Commit aff2be01c9
Changed files (2)
lib
std
math
lib/std/math/big/int.zig
@@ -1096,7 +1096,7 @@ pub const Mutable = struct {
/// Asserts there is enough memory to fit the result. The upper bound Limb count is
/// `a.limbs.len + (shift / (@sizeOf(Limb) * 8))`.
pub fn shiftLeft(r: *Mutable, a: Const, shift: usize) void {
- llshl(r.limbs[0..], a.limbs[0..a.limbs.len], shift);
+ llshl(r.limbs, a.limbs, shift);
r.normalize(a.limbs.len + (shift / limb_bits) + 1);
r.positive = a.positive;
}
@@ -1165,7 +1165,7 @@ pub const Mutable = struct {
// This shift should not be able to overflow, so invoke llshl and normalize manually
// to avoid the extra required limb.
- llshl(r.limbs[0..], a.limbs[0..a.limbs.len], shift);
+ llshl(r.limbs, a.limbs, shift);
r.normalize(a.limbs.len + (shift / limb_bits));
r.positive = a.positive;
}
@@ -1202,17 +1202,11 @@ pub const Mutable = struct {
break :nonzero a.limbs[full_limbs_shifted_out] << not_covered != 0;
};
- llshr(r.limbs[0..], a.limbs[0..a.limbs.len], shift);
+ llshr(r.limbs, a.limbs, shift);
r.len = a.limbs.len - full_limbs_shifted_out;
r.positive = a.positive;
- if (nonzero_negative_shiftout) {
- if (full_limbs_shifted_out > 0) {
- r.limbs[a.limbs.len - full_limbs_shifted_out] = 0;
- r.len += 1;
- }
- r.addScalar(r.toConst(), -1);
- }
+ if (nonzero_negative_shiftout) r.addScalar(r.toConst(), -1);
r.normalize(r.len);
}
lib/std/math/big/int_test.zig
@@ -2191,6 +2191,15 @@ test "shift-right negative" {
a.setSign(true);
try a.shiftRight(&arg7, 4);
try testing.expect(try a.toInt(i16) == -2048);
+
+ var arg8_limbs: [1]Limb = undefined;
+ var arg8: Mutable = .{
+ .limbs = &arg8_limbs,
+ .len = undefined,
+ .positive = undefined,
+ };
+ arg8.shiftRight(.{ .limbs = &.{ 1, 1 }, .positive = false }, @bitSizeOf(Limb));
+ try testing.expect(arg8.toConst().orderAgainstScalar(-2).compare(.eq));
}
test "sat shift-left simple unsigned" {