Fixed bug 3468 - _allshr in SDL_stdlib.c is not working properly

Mark Pizzolato

On Windows with Visual Studio, when building SDL as a static library using the x86 (32bit) mode, several intrinsic operations are implemented in code in SDL_stdlib.c.

One of these, _allshr() is not properly implemented and fails for some input.  As a result, some operations on 64bit data elements (long long) don't always work.

I classified this bug as a blocker since things absolutely don't work when the affected code is invoked.  The affected code is only invoked when SDL is compiled in x86 mode on Visual Studio when building a SDL as a static library.  This build environment isn't common, and hence the bug hasn't been noticed previously.

I reopened #2537 and mentioned this problem and provided a fix.  That fix is provided again here along with test code which could be added to some of the SDL test code.  This test code verifies that the x86 intrinsic routines produce the same results as the native x64 instructions which these routines emulate under the Microsoft compiler.  The point of the tests is to make sure that Visual Studio x86 code produces the same results as Visual Studio x64 code.  Some of the arguments (or boundary conditions) may produce different results on other compiler environments, so the tests really shouldn't be run on all compilers.  The test driver only actually exercised code when the compiler defines _MSC_VER, so the driver can generically be invoked without issue.

1 files changed, 215 insertions, 0 deletions

diff --git a/test/testplatform.c b/test/testplatform.c
index 98c894037..fd7cddf2a 100644
--- a/test/testplatform.c
+++ b/test/testplatform.c
@@ -128,6 +128,220 @@ TestEndian(SDL_bool verbose)
     return (error ? 1 : 0);
 }
 
+static int TST_allmul (void *a, void *b, int arg, void *result, void *expected)
+{
+    (*(long long *)result) = ((*(long long *)a) * (*(long long *)b));
+    return (*(long long *)result) == (*(long long *)expected);
+}
+
+static int TST_alldiv (void *a, void *b, int arg, void *result, void *expected)
+{
+    (*(long long *)result) = ((*(long long *)a) / (*(long long *)b));
+    return (*(long long *)result) == (*(long long *)expected);
+}
+
+static int TST_allrem (void *a, void *b, int arg, void *result, void *expected)
+{
+    (*(long long *)result) = ((*(long long *)a) % (*(long long *)b));
+    return (*(long long *)result) == (*(long long *)expected);
+}
+
+static int TST_ualldiv (void *a, void *b, int arg, void *result, void *expected)
+{
+    (*(unsigned long long *)result) = ((*(unsigned long long *)a) / (*(unsigned long long *)b));
+    return (*(unsigned long long *)result) == (*(unsigned long long *)expected);
+}
+
+static int TST_uallrem (void *a, void *b, int arg, void *result, void *expected)
+{
