[deliverable/linux.git] / arch / arm / lib / findbit.S

/*
 *  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:		ldrb	r3, [r0, r2, lsr #3]
		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
		ldrb	r3, [r0, r2, lsr #3]
		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:		ldrb	r3, [r0, r2, lsr #3]
		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
		ldrb	r3, [r0, r2, lsr #3]
		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
		ldrb	r3, [r0, r3, lsr #3]
		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
		ldrb	r3, [r0, r3, lsr #3]
		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
		ldrb	r3, [r0, r3, lsr #3]
		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
		ldrb	r3, [r0, r3, lsr #3]
		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	r1, r3, #0
		and	r3, r3, r1
		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
		mov	pc, lr
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/arch/arm/lib/findbit.S
	3	*
	4	* Copyright (C) 1995-2000 Russell King
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	* 16th March 2001 - John Ripley <jripley@sonicblue.com>
	11	* Fixed so that "size" is an exclusive not an inclusive quantity.
	12	* All users of these functions expect exclusive sizes, and may
	13	* also call with zero size.
	14	* Reworked by rmk.
	15	*/
	16	#include <linux/linkage.h>
	17	#include <asm/assembler.h>
	18	.text
	19
	20	/*
	21	* Purpose : Find a 'zero' bit
	22	* Prototype: int find_first_zero_bit(void *addr, unsigned int maxbit);
	23	*/
	24	ENTRY(_find_first_zero_bit_le)
	25	teq r1, #0
	26	beq 3f
	27	mov r2, #0
	28	1: ldrb r3, [r0, r2, lsr #3]
	29	eors r3, r3, #0xff @ invert bits
8adbb371	30	bne .L_found @ any now set - found zero bit
1da177e4 LT	31	add r2, r2, #8 @ next bit pointer
	32	2: cmp r2, r1 @ any more?
	33	blo 1b
	34	3: mov r0, r1 @ no free bits
7999d8d7	35	mov pc, lr
93ed3970	36	ENDPROC(_find_first_zero_bit_le)
1da177e4 LT	37
	38	/*
	39	* Purpose : Find next 'zero' bit
	40	* Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset)
	41	*/
	42	ENTRY(_find_next_zero_bit_le)
	43	teq r1, #0
	44	beq 3b
	45	ands ip, r2, #7
	46	beq 1b @ If new byte, goto old routine
	47	ldrb r3, [r0, r2, lsr #3]
	48	eor r3, r3, #0xff @ now looking for a 1 bit
	49	movs r3, r3, lsr ip @ shift off unused bits
8adbb371	50	bne .L_found
1da177e4 LT	51	orr r2, r2, #7 @ if zero, then no bits here
	52	add r2, r2, #1 @ align bit pointer
	53	b 2b @ loop for next bit
93ed3970	54	ENDPROC(_find_next_zero_bit_le)
1da177e4 LT	55
	56	/*
	57	* Purpose : Find a 'one' bit
	58	* Prototype: int find_first_bit(const unsigned long *addr, unsigned int maxbit);
	59	*/
	60	ENTRY(_find_first_bit_le)
	61	teq r1, #0
	62	beq 3f
	63	mov r2, #0
	64	1: ldrb r3, [r0, r2, lsr #3]
	65	movs r3, r3
8adbb371	66	bne .L_found @ any now set - found zero bit
1da177e4 LT	67	add r2, r2, #8 @ next bit pointer
	68	2: cmp r2, r1 @ any more?
