+/* Decrement a bignum in-place, return the borrow flag. */
+integerPart
+APInt::tcDecrement(integerPart *dst, unsigned int parts) {
+ for (unsigned int i = 0; i < parts; i++) {
+ // If the current word is non-zero, then the decrement has no effect on the
+ // higher-order words of the integer and no borrow can occur. Exit early.
+ if (dst[i]--)
+ return 0;
+ }
+ // If every word was zero, then there is a borrow.
+ return 1;
+}
+
+