sdcc/support/regression/tests/bug-3607.c

   1 /*
   2   bug-3607.c
   3 */
   4
   5 #include <testfwk.h>
   6
   7 #include <stdint.h>
   8 #include <stdbool.h>
   9
  10 //#ifdef __SDCC_mcs51
  11
  12 __xdata uint16_t g_arg_1 = 0;
  13 #ifdef __SDCC_mcs51
  14 __bit g_arg_2 = 0;
  15 #else
  16 _Bool g_arg_2 = 0;
  17 #endif
  18
  19 #define sel_const1 (uint16_t)((g_arg_2 ? 0x1F09FFFFu : 0x101FFFFEu) >> 16)
  20 #define sel_const2 (uint16_t)((g_arg_2 ? 0x101FFFF0u : 0x101FFFF1u) >> 16)
  21
  22 bool func_3 (void)
  23 {
  24   return true;
  25 }
  26
  27 __xdata uint8_t func_1_count = 0;
  28 __xdata uint8_t func_2_count = 0;
  29
  30 void func_1 (void)
  31 {
  32   ++func_1_count;
  33 }
  34
  35 void func_2 (void)
  36 {
  37   ++func_2_count;
  38 }
  39
  40 void func (uint32_t test_arg)
  41 {
  42   uint16_t t = test_arg >> 16;
  43
  44   if (func_3 ())
  45   {
  46     // the bug was the constant being loaded wrongly into the registers
  47     // before the comparision, where one of the bytes got overwritten with
  48     // another.
  49     // this gets tested twice with different inputs so we get two mutually
  50     // exclusive false positives if there is a bug, or two good hits if
  51     // there is no bug.
  52
  53     // when g_arg_2 = 0:
  54     // (t - g_arg_1 = 1020) > 101F   T
  55     // (t - g_arg_1 = 1020) > 1010   T (false positive)
  56     // (t - g_arg_1 = 1020) > 1F1F   F
  57     // (t - g_arg_1 = 1020) > 1F10   F
  58
  59     // when g_arg_2 = 1:
  60     // (t - g_arg_1 = 1F10) > 1F09   T
  61     // (t - g_arg_1 = 1F10) > 1F1F   F
  62     // (t - g_arg_1 = 1F10) > 0909   T (false positive)
  63     // (t - g_arg_1 = 1F10) > 091F   F
  64
  65     if (t - g_arg_1 > sel_const1)
  66       func_1 ();
  67   }
  68   else
  69   {
  70     if (t - g_arg_1 > sel_const2)
  71       func_2 ();
  72   }
  73 }
  74 //#endif
  75
  76 void testBug (void)
  77 {
  78 //#ifdef __SDCC_mcs51
  79
  80   g_arg_1 = 0;
  81   g_arg_2 = 0;
  82   func (0x10200000ul);
  83
  84   g_arg_1 = 0;
  85   g_arg_2 = 1;
  86   func (0x1F100000ul);
  87
  88   ASSERT (func_1_count == 2);
  89   ASSERT (func_2_count == 0);
  90
  91 //#endif
  92 }
  93