| 1 | //                               -*- Mode: Asm -*- 
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| 2 | //
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| 3 | // Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
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| 4 | //
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| 5 | // The contents of this file are covered under the licence agreement in the
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| 6 | // file "LICENCE" distributed with Cforall.
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| 7 | //
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| 8 | // CtxSwitch-x86_64.S --
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| 9 | //
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| 10 | // Author           : Thierry Delisle
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| 11 | // Created On       : Mon Nov 28 12:27:26 2016
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| 12 | // Last Modified By : Thierry Delisle
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| 13 | // Last Modified On : Mon Nov 28 12:27:26 2016
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| 14 | // Update Count     : 0
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| 15 | //
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| 16 | // This  library is free  software; you  can redistribute  it and/or  modify it
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| 17 | // under the terms of the GNU Lesser General Public License as published by the
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| 18 | // Free Software  Foundation; either  version 2.1 of  the License, or  (at your
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| 19 | // option) any later version.
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| 20 | // 
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| 21 | // This library is distributed in the  hope that it will be useful, but WITHOUT
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| 22 | // ANY  WARRANTY;  without even  the  implied  warranty  of MERCHANTABILITY  or
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| 23 | // FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
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| 24 | // for more details.
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| 25 | // 
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| 26 | // You should  have received a  copy of the  GNU Lesser General  Public License
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| 27 | // along  with this library.
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| 28 | // 
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| 29 | 
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| 30 | // This context switch routine depends on the fact that the stack of a new
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| 31 | // thread has been set up to look like the thread has saved its context in
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| 32 | // the normal manner.
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| 33 | //
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| 34 | // void CtxSwitch( machine_context *from, machine_context *to );
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| 35 | 
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| 36 | // Offsets in the context structure. This needs to be synchronized with the
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| 37 | // high level code a little better.
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| 38 | 
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| 39 | #define PTR_BYTE        8
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| 40 | #define SP_OFFSET       ( 0 * PTR_BYTE )
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| 41 | #define FP_OFFSET       ( 1 * PTR_BYTE )
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| 42 | #define PC_OFFSET       ( 2 * PTR_BYTE )
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| 43 | 
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| 44 | .text
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| 45 |         .align 2
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| 46 | .globl  CtxSwitch
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| 47 | CtxSwitch:
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| 48 | 
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| 49 |         // Save floating & SSE control words on the stack.
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| 50 | 
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| 51 |         subq   $8,%rsp
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| 52 |         stmxcsr 0(%rsp)         // 4 bytes
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| 53 |         fnstcw  4(%rsp)         // 2 bytes
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| 54 | 
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| 55 |         // Save volatile registers on the stack.
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| 56 | 
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| 57 |         pushq %r15
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| 58 |         pushq %r14
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| 59 |         pushq %r13
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| 60 |         pushq %r12
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| 61 |         pushq %rbx
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| 62 | 
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| 63 |         // Save old context in the "from" area.
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| 64 | 
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| 65 |         movq %rsp,SP_OFFSET(%rdi)
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| 66 |         movq %rbp,FP_OFFSET(%rdi)
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| 67 | 
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| 68 |         // Load new context from the "to" area.
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| 69 | 
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| 70 |         movq SP_OFFSET(%rsi),%rsp
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| 71 |         movq FP_OFFSET(%rsi),%rbp
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| 72 | 
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| 73 |         // Load volatile registers from the stack.
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| 74 | 
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| 75 |         popq %rbx
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| 76 |         popq %r12
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| 77 |         popq %r13
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| 78 |         popq %r14
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| 79 |         popq %r15
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| 80 | 
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| 81 |         // Load floating & SSE control words from the stack.
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| 82 | 
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| 83 |         fldcw   4(%rsp)
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| 84 |         ldmxcsr 0(%rsp)
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| 85 |         addq   $8,%rsp
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| 86 | 
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| 87 |         // Return to thread.
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| 88 | 
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| 89 |         ret
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| 90 | 
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| 91 | .text
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| 92 |         .align 2
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| 93 | .globl  CtxInvokeStub
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| 94 | CtxInvokeStub:
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| 95 |         movq %rbx, %rdi 
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| 96 |         jmp *%r12
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| 97 | 
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| 98 | .text
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| 99 |         .align 2
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| 100 | .globl  CtxGet
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| 101 | CtxGet:
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| 102 |         movq %rsp,SP_OFFSET(%rdi)
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| 103 |         movq %rbp,FP_OFFSET(%rdi)
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| 104 | 
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| 105 |         ret
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| 106 | 
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| 107 | // Local Variables: //
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| 108 | // mode: c //
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| 109 | // tab-width: 4 //
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| 110 | // End: //
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