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| 1 | // Iris: micro-kernel for a capability-based operating system. |
| 2 | // mips/boot.S: Kernel entry point, called by the boot loader. |
| 3 | // Copyright 2009 Bas Wijnen <wijnen@debian.org> |
| 4 | // |
| 5 | // This program is free software: you can redistribute it and/or modify |
| 6 | // it under the terms of the GNU General Public License as published by |
| 7 | // the Free Software Foundation, either version 3 of the License, or |
| 8 | // (at your option) any later version. |
| 9 | // |
| 10 | // This program is distributed in the hope that it will be useful, |
| 11 | // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | // GNU General Public License for more details. |
| 14 | // |
| 15 | // You should have received a copy of the GNU General Public License |
| 16 | // along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 17 | |
| 18 | #define ASM |
| 19 | #define ARCH |
| 20 | #include "arch.hh" |
| 21 | |
| 22 | #define MEMORY_SIZE (32 << 20) |
| 23 | #define KERNEL_STACK_SIZE 0x1000 |
| 24 | // The kernel stack. |
| 25 | .lcomm kernel_stack, KERNEL_STACK_SIZE |
| 26 | |
| 27 | .globl __start |
| 28 | .set noreorder |
| 29 | |
| 30 | __start: |
| 31 | bal 1f |
| 32 | // For some reason the disassembler considers everything |
| 33 | // after __start non-code until the next label. So I add a label. |
| 34 | start_hack_for_disassembler: |
| 35 | nop |
| 36 | .word _gp |
| 37 | 1: lw $gp, 0($ra) |
| 38 | |
| 39 | // Flush cache. |
| 40 | mtc0 $zero, $CP0_TAG_LO |
| 41 | lui $v1, 0x8000 |
| 42 | ori $v0, $v1, 0x8000 |
| 43 | 1: |
| 44 | // i-cache index invalidate. |
| 45 | cache 0, 0($v1) |
| 46 | // d-cache store tag. TagLo has the valid bit cleared, so this clears the d-cache. |
| 47 | cache 9, 0($v1) |
| 48 | bne $v1, $v0, 1b |
| 49 | addiu $v1, $v1, 32 |
| 50 | |
| 51 | // Set kseg0 cachable. |
| 52 | li $k0, 0x3 |
| 53 | mtc0 $k0, $CP0_CONFIG, 0 |
| 54 | |
| 55 | la $sp, kernel_stack + KERNEL_STACK_SIZE |
| 56 | |
| 57 | // Clear .bss |
| 58 | la $a0, _bss |
| 59 | la $a1, _end |
| 60 | 1: sw $zero, 0($a0) |
| 61 | bne $a1, $a0, 1b |
| 62 | addiu $a0, 4 |
| 63 | |
| 64 | // First argument is the memory size. |
| 65 | la $t9, init |
| 66 | jr $t9 |
| 67 | li $a0, MEMORY_SIZE |
| 68 |
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