From 0222a7adb9d3b49d6058de0016b5a3184920b1c3 Mon Sep 17 00:00:00 2001
From: deadvey <deadvey@deadvey.com>
Date: Mon, 17 Nov 2025 20:46:21 +0000
Subject: [PATCH] Disk reading partly done

---
 .Makefile.swo                   | Bin 0 -> 12288 bytes
 .gitignore                      |   1 +
 source/bootload/boot.asm        |   5 +-
 source/kernel/features/cli.asm  |   2 +
 source/kernel/features/disk.asm | 175 ++++++++++++++++++++++++++++++++
 source/kernel/features/math.asm |   3 +-
 source/kernel/features/text.asm |  25 +++++
 source/kernel/games/pong.asm    |  18 ++--
 source/kernel/kernel.asm        |  40 +++++++-
 test-linux.sh                   |  13 ++-
 10 files changed, 261 insertions(+), 21 deletions(-)
 create mode 100644 .Makefile.swo

diff --git a/.Makefile.swo b/.Makefile.swo
new file mode 100644
index 0000000000000000000000000000000000000000..2b1fc5fd7489055ac6758d19660455560b221ca8
GIT binary patch
literal 12288
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literal 0
HcmV?d00001

diff --git a/.gitignore b/.gitignore
index 747b558..6048758 100755
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 *.swp
 disk_images/*
+tmp-loop/*
diff --git a/source/bootload/boot.asm b/source/bootload/boot.asm
index 15bc38a..0ecb953 100644
--- a/source/bootload/boot.asm
+++ b/source/bootload/boot.asm
@@ -25,7 +25,7 @@ ebr_drive_number:           db 0 ; ignore
 ebr_signature:              db 29h ; boot signature, indicates that the next three fields are present (0x29)
 ebr_volume_id:              db 12h, 34h, 56h, 78h ; unique id for volume tracking
 ebr_volume_label:           db 'CrawShaw OS' ; must be 11 bytes
-ebr_system_id:              db 'FAT12   ' ' ; must be 8 bytes
+ebr_system_id:              db 'FAT12   ' ; must be 8 bytes
 
 main:
    ; Setup registers
@@ -117,6 +117,7 @@ found_kernel:
    mov ax, [di+26] ; di is the address of the kernel, 26 is the offset
    mov [kernel_cluster], ax
 
+   ; Setup registers for disk read
    mov ax, [bdb_reserved_sectors]
    mov bx, buffer
    mov cl, [bdb_sectors_per_fat]
@@ -334,7 +335,7 @@ print_string:
 	  pop si
 	  ret
 
-boot_text: db 'OK] Boot sequence begun', 0
+boot_text: db 'OK] Boot begun', 0
 kernel_found_text: db 'OK] Kernel located', 0
 kernel_loading: db 'OK] Loading kernel', 0
 disk_read_fail: db 'ERR] Disk read fail', 0
diff --git a/source/kernel/features/cli.asm b/source/kernel/features/cli.asm
index ee3e582..07ef453 100755
--- a/source/kernel/features/cli.asm
+++ b/source/kernel/features/cli.asm
@@ -17,6 +17,8 @@ os_start_cli:
 
 os_read_cli:
 	pusha
+	mov si, user_input
+	call os_upper_case ; Make the input uppercase so it's case insensitive
 
