Update to sector size of 512

boot/boot.68k

@@ -3,25 +3,16 @@ _start:
 move.b #0x4, d0
 bsr.w find_first_card
 | Load the header sector for the kernel binary
-move.l #0x1, (a0) | Set the sector number to 1
-| Transfer 0x100 (256) bytes from the storage card's data register to 0x100
-move.w #0x100, a1 | Load a1, the destination address register, with 0x100
-move.w #0xFF, d0 | Load d0 with the sector size - 1.
-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
+move.l #0x200, a1 | Set the destination address to 0x200
+move.l #0x1, d0 | Set the starting sector number to 1
+move.l #0x1, d1 | Set the sector count to 1
+bsr.w read_sectors
 | load the ELF kernel binary off the disk
-move.l #0x2, (a0) | Set the sector number to 2
-| Transfer 0x100 (256) * d0 bytes from the storage card's data register to 0xA000
-move.l #0xA000, a1 | Load a1, the destination address register, with 0xA000
-sectors_loop:
-move.w #0xFF, d1 | Load d0 with the sector size - 1.
-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 #0xA000, a1 | Set the destination address to 0xA000
+move.l #0x2, d0 | Set the starting sector number to 2
+clr.l d1
+move.w (0x202), d1 | Set the sector count
+bsr.b read_sectors
 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
 adda.w d0, a0
@@ -72,8 +63,32 @@ ffc_done:
   rts
 
 
-.if . != 256
-.org 255
+| Reads sectors from a storage card
+| 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
 .endif
 
+

initrd_maker.rs

@@ -5,7 +5,8 @@ use std::{
     path::Path,
 };
 
-const BLOCK_SIZE: u16 = 256;
+const BLOCK_SIZE: u16 = 512;
+const MAX_NAME_LEN: u16 = BLOCK_SIZE - 8;
 
 fn main() {
     let mut archive = File::create("initrd").expect("Could not open initrd");
@@ -13,9 +14,12 @@ fn main() {
         let file_path = Path::new(&file_path);
         let file_name = file_path.file_name().unwrap();
         let file_name_len =
-            u8::try_from(file_name.len()).expect("File name length greater than 256 bytes");
-        if file_name_len > 252 {
-            panic!("File {:?} has name longer than 252 bytes", file_name);
+            u16::try_from(file_name.len()).expect("File name length greater than 256 bytes");
+        if file_name_len > MAX_NAME_LEN {
+            panic!(
+                "File {:?} has name longer than {} bytes",
+                file_name, MAX_NAME_LEN
+            );
         }
         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())
@@ -24,7 +28,7 @@ fn main() {
         let mut header_block = Vec::new();
         header_block.extend_from_slice(&length.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.push(0);
         header_block.resize(BLOCK_SIZE as usize, 0);
@@ -41,6 +45,6 @@ fn main() {
         }
     }
     archive
-        .write_all(&[0; 256])
+        .write_all(&[0; BLOCK_SIZE as usize])
         .expect("Could not write to initrd");
 }

kernel/main.68k

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