/* ffsALib.s - i80x86 find first set function *//* Copyright 1984-2001 Wind River Systems, Inc. *//*modification history--------------------01d,22aug01,hdn  imported from T31 ver 01g01c,01jun93,hdn  updated to 5.1.		  - fixed #else and #endif		  - changed VOID to void		  - changed ASMLANGUAGE to _ASMLANGUAGE		  - changed copyright notice01b,13oct92,hdn  debugged.01a,07apr92,hdn  written based on TRON version.*//*DESCRIPTIONThis module defines an optimized version of the C routine in ffsLib.c.By taking advantage of the BSR instruction of 80X86 processors, theimplementation determines the first bit set in constant time.*/#define _ASMLANGUAGE#include "vxWorks.h"#include "asm.h"	.data	.globl  FUNC(copyright_wind_river)	.long   FUNC(copyright_wind_river)#if defined(PORTABLE)#define ffsALib_PORTABLE#endif#ifndef ffsALib_PORTABLE	/* internals */	.globl	GTEXT(ffsMsb)	.globl	GTEXT(ffsLsb)	.text	.balign 16/********************************************************************************* ffsMsb - find first set bit (searching from the most significant bit)** This routine finds the first bit set in the argument passed it and* returns the index of that bit.  Bits are numbered starting* at 1 from the least significant bit to 32 the most significant bit.* A return value of zero indicates that the value passed is zero.** RETURNS: bit position from 1 to 32, or 0 if the argument is zero.* int ffsMsb (i)*     int i;       /* argument to find first set bit in **/FUNC_LABEL(ffsMsb)	movl	SP_ARG1(%esp),%edx		/* %edx = i */	bsrl	%edx,%eax			/* search bit from 31 */	je	ffsNoBitSet 			/* zeros means no bit is set */	incl	%eax				/* found it, increment 1 */	retffsNoBitSet:					/* couldn't find it */	xorl	%eax,%eax			/* return 0 */	ret/********************************************************************************* ffsLsb - find first set bit (searching from the least significant bit)** This routine finds the first bit set in the argument passed it and* returns the index of that bit.  Bits are numbered starting* at 1 from the least significant bit to 32 the most significant bit.* A return value of zero indicates that the value passed is zero.** RETURNS: bit position from 1 to 32, or 0 if the argument is zero.* int ffsLsb (i)*     int i;       /* argument to find first set bit in **/	.balign 16,0x90FUNC_LABEL(ffsLsb)	movl	SP_ARG1(%esp),%edx		/* %edx = i */	bsfl	%edx,%eax			/* search bit from 0 */	je	ffsNoBitSet 			/* zeros means no bit is set */	incl	%eax				/* found it, increment 1 */	ret#endif /* ! ffsALib_PORTABLE */