93bb4f992b
Note that the scheduler does not load/restore floating point numbers yet upon task switching. This means only one task can use floating point numbers at the same time without the risk of race conditions. Note that this enables SSE in 32-bit x86 platforms - but not all models have such support, which limits which computers Sortix works on. Ideally, we should detect what features are available on the computer at runtime and enable/disable the proper kernel support. This is not a problem on x86_64.
68 lines
1.6 KiB
ArmAsm
68 lines
1.6 KiB
ArmAsm
/******************************************************************************
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COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2011.
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This file is part of Sortix.
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Sortix is free software: you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation, either version 3 of the License, or (at your option) any later
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version.
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Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along
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with Sortix. If not, see <http://www.gnu.org/licenses/>.
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boot.s
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Bootstraps the kernel and passes over control from the boot-loader to the
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kernel main function.
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******************************************************************************/
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.globl start, _start
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.section .text
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.text 0x100000
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.type _start, @function
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start:
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_start:
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jmp prepare_kernel_execution
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# Align 32 bits boundary.
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.align 4
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# Multiboot header.
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multiboot_header:
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# Magic.
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.long 0x1BADB002
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# Flags.
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.long 0x00000003
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# Checksum.
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.long -(0x1BADB002 + 0x00000003)
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prepare_kernel_execution:
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# Enable the floating point unit.
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mov %eax, 0x100000
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mov %cr0, %eax
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and $0xFFFD, %ax
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or $0x10, %ax
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mov %eax, %cr0
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fninit
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# Enable Streaming SIMD Extensions.
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mov %cr0, %eax
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and $0xFFFB, %ax
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or $0x2, %ax
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mov %eax, %cr0
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mov %cr4, %eax
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or $0x600, %eax
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mov %eax, %cr4
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mov 0x100000, %eax
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jmp beginkernel
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