+    (*(unsigned long long *)result) = ((*(unsigned long long *)a) % (*(unsigned long long *)b));
+    return (*(unsigned long long *)result) == (*(unsigned long long *)expected);
+}
+
+static int TST_allshl (void *a, void *b, int arg, void *result, void *expected)
+{
+    (*(long long *)result) = (*(long long *)a) << arg;
+    return (*(long long *)result) == (*(long long *)expected);
+}
+
+static int TST_aullshl (void *a, void *b, int arg, void *result, void *expected)
+{
+    (*(unsigned long long *)result) = (*(unsigned long long *)a) << arg;
+    return (*(unsigned long long *)result) == (*(unsigned long long *)expected);
+}
+
+static int TST_allshr (void *a, void *b, int arg, void *result, void *expected)
+{
+    (*(long long *)result) = (*(long long *)a) >> arg;
+    return (*(long long *)result) == (*(long long *)expected);
+}
+
+static int TST_aullshr (void *a, void *b, int arg, void *result, void *expected)
+{
+    (*(unsigned long long *)result) = (*(unsigned long long *)a) >> arg;
+    return (*(unsigned long long *)result) == (*(unsigned long long *)expected);
+}
+
+
+typedef int (*LL_Intrinsic)(void *a, void *b, int arg, void *result, void *expected);
+
+typedef struct {
+    const char *operation;
+    LL_Intrinsic routine;
+    unsigned long long a, b;
+    int arg;
+    unsigned long long expected_result;
+} LL_Test;
+
+static LL_Test LL_Tests[] = 
+{
+    {"_allshl",   &TST_allshl,   0xFFFFFFFFFFFFFFFFll,                  0ll, 65, 0x0000000000000000ll},
+    {"_allshl",   &TST_allshl,   0xFFFFFFFFFFFFFFFFll,                  0ll,  1, 0xFFFFFFFFFFFFFFFEll},
+    {"_allshl",   &TST_allshl,   0xFFFFFFFFFFFFFFFFll,                  0ll, 32, 0xFFFFFFFF00000000ll},
+    {"_allshl",   &TST_allshl,   0xFFFFFFFFFFFFFFFFll,                  0ll, 33, 0xFFFFFFFE00000000ll},
+    {"_allshl",   &TST_allshl,   0xFFFFFFFFFFFFFFFFll,                  0ll,  0, 0xFFFFFFFFFFFFFFFFll},
+
+    {"_allshr",   &TST_allshr,   0xAAAAAAAA55555555ll,                  0ll, 63, 0xFFFFFFFFFFFFFFFFll},
+    {"_allshr",   &TST_allshr,   0xFFFFFFFFFFFFFFFFll,                  0ll, 65, 0xFFFFFFFFFFFFFFFFll},
+    {"_allshr",   &TST_allshr,   0xFFFFFFFFFFFFFFFFll,                  0ll,  1, 0xFFFFFFFFFFFFFFFFll},
+    {"_allshr",   &TST_allshr,   0xFFFFFFFFFFFFFFFFll,                  0ll, 32, 0xFFFFFFFFFFFFFFFFll},
+    {"_allshr",   &TST_allshr,   0xFFFFFFFFFFFFFFFFll,                  0ll, 33, 0xFFFFFFFFFFFFFFFFll},
+    {"_allshr",   &TST_allshr,   0xFFFFFFFFFFFFFFFFll,                  0ll,  0, 0xFFFFFFFFFFFFFFFFll},
+    {"_allshr",   &TST_allshr,   0x5F5F5F5F5F5F5F5Fll,                  0ll, 65, 0x0000000000000000ll},
+    {"_allshr",   &TST_allshr,   0x5F5F5F5F5F5F5F5Fll,                  0ll,  1, 0x2FAFAFAFAFAFAFAFll},
+    {"_allshr",   &TST_allshr,   0x5F5F5F5F5F5F5F5Fll,                  0ll, 32, 0x000000005F5F5F5Fll},
