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patch 8.2.5004: right shift on negative number does not work as documented

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Problem:    Right shift on negative number does not work as documented.
Solution:   Use a uvarnumber_T type cast.
This commit is contained in:
Bram Moolenaar
2022-05-22 20:16:32 +01:00
parent a061f34191
commit 338bf58eba
7 changed files with 26 additions and 19 deletions
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1
src/charset.c
View File

@@ -2002,6 +2002,7 @@ vim_str2nr(
}
else
{
// prevent a larg unsigned number to become negative
if (un > VARNUM_MAX)
un = VARNUM_MAX;
*nptr = (varnumber_T)un;

6
src/eval.c
View File

@@ -3091,12 +3091,8 @@ eval5(char_u **arg, typval_T *rettv, evalarg_T *evalarg)
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);

11
src/testdir/test_expr.vim
View File

@@ -958,6 +958,8 @@ func Test_bitwise_shift()
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 @@ func Test_bitwise_shift()
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)

2
src/version.c
View File

@@ -734,6 +734,8 @@ static char *(features[]) =
static int included_patches[] =
{ /* Add new patch number below this line */
/**/
5004,
/**/
5003,
/**/

7
src/vim9execute.c
View File

@@ -4096,12 +4096,7 @@ exec_instructions(ectx_T *ectx)
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;
}

7
src/vim9expr.c
View File

@@ -2719,11 +2719,8 @@ compile_expr5(char_u **arg, cctx_T *cctx, ppconst_T *ppconst)
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;
}