include <tfm_private.h>
+
+void fp_add(fp_int *a, fp_int *b, fp_int *c)
+{
+  int     sa, sb;
+
+  /* get sign of both inputs */
+  sa = a->sign;
+  sb = b->sign;
+
+  /* handle two cases, not four */
+  if (sa == sb) {
+    /* both positive or both negative */
+    /* add their magnitudes, copy the sign */
+    c->sign = sa;
+    s_fp_add (a, b, c);
+  } else {
+    /* one positive, the other negative */
+    /* subtract the one with the greater magnitude from */
+    /* the one of the lesser magnitude.  The result gets */
+    /* the sign of the one with the greater magnitude. */
+    if (fp_cmp_mag (a, b) == FP_LT) {
+      c->sign = sb;
+      s_fp_sub (b, a, c);
+    } else {
+      c->sign = sa;
+      s_fp_sub (a, b, c);
+    }
+  }
+}
+
+/* $Source$ */
+/* $Revision$ */
+/* $Date$ */