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Annotation of sys/arch/arm/arm/setstack.S, Revision 1.1.1.1

1.1       nbrk        1: /*     $OpenBSD: setstack.S,v 1.2 2004/02/01 06:10:33 drahn Exp $      */
                      2: /*     $NetBSD: setstack.S,v 1.2 2002/08/15 01:37:02 briggs Exp $      */
                      3:
                      4: /*
                      5:  * Copyright (c) 1994 Mark Brinicombe.
                      6:  * Copyright (c) 1994 Brini.
                      7:  * All rights reserved.
                      8:  *
                      9:  * This code is derived from software written for Brini by Mark Brinicombe
                     10:  *
                     11:  * Redistribution and use in source and binary forms, with or without
                     12:  * modification, are permitted provided that the following conditions
                     13:  * are met:
                     14:  * 1. Redistributions of source code must retain the above copyright
                     15:  *    notice, this list of conditions and the following disclaimer.
                     16:  * 2. Redistributions in binary form must reproduce the above copyright
                     17:  *    notice, this list of conditions and the following disclaimer in the
                     18:  *    documentation and/or other materials provided with the distribution.
                     19:  * 3. All advertising materials mentioning features or use of this software
                     20:  *    must display the following acknowledgement:
                     21:  *     This product includes software developed by Brini.
                     22:  * 4. The name of the company nor the name of the author may be used to
                     23:  *    endorse or promote products derived from this software without specific
                     24:  *    prior written permission.
                     25:  *
                     26:  * THIS SOFTWARE IS PROVIDED BY BRINI ``AS IS'' AND ANY EXPRESS OR IMPLIED
                     27:  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
                     28:  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
                     29:  * IN NO EVENT SHALL BRINI OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
                     30:  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
                     31:  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
                     32:  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     33:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     34:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     35:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     36:  * SUCH DAMAGE.
                     37:  *
                     38:  * RiscBSD kernel project
                     39:  *
                     40:  * setstack.S
                     41:  *
                     42:  * Miscellaneous routine to play with the stack pointer in different CPU modes
                     43:  *
                     44:  * Eventually this routine can be inline assembly.
                     45:  *
                     46:  * Created      : 17/09/94
                     47:  *
                     48:  * Based of kate/display/setstack.s
                     49:  */
                     50:
                     51: #include <machine/cpu.h>
                     52: #include <machine/asm.h>
                     53:
                     54: /* To set the stack pointer for a particular mode we must switch
                     55:  * to that mode update the banked r13 and then switch back.
                     56:  * This routine provides an easy way of doing this for any mode
                     57:  *
                     58:  * r0 = CPU mode
                     59:  * r1 = stackptr
                     60:  */
                     61:
                     62: ENTRY(set_stackptr)
                     63:         mrs    r3, cpsr                /* Switch to the appropriate mode */
                     64:        bic     r2, r3, #(PSR_MODE)
                     65:        orr     r2, r2, r0
                     66:         msr    cpsr_all, r2
                     67:
                     68:        mov     sp, r1                  /* Set the stack pointer */
                     69:
                     70:         msr    cpsr_all, r3            /* Restore the old mode */
                     71:
                     72:        mov     pc, lr                  /* Exit */
                     73:
                     74: /* To get the stack pointer for a particular mode we must switch
                     75:  * to that mode copy the banked r13 and then switch back.
                     76:  * This routine provides an easy way of doing this for any mode
                     77:  *
                     78:  * r0 = CPU mode
                     79:  */
                     80:
                     81: ENTRY(get_stackptr)
                     82:         mrs    r3, cpsr                /* Switch to the appropriate mode */
                     83:        bic     r2, r3, #(PSR_MODE)
                     84:        orr     r2, r2, r0
                     85:         msr    cpsr_all, r2
                     86:
                     87:        mov     r0, sp                  /* Set the stack pointer */
                     88:
                     89:         msr    cpsr_all, r3            /* Restore the old mode */
                     90:
                     91:        mov     pc, lr                  /* Exit */
                     92:
                     93: /* End of setstack.S */