 .output_the_user_input:
 	call os_print_newline
diff --git a/source/kernel/features/disk.asm b/source/kernel/features/disk.asm
index e69de29..60cade1 100644
--- a/source/kernel/features/disk.asm
+++ b/source/kernel/features/disk.asm
@@ -0,0 +1,175 @@
+; Reset the disk system using int 13h / AH = 00h
+disk_reset:
+   pusha
+   stc
+   mov ah, 00h
+   int 13h
+   popa
+   ret
+
+; ------------------------------------
+
+; Load the root directory into memory (into disk_buffer which is 24000h)
+disk_load_root:
+   pusha
+   mov ax, 19 ; First sector of root entry
+   call math_lba_to_chs ; Assigns ch, cl and dh the correct values
+   xor ax,ax
+   mov dl, [ebr_drive_number]  ; Drive number
+   mov ah, 02h  ; BIOS ah code for read disk sectors to memory
+   mov al, 0Ch  ; Root directory has 12 sectors
+
+   mov si, root_buffer		; ES:BX should point to our buffer
+   mov bx, si
+
+   ; repeat drive read 3 times (incase of random error)
+   mov di, 3 ; counter
+   ; This is basically
+   ; for di in range(3,1,1):
+   ; We test to see if we can read the disk 3 times
+.try_read_disk: ; Try read the floppy three times
+   ; When the disk is tried to be read, the CF flag will be
+   ; set if there's an error, so we just clear it to return it to
+   ; the default state
+   stc ; sets the cf flag
+   int 13h
+   jnc .done_read ; jump if cf = 0
+
+   call disk_reset ; Reset drivers of disk
+
+   dec di       ; di -= 1
+   test di, di   ; if di = 0
+   jnz .try_read_disk
+   jmp .disk_error
+.disk_error:
+   mov si, disk_read_fail
+   call os_print_string
+   popa
+   ret
+.done_read:
+   popa
+   ret
+
+; ---------------------------------------------
+
+; Reads a certain number of sectors into memory
+; int 13h/ah = 02h read disk sectors into memory
+; al = number of sectors to read
+; ch = cylinder number
+; cl = sector number
+; dh = head number
+; dl = drive number
+; es:bx = points to data buffer
+disk_read:
+   push ax
+   push bx
+   push cx
+   push dx
+   push di
+
+
+   ; cl = sector
+   ; ch = cylinder
+   ; dh = head
+   ; dl = drive
+   call math_lba_to_chs  ; Get the chs address
+
+   mov ah, 02h  ; BIOS ah code for read disk sectors to memory
+
+   ; repeat drive read 3 times (incase of random error)
+   mov di, 3 ; counter
+
+; This is basically
+; for di in range(3,1,1):
+; We test to see if we can read the disk 3 times
+.retry:
+   ; When the disk is tried to be read, the CF flag will be
+   ; set if there's an error, so we just clear it to return it to
+   ; the default state
+   stc ; sets the cf flag
+   int 13h
+   jnc .done_read ; jump if cf = 0
+
+   call .disk_reset ; Reset drivers of disk
+
+   dec di       ; di -= 1
+   test di, di   ; if di = 0
+   jnz .retry
+
+.fail_disk_read:
+   pop di
+   pop dx
+   pop cx
+   pop bx
+   pop ax
+   ret
+
+; int 13h / ah = 00h reset disk system
+.disk_reset:
+   pusha
+   mov ah, 0 ; Reset drive
+   stc
+   int 13h
+   jc .fail_disk_read
+   popa
+   ret
+
+.done_read:
+   pop di
+   pop dx
+   pop cx
+   pop bx
+   pop ax
+   ret
+
+; -------------------------------------
+
+disk_load_file:
+   pusha
+   mov di, fat12_file_name
+   call os_format_fat_filename
+
+   ; Prepare values
+   mov si, root_buffer
+   xor bx,bx
+.search_root:
+   mov di, fat12_file_name ; Move the name of the kernel into di
+   mov cx, 11 ; length of 'KERNEL  BIN'
+   push si ; Preserve si
+   repe cmpsb ; Repeat a comparison of bytes between file name and current bytes until it finds a match
+   pop si ; Retrieve si
+   je .found_file
+
+   add si, 32 ; increment di to the next directory entry
+   inc bx
+   cmp bx, [bdb_dir_entries_count] ; Have we reached the number of directories that exist
+   jl .search_root ; Repeat search
+
+   jmp .file_not_found ; If the last dir has been searched, then there is no kernel
+.found_file:
+   mov ax, [si+26]   ; ax is now a pointer to the pointer to the file relative to the data segments :D
+   add ax, 20h
+   mov [file_cluster], ax
+   ; Setup registers for disk read
+   mov bx, data_buffer
+   mov dl, [ebr_drive_number]
+
+   call disk_read ; Load file from disk into memory
+   jmp .done
+.file_not_found:
+   mov si, file_not_found
+   call os_print_string
+   jmp .done
+.done:
+   popa
+   ret
+
+
+
+section .data:
+   disk_read_fail: db 'Error: Could not read disk\n', 0
+   file_not_found: db 'File not found\n', 0
+   file_found: db 'File found\n', 0
+   loading_root: db 'Loading root diretory\n', 0
+   file_cluster: dw 0
+   fat12_file_name: db '           '
diff --git a/source/kernel/features/math.asm b/source/kernel/features/math.asm
index 6f988f6..b98cb25 100644
--- a/source/kernel/features/math.asm
+++ b/source/kernel/features/math.asm
@@ -5,6 +5,7 @@
 ; H = T % heads
 ; C = T / headers
 ; input, LBA index: ax
+; ouput:
 ; sector number: cl
 ; cylinder: ch
 ; head: dh
@@ -29,7 +30,7 @@
 ; cylinder (ch) = 02h
 ; head (cl) = 00h
 ; sector (dh) = 09h
-os_lba_to_chs:
+math_lba_to_chs:
     push ax
     push dx
 
