summaryrefslogtreecommitdiff
path: root/arch/arm26/lib/findbit.S
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm26/lib/findbit.S')
-rw-r--r--arch/arm26/lib/findbit.S67
1 files changed, 67 insertions, 0 deletions
diff --git a/arch/arm26/lib/findbit.S b/arch/arm26/lib/findbit.S
new file mode 100644
index 000000000000..26f67cccc37c
--- /dev/null
+++ b/arch/arm26/lib/findbit.S
@@ -0,0 +1,67 @@
+/*
+ * 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 2b
+ 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
+
+/*
+ * One or more bits in the LSB of r3 are assumed to be set.
+ */
+.found: 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
+ RETINSTR(mov,pc,lr)
+