49 lines
1.1 KiB
C
49 lines
1.1 KiB
C
/*
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* Copyright (c) 2011-2015 Wind River Systems, Inc.
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <zephyr/kernel.h>
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#include <zephyr/tracing/tracing.h>
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#include <zephyr/arch/cpu.h>
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#ifndef CONFIG_ARCH_HAS_CUSTOM_CPU_IDLE
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__pinned_func
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void arch_cpu_idle(void)
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{
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sys_trace_idle();
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__asm__ volatile (
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"sti\n\t"
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"hlt\n\t");
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}
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#endif
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#ifndef CONFIG_ARCH_HAS_CUSTOM_CPU_ATOMIC_IDLE
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__pinned_func
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void arch_cpu_atomic_idle(unsigned int key)
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{
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sys_trace_idle();
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__asm__ volatile (
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"sti\n\t"
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/*
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* The following statement appears in "Intel 64 and IA-32
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* Architectures Software Developer's Manual", regarding the 'sti'
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* instruction:
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*
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* "After the IF flag is set, the processor begins responding to
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* external, maskable interrupts after the next instruction is
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* executed."
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*
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* Thus the IA-32 implementation of arch_cpu_atomic_idle() will
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* atomically re-enable interrupts and enter a low-power mode.
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*/
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"hlt\n\t");
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/* restore interrupt lockout state before returning to caller */
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if ((key & 0x200U) == 0U) {
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__asm__ volatile("cli");
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}
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}
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#endif
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