49 lines
981 B
ArmAsm
49 lines
981 B
ArmAsm
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/*
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* Copyright (c) 2020, 2021 Antony Pavlov <antonynpavlov@gmail.com>
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*
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* based on arch/riscv/core/swap.S
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <toolchain.h>
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#include <offsets_short.h>
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#include <arch/cpu.h>
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#include <mips/regdef.h>
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/*
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* unsigned int arch_swap(unsigned int key)
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*
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* Always called with interrupts locked
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* key is stored in a0 register
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*/
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GTEXT(arch_swap)
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SECTION_FUNC(exception.other, arch_swap)
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/* Make a system call to perform context switch */
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syscall
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/*
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* when thread is rescheduled, unlock irq and return.
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* Restored register v0 contains IRQ lock state of thread.
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*/
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la k0, _kernel
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/* Get pointer to _kernel.current */
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lw k1, _kernel_offset_to_current(k0)
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/* Load return value of arch_swap function in register v0 */
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lw v0, _thread_offset_to_swap_return_value(k1)
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/*
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* Unlock irq, following IRQ lock state in v0 register.
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*/
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mfc0 k0, CP0_STATUS
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or k0, k0, a0
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mtc0 k0, CP0_STATUS
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ehb
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/* Return */
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jr ra
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