arch/arm/lib/bitops.h

   1 #include <linux/config.h>
   2
   3 #if __LINUX_ARM_ARCH__ >= 6 && defined(CONFIG_CPU_MPCORE)
   4         .macro  bitop, instr
   5         mov     r2, #1
   6         and     r3, r0, #7              @ Get bit offset
   7         add     r1, r1, r0, lsr #3      @ Get byte offset
   8         mov     r3, r2, lsl r3
   9 1:      ldrexb  r2, [r1]
  10         \instr  r2, r2, r3
  11         strexb  r0, r2, [r1]
  12         cmp     r0, #0
  13         bne     1b
  14         mov     pc, lr
  15         .endm
  16
  17         .macro  testop, instr, store
  18         and     r3, r0, #7              @ Get bit offset
  19         mov     r2, #1
  20         add     r1, r1, r0, lsr #3      @ Get byte offset
  21         mov     r3, r2, lsl r3          @ create mask
  22 1:      ldrexb  r2, [r1]
  23         ands    r0, r2, r3              @ save old value of bit
  24         \instr  r2, r2, r3                      @ toggle bit
  25         strexb  ip, r2, [r1]
  26         cmp     ip, #0
  27         bne     1b
  28         cmp     r0, #0
  29         movne   r0, #1
  30 2:      mov     pc, lr
  31         .endm
  32 #else
  33         .macro  bitop, instr
  34         and     r2, r0, #7
  35         mov     r3, #1
  36         mov     r3, r3, lsl r2
  37         save_and_disable_irqs ip, r2
  38         ldrb    r2, [r1, r0, lsr #3]
  39         \instr  r2, r2, r3
  40         strb    r2, [r1, r0, lsr #3]
  41         restore_irqs ip
  42         mov     pc, lr
  43         .endm
  44
  45 /**
  46  * testop - implement a test_and_xxx_bit operation.
  47  * @instr: operational instruction
  48  * @store: store instruction
  49  *
  50  * Note: we can trivially conditionalise the store instruction
  51  * to avoid dirting the data cache.
  52  */
  53         .macro  testop, instr, store
  54         add     r1, r1, r0, lsr #3
  55         and     r3, r0, #7
  56         mov     r0, #1
  57         save_and_disable_irqs ip, r2
  58         ldrb    r2, [r1]
  59         tst     r2, r0, lsl r3
  60         \instr  r2, r2, r0, lsl r3
  61         \store  r2, [r1]
  62         restore_irqs ip
  63         moveq   r0, #0
  64         mov     pc, lr
  65         .endm
  66 #endif