+    {"_allshr",   &TST_allshr,   0x5F5F5F5F5F5F5F5Fll,                  0ll, 33, 0x000000002FAFAFAFll},
+
+    {"_aullshl",  &TST_aullshl,  0xFFFFFFFFFFFFFFFFll,                  0ll, 65, 0x0000000000000000ll},
+    {"_aullshl",  &TST_aullshl,  0xFFFFFFFFFFFFFFFFll,                  0ll,  1, 0xFFFFFFFFFFFFFFFEll},
+    {"_aullshl",  &TST_aullshl,  0xFFFFFFFFFFFFFFFFll,                  0ll, 32, 0xFFFFFFFF00000000ll},
+    {"_aullshl",  &TST_aullshl,  0xFFFFFFFFFFFFFFFFll,                  0ll, 33, 0xFFFFFFFE00000000ll},
+    {"_aullshl",  &TST_aullshl,  0xFFFFFFFFFFFFFFFFll,                  0ll,  0, 0xFFFFFFFFFFFFFFFFll},
+
+    {"_aullshr",  &TST_aullshr,  0xFFFFFFFFFFFFFFFFll,                  0ll, 65, 0x0000000000000000ll},
+    {"_aullshr",  &TST_aullshr,  0xFFFFFFFFFFFFFFFFll,                  0ll,  1, 0x7FFFFFFFFFFFFFFFll},
+    {"_aullshr",  &TST_aullshr,  0xFFFFFFFFFFFFFFFFll,                  0ll, 32, 0x00000000FFFFFFFFll},
+    {"_aullshr",  &TST_aullshr,  0xFFFFFFFFFFFFFFFFll,                  0ll, 33, 0x000000007FFFFFFFll},
+    {"_aullshr",  &TST_aullshr,  0xFFFFFFFFFFFFFFFFll,                  0ll,  0, 0xFFFFFFFFFFFFFFFFll},
+
+    {"_allmul",   &TST_allmul,   0xFFFFFFFFFFFFFFFFll, 0x0000000000000000ll,  0, 0x0000000000000000ll},
+    {"_allmul",   &TST_allmul,   0x0000000000000000ll, 0xFFFFFFFFFFFFFFFFll,  0, 0x0000000000000000ll},
+    {"_allmul",   &TST_allmul,   0x000000000FFFFFFFll, 0x0000000000000001ll,  0, 0x000000000FFFFFFFll},
+    {"_allmul",   &TST_allmul,   0x0000000000000001ll, 0x000000000FFFFFFFll,  0, 0x000000000FFFFFFFll},
+    {"_allmul",   &TST_allmul,   0x000000000FFFFFFFll, 0x0000000000000010ll,  0, 0x00000000FFFFFFF0ll},
+    {"_allmul",   &TST_allmul,   0x0000000000000010ll, 0x000000000FFFFFFFll,  0, 0x00000000FFFFFFF0ll},
+    {"_allmul",   &TST_allmul,   0x000000000FFFFFFFll, 0x0000000000000100ll,  0, 0x0000000FFFFFFF00ll},
+    {"_allmul",   &TST_allmul,   0x0000000000000100ll, 0x000000000FFFFFFFll,  0, 0x0000000FFFFFFF00ll},
+    {"_allmul",   &TST_allmul,   0x000000000FFFFFFFll, 0x0000000010000000ll,  0, 0x00FFFFFFF0000000ll},
+    {"_allmul",   &TST_allmul,   0x0000000010000000ll, 0x000000000FFFFFFFll,  0, 0x00FFFFFFF0000000ll},
+    {"_allmul",   &TST_allmul,   0x000000000FFFFFFFll, 0x0000000080000000ll,  0, 0x07FFFFFF80000000ll},
+    {"_allmul",   &TST_allmul,   0x0000000080000000ll, 0x000000000FFFFFFFll,  0, 0x07FFFFFF80000000ll},
+    {"_allmul",   &TST_allmul,   0xFFFFFFFFFFFFFFFEll, 0x0000000080000000ll,  0, 0xFFFFFFFF00000000ll},
+    {"_allmul",   &TST_allmul,   0x0000000080000000ll, 0xFFFFFFFFFFFFFFFEll,  0, 0xFFFFFFFF00000000ll},
+    {"_allmul",   &TST_allmul,   0xFFFFFFFFFFFFFFFEll, 0x0000000080000008ll,  0, 0xFFFFFFFEFFFFFFF0ll},
+    {"_allmul",   &TST_allmul,   0x0000000080000008ll, 0xFFFFFFFFFFFFFFFEll,  0, 0xFFFFFFFEFFFFFFF0ll},
