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| /* SPDX-License-Identifier: GPL-2.0-only */
| /*
| * linux/arch/arm/lib/findbit.S
| *
| * Copyright (C) 1995-2000 Russell King
| *
| * 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
| ret 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)
| cmp r2, r1
| bhs 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
| ret 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)
| cmp r2, r1
| bhs 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
| ret lr
| ENDPROC(_find_first_zero_bit_be)
|
| ENTRY(_find_next_zero_bit_be)
| cmp r2, r1
| bhs 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
| ret lr
| ENDPROC(_find_first_bit_be)
|
| ENTRY(_find_next_bit_be)
| cmp r2, r1
| bhs 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
| ret lr
|
|
