| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame^] | 1 | /* bitops.S: Low level assembler bit operations. |
| 2 | * |
| 3 | * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu) |
| 4 | */ |
| 5 | |
| 6 | #include <linux/config.h> |
| 7 | #include <asm/ptrace.h> |
| 8 | #include <asm/psr.h> |
| 9 | |
| 10 | .text |
| 11 | .align 4 |
| 12 | |
| 13 | .globl __bitops_begin |
| 14 | __bitops_begin: |
| 15 | |
| 16 | /* Take bits in %g2 and set them in word at %g1, |
| 17 | * return whether bits were set in original value |
| 18 | * in %g2. %g4 holds value to restore into %o7 |
| 19 | * in delay slot of jmpl return, %g3 + %g5 + %g7 can be |
| 20 | * used as temporaries and thus is considered clobbered |
| 21 | * by all callers. |
| 22 | */ |
| 23 | .globl ___set_bit |
| 24 | ___set_bit: |
| 25 | rd %psr, %g3 |
| 26 | nop; nop; nop; |
| 27 | or %g3, PSR_PIL, %g5 |
| 28 | wr %g5, 0x0, %psr |
| 29 | nop; nop; nop |
| 30 | #ifdef CONFIG_SMP |
| 31 | set bitops_spinlock, %g5 |
| 32 | 2: ldstub [%g5], %g7 ! Spin on the byte lock for SMP. |
| 33 | orcc %g7, 0x0, %g0 ! Did we get it? |
| 34 | bne 2b ! Nope... |
| 35 | #endif |
| 36 | ld [%g1], %g7 |
| 37 | or %g7, %g2, %g5 |
| 38 | and %g7, %g2, %g2 |
| 39 | #ifdef CONFIG_SMP |
| 40 | st %g5, [%g1] |
| 41 | set bitops_spinlock, %g5 |
| 42 | stb %g0, [%g5] |
| 43 | #else |
| 44 | st %g5, [%g1] |
| 45 | #endif |
| 46 | wr %g3, 0x0, %psr |
| 47 | nop; nop; nop |
| 48 | jmpl %o7, %g0 |
| 49 | mov %g4, %o7 |
| 50 | |
| 51 | /* Same as above, but clears the bits from %g2 instead. */ |
| 52 | .globl ___clear_bit |
| 53 | ___clear_bit: |
| 54 | rd %psr, %g3 |
| 55 | nop; nop; nop |
| 56 | or %g3, PSR_PIL, %g5 |
| 57 | wr %g5, 0x0, %psr |
| 58 | nop; nop; nop |
| 59 | #ifdef CONFIG_SMP |
| 60 | set bitops_spinlock, %g5 |
| 61 | 2: ldstub [%g5], %g7 ! Spin on the byte lock for SMP. |
| 62 | orcc %g7, 0x0, %g0 ! Did we get it? |
| 63 | bne 2b ! Nope... |
| 64 | #endif |
| 65 | ld [%g1], %g7 |
| 66 | andn %g7, %g2, %g5 |
| 67 | and %g7, %g2, %g2 |
| 68 | #ifdef CONFIG_SMP |
| 69 | st %g5, [%g1] |
| 70 | set bitops_spinlock, %g5 |
| 71 | stb %g0, [%g5] |
| 72 | #else |
| 73 | st %g5, [%g1] |
| 74 | #endif |
| 75 | wr %g3, 0x0, %psr |
| 76 | nop; nop; nop |
| 77 | jmpl %o7, %g0 |
| 78 | mov %g4, %o7 |
| 79 | |
| 80 | /* Same thing again, but this time toggles the bits from %g2. */ |
| 81 | .globl ___change_bit |
| 82 | ___change_bit: |
| 83 | rd %psr, %g3 |
| 84 | nop; nop; nop |
| 85 | or %g3, PSR_PIL, %g5 |
| 86 | wr %g5, 0x0, %psr |
| 87 | nop; nop; nop |
| 88 | #ifdef CONFIG_SMP |
| 89 | set bitops_spinlock, %g5 |
| 90 | 2: ldstub [%g5], %g7 ! Spin on the byte lock for SMP. |
| 91 | orcc %g7, 0x0, %g0 ! Did we get it? |
| 92 | bne 2b ! Nope... |
| 93 | #endif |
| 94 | ld [%g1], %g7 |
| 95 | xor %g7, %g2, %g5 |
| 96 | and %g7, %g2, %g2 |
| 97 | #ifdef CONFIG_SMP |
| 98 | st %g5, [%g1] |
| 99 | set bitops_spinlock, %g5 |
| 100 | stb %g0, [%g5] |
| 101 | #else |
| 102 | st %g5, [%g1] |
| 103 | #endif |
| 104 | wr %g3, 0x0, %psr |
| 105 | nop; nop; nop |
| 106 | jmpl %o7, %g0 |
| 107 | mov %g4, %o7 |
| 108 | |
| 109 | .globl __bitops_end |
| 110 | __bitops_end: |