+    {"_allmul",   &TST_allmul,   0x00000000FFFFFFFFll, 0x00000000FFFFFFFFll,  0, 0xFFFFFFFE00000001ll},
+
+    {"_alldiv",   &TST_alldiv,   0x0000000000000000ll, 0x0000000000000001ll,  0, 0x0000000000000000ll},
+    {"_alldiv",   &TST_alldiv,   0x0000000000000000ll, 0xFFFFFFFFFFFFFFFFll,  0, 0x0000000000000000ll},
+    {"_alldiv",   &TST_alldiv,   0x0000000000000001ll, 0xFFFFFFFFFFFFFFFFll,  0, 0xFFFFFFFFFFFFFFFFll},
+    {"_alldiv",   &TST_alldiv,   0xFFFFFFFFFFFFFFFFll, 0x0000000000000001ll,  0, 0xFFFFFFFFFFFFFFFFll},
+    {"_alldiv",   &TST_alldiv,   0x0000000000000001ll, 0xFFFFFFFFFFFFFFFFll,  0, 0xFFFFFFFFFFFFFFFFll},
+    {"_alldiv",   &TST_alldiv,   0x0000000000000001ll, 0x0000000000000001ll,  0, 0x0000000000000001ll},
+    {"_alldiv",   &TST_alldiv,   0xFFFFFFFFFFFFFFFFll, 0xFFFFFFFFFFFFFFFFll,  0, 0x0000000000000001ll},
+    {"_alldiv",   &TST_alldiv,   0x000000000FFFFFFFll, 0x0000000000000001ll,  0, 0x000000000FFFFFFFll},
+    {"_alldiv",   &TST_alldiv,   0x0000000FFFFFFFFFll, 0x0000000000000010ll,  0, 0x00000000FFFFFFFFll},
+    {"_alldiv",   &TST_alldiv,   0x0000000000000100ll, 0x000000000FFFFFFFll,  0, 0x0000000000000000ll},
+    {"_alldiv",   &TST_alldiv,   0x00FFFFFFF0000000ll, 0x0000000010000000ll,  0, 0x000000000FFFFFFFll},
+    {"_alldiv",   &TST_alldiv,   0x07FFFFFF80000000ll, 0x0000000080000000ll,  0, 0x000000000FFFFFFFll},
+    {"_alldiv",   &TST_alldiv,   0xFFFFFFFFFFFFFFFEll, 0x0000000080000000ll,  0, 0x0000000000000000ll},
+    {"_alldiv",   &TST_alldiv,   0xFFFFFFFEFFFFFFF0ll, 0xFFFFFFFFFFFFFFFEll,  0, 0x0000000080000008ll},
+    {"_alldiv",   &TST_alldiv,   0x7FFFFFFEFFFFFFF0ll, 0xFFFFFFFFFFFFFFFEll,  0, 0xC000000080000008ll},
+    {"_alldiv",   &TST_alldiv,   0x7FFFFFFEFFFFFFF0ll, 0x0000FFFFFFFFFFFEll,  0, 0x0000000000007FFFll},
+    {"_alldiv",   &TST_alldiv,   0x7FFFFFFEFFFFFFF0ll, 0x7FFFFFFEFFFFFFF0ll,  0, 0x0000000000000001ll},
+
+    {"_allrem",   &TST_allrem,   0x0000000000000000ll, 0x0000000000000001ll,  0, 0x0000000000000000ll},
+    {"_allrem",   &TST_allrem,   0x0000000000000000ll, 0xFFFFFFFFFFFFFFFFll,  0, 0x0000000000000000ll},
+    {"_allrem",   &TST_allrem,   0x0000000000000001ll, 0xFFFFFFFFFFFFFFFFll,  0, 0x0000000000000000ll},
+    {"_allrem",   &TST_allrem,   0xFFFFFFFFFFFFFFFFll, 0x0000000000000001ll,  0, 0x0000000000000000ll},
+    {"_allrem",   &TST_allrem,   0x0000000000000001ll, 0xFFFFFFFFFFFFFFFFll,  0, 0x0000000000000000ll},
+    {"_allrem",   &TST_allrem,   0x0000000000000001ll, 0x0000000000000001ll,  0, 0x0000000000000000ll},
+    {"_allrem",   &TST_allrem,   0xFFFFFFFFFFFFFFFFll, 0xFFFFFFFFFFFFFFFFll,  0, 0x0000000000000000ll},
+    {"_allrem",   &TST_allrem,   0x000000000FFFFFFFll, 0x0000000000000001ll,  0, 0x0000000000000000ll},
