1 /* 2 * Handler routines. 3 * 4 * Copyright (C) 2015 Nicholas FitzRoy-Dale <wzdd.code@lardcave.net> 5 * Copyright (C) 2015, 2016 Paul Boddie <paul@boddie.org.uk> 6 * 7 * This program is free software: you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation, either version 3 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program. If not, see <http://www.gnu.org/licenses/>. 19 */ 20 21 #include "mips.h" 22 23 .text 24 .extern irq_handle 25 .extern current_registers 26 .extern current_stack_pointer 27 .extern current_task 28 .extern enter_task 29 .globl interrupt_handler 30 .set noreorder 31 .set noat 32 33 interrupt_handler: 34 /* gp should have been set in the entrypoint. */ 35 36 jal save_state 37 nop 38 39 /* Invoke the handler. */ 40 41 jal irq_handle 42 nop 43 44 /* Switch the stack pointer. */ 45 46 la $k0, current_stack_pointer 47 lw $k1, 0($k0) /* &stack_pointers[current_task] */ 48 lw $sp, 0($k1) 49 50 /* Set the current task ASID. */ 51 52 la $k0, current_task 53 lw $k1, 0($k0) 54 mtc0 $k1, CP0_ENTRYHI 55 nop 56 57 /* Obtain the current task's registers. */ 58 59 j load_and_return 60 nop 61 62 save_state: 63 /* Obtain a store of registers for the current task. */ 64 65 la $k0, current_registers 66 lw $k1, 0($k0) 67 68 sw $at, 4($k1) 69 sw $v0, 8($k1) 70 sw $v1, 12($k1) 71 sw $a0, 16($k1) 72 sw $a1, 20($k1) 73 sw $a2, 24($k1) 74 sw $a3, 28($k1) 75 sw $t0, 32($k1) 76 sw $t1, 36($k1) 77 sw $t2, 40($k1) 78 sw $t3, 44($k1) 79 sw $t4, 48($k1) 80 sw $t5, 52($k1) 81 sw $t6, 56($k1) 82 sw $t7, 60($k1) 83 sw $s0, 64($k1) 84 sw $s1, 68($k1) 85 sw $s2, 72($k1) 86 sw $s3, 76($k1) 87 sw $s4, 80($k1) 88 sw $s5, 84($k1) 89 sw $s6, 88($k1) 90 sw $s7, 92($k1) 91 sw $t8, 96($k1) 92 93 /* t9, gp and ra are already saved */ 94 95 sw $fp, 108($k1) 96 97 mfc0 $k0, CP0_EPC 98 nop 99 sw $k0, 116($k1) 100 101 mflo $k0 102 sw $k0, 120($k1) 103 mfhi $k0 104 sw $k0, 124($k1) 105 106 jr $ra 107 nop 108 109 load_and_return: 110 /* Obtain a store of registers for the current task. */ 111 112 la $k0, current_registers 113 lw $k1, 0($k0) 114 115 lw $at, 4($k1) 116 lw $v0, 8($k1) 117 lw $v1, 12($k1) 118 lw $a0, 16($k1) 119 lw $a1, 20($k1) 120 lw $a2, 24($k1) 121 lw $a3, 28($k1) 122 lw $t0, 32($k1) 123 lw $t1, 36($k1) 124 lw $t2, 40($k1) 125 lw $t3, 44($k1) 126 lw $t4, 48($k1) 127 lw $t5, 52($k1) 128 lw $t6, 56($k1) 129 lw $t7, 60($k1) 130 lw $s0, 64($k1) 131 lw $s1, 68($k1) 132 lw $s2, 72($k1) 133 lw $s3, 76($k1) 134 lw $s4, 80($k1) 135 lw $s5, 84($k1) 136 lw $s6, 88($k1) 137 lw $s7, 92($k1) 138 lw $t8, 96($k1) 139 lw $t9, 100($k1) 140 lw $gp, 104($k1) 141 lw $fp, 108($k1) 142 lw $ra, 112($k1) 143 144 lw $k0, 116($k1) 145 mtc0 $k0, CP0_EPC 146 nop 147 148 lw $k0, 120($k1) 149 mtlo $k0 150 lw $k0, 124($k1) 151 mthi $k0 152 153 j enter_task 154 nop 155 156 .set reorder 157 .set at
