Compare commits

..

2 Commits

Author SHA1 Message Date
52d5e67f44 Run clippy on initrd_maker 2022-11-18 16:29:58 -06:00
9e48568e22 Update to sector size of 512 2022-11-18 16:05:13 -06:00
4 changed files with 55 additions and 32 deletions

View File

@ -3,25 +3,16 @@ _start:
move.b #0x4, d0 move.b #0x4, d0
bsr.w find_first_card bsr.w find_first_card
| Load the header sector for the kernel binary | Load the header sector for the kernel binary
move.l #0x1, (a0) | Set the sector number to 1 move.l #0x200, a1 | Set the destination address to 0x200
| Transfer 0x100 (256) bytes from the storage card's data register to 0x100 move.l #0x1, d0 | Set the starting sector number to 1
move.w #0x100, a1 | Load a1, the destination address register, with 0x100 move.l #0x1, d1 | Set the sector count to 1
move.w #0xFF, d0 | Load d0 with the sector size - 1. bsr.w read_sectors
hdr_sector_loop:
move.b (4, a0), (a1)+ | Transfer a byte of sector data to the destination
dbra d0, hdr_sector_loop | Loop back if there is more to transfer
move.w (0x102), d0 | Load d0 with the number of sectors for the kernel - 1
subq.w #0x1, d0
| load the ELF kernel binary off the disk | load the ELF kernel binary off the disk
move.l #0x2, (a0) | Set the sector number to 2 move.l #0xA000, a1 | Set the destination address to 0xA000
| Transfer 0x100 (256) * d0 bytes from the storage card's data register to 0xA000 move.l #0x2, d0 | Set the starting sector number to 2
move.l #0xA000, a1 | Load a1, the destination address register, with 0xA000 clr.l d1
sectors_loop: move.w (0x202), d1 | Set the sector count
move.w #0xFF, d1 | Load d0 with the sector size - 1. bsr.b read_sectors
sector_loop:
move.b (4, a0), (a1)+ | Transfer a byte of sector data to the destination
dbra d1, sector_loop | Loop back if there is more to transfer
dbra d0, sectors_loop | Loop back if there are more sectors to transfer
move.l (0xA01C), d0 | Load the offset of the program headers in the file move.l (0xA01C), d0 | Load the offset of the program headers in the file
move.l #0xA000, a0 | Put the address of the program headers in a0 move.l #0xA000, a0 | Put the address of the program headers in a0
adda.w d0, a0 adda.w d0, a0
@ -72,8 +63,32 @@ ffc_done:
rts rts
.if . != 256 | Reads sectors from a storage card
.org 255 | Card base in a0
| Destination in a1
| Start sector in d0.l
| Sector count in d1.l
| Clobbers a1, d1
read_sectors:
move.l d0, (a0) | Set the sector number
move.l d1, (4, a0) | Set the sector count
move.w #0x0, (8, a0) | Issue a read command
| Transfer 0x200 (512) * sector_count bytes from the storage card's data register to (a1)
lsl.l #8, d1 | d0 = d0 * 256 to compute the number of words to transfer
subq.l #0x1, d1 | Subtract 1 from the word count to account for the extra loop done by dbra
bra.b rs_loop
rs_loop_swap:
swap.w d1
rs_loop:
move.w (0xA, a0), (a1)+ | Transfer a word of sector data to the destination
dbra.w d1, rs_loop
swap.w d1
dbra.w d1, rs_loop_swap
rts
.if . != 512
.org 511
.byte 0 .byte 0
.endif .endif

View File

@ -5,7 +5,8 @@ use std::{
path::Path, path::Path,
}; };
const BLOCK_SIZE: u16 = 256; const BLOCK_SIZE: u16 = 512;
const MAX_NAME_LEN: u16 = BLOCK_SIZE - 8;
fn main() { fn main() {
let mut archive = File::create("initrd").expect("Could not open initrd"); let mut archive = File::create("initrd").expect("Could not open initrd");
@ -13,34 +14,38 @@ fn main() {
let file_path = Path::new(&file_path); let file_path = Path::new(&file_path);
let file_name = file_path.file_name().unwrap(); let file_name = file_path.file_name().unwrap();
let file_name_len = let file_name_len =
u8::try_from(file_name.len()).expect("File name length greater than 256 bytes"); u16::try_from(file_name.len()).expect("File name length greater than 256 bytes");
if file_name_len > 252 { assert!(
panic!("File {:?} has name longer than 252 bytes", file_name); file_name_len <= MAX_NAME_LEN,
} "File {:?} has name longer than {} bytes",
file_name,
MAX_NAME_LEN
);
let mut file = File::open(file_path).expect("File did not exist"); let mut file = File::open(file_path).expect("File did not exist");
let length = u16::try_from(file.metadata().expect("Could not get file metadata").len()) let length = u16::try_from(file.metadata().expect("Could not get file metadata").len())
.expect("File size greater than 64 KiB"); .expect("File size greater than 64 KiB");
let file_num_blocks = (length / BLOCK_SIZE) + if length % BLOCK_SIZE != 0 { 1 } else { 0 }; let file_num_blocks = (length / BLOCK_SIZE) + if length % BLOCK_SIZE == 0 { 0 } else { 1 };
let mut header_block = Vec::new(); let mut header_block = Vec::new();
header_block.extend_from_slice(&length.to_be_bytes()); header_block.extend_from_slice(&length.to_be_bytes());
header_block.extend_from_slice(&file_num_blocks.to_be_bytes()); header_block.extend_from_slice(&file_num_blocks.to_be_bytes());
header_block.push(file_name_len); header_block.extend_from_slice(&file_name_len.to_be_bytes());
header_block.extend_from_slice(file_name.to_str().unwrap().as_bytes()); header_block.extend_from_slice(file_name.to_str().unwrap().as_bytes());
header_block.push(0); header_block.push(0);
header_block.resize(BLOCK_SIZE as usize, 0); header_block.resize(BLOCK_SIZE as usize, 0);
archive archive
.write_all(&header_block) .write_all(&header_block)
.expect("Could not write to initrd"); .expect("Could not write to initrd");
let bytes_written = #[allow(clippy::cast_possible_truncation)]
io::copy(&mut file, &mut archive).expect("Could not read from file/write to initrd"); let bytes_written = io::copy(&mut file, &mut archive)
if (bytes_written as u16 % BLOCK_SIZE) != 0 { .expect("Could not read from file/write to initrd") as u16;
let bytes_padding = (BLOCK_SIZE) - (bytes_written as u16 % BLOCK_SIZE); if (bytes_written % BLOCK_SIZE) != 0 {
let bytes_padding = (BLOCK_SIZE) - (bytes_written % BLOCK_SIZE);
for _ in 0..bytes_padding { for _ in 0..bytes_padding {
archive.write_all(&[0]).expect("Could not write to initrd"); archive.write_all(&[0]).expect("Could not write to initrd");
} }
} }
} }
archive archive
.write_all(&[0; 256]) .write_all(&[0; BLOCK_SIZE as usize])
.expect("Could not write to initrd"); .expect("Could not write to initrd");
} }

View File

@ -1,3 +1,6 @@
.global _start .global _start
_start: _start:
move.b #'H', 0xFF0200
move.b #'i', 0xFF0200
move.b #0xA, 0xFF0200
stop #0x2700 stop #0x2700

BIN
rom.bin

Binary file not shown.