Clarify comments about use of rzr on ge functions and abs function.

2020-01-09 13:07:36 +00:00
parent 2241ae6d14
commit d567b779fe
2 changed files with 4 additions and 3 deletions
--- a/src/ecmult_const_impl.h
+++ b/src/ecmult_const_impl.h
@@ -15,6 +15,7 @@
 /* This is like `ECMULT_TABLE_GET_GE` but is constant time */
 #define ECMULT_CONST_TABLE_GET_GE(r,pre,n,w) do { \
    int m; \
+    /* Extract the sign-bit for a constant time absolute-value. */ \
    int mask = (n) >> (sizeof(n) * CHAR_BIT - 1); \
    int abs_n = ((n) + mask) ^ mask; \
    int idx_n = abs_n >> 1; \