1/*
2            Copyright Jiaxun Yang 2018.
3   Distributed under the Boost Software License, Version 1.0.
4      (See accompanying file LICENSE_1_0.txt or copy at
5          http://www.boost.org/LICENSE_1_0.txt)
6*/
7
8/*******************************************************
9 *                                                     *
10 *  -------------------------------------------------  *
11 *  |  0  |  1  |  2  |  3  |  4  |  5  |  6  |  7  |  *
12 *  -------------------------------------------------  *
13 *  |     0     |     8     |    16     |     24    |  *
14 *  -------------------------------------------------  *
15 *  |    F24    |    F25    |    F26    |    F27    |  *
16 *  -------------------------------------------------  *
17 *  -------------------------------------------------  *
18 *  |  8  |  9  |  10 |  11 |  12 |  13 |  14 |  15 |  *
19 *  -------------------------------------------------  *
20 *  |     32    |    40     |     48    |     56    |  *
21 *  -------------------------------------------------  *
22 *  |    F28    |    F29    |    F30    |    F31    |  *
23 *  -------------------------------------------------  *
24 *  -------------------------------------------------  *
25 *  |  16 |  17 |  18 |  19 |  20 |  21 |  22 |  23 |  *
26 *  -------------------------------------------------  *
27 *  |     64    |    72     |     80    |     88    |  *
28 *  -------------------------------------------------  *
29 *  |    S0     |    S1     |     S2    |     S3    |  *
30 *  -------------------------------------------------  *
31 *  -------------------------------------------------  *
32 *  |  24 |  25 |  26 |  27 |  28 |  29 |  30 |  31 |  *
33 *  -------------------------------------------------  *
34 *  |  96 | 100 | 104 | 108 | 112 | 116 | 120 | 124 |  *
35 *  -------------------------------------------------  *
36 *  |    S4     |    S5     |     S6    |     S7    |  *
37 *  -------------------------------------------------  *
38 *  -------------------------------------------------  *
39 *  |  32 |  33 |  34 |  35 |  36 |  37 |  38 |  39 |  *
40 *  -------------------------------------------------  *
41 *  | 128 | 132 | 136 | 140 | 144 | 148 | 152 | 156 |  *
42 *  -------------------------------------------------  *
43 *  |    FP     |    GP     |     RA    |     PC    |  *
44 *  -------------------------------------------------  *
45 *                                                     *
46 * *****************************************************/
47
48.file "make_mips64_n64_elf_gas.S"
49.text
50.globl make_fcontext
51.align 3
52.type make_fcontext,@function
53.ent make_fcontext
54make_fcontext:
55#ifdef __PIC__
56.set    noreorder
57.cpload $t9
58.set    reorder
59#endif
60    # shift address in A0 to lower 16 byte boundary
61    li $v1, 0xfffffffffffffff0
62    and $v0, $v1, $a0
63
64    # reserve space for context-data on context-stack
65    daddiu $v0, $v0, -160
66
67    # third arg of make_fcontext() == address of context-function
68    sd  $a2, 152($v0)
69    # save global pointer in context-data
70    sd  $gp, 136($v0)
71
72    # psudo instruction compute abs address of label finish based on GP
73    dla  $t9, finish
74
75    # save address of finish as return-address for context-function
76    # will be entered after context-function returns
77    sd  $t9, 144($v0)
78
79    jr  $ra # return pointer to context-data
80
81finish:
82    # reload our gp register (needed for la)
83    daddiu $t0, $sp, -160
84    ld $gp, 136($t0)
85
86    # call _exit(0)
87    #  the previous function should have left the 16 bytes incoming argument
88    #  area on the stack which we reuse for calling _exit
89    dla $t9, _exit
90    move $a0, $zero
91    jr $t9
92.end make_fcontext
93.size make_fcontext, .-make_fcontext
94
95/* Mark that we don't need executable stack.  */
96.section .note.GNU-stack,"",%progbits
97