patch 8.2.5004: right shift on negative number does not work as documented
Problem: Right shift on negative number does not work as documented.
Solution: Use a uvarnumber_T type cast.
diff --git a/src/charset.c b/src/charset.c
index 34751e1..203a8fe 100644
--- a/src/charset.c
+++ b/src/charset.c
@@ -2002,6 +2002,7 @@
}
else
{
+ // prevent a larg unsigned number to become negative
if (un > VARNUM_MAX)
un = VARNUM_MAX;
*nptr = (varnumber_T)un;
diff --git a/src/eval.c b/src/eval.c
index 0ac2dfb..7f90954 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -3091,12 +3091,8 @@
rettv->vval.v_number =
rettv->vval.v_number << var2.vval.v_number;
else
- {
rettv->vval.v_number =
- rettv->vval.v_number >> var2.vval.v_number;
- // clear the topmost sign bit
- rettv->vval.v_number &= ~((uvarnumber_T)1 << MAX_LSHIFT_BITS);
- }
+ (uvarnumber_T)rettv->vval.v_number >> var2.vval.v_number;
}
clear_tv(&var2);
diff --git a/src/testdir/test_expr.vim b/src/testdir/test_expr.vim
index 24daeb6..ffac6df 100644
--- a/src/testdir/test_expr.vim
+++ b/src/testdir/test_expr.vim
@@ -958,6 +958,8 @@
call assert_equal(0, 0 >> 4)
call assert_equal(0, 999999 >> 100)
call assert_equal(0, 999999 << 100)
+ call assert_equal(-1, -1 >> 0)
+ call assert_equal(-1, -1 << 0)
VAR a = 8
VAR b = 2
call assert_equal(2, a >> b)
@@ -976,6 +978,15 @@
for i in range(0, v:numbersize - 2)
LET val = and(val, invert(1 << i))
endfor
+ #" -1 has all the bits set
+ call assert_equal(-2, -1 << 1)
+ call assert_equal(-4, -1 << 2)
+ call assert_equal(-8, -1 << 3)
+ if v:numbersize == 64
+ call assert_equal(0x7fffffffffffffff, -1 >> 1)
+ call assert_equal(0x3fffffffffffffff, -1 >> 2)
+ call assert_equal(0x1fffffffffffffff, -1 >> 3)
+ endif
call assert_equal(0, val)
#" multiple operators
call assert_equal(16, 1 << 2 << 2)
diff --git a/src/version.c b/src/version.c
index a6570a3..e8799ad 100644
--- a/src/version.c
+++ b/src/version.c
@@ -735,6 +735,8 @@
static int included_patches[] =
{ /* Add new patch number below this line */
/**/
+ 5004,
+/**/
5003,
/**/
5002,
diff --git a/src/vim9execute.c b/src/vim9execute.c
index b4fd9d5..5410aa2 100644
--- a/src/vim9execute.c
+++ b/src/vim9execute.c
@@ -4096,12 +4096,7 @@
case EXPR_RSHIFT: if (arg2 > MAX_LSHIFT_BITS)
res = 0;
else
- {
- res = arg1 >> arg2;
- // clear the topmost sign bit
- res &= ~((uvarnumber_T)1
- << MAX_LSHIFT_BITS);
- }
+ res = (uvarnumber_T)arg1 >> arg2;
break;
default: break;
}
diff --git a/src/vim9expr.c b/src/vim9expr.c
index c84be87..3e720d9 100644
--- a/src/vim9expr.c
+++ b/src/vim9expr.c
@@ -2719,11 +2719,8 @@
else if (type == EXPR_LSHIFT)
tv1->vval.v_number = tv1->vval.v_number << tv2->vval.v_number;
else
- {
- tv1->vval.v_number = tv1->vval.v_number >> tv2->vval.v_number;
- // clear the topmost sign bit
- tv1->vval.v_number &= ~((uvarnumber_T)1 << MAX_LSHIFT_BITS);
- }
+ tv1->vval.v_number =
+ (uvarnumber_T)tv1->vval.v_number >> tv2->vval.v_number;
clear_tv(tv2);
--ppconst->pp_used;
}