1 /* $NetBSD: cpufunc_asm.S,v 1.12 2003/09/06 09:14:52 rearnsha Exp $ */
4 * Copyright (c) 1997,1998 Mark Brinicombe.
5 * Copyright (c) 1997 Causality Limited
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18 * This product includes software developed by Causality Limited.
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20 * products derived from this software without specific prior written
23 * THIS SOFTWARE IS PROVIDED BY CAUSALITY LIMITED ``AS IS'' AND ANY EXPRESS
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35 * RiscBSD kernel project
39 * Assembly functions for CPU / MMU / TLB specific operations
45 #include <machine/asm.h>
46 #include <machine/sysreg.h>
56 * Generic functions to read/modify/write the internal coprocessor registers
59 * Currently these registers are
62 * All other registers are CPU architecture specific
65 ENTRY(cpufunc_control)
66 mrc CP15_SCTLR(r3) /* Read the control register */
67 bic r2, r3, r0 /* Clear bits */
68 eor r2, r2, r1 /* XOR bits */
71 teq r2, r3 /* Only write if there is a change */
72 mcrne CP15_SCTLR(r2) /* Write new control register */
73 mov r0, r3 /* Return old value */