Home | History | Annotate | Line # | Download | only in string
swab.S revision 1.3 
      1  1.1    fvdl /*
      2  1.2    salo  * Written by J.T. Conklin <jtc (at) NetBSD.org>.
      3  1.1    fvdl  * Public domain.
      4  1.1    fvdl  */
      5  1.1    fvdl 
      6  1.1    fvdl #include <machine/asm.h>
      7  1.1    fvdl 
      8  1.1    fvdl #if defined(LIBC_SCCS)
      9  1.3  rpaulo 	RCSID("$NetBSD: swab.S,v 1.3 2005/08/02 14:20:49 rpaulo Exp $")
     10  1.1    fvdl #endif
     11  1.1    fvdl 
     12  1.1    fvdl #define LOAD_SWAP_STORE_WORD \
     13  1.1    fvdl 	lodsw	; \
     14  1.1    fvdl 	xchgb	%al,%ah ; \
     15  1.1    fvdl 	stosw
     16  1.1    fvdl 
     17  1.1    fvdl ENTRY(swab)
     18  1.1    fvdl 	xchgq	%rdi,%rsi
     19  1.1    fvdl 	cld				# set direction forward
     20  1.1    fvdl 
     21  1.1    fvdl 	shrq	$1,%rdx
     22  1.1    fvdl 	testq	$7,%rdx			# copy first group of 1 to 7 words
     23  1.3  rpaulo 	jz	L2			# while swapping alternate bytes.
     24  1.1    fvdl L1:	lodsw
     25  1.1    fvdl 	rorw	$8,%ax
     26  1.1    fvdl 	stosw
     27  1.1    fvdl 	decq	%rdx
     28  1.1    fvdl 	testq	$7,%rdx
     29  1.1    fvdl 	jnz	L1
     30  1.1    fvdl 
     31  1.1    fvdl L2:	shrq	$3,%rdx			# copy remainder 8 words at a time
     32  1.1    fvdl 	jz	L4			# while swapping alternate bytes.
     33  1.1    fvdl L3:
     34  1.1    fvdl 	LOAD_SWAP_STORE_WORD
     35  1.1    fvdl 	LOAD_SWAP_STORE_WORD
     36  1.1    fvdl 	LOAD_SWAP_STORE_WORD
     37  1.1    fvdl 	LOAD_SWAP_STORE_WORD
     38  1.1    fvdl 	LOAD_SWAP_STORE_WORD
     39  1.1    fvdl 	LOAD_SWAP_STORE_WORD
     40  1.1    fvdl 	LOAD_SWAP_STORE_WORD
     41  1.1    fvdl 	LOAD_SWAP_STORE_WORD
     42  1.1    fvdl 
     43  1.1    fvdl 	decq	%rdx
     44  1.1    fvdl 	jnz	L3
     45  1.1    fvdl L4:
     46  1.1    fvdl 	ret
     47