| 1 | // |
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| 2 | // Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo |
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| 3 | // |
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| 4 | // The contents of this file are covered under the licence agreement in the |
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| 5 | // file "LICENCE" distributed with Cforall. |
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| 6 | // |
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| 7 | // CtxSwitch-x86_64.S -- |
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| 8 | // |
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| 9 | // Author : Peter A. Buhr |
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| 10 | // Created On : Mon Aug 10 08:10:26 2020 |
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| 11 | // Last Modified By : Peter A. Buhr |
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| 12 | // Last Modified On : Sat Oct 24 14:36:25 2020 |
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| 13 | // Update Count : 10 |
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| 14 | // |
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| 15 | |
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| 16 | // The context switch routine requires the initial the stack of a thread to |
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| 17 | // look like the thread has saved its context in the normal manner. |
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| 18 | |
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| 19 | // Offsets must synchronized with the __stack_context_t in invoke.h. |
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| 20 | |
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| 21 | #define PTR_BYTE 8 |
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| 22 | #define SP_OFFSET ( 0 * PTR_BYTE ) |
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| 23 | #define FP_OFFSET ( 1 * PTR_BYTE ) |
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| 24 | |
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| 25 | // Context switch between coroutines/tasks. |
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| 26 | // void __cfactx_switch( struct __stack_context_t * from, struct __stack_context_t * to ) ; |
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| 27 | // Arguments "from" in register rdi, "to" in register rsi. |
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| 28 | |
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| 29 | .file "CtxSwitch-x86_64.S" |
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| 30 | .text |
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| 31 | .align 2 |
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| 32 | .global __cfactx_switch |
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| 33 | .type __cfactx_switch, @function |
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| 34 | __cfactx_switch: |
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| 35 | |
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| 36 | // Save volatile registers on the stack. |
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| 37 | |
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| 38 | pushq %r15 |
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| 39 | pushq %r14 |
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| 40 | pushq %r13 |
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| 41 | pushq %r12 |
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| 42 | pushq %rbx |
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| 43 | |
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| 44 | // Save old context in the "from" area. |
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| 45 | |
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| 46 | movq %rsp,SP_OFFSET(%rdi) |
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| 47 | movq %rbp,FP_OFFSET(%rdi) |
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| 48 | |
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| 49 | // Load new context from the "to" area. |
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| 50 | |
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| 51 | movq SP_OFFSET(%rsi),%rsp |
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| 52 | movq FP_OFFSET(%rsi),%rbp |
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| 53 | |
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| 54 | // Load volatile registers from the stack. |
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| 55 | |
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| 56 | popq %rbx |
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| 57 | popq %r12 |
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| 58 | popq %r13 |
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| 59 | popq %r14 |
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| 60 | popq %r15 |
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| 61 | |
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| 62 | // Return to thread. |
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| 63 | |
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| 64 | ret |
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| 65 | .size __cfactx_switch, .-__cfactx_switch |
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| 66 | |
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| 67 | // Stub to create new stacks which can be context switched to |
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| 68 | // void __cfactx_invoke_stub( void ); |
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| 69 | |
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| 70 | .text |
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| 71 | .align 2 |
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| 72 | .global __cfactx_invoke_stub |
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| 73 | .type __cfactx_invoke_stub, @function |
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| 74 | __cfactx_invoke_stub: |
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| 75 | movq %rbx, %rdi // move main and this to first two arguments |
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| 76 | movq %r12, %rsi |
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| 77 | jmp *%r13 // jmp to invoke |
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| 78 | .size __cfactx_invoke_stub, .-__cfactx_invoke_stub |
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| 79 | |
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| 80 | // Local Variables: // |
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| 81 | // mode: asm // |
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| 82 | // tab-width: 4 // |
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| 83 | // End: // |
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