/* Copyright (C) 2021,2022 fef <owo@fef.moe>.  All rights reserved. */

#pragma once

#ifndef _ARCH_SCHED_H_
#error "This file is not meant to be included directly, use <arch/sched.h>"
#endif

/**
 * @brief In-kernel context save for the x86_64.
 * This precise structure layout is hardcoded in assembly, so don't forget to
 * update `arch/x86/sys/amd64/switch.S` when changing it.
 */
struct amd64_context {
	/*
	 * the register itself is %rsp, but it points to the %rip that was
	 * pushed by the function calling `arch_switch_to()` as a result of
	 * the CALL instruction
	 */
	union {
		u64 rsp;
		u64 *rip;
	};
	u64 rbx;
	u64 rbp;
	u64 r12;
	u64 r13;
	u64 r14;
	u64 r15;
} __packed;

/**
 * @brief Arch dependent Task Control Block (amd64 version).
 * This is what's required for in-kernel task switching.
 * Treat as a completely opaque type outside of the `arch/x86` directory.
 */
typedef struct amd64_context tcb_t;