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Diffstat (limited to 'arch/unicore32/lib/findbit.S')
| -rw-r--r-- | arch/unicore32/lib/findbit.S | 98 |
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 index 0000000..c360ce9 --- /dev/null +++ b/arch/unicore32/lib/findbit.S @@ -0,0 +1,98 @@ +/* + * 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 + |