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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
commit5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch)
treea94efe259b9009378be6d90eb30d2b019d95c194 /arch/arm/lib/findbit.S
parentInitial commit. (diff)
downloadlinux-430c2fc249ea5c0536abd21c23382884005c9093.tar.xz
linux-430c2fc249ea5c0536abd21c23382884005c9093.zip
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/arm/lib/findbit.S')
-rw-r--r--arch/arm/lib/findbit.S193
1 files changed, 193 insertions, 0 deletions
diff --git a/arch/arm/lib/findbit.S b/arch/arm/lib/findbit.S
new file mode 100644
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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
+