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-rw-r--r--arch/unicore32/lib/findbit.S98
1 files changed, 98 insertions, 0 deletions
diff --git a/arch/unicore32/lib/findbit.S b/arch/unicore32/lib/findbit.S
new file mode 100644
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+++ b/arch/unicore32/lib/findbit.S
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+/*
+ * linux/arch/unicore32/lib/findbit.S
+ *
+ * Code specific to PKUnity SoC and UniCore ISA
+ *
+ * Copyright (C) 2001-2010 GUAN Xue-tao
+ *
+ * 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.
+ */
+#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);
+ */
+__uc32_find_first_zero_bit:
+ cxor.a r1, #0
+ beq 3f
+ mov r2, #0
+1: ldb r3, [r0+], r2 >> #3
+ xor.a r3, r3, #0xff @ invert bits
+ bne .L_found @ any now set - found zero bit
+ add r2, r2, #8 @ next bit pointer
+2: csub.a r2, r1 @ any more?
+ bub 1b
+3: mov r0, r1 @ no free bits
+ mov pc, lr
+
+/*
+ * Purpose : Find next 'zero' bit
+ * Prototype: int find_next_zero_bit
+ * (void *addr, unsigned int maxbit, int offset)
+ */
+ENTRY(__uc32_find_next_zero_bit)
+ cxor.a r1, #0
+ beq 3b
+ and.a ip, r2, #7
+ beq 1b @ If new byte, goto old routine
+ ldb r3, [r0+], r2 >> #3
+ xor r3, r3, #0xff @ now looking for a 1 bit
+ mov.a r3, r3 >> ip @ shift off unused bits
+ bne .L_found
+ or r2, r2, #7 @ if zero, then no bits here
+ add r2, r2, #1 @ align bit pointer
+ b 2b @ loop for next bit
+ENDPROC(__uc32_find_next_zero_bit)
+
+/*
+ * Purpose : Find a 'one' bit
+ * Prototype: int find_first_bit
+ * (const unsigned long *addr, unsigned int maxbit);
+ */
+__uc32_find_first_bit:
+ cxor.a r1, #0
+ beq 3f
+ mov r2, #0
+1: ldb r3, [r0+], r2 >> #3
+ mov.a r3, r3
+ bne .L_found @ any now set - found zero bit
+ add r2, r2, #8 @ next bit pointer
+2: csub.a r2, r1 @ any more?
+ bub 1b
+3: mov r0, r1 @ no free bits
+ mov pc, lr
+
+/*
+ * Purpose : Find next 'one' bit
+ * Prototype: int find_next_zero_bit
+ * (void *addr, unsigned int maxbit, int offset)
+ */
+ENTRY(__uc32_find_next_bit)
+ cxor.a r1, #0
+ beq 3b
+ and.a ip, r2, #7
+ beq 1b @ If new byte, goto old routine
+ ldb r3, [r0+], r2 >> #3
+ mov.a r3, r3 >> ip @ shift off unused bits
+ bne .L_found
+ or r2, r2, #7 @ if zero, then no bits here
+ add r2, r2, #1 @ align bit pointer
+ b 2b @ loop for next bit
+ENDPROC(__uc32_find_next_bit)
+
+/*
+ * One or more bits in the LSB of r3 are assumed to be set.
+ */
+.L_found:
+ rsub r1, r3, #0
+ and r3, r3, r1
+ cntlz r3, r3
+ rsub r3, r3, #31
+ add r0, r2, r3
+ mov pc, lr
+