source: soft/giet_vm/giet_kernel/switch.s

Last change on this file was 818, checked in by cfuguet, 10 years ago

Optimization: When doing a context switch between threads of the
same vspace and cluster, do not rewrite the PTPR register.
  • Property svn:executable set to *
File size: 4.9 KB
Line 
1/******************************************************************************
2* This function receives two arguments that are the current thread context
3* (virtual) addresses and the next thread context (virtual) address.
4*
5* This function should be called in a critical section
6*
7* TODO (AG) Il semble possible de limiter le nombre de registres à sauver:
8* - s0 à s8 ($16 à $23 + $30)
9* - sp ($29)
10* - ra ($31)
11* - hi et lo
12* - sr
13* - epc
14* - ptpr
15******************************************************************************/
16
17 .globl _thread_switch
18 .func _thread_switch
19 .type _thread_switch, %function
20
21_thread_switch:
22
23 /* first step : save current thread context */
24 add $27, $4, $0 /* $27 <= &context[current] */
25
26 .set noat
27 sw $1, 1*4($27) /* ctx[1] <= $1 */
28 .set at
29 sw $2, 2*4($27) /* ctx[2] <= $2 */
30 sw $3, 3*4($27) /* ctx[3] <= $3 */
31 sw $4, 4*4($27) /* ctx[4] <= $4 */
32 sw $5, 5*4($27) /* ctx[5] <= $5 */
33 sw $6, 6*4($27) /* ctx[6] <= $6 */
34 sw $7, 7*4($27) /* ctx[7] <= $7 */
35 sw $8, 8*4($27) /* ctx[8] <= $8 */
36 sw $9, 9*4($27) /* ctx[9] <= $9 */
37 sw $10, 10*4($27) /* ctx[10] <= $10 */
38 sw $11, 11*4($27) /* ctx[11] <= $11 */
39 sw $12, 12*4($27) /* ctx[12] <= $12 */
40 sw $13, 13*4($27) /* ctx[13] <= $13 */
41 sw $14, 14*4($27) /* ctx[14] <= $14 */
42 sw $15, 15*4($27) /* ctx[15] <= $15 */
43 sw $16, 16*4($27) /* ctx[16] <= $16 */
44 sw $17, 17*4($27) /* ctx[17] <= $17 */
45 sw $18, 18*4($27) /* ctx[18] <= $18 */
46 sw $19, 19*4($27) /* ctx[19] <= $19 */
47 sw $20, 20*4($27) /* ctx[20] <= $20 */
48 sw $21, 21*4($27) /* ctx[21] <= $21 */
49 sw $22, 22*4($27) /* ctx[22] <= $22 */
50 sw $23, 23*4($27) /* ctx[23] <= $23 */
51 sw $24, 24*4($27) /* ctx[24] <= $24 */
52 sw $25, 25*4($27) /* ctx[25] <= $25 */
53 mflo $26
54 sw $26, 26*4($27) /* ctx[26] <= LO */
55 mfhi $26
56 sw $26, 27*4($27) /* ctx[27] <= H1 */
57 sw $28, 28*4($27) /* ctx[28] <= $28 */
58 sw $29, 29*4($27) /* ctx[29] <= $29 */
59 sw $30, 30*4($27) /* ctx[30] <= $30 */
60 sw $31, 31*4($27) /* ctx[31] <= $31 */
61 mfc0 $26, $14
62 sw $26, 32*4($27) /* ctx[32] <= EPC */
63 mfc0 $26, $13
64 sw $26, 33*4($27) /* ctx[33] <= CR */
65 mfc0 $26, $12
66 sw $26, 34*4($27) /* ctx[34] <= SR */
67 mfc0 $26, $8
68 sw $26, 35*4($27) /* ctx[34] <= BVAR */
69 mfc2 $26, $0
70 sw $26, 39*4($27) /* ctx[35] <= PTPR */
71
72 /* second step : restore next thread context */
73 add $27, $5, $0 /* $27<= &context[next] */
74
75 .set noat
76 lw $1, 1*4($27) /* restore $1 */
77 .set at
78 lw $2, 2*4($27) /* restore $2 */
79 lw $3, 3*4($27) /* restore $3 */
80 lw $4, 4*4($27) /* restore $4 */
81 lw $5, 5*4($27) /* restore $5 */
82 lw $6, 6*4($27) /* restore $6 */
83 lw $7, 7*4($27) /* restore $7 */
84 lw $8, 8*4($27) /* restore $8 */
85 lw $9, 9*4($27) /* restore $9 */
86 lw $10, 10*4($27) /* restore $10 */
87 lw $11, 11*4($27) /* restore $11 */
88 lw $12, 12*4($27) /* restore $12 */
89 lw $13, 13*4($27) /* restore $13 */
90 lw $14, 14*4($27) /* restore $14 */
91 lw $15, 15*4($27) /* restore $15 */
92 lw $16, 16*4($27) /* restore $16 */
93 lw $17, 17*4($27) /* restore $17 */
94 lw $18, 18*4($27) /* restore $18 */
95 lw $19, 19*4($27) /* restore $19 */
96 lw $20, 20*4($27) /* restore $20 */
97 lw $21, 21*4($27) /* restore $21 */
98 lw $22, 22*4($27) /* restore $22 */
99 lw $23, 23*4($27) /* restore $23 */
100 lw $24, 24*4($27) /* restore $24 */
101 lw $25, 25*4($27) /* restore $25 */
102 lw $26, 26*4($27)
103 mtlo $26 /* restore LO */
104 lw $26, 27*4($27)
105 mthi $26 /* restore HI */
106 lw $28, 28*4($27) /* restore $28 */
107 lw $29, 29*4($27) /* restore $29 */
108 lw $30, 30*4($27) /* restore $30 */
109 lw $31, 31*4($27) /* restore $31 */
110 lw $26, 32*4($27)
111 mtc0 $26, $14 /* restore EPC */
112 lw $26, 33*4($27)
113 mtc0 $26, $13 /* restore CR */
114 lw $26, 34*4($27)
115 mtc0 $26, $12 /* restore SR */
116 lw $26, 35*4($27)
117 mtc0 $26, $8 /* restore BVAR */
118
119 /* returns to caller */
120 jr $31
121
122 .endfunc
123 .size _thread_switch, .-_thread_switch
124
Note: See TracBrowser for help on using the repository browser.