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[/] [darkriscv/] [trunk/] [src/] [boot.s] - Blame information for rev 4

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/*
 * Copyright (c) 2018, Marcelo Samsoniuk
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice, this
 *   list of conditions and the following disclaimer.
 *
 * * Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 *
 * * Neither the name of the copyright holder nor the names of its
 *   contributors may be used to endorse or promote products derived from
 *   this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
        .option nopic
        .text
        .section .boot
        .align  2
        .globl  check4rv32i
 
/*
        boot:
        - read and increent thread counter
        - case not zero, jump to multi thread boot
        - otherwise continue
*/
 
_boot:
 
        la      a0,threads
        lw      a1,0(a0)
        addi    a2,a1,1
        sw      a2,0(a0)
        la      a3,io
        bne     a1,x0,_multi_thread_boot
 
/*
        normal boot here:
        - set stack
        - set global pointer
        - plot boot banner
        - print memory setup
        - call main
        - repeat forever
*/
 
_normal_boot:
 
        la      sp,_stack
        la      gp,_global
 
        call    banner
 
        la      a3,_stack
        la      a2,_heap
        sub     a4,a3,a2
        la      a1,_boot
        la      a0,_boot0msg
        call    printf
 
        call    main
 
        j       _normal_boot
 
/*
        multi-thread boot:
        - set io base
        - write thread number to io.gpio
        - increent thread number
        - repeat forever
*/
 
_multi_thread_boot:
 
        sh      a1,10(a3)
        addi    a1,a1,1
        j       _multi_thread_boot
 
/*
        rv32e/rv32i detection:
        - set x15 0
        - set x31 1
        - sub x31-x15 and return the value
        why this works?!
        - the rv32i have separate x15 and x31, but the rv32e will make x15 = x31
        - this "feature" probably works only in the darkriscv! :)
*/
 
check4rv32i:
 
        .word   0x00000793      /* addi    x15,x0,0   */
        .word   0x00100f93      /* addi    x31,x0,1   */
        .word   0x40ff8533      /* sub     a0,x31,x15 */
 
        ret
 
/*
        data segment here!
*/
 
        .section .rodata
        .align  2
 
_boot0msg:
        .string "boot0: text@%d data@%d stack@%d (%d bytes free)\n"

Line No.	Rev	Author	Line
1	4	marcelos	`/*`
2			`* Copyright (c) 2018, Marcelo Samsoniuk`
3			`* All rights reserved.`
4			`*`
5			`* Redistribution and use in source and binary forms, with or without`
6			`* modification, are permitted provided that the following conditions are met:`
7			`*`
8			`* * Redistributions of source code must retain the above copyright notice, this`
9			`* list of conditions and the following disclaimer.`
10			`*`
11			`* * Redistributions in binary form must reproduce the above copyright notice,`
12			`* this list of conditions and the following disclaimer in the documentation`
13			`* and/or other materials provided with the distribution.`
14			`*`
15			`* * Neither the name of the copyright holder nor the names of its`
16			`* contributors may be used to endorse or promote products derived from`
17			`* this software without specific prior written permission.`
18			`*`
19			`* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"`
20			`* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE`
21			`* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE`
22			`* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE`
23			`* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL`
24			`* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR`
25			`* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER`
26			`* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,`
27			`* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE`
28			`* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.`
29			`*/`
30
31	2	marcelos	`.option nopic`
32			`.text`
33	4	marcelos	`.section .boot`
34	2	marcelos	`.align 2`
35	4	marcelos	`.globl check4rv32i`
36
37			`/*`
38			`boot:`
39			`- read and increent thread counter`
40			`- case not zero, jump to multi thread boot`
41			`- otherwise continue`
42			`*/`
43
44			`_boot:`
45
46			`la a0,threads`
47			`lw a1,0(a0)`
48			`addi a2,a1,1`
49			`sw a2,0(a0)`
50			`la a3,io`
51			`bne a1,x0,_multi_thread_boot`
52
53			`/*`
54			`normal boot here:`
55			`- set stack`
56			`- set global pointer`
57			`- plot boot banner`
58			`- print memory setup`
59			`- call main`
60			`- repeat forever`
61			`*/`
62
63			`_normal_boot:`
64
65			`la sp,_stack`
66			`la gp,_global`
67
68			`call banner`
69
70			`la a3,_stack`
71			`la a2,_heap`
72			`sub a4,a3,a2`
73			`la a1,_boot`
74			`la a0,_boot0msg`
75	2	marcelos	`call printf`
76	4	marcelos
77	2	marcelos	`call main`
78	4	marcelos
79			`j _normal_boot`
80
81			`/*`
82			`multi-thread boot:`
83			`- set io base`
84			`- write thread number to io.gpio`
85			`- increent thread number`
86			`- repeat forever`
87			`*/`
88
89			`_multi_thread_boot:`
90
91			`sh a1,10(a3)`
92			`addi a1,a1,1`
93			`j _multi_thread_boot`
94
95			`/*`
96			`rv32e/rv32i detection:`
97			`- set x15 0`
98			`- set x31 1`
99			`- sub x31-x15 and return the value`
100			`why this works?!`
101			`- the rv32i have separate x15 and x31, but the rv32e will make x15 = x31`
102			`- this "feature" probably works only in the darkriscv! :)`
103			`*/`
104
105			`check4rv32i:`
106
107			`.word 0x00000793 /* addi x15,x0,0 */`
108			`.word 0x00100f93 /* addi x31,x0,1 */`
109			`.word 0x40ff8533 /* sub a0,x31,x15 */`
110
111			`ret`
112
113			`/*`
114			`data segment here!`
115			`*/`
116
117			`.section .rodata`
118	2	marcelos	`.align 2`
119	4	marcelos
120			`_boot0msg:`
121			`.string "boot0: text@%d data@%d stack@%d (%d bytes free)\n"`

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[/] [darkriscv/] [trunk/] [src/] [boot.s] - Blame information for rev 4