diff --git a/source/kernel/features/text.asm b/source/kernel/features/text.asm
index 0458192..500fb01 100755
--- a/source/kernel/features/text.asm
+++ b/source/kernel/features/text.asm
@@ -48,6 +48,31 @@ os_print_string:
 	popa
 	ret
 
+; This is similar to the previous, however it prints
+; raw output (including null) and prints the number
+; of character defined by ax
+; IN:
+; SI = pointer to start of string to be printed
+; AX = Length of string to print
+text_raw_output:
+	pusha
+
+	mov di, ax
+
+	mov ah, 0Eh			; int 10h teletype function, we're telling the BIOS we will print something
+
+.repeat:
+	lodsb				; Get char from si into al
+	int 10h				; Otherwise, print it
+	dec di
+	cmp di, 00h
+	je .done
+	jne .repeat
+.done:
+	popa
+	ret
+
+
 ; --------------------------------------------
 
 os_print_newline:
diff --git a/source/kernel/games/pong.asm b/source/kernel/games/pong.asm
index 71745a3..4d3fb90 100644
--- a/source/kernel/games/pong.asm
+++ b/source/kernel/games/pong.asm
@@ -48,24 +48,24 @@ game_pong:
    mov dx, [p1_y]
    sub dx, 5
    mov [p1_y], dx
-   jmp .detect_input
+   ret
 .p1_down:
    mov dx, [p1_y]
    add dx, 5
    mov [p1_y], dx
-   jmp .detect_input
+   ret
 
 ; Player 2 movements
 .p2_up:
    mov dx, [p2_y]
    sub dx, 5
    mov [p2_y], dx
-   jmp .detect_input
+   ret
 .p2_down:
    mov dx, [p2_y]
    add dx, 5
    mov [p2_y], dx
-   jmp .detect_input
+   ret
 
 ; Ball bouncing
 ; This should move the ball along one frame
@@ -97,17 +97,17 @@ game_pong:
 
    ; Player 1
    cmp al, 77h       ; Pressed 'w' (player 1 up)
-   je .p1_up
+   call .p1_up
    cmp al, 73h       ; Pressed 's' (player 1 down)
-   je .p1_down
+   call .p1_down
 
    ; Player 2
    cmp al, 5bh       ; Pressed '[' (player 2 up)
-   je .p2_up
+   call .p2_up
    cmp al, 27h       ; Pressed ''' (player 2 down)
-   je .p2_down
+   call .p2_down
 
