diff options
Diffstat (limited to 'arch/arm/lib/bitops.h')
| -rw-r--r-- | arch/arm/lib/bitops.h | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/arch/arm/lib/bitops.h b/arch/arm/lib/bitops.h new file mode 100644 index 0000000..2e787d4 --- /dev/null +++ b/arch/arm/lib/bitops.h @@ -0,0 +1,65 @@ + +#if __LINUX_ARM_ARCH__ >= 6 && defined(CONFIG_CPU_32v6K) + .macro bitop, instr + mov r2, #1 + and r3, r0, #7 @ Get bit offset + add r1, r1, r0, lsr #3 @ Get byte offset + mov r3, r2, lsl r3 +1: ldrexb r2, [r1] + \instr r2, r2, r3 + strexb r0, r2, [r1] + cmp r0, #0 + bne 1b + mov pc, lr + .endm + + .macro testop, instr, store + and r3, r0, #7 @ Get bit offset + mov r2, #1 + add r1, r1, r0, lsr #3 @ Get byte offset + mov r3, r2, lsl r3 @ create mask +1: ldrexb r2, [r1] + ands r0, r2, r3 @ save old value of bit + \instr r2, r2, r3 @ toggle bit + strexb ip, r2, [r1] + cmp ip, #0 + bne 1b + cmp r0, #0 + movne r0, #1 +2: mov pc, lr + .endm +#else + .macro bitop, instr + and r2, r0, #7 + mov r3, #1 + mov r3, r3, lsl r2 + save_and_disable_irqs ip + ldrb r2, [r1, r0, lsr #3] + \instr r2, r2, r3 + strb r2, [r1, r0, lsr #3] + restore_irqs ip + mov pc, lr + .endm + +/** + * testop - implement a test_and_xxx_bit operation. + * @instr: operational instruction + * @store: store instruction + * + * Note: we can trivially conditionalise the store instruction + * to avoid dirtying the data cache. + */ + .macro testop, instr, store + add r1, r1, r0, lsr #3 + and r3, r0, #7 + mov r0, #1 + save_and_disable_irqs ip + ldrb r2, [r1] + tst r2, r0, lsl r3 + \instr r2, r2, r0, lsl r3 + \store r2, [r1] + restore_irqs ip + moveq r0, #0 + mov pc, lr + .endm +#endif |
