/*
   *  linux/arch/arm/lib/findbit.S
   *
   *  Copyright (C) 1995-2000 Russell King
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   * 16th March 2001 - John Ripley <jripley@sonicblue.com>
   *   Fixed so that "size" is an exclusive not an inclusive quantity.
   *   All users of these functions expect exclusive sizes, and may
   *   also call with zero size.
   * Reworked by rmk.
   */
  #include <linux/linkage.h>
  #include <asm/assembler.h>
                  .text
  
  /*
   * Purpose  : Find a 'zero' bit
   * Prototype: int find_first_zero_bit(void *addr, unsigned int maxbit);
   */
  ENTRY(_find_first_zero_bit_le)
  		teq	r1, #0	
  		beq	3f
  		mov	r2, #0

  1:
   ARM(		ldrb	r3, [r0, r2, lsr #3]	)
   THUMB(		lsr	r3, r2, #3		)
   THUMB(		ldrb	r3, [r0, r3]		)

  		eors	r3, r3, #0xff		@ invert bits

  		bne	.L_found		@ any now set - found zero bit

  		add	r2, r2, #8		@ next bit pointer
  2:		cmp	r2, r1			@ any more?
  		blo	1b
  3:		mov	r0, r1			@ no free bits

  		mov	pc, lr

  ENDPROC(_find_first_zero_bit_le)

  
  /*
   * Purpose  : Find next 'zero' bit
   * Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset)
   */
  ENTRY(_find_next_zero_bit_le)
  		teq	r1, #0
  		beq	3b
  		ands	ip, r2, #7
  		beq	1b			@ If new byte, goto old routine

   ARM(		ldrb	r3, [r0, r2, lsr #3]	)
   THUMB(		lsr	r3, r2, #3		)
   THUMB(		ldrb	r3, [r0, r3]		)

  		eor	r3, r3, #0xff		@ now looking for a 1 bit
  		movs	r3, r3, lsr ip		@ shift off unused bits

  		bne	.L_found

  		orr	r2, r2, #7		@ if zero, then no bits here
  		add	r2, r2, #1		@ align bit pointer
  		b	2b			@ loop for next bit

  ENDPROC(_find_next_zero_bit_le)

  
  /*
   * Purpose  : Find a 'one' bit
   * Prototype: int find_first_bit(const unsigned long *addr, unsigned int maxbit);
   */
  ENTRY(_find_first_bit_le)
  		teq	r1, #0	
  		beq	3f
  		mov	r2, #0

  1:
   ARM(		ldrb	r3, [r0, r2, lsr #3]	)
   THUMB(		lsr	r3, r2, #3		)
   THUMB(		ldrb	r3, [r0, r3]		)

  		movs	r3, r3

  		bne	.L_found		@ any now set - found zero bit

  		add	r2, r2, #8		@ next bit pointer
  2:		cmp	r2, r1			@ any more?
  		blo	1b
  3:		mov	r0, r1			@ no free bits

  		mov	pc, lr

  ENDPROC(_find_first_bit_le)

  
  /*
   * Purpose  : Find next 'one' bit
   * Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset)
   */
  ENTRY(_find_next_bit_le)
  		teq	r1, #0
  		beq	3b
  		ands	ip, r2, #7
  		beq	1b			@ If new byte, goto old routine

   ARM(		ldrb	r3, [r0, r2, lsr #3]	)
   THUMB(		lsr	r3, r2, #3		)
   THUMB(		ldrb	r3, [r0, r3]		)

  		movs	r3, r3, lsr ip		@ shift off unused bits

  		bne	.L_found

  		orr	r2, r2, #7		@ if zero, then no bits here
  		add	r2, r2, #1		@ align bit pointer
  		b	2b			@ loop for next bit

  ENDPROC(_find_next_bit_le)

  
  #ifdef __ARMEB__
  
  ENTRY(_find_first_zero_bit_be)
  		teq	r1, #0
  		beq	3f
  		mov	r2, #0
  1:		eor	r3, r2, #0x18		@ big endian byte ordering

   ARM(		ldrb	r3, [r0, r3, lsr #3]	)
   THUMB(		lsr	r3, #3			)
   THUMB(		ldrb	r3, [r0, r3]		)

  		eors	r3, r3, #0xff		@ invert bits

  		bne	.L_found		@ any now set - found zero bit

  		add	r2, r2, #8		@ next bit pointer
  2:		cmp	r2, r1			@ any more?
  		blo	1b
  3:		mov	r0, r1			@ no free bits

  		mov	pc, lr

  ENDPROC(_find_first_zero_bit_be)

  
  ENTRY(_find_next_zero_bit_be)
  		teq	r1, #0
  		beq	3b
  		ands	ip, r2, #7
  		beq	1b			@ If new byte, goto old routine
  		eor	r3, r2, #0x18		@ big endian byte ordering

   ARM(		ldrb	r3, [r0, r3, lsr #3]	)
   THUMB(		lsr	r3, #3			)
   THUMB(		ldrb	r3, [r0, r3]		)

  		eor	r3, r3, #0xff		@ now looking for a 1 bit
  		movs	r3, r3, lsr ip		@ shift off unused bits

  		bne	.L_found

  		orr	r2, r2, #7		@ if zero, then no bits here
  		add	r2, r2, #1		@ align bit pointer
  		b	2b			@ loop for next bit

  ENDPROC(_find_next_zero_bit_be)

  
  ENTRY(_find_first_bit_be)
  		teq	r1, #0
  		beq	3f
  		mov	r2, #0
  1:		eor	r3, r2, #0x18		@ big endian byte ordering

   ARM(		ldrb	r3, [r0, r3, lsr #3]	)
   THUMB(		lsr	r3, #3			)
   THUMB(		ldrb	r3, [r0, r3]		)

  		movs	r3, r3

  		bne	.L_found		@ any now set - found zero bit

  		add	r2, r2, #8		@ next bit pointer
  2:		cmp	r2, r1			@ any more?
  		blo	1b
  3:		mov	r0, r1			@ no free bits

  		mov	pc, lr

  ENDPROC(_find_first_bit_be)

  
  ENTRY(_find_next_bit_be)
  		teq	r1, #0
  		beq	3b
  		ands	ip, r2, #7
  		beq	1b			@ If new byte, goto old routine
  		eor	r3, r2, #0x18		@ big endian byte ordering

   ARM(		ldrb	r3, [r0, r3, lsr #3]	)
   THUMB(		lsr	r3, #3			)
   THUMB(		ldrb	r3, [r0, r3]		)

  		movs	r3, r3, lsr ip		@ shift off unused bits

  		bne	.L_found

  		orr	r2, r2, #7		@ if zero, then no bits here
  		add	r2, r2, #1		@ align bit pointer
  		b	2b			@ loop for next bit

  ENDPROC(_find_next_bit_be)

  
  #endif
  
  /*
   * One or more bits in the LSB of r3 are assumed to be set.
   */

  .L_found:

  #if __LINUX_ARM_ARCH__ >= 5

  		rsb	r0, r3, #0
  		and	r3, r3, r0

  		clz	r3, r3
  		rsb	r3, r3, #31
  		add	r0, r2, r3
  #else
  		tst	r3, #0x0f
  		addeq	r2, r2, #4
  		movne	r3, r3, lsl #4
  		tst	r3, #0x30
  		addeq	r2, r2, #2
  		movne	r3, r3, lsl #2
  		tst	r3, #0x40
  		addeq	r2, r2, #1
  		mov	r0, r2
  #endif

  		cmp	r1, r0			@ Clamp to maxbit
  		movlo	r0, r1

  		mov	pc, lr