| 1 |
2 |
idiolatrie |
################################################################################
|
| 2 |
|
|
# Boot Up Code #
|
| 3 |
|
|
#------------------------------------------------------------------------------#
|
| 4 |
|
|
# REFERENCES #
|
| 5 |
|
|
# #
|
| 6 |
|
|
# [1] The MIPS programmer's handbook #
|
| 7 |
|
|
# Erin Frquhar and Philip Bunce #
|
| 8 |
|
|
# San Francisco, CA, Morgan Kaufmann Publishers, 1994 #
|
| 9 |
|
|
# ISBN 1-55860-297-6 #
|
| 10 |
|
|
# #
|
| 11 |
|
|
#------------------------------------------------------------------------------#
|
| 12 |
|
|
# Copyright (C)2011 Mathias Hörtnagl <mathias.hoertnagl@gmail.com> #
|
| 13 |
|
|
# #
|
| 14 |
|
|
# This program is free software: you can redistribute it and/or modify #
|
| 15 |
|
|
# it under the terms of the GNU General Public License as published by #
|
| 16 |
|
|
# the Free Software Foundation, either version 3 of the License, or #
|
| 17 |
|
|
# (at your option) any later version. #
|
| 18 |
|
|
# #
|
| 19 |
|
|
# This program is distributed in the hope that it will be useful, #
|
| 20 |
|
|
# but WITHOUT ANY WARRANTY; without even the implied warranty of #
|
| 21 |
|
|
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the #
|
| 22 |
|
|
# GNU General Public License for more details. #
|
| 23 |
|
|
# #
|
| 24 |
|
|
# You should have received a copy of the GNU General Public License #
|
| 25 |
|
|
# along with this program. If not, see <http://www.gnu.org/licenses/>. #
|
| 26 |
|
|
################################################################################
|
| 27 |
|
|
|
| 28 |
|
|
.ifndef STACKSIZE # Stack size in byte.
|
| 29 |
|
|
.set STACKSIZE, 8192
|
| 30 |
|
|
.endif
|
| 31 |
|
|
|
| 32 |
|
|
.comm stack, STACKSIZE # Global memory: stack.
|
| 33 |
|
|
|
| 34 |
|
|
.text
|
| 35 |
|
|
.align 2
|
| 36 |
|
|
################################################################################
|
| 37 |
|
|
# Execution Start #
|
| 38 |
|
|
#------------------------------------------------------------------------------#
|
| 39 |
|
|
.globl boot
|
| 40 |
|
|
.ent boot
|
| 41 |
|
|
boot:
|
| 42 |
|
|
.set noreorder
|
| 43 |
|
|
|
| 44 |
|
|
la $gp, _gp # Set global pointer.
|
| 45 |
|
|
la $sp, stack+STACKSIZE-24 # Set stack pointer.
|
| 46 |
|
|
|
| 47 |
|
|
la $v0, _bss_start # Global variable region start.
|
| 48 |
|
|
la $v1, _bss_end # Global variable region end.
|
| 49 |
|
|
|
| 50 |
|
|
clrbss: # Clear global variable region.
|
| 51 |
|
|
sw $0, ($v0)
|
| 52 |
|
|
addiu $v0, 4
|
| 53 |
|
|
blt $v0, $v1, clrbss # Continue execution when .bss region is clear.
|
| 54 |
|
|
nop
|
| 55 |
|
|
|
| 56 |
|
|
.set noat
|
| 57 |
|
|
and $at, $0, $0 # Clear all registers.
|
| 58 |
|
|
.set at
|
| 59 |
|
|
and $v0, $0, $0
|
| 60 |
|
|
and $v1, $0, $0
|
| 61 |
|
|
and $a0, $0, $0
|
| 62 |
|
|
and $a1, $0, $0
|
| 63 |
|
|
and $a2, $0, $0
|
| 64 |
|
|
and $a3, $0, $0
|
| 65 |
|
|
and $t0, $0, $0
|
| 66 |
|
|
and $t1, $0, $0
|
| 67 |
|
|
and $t2, $0, $0
|
| 68 |
|
|
and $t3, $0, $0
|
| 69 |
|
|
and $t4, $0, $0
|
| 70 |
|
|
and $t5, $0, $0
|
| 71 |
|
|
and $t6, $0, $0
|
| 72 |
|
|
and $t7, $0, $0
|
| 73 |
|
|
and $s0, $0, $0
|
| 74 |
|
|
and $s1, $0, $0
|
| 75 |
|
|
and $s2, $0, $0
|
| 76 |
|
|
and $s3, $0, $0
|
| 77 |
|
|
and $s4, $0, $0
|
| 78 |
|
|
and $s5, $0, $0
|
| 79 |
|
|
and $s6, $0, $0
|
| 80 |
|
|
and $s7, $0, $0
|
| 81 |
|
|
and $t8, $0, $0
|
| 82 |
|
|
and $t9, $0, $0
|
| 83 |
|
|
and $k0, $0, $0
|
| 84 |
|
|
and $k1, $0, $0
|
| 85 |
|
|
and $fp, $0, $0
|
| 86 |
|
|
and $ra, $0, $0
|
| 87 |
|
|
|
| 88 |
|
|
jal main # Start execution of the C main procedure.
|
| 89 |
|
|
nop
|
| 90 |
|
|
|
| 91 |
|
|
loop: # Final loop. Afer returning from C main loop.
|
| 92 |
|
|
nop
|
| 93 |
|
|
j loop # Real Infinity.
