[mirror_ubuntu-zesty-kernel.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	.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
		RETINSTR(mov,pc,lr)

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

/*
 * 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	.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
		RETINSTR(mov,pc,lr)

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

#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	.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
		RETINSTR(mov,pc,lr)

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

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	.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
		RETINSTR(mov,pc,lr)

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

#endif

/*
 * One or more bits in the LSB of r3 are assumed to be set.
 */
.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
		RETINSTR(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
	30	bne .found @ any now set - found zero bit
	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
	35	RETINSTR(mov,pc,lr)
	36
	37	/*
	38	* Purpose : Find next 'zero' bit
	39	* Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset)
	40	*/
	41	ENTRY(_find_next_zero_bit_le)
	42	teq r1, #0
	43	beq 3b
	44	ands ip, r2, #7
	45	beq 1b @ If new byte, goto old routine
	46	ldrb r3, [r0, r2, lsr #3]
	47	eor r3, r3, #0xff @ now looking for a 1 bit
	48	movs r3, r3, lsr ip @ shift off unused bits
	49	bne .found
	50	orr r2, r2, #7 @ if zero, then no bits here
	51	add r2, r2, #1 @ align bit pointer
	52	b 2b @ loop for next bit
	53
	54	/*
	55	* Purpose : Find a 'one' bit
	56	* Prototype: int find_first_bit(const unsigned long *addr, unsigned int maxbit);
	57	*/
	58	ENTRY(_find_first_bit_le)
	59	teq r1, #0
	60	beq 3f
	61	mov r2, #0
	62	1: ldrb r3, [r0, r2, lsr #3]
	63	movs r3, r3
	64	bne .found @ any now set - found zero bit
65	add r2, r2, #8 @ next bit pointer
66	2: cmp r2, r1 @ any more?
67	blo 1b
68	3: mov r0, r1 @ no free bits
69	RETINSTR(mov,pc,lr)
70
71	/*
72	* Purpose : Find next 'one' bit
73	* Prototype: int find_next_zero_bit(void *addr, unsigned int maxbit, int offset)
74	*/
75	ENTRY(_find_next_bit_le)
76	teq r1, #0
77	beq 3b
78	ands ip, r2, #7
79	beq 1b @ If new byte, goto old routine
80	ldrb r3, [r0, r2, lsr #3]
81	movs r3, r3, lsr ip @ shift off unused bits
82	bne .found
83	orr r2, r2, #7 @ if zero, then no bits here
84	add r2, r2, #1 @ align bit pointer
85	b 2b @ loop for next bit
86
87	#ifdef __ARMEB__
88
89	ENTRY(_find_first_zero_bit_be)
90	teq r1, #0
91	beq 3f
92	mov r2, #0
93	1: eor r3, r2, #0x18 @ big endian byte ordering
94	ldrb r3, [r0, r3, lsr #3]
95	eors r3, r3, #0xff @ invert bits
96	bne .found @ any now set - found zero bit
97	add r2, r2, #8 @ next bit pointer
98	2: cmp r2, r1 @ any more?
99	blo 1b
100	3: mov r0, r1 @ no free bits
101	RETINSTR(mov,pc,lr)
102
103	ENTRY(_find_next_zero_bit_be)
104	teq r1, #0
105	beq 3b
106	ands ip, r2, #7
107	beq 1b @ If new byte, goto old routine
108	eor r3, r2, #0x18 @ big endian byte ordering
109	ldrb r3, [r0, r3, lsr #3]
110	eor r3, r3, #0xff @ now looking for a 1 bit
111	movs r3, r3, lsr ip @ shift off unused bits
112	bne .found
113	orr r2, r2, #7 @ if zero, then no bits here
114	add r2, r2, #1 @ align bit pointer
115	b 2b @ loop for next bit
116
117	ENTRY(_find_first_bit_be)
118	teq r1, #0
119	beq 3f
120	mov r2, #0
121	1: eor r3, r2, #0x18 @ big endian byte ordering
122	ldrb r3, [r0, r3, lsr #3]
123	movs r3, r3
124	bne .found @ any now set - found zero bit
125	add r2, r2, #8 @ next bit pointer
126	2: cmp r2, r1 @ any more?
127	blo 1b
128	3: mov r0, r1 @ no free bits
129	RETINSTR(mov,pc,lr)
130
131	ENTRY(_find_next_bit_be)
132	teq r1, #0
133	beq 3b
134	ands ip, r2, #7
135	beq 1b @ If new byte, goto old routine
136	eor r3, r2, #0x18 @ big endian byte ordering
137	ldrb r3, [r0, r3, lsr #3]
138	movs r3, r3, lsr ip @ shift off unused bits
139	bne .found
140	orr r2, r2, #7 @ if zero, then no bits here
141	add r2, r2, #1 @ align bit pointer
142	b 2b @ loop for next bit
143
144	#endif
145
146	/*
147	* One or more bits in the LSB of r3 are assumed to be set.
148	*/
149	.found:
150	#if __LINUX_ARM_ARCH__ >= 5
151	rsb r1, r3, #0
152	and r3, r3, r1
153	clz r3, r3
154	rsb r3, r3, #31
155	add r0, r2, r3
156	#else
157	tst r3, #0x0f
158	addeq r2, r2, #4
159	movne r3, r3, lsl #4
160	tst r3, #0x30
161	addeq r2, r2, #2
162	movne r3, r3, lsl #2
163	tst r3, #0x40
164	addeq r2, r2, #1
165	mov r0, r2
166	#endif
167	RETINSTR(mov,pc,lr)
168