/*
 * Copyright (C) 2017 JP Bonn
 *
 * This file is subject to the terms and conditions of the GNU Lesser
 * General Public License v2.1. See the file LICENSE in the top level
 * directory for more details.
 */

/**
 * @defgroup    cpu_fe310
 * @ingroup     cpu
 * @brief       Freedom E cpu
 * @{
 *
 * @file
 * @brief       Thread context frame stored on stack.
 *
 * @author      JP Bonn
 */

#ifndef CONTEXT_FRAME_H
#define CONTEXT_FRAME_H

#if !defined(__ASSEMBLER__)
#include <stdint.h>
#include <assert.h>
#endif /* __ASSEMBLER__ */


#ifdef __cplusplus
extern "C" {
#endif

/**
 * @brief   context_switch_frame stores the registers and PC for a context switch.
 *
 * This also defines context_switch_frame offsets for assembly language.  The
 * structure is sized to maintain 16 byte stack alignment per the ABI.
 * https://github.com/riscv/riscv-elf-psabi-doc
 *
 */
#if !defined(__ASSEMBLER__)

/* N.B.: update the definitions below if this changes */
struct context_switch_frame {
    uint32_t filler0;   /* filler to maintain 16 byte alignment */
    uint32_t filler1;   /* filler to maintain 16 byte alignment */
    uint32_t pc;
    /* Callee saved registers */
    uint32_t s0;
    uint32_t s1;
    uint32_t s2;
    uint32_t s3;
    uint32_t s4;
    uint32_t s5;
    uint32_t s6;
    uint32_t s7;
    uint32_t s8;
    uint32_t s9;
    uint32_t s10;
    uint32_t s11;
    /* Caller saved register */
    uint32_t ra;
    uint32_t tp;
    uint32_t t0;
    uint32_t t1;
    uint32_t t2;
    uint32_t t3;
    uint32_t t4;
    uint32_t t5;
    uint32_t t6;
    uint32_t a0;
    uint32_t a1;
    uint32_t a2;
    uint32_t a3;
    uint32_t a4;
    uint32_t a5;
    uint32_t a6;
    uint32_t a7;
};
#endif /* __ASSEMBLER__ */


/* These values are checked for correctness in context_frame.c */
#define filler0_OFFSET 0
#define filler1_OFFSET 4
#define pc_OFFSET     8
#define s0_OFFSET     12
#define s1_OFFSET     16
#define s2_OFFSET     20
#define s3_OFFSET     24
#define s4_OFFSET     28
#define s5_OFFSET     32
#define s6_OFFSET     36
#define s7_OFFSET     40
#define s8_OFFSET     44
#define s9_OFFSET     48
#define s10_OFFSET    52
#define s11_OFFSET    56
#define ra_OFFSET     60
#define tp_OFFSET     64
#define t0_OFFSET     68
#define t1_OFFSET     72
#define t2_OFFSET     76
#define t3_OFFSET     80
#define t4_OFFSET     84
#define t5_OFFSET     88
#define t6_OFFSET     92
#define a0_OFFSET     96
#define a1_OFFSET     100
#define a2_OFFSET     104
#define a3_OFFSET     108
#define a4_OFFSET     112
#define a5_OFFSET     116
#define a6_OFFSET     120
#define a7_OFFSET     124

#define CONTEXT_FRAME_SIZE (a7_OFFSET + 4)

#define SP_OFFSET_IN_THREAD 0


#ifdef __cplusplus
}
#endif

#endif /* CONTEXT_FRAME_H */
/** @} */