head.c

#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <types.h>

typedef struct boot_file_head {
    uint32_t jump_instruction; /* one intruction jumping to real code */
    uint8_t magic[8];          /* ="eGON.BT0" */
    uint32_t check_sum;        /* generated by PC */
    uint32_t *length;          /* generated by LD */
    uint32_t pub_head_size;    /* the size of boot_file_head_t */
    uint8_t pub_head_vsn[4];   /* the version of boot_file_head_t */
    uint32_t *ret_addr;        /* the return value */
    uint32_t *run_addr;        /* run addr */
    uint32_t boot_cpu;         /* eGON version */
    uint8_t platform[8];       /* platform information */
} boot_file_head_t;

#define BROM_FILE_HEAD_SIZE_OFFSET (((sizeof(boot_file_head_t) + sizeof(int)) / sizeof(int) + 1))
#define JUMP_INSTRUCTION (BROM_FILE_HEAD_SIZE_OFFSET | 0xEA000000)

#define BOOT0_MAGIC "eGON.BT0"
#define STAMP_VALUE (0x12345678)
#define BOOT_PUB_HEAD_VERSION "3000"

extern uint32_t __spl_size[];
extern uint32_t __code_start_address[];

const __attribute__((section(".boot0_head"))) boot_file_head_t boot_head = {
        .jump_instruction = JUMP_INSTRUCTION,
        .magic = BOOT0_MAGIC,
        .check_sum = STAMP_VALUE,
        .length = __spl_size,
        .pub_head_size = sizeof(boot_file_head_t),
        .pub_head_vsn = BOOT_PUB_HEAD_VERSION,
        .ret_addr = __code_start_address,
        .run_addr = __code_start_address,
        .boot_cpu = 0,
        .platform = {0, 0, '3', '.', '0', '.', '0', 0},
};