source: trunk/boot/tsar_mips32/boot_entry.S

Last change on this file was 653, checked in by alain, 7 years ago

Remove the hard_config.h file include.
File size: 4.1 KB
Line 
1/*
2 * boot_entry.S - TSAR bootloader entry point.
3 *
4 * Authors : Alain Greiner / Vu Son (2016)
5 *
6 * Copyright (c) UPMC Sorbonne Universites
7 *
8 * This file is part of ALMOS-MKH.
9 *
10 * ALMOS-MKH is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; version 2.0 of the License.
13 *
14 * ALMOS-MKH is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
21 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24/**********************************************************************************************/
25/* This file contains the entry point of the ALMOS-MK boot-loader for the TSAR architecture, */
26/* that is a generic multi-clusters / multi-processors architecture. */
27/* */
28/* This assembly code is executed by all cores, but not at the same time, because all cores */
29/* are not simultaneously activated. It makes the assuption that the CPO register containing */
30/* the core gid (global hardware identifier) has a fixed format: */
31/* gid == (((x << Y_WIDTH) + y) << P_WIDTH) + lid */
32/* */
33/* It does 3 things: */
34/* - It initializes the stack pointer depending on the lid extracted from the gid, */
35/* using the BOOT_STACK_BASE and BOOT_STACK_SIZE parameters that are defined in */
36/* the boot_config.h file, */
37/* - It changes the value of the DATA address extension register using the cxy extracted */
38/* from the gid, with X_WIDTH, Y_WIDTH, P_WIDTH defined in the boot¨config.h file. */
39/* - It jumps to the boot_loader() function defined in the 'boot.c' file, passing the two */
40/* arguments (cxy and lid). */
41/**********************************************************************************************/
42
43#include "mips32_registers.h"
44#include "boot_config.h"
45
46 .section .text, "ax", @progbits
47
48 .globl boot_entry
49 .ent boot_entry
50
51 .align 2
52 .set noreorder
53
54boot_entry:
55
56 /* Get (cxy, lid) values from gid contained in CP0 register */
57
58 mfc0 k0, CP0_PROCID
59 andi k0, k0, 0xFFF /* k0 <= gid */
60 andi t1, k0, ((1 << P_WIDTH) - 1) /* t1 <= lid */
61 srl t2, k0, P_WIDTH /* t2 <= cxy */
62
63 /* Initialize stack pointer from lid value */
64
65 la t0, BOOT_STACK_BASE /* t0 <= BOOT_STACK_BASE */
66 li k1, BOOT_STACK_SIZE /* k1 <= BOOT_STACK_SIZE */
67 multu k1, t1
68 mflo k0 /* k0 <= BOOT_STACK_SIZE * lid */
69 subu sp, t0, k0 /* P[cxy,lid] sp initialized */
70
71 /* Switch to local DSPACE by changing the value of the address extension register */
72
73 mtc2 t2, CP2_DATA_PADDR_EXT
74
75 /* Jump to boot_loader() function after passing (cxy,lid) arguments in the registers */
76
77 or a0, zero, t1 /* a0 <= lid */
78 or a1, zero, t2 /* a1 <= cxy */
79 la ra, boot_loader
80 jr ra
81 nop
82
83 .end boot_entry
84
85 .set reorder
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