| 1 | #
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| 2 | # Copyright (C) 2001-2004 Jakub Jermar
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| 3 | # All rights reserved.
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| 4 | #
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| 5 | # Redistribution and use in source and binary forms, with or without
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| 6 | # modification, are permitted provided that the following conditions
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| 7 | # are met:
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| 8 | #
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| 9 | # - Redistributions of source code must retain the above copyright
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| 10 | # notice, this list of conditions and the following disclaimer.
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| 11 | # - Redistributions in binary form must reproduce the above copyright
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| 12 | # notice, this list of conditions and the following disclaimer in the
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| 13 | # documentation and/or other materials provided with the distribution.
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| 14 | # - The name of the author may not be used to endorse or promote products
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| 15 | # derived from this software without specific prior written permission.
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| 16 | #
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| 17 | # THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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| 18 | # IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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| 19 | # OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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| 20 | # IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 21 | # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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| 22 | # NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| 23 | # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| 24 | # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 25 | # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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| 26 | # THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 27 | #
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| 28 |
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| 29 | # The code below just interfaces the CPUID instruction.
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| 30 | # CPU recognition logic is contained in higher-level functions.
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| 31 |
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| 32 | .text
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| 33 |
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| 34 | .global has_cpuid
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| 35 | .global cpuid
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| 36 | .global rdtsc
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| 37 |
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| 38 |
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| 39 | ## Determine CPUID support
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| 40 | #
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| 41 | # Return 0 in EAX if CPUID is not support, 1 if supported.
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| 42 | #
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| 43 | has_cpuid:
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| 44 | push %ebx
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| 45 |
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| 46 | pushf # store flags
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| 47 | popl %eax # read flags
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| 48 | movl %eax,%ebx # copy flags
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| 49 | btcl $21,%ebx # swap the ID bit
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| 50 | pushl %ebx
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| 51 | popf # propagate the change into flags
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| 52 | pushf
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| 53 | popl %ebx # read flags
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| 54 | andl $(1<<21),%eax # interested only in ID bit
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| 55 | andl $(1<<21),%ebx
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| 56 | xorl %ebx,%eax # 0 if not supported, 1 if supported
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| 57 |
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| 58 | pop %ebx
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| 59 | ret
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| 60 |
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| 61 |
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| 62 | ## Get CPUID data
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| 63 | #
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| 64 | # This code is just an interfaces the CPUID instruction, CPU recognition
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| 65 | # logic is contained in higher-level functions.
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| 66 | #
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| 67 | # The C prototype is:
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| 68 | # void cpuid(__u32 cmd, struct cpu_info *info)
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| 69 | #
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| 70 | # @param cmd CPUID command.
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| 71 | # @param info Buffer to store CPUID output.
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| 72 | #
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| 73 | cpuid:
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| 74 | pushl %ebp
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| 75 | movl %esp,%ebp
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| 76 | pusha
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| 77 |
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| 78 | movl 8(%ebp),%eax # load the command into %eax
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| 79 | movl 12(%ebp),%esi # laod the address of the info struct
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| 80 |
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| 81 | cpuid
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| 82 | movl %eax,0(%esi)
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| 83 | movl %ebx,4(%esi)
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| 84 | movl %ecx,8(%esi)
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| 85 | movl %edx,12(%esi)
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| 86 |
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| 87 | popa
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| 88 | popl %ebp
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| 89 | ret
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| 90 |
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| 91 | rdtsc:
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| 92 | rdtsc
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| 93 | ret
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