+    {"_allrem",   &TST_allrem,   0x0000000FFFFFFFFFll, 0x0000000000000010ll,  0, 0x000000000000000Fll},
+    {"_allrem",   &TST_allrem,   0x0000000000000100ll, 0x000000000FFFFFFFll,  0, 0x0000000000000100ll},
+    {"_allrem",   &TST_allrem,   0x00FFFFFFF0000000ll, 0x0000000010000000ll,  0, 0x0000000000000000ll},
+    {"_allrem",   &TST_allrem,   0x07FFFFFF80000000ll, 0x0000000080000000ll,  0, 0x0000000000000000ll},
+    {"_allrem",   &TST_allrem,   0xFFFFFFFFFFFFFFFEll, 0x0000000080000000ll,  0, 0xFFFFFFFFFFFFFFFEll},
+    {"_allrem",   &TST_allrem,   0xFFFFFFFEFFFFFFF0ll, 0xFFFFFFFFFFFFFFFEll,  0, 0x0000000000000000ll},
+    {"_allrem",   &TST_allrem,   0x7FFFFFFEFFFFFFF0ll, 0xFFFFFFFFFFFFFFFEll,  0, 0x0000000000000000ll},
+    {"_allrem",   &TST_allrem,   0x7FFFFFFEFFFFFFF0ll, 0x0000FFFFFFFFFFFEll,  0, 0x0000FFFF0000FFEEll},
+    {"_allrem",   &TST_allrem,   0x7FFFFFFEFFFFFFF0ll, 0x7FFFFFFEFFFFFFF0ll,  0, 0x0000000000000000ll},
+
+
+    {"_ualldiv",  &TST_ualldiv,  0x0000000000000000ll, 0x0000000000000001ll,  0, 0x0000000000000000ll},
+    {"_ualldiv",  &TST_ualldiv,  0x0000000000000000ll, 0xFFFFFFFFFFFFFFFFll,  0, 0x0000000000000000ll},
+    {"_ualldiv",  &TST_ualldiv,  0x0000000000000001ll, 0xFFFFFFFFFFFFFFFFll,  0, 0x0000000000000000ll},
+    {"_ualldiv",  &TST_ualldiv,  0xFFFFFFFFFFFFFFFFll, 0x0000000000000001ll,  0, 0xFFFFFFFFFFFFFFFFll},
+    {"_ualldiv",  &TST_ualldiv,  0x0000000000000001ll, 0xFFFFFFFFFFFFFFFFll,  0, 0x0000000000000000ll},
+    {"_ualldiv",  &TST_ualldiv,  0x0000000000000001ll, 0x0000000000000001ll,  0, 0x0000000000000001ll},
+    {"_ualldiv",  &TST_ualldiv,  0xFFFFFFFFFFFFFFFFll, 0xFFFFFFFFFFFFFFFFll,  0, 0x0000000000000001ll},
+    {"_ualldiv",  &TST_ualldiv,  0x000000000FFFFFFFll, 0x0000000000000001ll,  0, 0x000000000FFFFFFFll},
+    {"_ualldiv",  &TST_ualldiv,  0x0000000FFFFFFFFFll, 0x0000000000000010ll,  0, 0x00000000FFFFFFFFll},
+    {"_ualldiv",  &TST_ualldiv,  0x0000000000000100ll, 0x000000000FFFFFFFll,  0, 0x0000000000000000ll},
+    {"_ualldiv",  &TST_ualldiv,  0x00FFFFFFF0000000ll, 0x0000000010000000ll,  0, 0x000000000FFFFFFFll},
+    {"_ualldiv",  &TST_ualldiv,  0x07FFFFFF80000000ll, 0x0000000080000000ll,  0, 0x000000000FFFFFFFll},
+    {"_ualldiv",  &TST_ualldiv,  0xFFFFFFFFFFFFFFFEll, 0x0000000080000000ll,  0, 0x00000001FFFFFFFFll},
+    {"_ualldiv",  &TST_ualldiv,  0xFFFFFFFEFFFFFFF0ll, 0xFFFFFFFFFFFFFFFEll,  0, 0x0000000000000000ll},
+    {"_ualldiv",  &TST_ualldiv,  0x7FFFFFFEFFFFFFF0ll, 0xFFFFFFFFFFFFFFFEll,  0, 0x0000000000000000ll},
+    {"_ualldiv",  &TST_ualldiv,  0x7FFFFFFEFFFFFFF0ll, 0x0000FFFFFFFFFFFEll,  0, 0x0000000000007FFFll},
+    {"_ualldiv",  &TST_ualldiv,  0x7FFFFFFEFFFFFFF0ll, 0x7FFFFFFEFFFFFFF0ll,  0, 0x0000000000000001ll},
+
+    {"_uallrem",  &TST_uallrem,  0x0000000000000000ll, 0x0000000000000001ll,  0, 0x0000000000000000ll},