-   call .bounce_ball
+   ;call .bounce_ball
    call .draw_screen
 
    jmp .detect_input
diff --git a/source/kernel/kernel.asm b/source/kernel/kernel.asm
index a1ef637..ab044c5 100644
--- a/source/kernel/kernel.asm
+++ b/source/kernel/kernel.asm
@@ -1,12 +1,17 @@
-ORG 0h
+ORG 00h
 BITS 16
+root_buffer equ 24000h
+data_buffer equ 26000h
 
 start:
    mov si, boot_message
    call os_print_string
 
-   mov si, help_text
-   call os_print_string
+   call disk_load_root ; Loads the root directory into disk_buffer
+
+   ; Physical address = (segment * 16) + offset
+   mov si, file_name
+   call disk_load_file
 
    call os_start_cli
    hlt
@@ -14,7 +19,31 @@ start:
 halt:
    jmp halt
 
-boot_message: db 'OK] Kernel successfully loaded!\n', 0
+boot_message: db 'OK] Kernel successfully loaded!\n\n', 0
+file_name: db 'hello.cws', 0
+
+; Define Fat12 header
+bdb_oem:                    db 'MSWIN4.1' ; ignore
+bdb_bytes_per_sector:       dw 200h ; = 512d
+bdb_sectors_per_cluster:    db 01h ; sector = cluster
+bdb_reserved_sectors:       dw 01h
+bdb_fat_count:              db 02h  ; We've got a fat1 and fat2
+bdb_dir_entries_count:      dw 0E0h ; Maximum number of root directory entries
+bdb_total_sectors:          dw 0B40h ; = 2880d
+bdb_media_descriptor_type:  db 0F0h ; ignore
+bdb_sectors_per_fat:        dw 09h
+bdb_sectors_per_track:      dw 12h ; = 18d
+bdb_number_of_heads:        dw 02h ; top and bottom of the floppy disk
+bdb_hidden_sectors:         dd 0 ; ignore
+bdb_large_sector_count:     dd 0 ; total sector count for fat32 (0 for fat12 or fat16)
+
+; extended boot record
+ebr_drive_number:           db 0 ; ignore
+                            db 0 ; ignore
+ebr_signature:              db 29h ; boot signature, indicates that the next three fields are present (0x29)
+ebr_volume_id:              db 12h, 34h, 56h, 78h ; unique id for volume tracking
+ebr_volume_label:           db 'CrawShaw OS' ; must be 11 bytes
+ebr_system_id:              db 'FAT12   ' ; must be 8 bytes
 
 ; ------------------------------------------------------------------
 ; FEATURES -- Code to pull into the kernel
@@ -25,5 +54,8 @@ boot_message: db 'OK] Kernel successfully loaded!\n', 0
 	%INCLUDE "source/kernel/features/strings.asm"
 	%INCLUDE "source/kernel/features/graphics.asm"
     %INCLUDE "source/kernel/features/disk.asm"
+    %INCLUDE "source/kernel/features/math.asm"
 ; GAMES -- Games that I wrote for it
 	%INCLUDE "source/kernel/games/pong.asm"
+
+
diff --git a/test-linux.sh b/test-linux.sh
index bb5be71..af9b2fa 100755
--- a/test-linux.sh
+++ b/test-linux.sh
@@ -1,6 +1,9 @@
 #!/bin/sh
-
-# This script starts the QEMU PC emulator, booting from the
-# MikeOS floppy disk image
-
-qemu-system-i386 -soundhw pcspk -drive format=raw,file=disk_images/mikeos.flp,index=0,if=floppy
+make clean
+sudo make
+sudo chown $(whoami) disk_images/*
+qemu-system-i386\
+	-drive file=disk_images/crawos.img,if=floppy,format=raw\
+	-m 512m\
+       	-object memory-backend-file,id=pc.ram,size=512m,mem-path=/dev/shm/qemu-ram,share=on -machine memory-backend=pc.ram\
+       	$1 $2