f3c7ac9696
Instead of using the bootsector to load a bootloader, just put the bootloader in the ROM and call it a day. It looks for a file on the SD card in the root directory named `kernel.bin` and loads it into memory. This is not a perfect solution, as the kernel will grow larger and the kernel load address will have to change. At this point I could add back the bootloader, but that is for later. Also the bootloader is just a copy of the kernel, so that can be trimmed down a lot.
64 lines
1.2 KiB
C
64 lines
1.2 KiB
C
#include <stdint.h>
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#include <conio.h>
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#include <string.h>
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#include <stdlib.h>
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#include "devices/board_io.h"
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#include "devices/uart.h"
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#include "devices/mapper.h"
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#include "devices/sd_card.h"
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#include "filesystem/fat.h"
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#include "exec.h"
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#define KERNEL_LOAD_ADDR 0xD000
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uint8_t buf[512];
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int main() {
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int i;
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uint16_t rca;
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char* filename;
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uint32_t cluster;
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uint8_t* kernel_load;
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clrscr();
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cprintf("boot\n");
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for (i = 0; i < 16; i++){
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//cprintf("Mapping %1xxxx to %2xxxx\n", i, i);
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mapper_write(i, i);
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}
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cprintf("Enabling Mapper\n");
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mapper_enable(1);
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mapper_write(0x10, 0xd);
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mapper_write(0x11, 0xe);
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mapper_write(0x12, 0xf);
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sd_init();
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rca = sd_get_rca();
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cprintf("rca: %x\n", rca);
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sd_select_card(rca);
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fat_init();
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filename = (char*)malloc(FAT_MAX_FILE_NAME);
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cluster = fat_parse_path_to_cluster("/kernel.bin");
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for (kernel_load = (uint8_t*)KERNEL_LOAD_ADDR; cluster < FAT_CLUSTERMASK; kernel_load+=(8*512)) {
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cprintf("cluster: %lx\n", cluster);
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cprintf("Writing to %p\n", kernel_load);
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fat_read_cluster(cluster, kernel_load);
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cluster = fat_get_chain_value(cluster);
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}
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cprintf("Done!\n");
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cprintf("Reset vector: %x\n", *((uint16_t*)0xfffc));
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return 0;
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}
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