+    {"_uallrem",  &TST_uallrem,  0x0000000000000000ll, 0xFFFFFFFFFFFFFFFFll,  0, 0x0000000000000000ll},
+    {"_uallrem",  &TST_uallrem,  0x0000000000000001ll, 0xFFFFFFFFFFFFFFFFll,  0, 0x0000000000000001ll},
+    {"_uallrem",  &TST_uallrem,  0xFFFFFFFFFFFFFFFFll, 0x0000000000000001ll,  0, 0x0000000000000000ll},
+    {"_uallrem",  &TST_uallrem,  0x0000000000000001ll, 0xFFFFFFFFFFFFFFFFll,  0, 0x0000000000000001ll},
+    {"_uallrem",  &TST_uallrem,  0x0000000000000001ll, 0x0000000000000001ll,  0, 0x0000000000000000ll},
+    {"_uallrem",  &TST_uallrem,  0xFFFFFFFFFFFFFFFFll, 0xFFFFFFFFFFFFFFFFll,  0, 0x0000000000000000ll},
+    {"_uallrem",  &TST_uallrem,  0x000000000FFFFFFFll, 0x0000000000000001ll,  0, 0x0000000000000000ll},
+    {"_uallrem",  &TST_uallrem,  0x0000000FFFFFFFFFll, 0x0000000000000010ll,  0, 0x000000000000000Fll},
+    {"_uallrem",  &TST_uallrem,  0x0000000000000100ll, 0x000000000FFFFFFFll,  0, 0x0000000000000100ll},
+    {"_uallrem",  &TST_uallrem,  0x00FFFFFFF0000000ll, 0x0000000010000000ll,  0, 0x0000000000000000ll},
+    {"_uallrem",  &TST_uallrem,  0x07FFFFFF80000000ll, 0x0000000080000000ll,  0, 0x0000000000000000ll},
+    {"_uallrem",  &TST_uallrem,  0xFFFFFFFFFFFFFFFEll, 0x0000000080000000ll,  0, 0x000000007FFFFFFEll},
+    {"_uallrem",  &TST_uallrem,  0xFFFFFFFEFFFFFFF0ll, 0xFFFFFFFFFFFFFFFEll,  0, 0xFFFFFFFEFFFFFFF0ll},
+    {"_uallrem",  &TST_uallrem,  0x7FFFFFFEFFFFFFF0ll, 0xFFFFFFFFFFFFFFFEll,  0, 0x7FFFFFFEFFFFFFF0ll},
+    {"_uallrem",  &TST_uallrem,  0x7FFFFFFEFFFFFFF0ll, 0x0000FFFFFFFFFFFEll,  0, 0x0000FFFF0000FFEEll},
+    {"_uallrem",  &TST_uallrem,  0x7FFFFFFEFFFFFFF0ll, 0x7FFFFFFEFFFFFFF0ll,  0, 0x0000000000000000ll},
+
+    {NULL}
+};
+
+int
+Test64Bit (SDL_bool verbose)
+{
+    LL_Test *t;
+    int failed = 0;
+
+    for (t = LL_Tests; t->routine != NULL; t++) {
+        unsigned long long result = 0;
+        unsigned int *al = (unsigned int *)&t->a;
+        unsigned int *bl = (unsigned int *)&t->b;
+        unsigned int *el = (unsigned int *)&t->expected_result;
+        unsigned int *rl = (unsigned int *)&result;
+
+        if (!t->routine(&t->a, &t->b, t->arg, &result, &t->expected_result)) {
+            if (verbose)
+                SDL_Log("%s(0x%08X%08X, 0x%08X%08X, %3d, produced: 0x%08X%08X, expected: 0x%08X%08X\n",
+                        t->operation, al[1], al[0], bl[1], bl[0], t->arg, rl[1], rl[0], el[1], el[0]);
+            ++failed;
+        }
+    }
+    if (verbose && (failed == 0))
+        SDL_Log("All 64bit instrinsic tests passed\n");
+    return (failed ? 1 : 0);
+}
 
 int
 TestCPUInfo(SDL_bool verbose)
@@ -198,6 +412,7 @@ main(int argc, char *argv[])
 
     status += TestTypes(verbose);
     status += TestEndian(verbose);
+    status += Test64Bit(verbose);
     status += TestCPUInfo(verbose);
     status += TestAssertions(verbose);