	69	blo 1b
	70	3: mov r0, r1 @ no free bits
7999d8d7	71	mov pc, lr
93ed3970	72	ENDPROC(_find_first_bit_le)
1da177e4 LT	73
	74	/*
	75	* Purpose : Find next 'one' bit
	76	* Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset)
	77	*/
	78	ENTRY(_find_next_bit_le)
	79	teq r1, #0
	80	beq 3b
	81	ands ip, r2, #7
	82	beq 1b @ If new byte, goto old routine
	83	ldrb r3, [r0, r2, lsr #3]
	84	movs r3, r3, lsr ip @ shift off unused bits
8adbb371	85	bne .L_found
1da177e4 LT	86	orr r2, r2, #7 @ if zero, then no bits here
	87	add r2, r2, #1 @ align bit pointer
	88	b 2b @ loop for next bit
93ed3970	89	ENDPROC(_find_next_bit_le)
1da177e4 LT	90
	91	#ifdef __ARMEB__
	92
	93	ENTRY(_find_first_zero_bit_be)
	94	teq r1, #0
	95	beq 3f
	96	mov r2, #0
	97	1: eor r3, r2, #0x18 @ big endian byte ordering
	98	ldrb r3, [r0, r3, lsr #3]
	99	eors r3, r3, #0xff @ invert bits
8adbb371	100	bne .L_found @ any now set - found zero bit
1da177e4 LT	101	add r2, r2, #8 @ next bit pointer
	102	2: cmp r2, r1 @ any more?
	103	blo 1b
	104	3: mov r0, r1 @ no free bits
7999d8d7	105	mov pc, lr
93ed3970	106	ENDPROC(_find_first_zero_bit_be)
1da177e4 LT	107
	108	ENTRY(_find_next_zero_bit_be)
	109	teq r1, #0
	110	beq 3b
	111	ands ip, r2, #7
	112	beq 1b @ If new byte, goto old routine
	113	eor r3, r2, #0x18 @ big endian byte ordering
	114	ldrb r3, [r0, r3, lsr #3]
	115	eor r3, r3, #0xff @ now looking for a 1 bit
	116	movs r3, r3, lsr ip @ shift off unused bits
8adbb371	117	bne .L_found
1da177e4 LT	118	orr r2, r2, #7 @ if zero, then no bits here
	119	add r2, r2, #1 @ align bit pointer
	120	b 2b @ loop for next bit
93ed3970	121	ENDPROC(_find_next_zero_bit_be)
1da177e4 LT	122
	123	ENTRY(_find_first_bit_be)
	124	teq r1, #0
	125	beq 3f
	126	mov r2, #0
	127	1: eor r3, r2, #0x18 @ big endian byte ordering
	128	ldrb r3, [r0, r3, lsr #3]
	129	movs r3, r3
8adbb371	130	bne .L_found @ any now set - found zero bit
1da177e4 LT	131	add r2, r2, #8 @ next bit pointer
	132	2: cmp r2, r1 @ any more?
	133	blo 1b
	134	3: mov r0, r1 @ no free bits
7999d8d7	135	mov pc, lr
93ed3970	136	ENDPROC(_find_first_bit_be)
1da177e4 LT	137
	138	ENTRY(_find_next_bit_be)
	139	teq r1, #0
	140	beq 3b
	141	ands ip, r2, #7
	142	beq 1b @ If new byte, goto old routine
	143	eor r3, r2, #0x18 @ big endian byte ordering
	144	ldrb r3, [r0, r3, lsr #3]
	145	movs r3, r3, lsr ip @ shift off unused bits
8adbb371	146	bne .L_found
1da177e4 LT	147	orr r2, r2, #7 @ if zero, then no bits here
	148	add r2, r2, #1 @ align bit pointer
	149	b 2b @ loop for next bit
93ed3970	150	ENDPROC(_find_next_bit_be)
1da177e4 LT	151
	152	#endif
	153
	154	/*
	155	* One or more bits in the LSB of r3 are assumed to be set.
	156	*/
8adbb371	157	.L_found:
1da177e4 LT	158	#if __LINUX_ARM_ARCH__ >= 5
	159	rsb r1, r3, #0
	160	and r3, r3, r1
	161	clz r3, r3
	162	rsb r3, r3, #31
	163	add r0, r2, r3
	164	#else
	165	tst r3, #0x0f
	166	addeq r2, r2, #4
	167	movne r3, r3, lsl #4
	168	tst r3, #0x30
	169	addeq r2, r2, #2
	170	movne r3, r3, lsl #2
	171	tst r3, #0x40
	172	addeq r2, r2, #1
	173	mov r0, r2
	174	#endif
7999d8d7	175	mov pc, lr
1da177e4	176