_PyLong_AsByteArray: simplify the logic for dealing with the most-
significant digits sign bits. Again no change in semantics.
diff --git a/Objects/longobject.c b/Objects/longobject.c
index 54d59c3..250db7c 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -388,7 +388,6 @@
accumbits = 0;
carry = do_twos_comp ? 1 : 0;
for (i = 0; i < ndigits; ++i) {
- unsigned int numnewbits = SHIFT;
twodigits thisdigit = v->ob_digit[i];
if (do_twos_comp) {
thisdigit = (thisdigit ^ MASK) + carry;
@@ -399,22 +398,25 @@
significant than what's already in accum, so needs to be
prepended to accum. */
accum |= thisdigit << accumbits;
+ accumbits += SHIFT;
- /* How many new bits did we add? The most-significant digit
- may be (probably is) at least partly empty. */
+ /* The most-significant digit may be (probably is) at least
+ partly empty. */
if (i == ndigits - 1) {
- twodigits bitmask = 1 << (SHIFT - 1);
- twodigits signbit = do_twos_comp << (SHIFT - 1);
+ /* Count # of sign bits -- they needn't be stored,
+ * although for signed conversion we need later to
+ * make sure at least one sign bit gets stored.
+ * First shift conceptual sign bit to real sign bit.
+ */
+ stwodigits s = (stwodigits)(thisdigit <<
+ (8*sizeof(stwodigits) - SHIFT));
unsigned int nsignbits = 0;
- while ((thisdigit & bitmask) == signbit && bitmask) {
+ while ((s < 0) == do_twos_comp && nsignbits < SHIFT) {
++nsignbits;
- bitmask >>= 1;
- signbit >>= 1;
+ s <<= 1;
}
- assert(nsignbits <= SHIFT);
- numnewbits -= nsignbits;
+ accumbits -= nsignbits;
}
- accumbits += numnewbits;
/* Store as many bytes as possible. */
while (accumbits >= 8) {