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