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Separate kernel code from test code

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Eventually I want the kernel to be loaded from the SD card as well, but
it still needs to separate from user programs.

At some point there should be a folder just for the BIOS, which should
read from the boot block of the SD card and start executing, and thats
it.
This commit is contained in:
Byron Lathi
2022-04-16 21:58:37 -05:00
parent 238a4b6f98
commit c6098f2d1f
26 changed files with 5 additions and 5 deletions
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73
sw/kernel/filesystem/fat.c Normal file
View File

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#include <conio.h>
#include <string.h>
#include "fat.h"
#include "devices/sd_card.h"
uint8_t fat_buf[512];
static full_bpb_t bpb;
static uint32_t data_region_start;
void fat_print_pbp_info(ebpb_t* epbp){
cprintf("Bytes per sector: %d\n", epbp->bpb3.bpb2.bytes_per_sector);
cprintf("Sectors per cluster: %d\n", epbp->bpb3.bpb2.sectors_per_cluster);
cprintf("Reserved Sectors: %d\n", epbp->bpb3.bpb2.reserved_sectors);
cprintf("Fat Count: %d\n", epbp->bpb3.bpb2.fat_count);
cprintf("Max Dir Entries: %d\n", epbp->bpb3.bpb2.max_dir_entries);
cprintf("Total Sector Count: %d\n", epbp->bpb3.bpb2.total_sector_count);
cprintf("Media Descriptor: 0x%x\n", epbp->bpb3.bpb2.media_descriptor);
cprintf("Sectors per Fat: %d\n", epbp->bpb3.bpb2.sectors_per_fat);
cprintf("\n");
cprintf("Sectors per track: %d\n", epbp->bpb3.sectors_per_track);
cprintf("Head Count: %d\n", epbp->bpb3.head_count);
cprintf("Hidden Sector Count: %ld\n", epbp->bpb3.hidden_sector_count);
cprintf("Logical Sector Count: %ld\n", epbp->bpb3.logical_sector_count);
cprintf("Sectors per Fat: %ld\n", epbp->bpb3.sectors_per_fat);
cprintf("Extended Flags: 0x%x\n", epbp->bpb3.extended_flags);
cprintf("Version: %d\n", epbp->bpb3.version);
cprintf("Root Cluster: 0x%lx\n", epbp->bpb3.root_cluster);
cprintf("System Information: 0x%x\n", epbp->bpb3.system_information);
cprintf("Backup Boot Sector: 0x%x\n", epbp->bpb3.backup_boot_sector);
cprintf("\n");
cprintf("Drive Number: %d\n", epbp->drive_num);
cprintf("Extended Signature: 0x%x\n", epbp->extended_signature);
cprintf("Volume ID: 0x%lx\n", epbp->volume_id);
cprintf("Partition Label: %.11s\n", &epbp->partition_label);
cprintf("Partition Label: %.8s\n", &epbp->filesystem_type);
cprintf("\n");
}
void fat_init(){
sd_readblock(0, fat_buf);
memcpy(&bpb, &fat_buf[11], sizeof(ebpb_t));
sd_readblock(1, fat_buf);
sd_readblock(32, fat_buf);
data_region_start = bpb.reserved_sectors + bpb.fat_count*bpb.sectors_per_fat_32;
}
void fat_read(char* filename, void* buf) {
vfat_dentry_t* vfat_dentry;
dos_dentry_t* dos_dentry;
uint32_t cluster;
(void)filename; //just ignore filename
sd_readblock(data_region_start, buf);
vfat_dentry = (vfat_dentry_t*)buf;
while(vfat_dentry->sequence_number == 0xe5)
vfat_dentry++;
dos_dentry = (dos_dentry_t*)(vfat_dentry + 1);
cluster = ((uint32_t)dos_dentry->first_cluster_h << 16) + dos_dentry->first_cluster_l;
sd_readblock(data_region_start + (cluster - 2) * 8, buf);
}