none/tests/arm/intdiv.c

   1
   2 #include <stdio.h>
   3
   4 typedef    signed int  Int;
   5 typedef  unsigned int  UInt;
   6
   7 __attribute__((noinline)) UInt do_udiv32 ( UInt x, UInt y )
   8 {
   9   UInt res;
  10   __asm__ __volatile__(
  11      "mov r9, %1 ; mov r10, %2 ; udiv r3,r9,r10 ; mov %0, r3"
  12      : "=r"(res) : "r"(x), "r"(y) : "r3", "r9", "r10"
  13   );
  14   return res;
  15 }
  16
  17 __attribute__((noinline)) Int do_sdiv32 ( Int x, Int y )
  18 {
  19   UInt res;
  20   __asm__ __volatile__(
  21      "mov r9, %1 ; mov r10, %2 ; sdiv r3,r9,r10 ; mov %0, r3"
  22      : "=r"(res) : "r"(x), "r"(y) : "r3", "r9", "r10"
  23   );
  24   return res;
  25 }
  26
  27 void test ( UInt x, UInt y )
  28 {
  29   UInt ru = do_udiv32(x,y);
  30   Int rs = do_sdiv32(x,y);
  31   printf( "%08x %08x -> u:%08x s:%08x\n", x, y, ru, (UInt)rs);
  32 }
  33
  34 int main ( void )
  35 {
  36   // Check basic operation
  37   test( 500, 50 );
  38   test( 500, -50 );
  39   test( -500, 50 );
  40   test( -500, -50 );
  41   // Check for rounding towards zero
  42   test( 100, 7 );   // 14.285
  43   test( -100, 7 );
  44   test( 100, -7 );
  45   test( -100, -7 );
  46   // Division by zero produces zero
  47   test( 1, 0 );
  48   test( 0, 0 );
  49   test( -1, 0 );
  50   test( 0x80000000, 0 );
  51   test( 0x7FFFFFFF, 0 );
  52   // Test signed range ends
  53   test( 0x80000000, -1 ); // unrepresentable as signed 32
  54   return 0;
  55 }