|
| 94 |
|
|
nop
|
| 95 |
|
|
nop
|
| 96 |
|
|
|
| 97 |
|
|
.set reorder
|
| 98 |
|
|
.end boot
|
| 99 |
|
|
|
| 100 |
|
|
|
| 101 |
|
|
################################################################################
|
| 102 |
|
|
# Interrupt Start #
|
| 103 |
|
|
#------------------------------------------------------------------------------#
|
| 104 |
|
|
# .ent intr_handler
|
| 105 |
|
|
# intr_handler:
|
| 106 |
|
|
# .set noreorder
|
| 107 |
|
|
# .set noat
|
| 108 |
|
|
|
| 109 |
|
|
# If we do not include the Interrupt API, simply return to normal execution
|
| 110 |
|
|
# immediately.
|
| 111 |
|
|
# .ifdef _INTERRUPT
|
| 112 |
|
|
|
| 113 |
|
|
# addiu $sp, $sp, -72 # Allocate space for all relevant registers.
|
| 114 |
|
|
# sw $at, 4($sp) # Save all registers, that are used directily
|
| 115 |
|
|
# sw $v0, 8($sp) # after a successful execution of the interrupt
|
| 116 |
|
|
# sw $v1, 12($sp) # service routines.
|
| 117 |
|
|
# sw $a0, 16($sp) # Registers $s0 - $s8 do not need to be saved,
|
| 118 |
|
|
# sw $a1, 20($sp) # since the compiler stores them if they are
|
| 119 |
|
|
# sw $a2, 24($sp) # used in a procedure.
|
| 120 |
|
|
# sw $a3, 28($sp) # $gp is the same for the entire source code.
|
| 121 |
|
|
# sw $t0, 32($sp) # Registers $k0 and $k1 are reserved for ASM
|
| 122 |
|
|
# sw $t1, 36($sp) # routines. The C compiler does not use them.
|
| 123 |
|
|
# sw $t2, 40($sp)
|
| 124 |
|
|
# sw $t3, 44($sp)
|
| 125 |
|
|
# sw $t4, 48($sp)
|
| 126 |
|
|
# sw $t5, 52($sp)
|
| 127 |
|
|
# sw $t6, 56($sp)
|
| 128 |
|
|
# sw $t7, 60($sp)
|
| 129 |
|
|
# sw $t8, 64($sp)
|
| 130 |
|
|
# sw $t9, 68($sp)
|
| 131 |
|
|
# sw $ra, 72($sp)
|
| 132 |
|
|
|
| 133 |
|
|
# mfc0 $k0, $13 # Retrieve CAUSE (Pending Interrupts).
|
| 134 |
|
|
#nop
|
| 135 |
|
|
# mfc0 $k1, $12 # Retrieve SR (Interrupt mask and global IE).
|
| 136 |
|
|
# nop
|
| 137 |
|
|
# and $k0, $k0, $k1 # Get legal pending interrupts.
|
| 138 |
|
|
# addiu $sp, $sp, -24
|
| 139 |
|
|
# jal intr_dispatch # Jump to C interrupt dispatch routine.
|
| 140 |
|
|
# srl $a0, $k0, 8
|
| 141 |
|
|
# addiu $sp, $sp, 24
|
| 142 |
|
|
|
| 143 |
|
|
# lw $at, 4($sp) # Restore saved registers.
|
| 144 |
|
|
# lw $v0, 8($sp)
|
| 145 |
|
|
# lw $v1, 12($sp)
|
| 146 |
|
|
# lw $a0, 16($sp)
|
| 147 |
|
|
# lw $a1, 20($sp)
|
| 148 |
|
|
# lw $a2, 24($sp)
|
| 149 |
|
|
# lw $a3, 28($sp)
|
| 150 |
|
|
# lw $t0, 32($sp)
|
| 151 |
|
|
# lw $t1, 36($sp)
|
| 152 |
|
|
# lw $t2, 40($sp)
|
| 153 |
|
|
# lw $t3, 44($sp)
|
| 154 |
|
|
# lw $t4, 48($sp)
|
| 155 |
|
|
# lw $t5, 52($sp)
|
| 156 |
|
|
# lw $t6, 56($sp)
|
| 157 |
|
|
# lw $t7, 60($sp)
|
| 158 |
|
|
# lw $t8, 64($sp)
|
| 159 |
|
|
# lw $t9, 68($sp)
|
| 160 |
|
|
# lw $ra, 72($sp)
|
| 161 |
|
|
# addiu $sp, $sp, 72 # Undo stack allocation.
|
| 162 |
|
|
|
| 163 |
|
|
# .endif
|
| 164 |
|
|
|
| 165 |
|
|
# mfc0 $k1, $14 # Retrieve EPC
|
| 166 |
|
|
# nop
|
| 167 |
|
|
# jr $k1 # Return to normal execution.
|
| 168 |
|
|
# rfe # Restore from exception. Pop IE stack.
|
| 169 |
|
|
|
| 170 |
|
|
# .set at
|
| 171 |
|
|
# .set reorder
|
| 172 |
|
|
# .end intr_handler
|
| 173 |
|
|
|
| 174 |
|
|
|
| 175 |
|
|
################################################################################
|
| 176 |
|
|
# Start Flash Application #
|
| 177 |
|
|
#------------------------------------------------------------------------------#
|
| 178 |
|
|
.globl start
|
| 179 |
|
|
.ent start
|
| 180 |
|
|
start:
|
| 181 |
|
|
.set noreorder
|
| 182 |
|
|
|
| 183 |
|
|
lui $k0, 0x2000
|
| 184 |
|
|
jr $k0
|
| 185 |
|
|
nop
|
| 186 |
|
|
|
| 187 |
|
|
.set reorder
|
| 188 |
|
|
.end start
|
