mpeg2enc/fastintfns.h

   1 /* fast int primitives. min,max,abs,samesign
   2  *
   3  * WARNING: Assumes 2's complement arithmetic.
   4  *
   5  */
   6
   7 #define fabsshift ((8*sizeof(unsigned int))-1)
   8 #ifdef P6_CPU
   9 static __inline__ int intmax( register int x, register int y )
  10 {
  11         asm( "cmpl %1, %0\n"
  12              "cmovl %1, %0\n"
  13          : "+r" (x) :  "r" (y)
  14        );
  15         return x;
  16 }
  17
  18 static __inline__ int intmin( register int x, register int y )
  19 {
  20         asm( "cmpl %1, %0\n"
  21              "cmovg %1, %0\n"
  22          : "+r" (x) :  "rm" (y)
  23        );
  24         return x;
  25 }
  26
  27 static __inline__ int intabs( register int x )
  28 {
  29         register int neg = -x;
  30         asm( "cmpl %1, %0\n"
  31              "cmovl %1, %0\n"
  32          : "+r" (x) :  "r" (neg)
  33        );
  34         return x;
  35 }
  36 #else
  37
  38 static __inline__ int intabs(int x)
  39 {
  40         return ((x)-(((unsigned int)(x))>>fabsshift)) ^ ((x)>>fabsshift);
  41 }
  42
  43 static __inline__ int intmax(int x, int y)
  44 {
  45         return (((x-y)>>fabsshift) & y) |  ((~((x-y)>>fabsshift)) & x);
  46 }
  47
  48 static __inline__ int intmin(int x,int y)
  49 {
  50         return (((y-x)>>fabsshift) & y) |  ((~((y-x)>>fabsshift)) & x);
  51 }
  52
  53 #endif
  54
  55 #define signmask(x) (((int)x)>>fabsshift)
  56 static __inline__ int intsamesign(int x, int y)
  57 {
  58         return (y+(signmask(x) & -(y<<1)));
  59 }
  60 #undef signmask
  61 #undef fabsshift
  62