[LV-kern-commit] CVS: kernel/include/asm-vax byteorder.h,1.2,1.3

[Andy P. <at...@us...>]

Update of /cvsroot/linux-vax/kernel/include/asm-vax
In directory usw-pr-cvs1:/tmp/cvs-serv4990

Modified Files:
	byteorder.h 
Log Message:
 integrate ragge's suggestions for byteorder.h


Index: byteorder.h
===================================================================
RCS file: /cvsroot/linux-vax/kernel/include/asm-vax/byteorder.h,v
retrieving revision 1.2
retrieving revision 1.3
diff -C2 -r1.2 -r1.3
*** byteorder.h	2001/01/20 12:36:16	1.2
--- byteorder.h	2001/01/20 13:47:32	1.3
***************
*** 7,38 ****
  
  #ifdef __GNUC__
! 
  static __inline__ __const__ __u32 ___arch__swab32(__u32 x)
  {
!   __u32 t1, t2;                     /* assume input is aabbccdd in x*/
     
!        __asm__("clrl %0\n\t" 		     /* clear t1 */ 
!                "rotl $8, %2, %1\n\t"         /* %1 = bbccddaa */ 
!                "bisl3 $0xff00ff, %1, %0\n\t" /* %0 = 00cc00aa */ 
!                "rotl $-8, %2, %1\n\t"        /* %1 = ddaabbcc */
!                "bicl2 $0xff00ff, %1\n\t"     /* %1 = dd00bb00 */
!                "bisl2 %1, %0\n\t"            /* %0 = ddccbbaa */ 
!                : "=g" (t1), "=g" (t2) : "g" (x) ); 
       return t1; 
  }
  
  static __inline__ __const__ __u16 ___arch__swab16(__u16 x)
  {
!   __u32 t1, t2, t3;
! 	__asm__("clrl %2\n\t"
! 		"movw %3,%2\n\t"    /* %2=0000aabb */
! 		"rotl $-8,%2,%0\n\t"  /* %0=bb0000aa */
! 		"ashl $24,%0,%1\n\t"  /* %1=aa000000 */
! 		"rotl $8,%1,%0\n\t"   /* %0=000000aa */
! 		"ashl $8,%2,%1\n\t"   /* %1=00aabb00 */
! 		"bicl2 $0xfffff00ff, %1\n\t"   /* %1=0000bb00 */
! 		"addl2 %1,%0\n\t"    /* %0=0000bbaa */
! 		: "=g" (t1), "=g" (t2), "=g"(t3) : "g" (x));
! 	return (__u16) t1;
  }
  
--- 7,34 ----
  
  #ifdef __GNUC__
! /* 
!  * ragge has a 1 insn shorter sequence which will probably replace this one 
!  * later, depending on the relative instruction costs. 
!  */
  static __inline__ __const__ __u32 ___arch__swab32(__u32 x)
  {
!   __u32 t1;                     /* assume input is aabbccdd in x*/
     
!        __asm__("rotl $8, %1, r1\n\t"         /* r1 = bbccddaa */ 
!                "bisl3 $0xff00ff, r1, %0\n\t" /* %0 = 00cc00aa */ 
!                "rotl $-8, %1, r1\n\t"        /* r1 = ddaabbcc */
!                "bicl2 $0xff00ff, r1\n\t"     /* r1 = dd00bb00 */
!                "bisl2 r1, %0\n\t"            /* %0 = ddccbbaa */ 
!                : "=g" (t1) : "g" (x) : "r1" ); 
       return t1; 
  }
  
+ /* 
+  * according to the resident expert, this is as fast as assembly 
+  */
  static __inline__ __const__ __u16 ___arch__swab16(__u16 x)
  {
!    register __u16 __x = (x);
!    return (u_int16_t)(__x << 8 | __x >> 8);               
  }