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Annotation of XNU/osfmk/i386/cpu_number.h, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
        !             3:  *
        !             4:  * @APPLE_LICENSE_HEADER_START@
        !             5:  * 
        !             6:  * The contents of this file constitute Original Code as defined in and
        !             7:  * are subject to the Apple Public Source License Version 1.1 (the
        !             8:  * "License").  You may not use this file except in compliance with the
        !             9:  * License.  Please obtain a copy of the License at
        !            10:  * http://www.apple.com/publicsource and read it before using this file.
        !            11:  * 
        !            12:  * This Original Code and all software distributed under the License are
        !            13:  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
        !            14:  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
        !            15:  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
        !            16:  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
        !            17:  * License for the specific language governing rights and limitations
        !            18:  * under the License.
        !            19:  * 
        !            20:  * @APPLE_LICENSE_HEADER_END@
        !            21:  */
        !            22: /*
        !            23:  * @OSF_COPYRIGHT@
        !            24:  */
        !            25: /* 
        !            26:  * Mach Operating System
        !            27:  * Copyright (c) 1991,1990 Carnegie Mellon University
        !            28:  * All Rights Reserved.
        !            29:  * 
        !            30:  * Permission to use, copy, modify and distribute this software and its
        !            31:  * documentation is hereby granted, provided that both the copyright
        !            32:  * notice and this permission notice appear in all copies of the
        !            33:  * software, derivative works or modified versions, and any portions
        !            34:  * thereof, and that both notices appear in supporting documentation.
        !            35:  * 
        !            36:  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
        !            37:  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
        !            38:  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
        !            39:  * 
        !            40:  * Carnegie Mellon requests users of this software to return to
        !            41:  * 
        !            42:  *  Software Distribution Coordinator  or  [email protected]
        !            43:  *  School of Computer Science
        !            44:  *  Carnegie Mellon University
        !            45:  *  Pittsburgh PA 15213-3890
        !            46:  * 
        !            47:  * any improvements or extensions that they make and grant Carnegie Mellon
        !            48:  * the rights to redistribute these changes.
        !            49:  */
        !            50: 
        !            51: /*
        !            52:  */
        !            53: 
        !            54: /*
        !            55:  *     Machine-dependent definitions for cpu identification.
        !            56:  *
        !            57:  */
        !            58: #ifndef        _I386_CPU_NUMBER_H_
        !            59: #define        _I386_CPU_NUMBER_H_
        !            60: 
        !            61: extern int     cpu_number(void);
        !            62: 
        !            63: #ifdef MACH_KERNEL_PRIVATE
        !            64: 
        !            65: #include <platforms.h>
        !            66: #include <cpus.h>
        !            67: 
        !            68: #include <mp_v1_1.h>
        !            69: 
        !            70: #if    MP_V1_1
        !            71: #include <i386/apic.h>
        !            72: #include <i386/asm.h>
        !            73: 
        !            74: extern int lapic_id;
        !            75: 
        !            76: extern __inline__ int cpu_number(void)
        !            77: {
        !            78:        register int cpu;
        !            79: 
        !            80:        __asm__ volatile ("movl " CC_SYM_PREFIX "lapic_id, %0\n"
        !            81:                          "     movl 0(%0), %0\n"
        !            82:                          "     shrl %1, %0\n"
        !            83:                          "     andl %2, %0"
        !            84:                    : "=r" (cpu)
        !            85:                    : "i" (LAPIC_ID_SHIFT), "i" (LAPIC_ID_MASK));
        !            86: 
        !            87:        return(cpu);
        !            88: }
        !            89: #else  /* MP_V1_1 */
        !            90: /*
        !            91:  * At least one corollary cpu type does not have local memory at all.
        !            92:  * The only way I found to store the cpu number was in some 386/486
        !            93:  * system register. cr3 has bits 0, 1, 2 and 5, 6, 7, 8, 9, 10, 11
        !            94:  * available. Right now we use 0, 1 and 2. So we are limited to 8 cpus.
        !            95:  * For more cpus, we could use bits 5 - 11 with a shift.
        !            96:  *
        !            97:  * Even for other machines, like COMPAQ this is much faster the inb/outb
        !            98:  * 4 cycles instead of 10 to 30.
        !            99:  */
        !           100: #if    defined(__GNUC__)
        !           101: #if    NCPUS   > 8
        !           102: #error cpu_number() definition only works for #cpus <= 8
        !           103: #else
        !           104: 
        !           105: extern __inline__ int cpu_number(void)
        !           106: {
        !           107:        register int cpu;
        !           108: 
        !           109:        __asm__ volatile ("movl %%cr3, %0\n"
        !           110:                "       andl $0x7, %0"
        !           111:                    : "=r" (cpu));
        !           112:        return(cpu);
        !           113: }
        !           114: #endif
        !           115: #endif /* defined(__GNUC__) */
        !           116: 
        !           117: #endif /* MP_V1_1 */
        !           118: 
        !           119: #endif /* MACH_KERNEL_PRIVATE */
        !           120: 
        !           121: #endif /* _I386_CPU_NUMBER_H_ */

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