source: libcfa/src/concurrency/CtxSwitch-arm64.S @ 8ec4a52

arm-ehjacob/cs343-translationnew-ast-unique-expr
Last change on this file since 8ec4a52 was 8ec4a52, checked in by Peter A. Buhr <pabuhr@…>, 15 months ago

harmonize with 32-bit ARM context switch

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File size: 2.7 KB
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1//
2// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
3//
4// CtxSwitch-arm64.S --
5//
6// Author           : Peter A. Buhr
7// Created On       : Sun Aug 16 07:50:13 2020
8// Last Modified By : Peter A. Buhr
9// Last Modified On : Wed Aug 26 16:24:59 2020
10// Update Count     : 25
11//
12
13// The context switch routine requires the initial the stack of a thread to
14// look like the thread has saved its context in the normal manner.
15
16// Offsets must synchronized with the __stack_context_t in invoke.h.
17
18#define PTR_BYTE        8
19#define SP_OFFSET       ( 0 * PTR_BYTE )
20#define FP_OFFSET       ( 1 * PTR_BYTE )
21
22// Context switch between coroutines/tasks.
23//   void __cfactx_switch( struct __stack_context_t * from, struct __stack_context_t * to ) ;
24// Arguments "from" in register x0, "to" in register x1.
25
26#define SAVE            20 * 8
27
28        .file "CtxSwitch-arm64.S"
29        .text
30        .align 2
31        .global __cfactx_switch
32        .type __cfactx_switch, %function
33__cfactx_switch:
34
35        sub  sp, sp, #SAVE                                      // push stack
36
37        // Save volatile GP registers x19-x30 on the stack.
38
39        stp  x19, x20, [sp, #0x00]
40        stp  x21, x22, [sp, #0x10]
41        stp  x23, x24, [sp, #0x20]
42        stp  x25, x26, [sp, #0x30]
43        stp  x27, x28, [sp, #0x40]
44        stp  x29, x30, [sp, #0x50]                      // x29 => fp
45
46        // Save volatile SIMD/FPU registers d8-d15 on the stack.
47
48        stp  d8,  d9,  [sp, #0x60]
49        stp  d10, d11, [sp, #0x70]
50        stp  d12, d13, [sp, #0x80]
51        stp  d14, d15, [sp, #0x90]
52
53        // Save old context in the "from" area.
54
55        mov  x4, sp                                                     // cannot store sp directly
56        str  x4, [x0, #SP_OFFSET]
57        str  fp, [x0, #FP_OFFSET]
58
59        // Load new context from the "to" area.
60
61        ldr  fp, [x1, #FP_OFFSET]
62        ldr  x4, [x1, #SP_OFFSET]
63        mov  sp, x4                                                     // cannot store sp directly
64
65        // Load volatile GP registers x19-x30 from the stack.
66
67        ldp  x19, x20, [sp, #0x00]
68        ldp  x21, x22, [sp, #0x10]
69        ldp  x23, x24, [sp, #0x20]
70        ldp  x25, x26, [sp, #0x30]
71        ldp  x27, x28, [sp, #0x40]
72        ldp  x29, x30, [sp, #0x50]
73       
74        // Load volatile SIMD/FPU registers d8-d15 from the stack.
75
76        ldp  d8,  d9,  [sp, #0x60]
77        ldp  d10, d11, [sp, #0x70]
78        ldp  d12, d13, [sp, #0x80]
79        ldp  d14, d15, [sp, #0x90]
80
81        add  sp, sp, #SAVE                                      // pop stack
82        ret                                                                     // return to new thread (mov pc, x30)
83
84        .size __cfactx_switch, .-__cfactx_switch
85        .section .note.GNU-stack,"",%progbits // mark no executable stack needed
86
87// Stub to create new stacks which can be context switched to
88//   void __cfactx_invoke_stub( void );
89
90        .text
91        .align 2
92        .global __cfactx_invoke_stub
93        .type __cfactx_invoke_stub, %function
94__cfactx_invoke_stub:
95        mov x0, x19                                                     // load main as parameter 0
96        mov x1, x20                                                     // load this as parameter 1
97        mov x30, x21                                            // load coroutine invoke routine
98        ret                                                                     //   and jmp to it (mov pc, x30)
99        .size __cfactx_invoke_stub, .-__cfactx_invoke_stub
100
101// Local Variables: //
102// mode: c //
103// tab-width: 4 //
104// End: //
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