Added text file printing

build.sh

@@ -15,7 +15,8 @@ nasm -fbin src/kernel.asm -o build/kernel.bin
 
 # Final binary
 nasm -fbin src/calc.asm -o build/calc.bin
-cat build/bootloader.bin build/kernel.bin build/calc.bin > build/os.bin
+nasm -fbin src/message.asm -o build/message.bin
+cat build/bootloader.bin build/kernel.bin build/calc.bin build/message.bin > build/os.bin
 
 # Run QEMU
 qemu-system-x86_64 -drive format=raw,file="./build/os.bin",index=0,media=disk -m 256M

src/boot.asm

@@ -43,7 +43,7 @@ start:
     xor bx, bx
 
     mov ah, 2           ; Read from disk
-    mov al, 2           ; Read 2 sectors (1024B)
+    mov al, 3           ; Read 3 sectors (1.5kB)
 
     mov dl, byte [driveNumber] ; Drive number
     mov ch, 0           ; Cylinder

src/filetable.asm

@@ -13,8 +13,9 @@
 
 filetable:
     db 'boot',0,0,0,0,0,0,'bin',0,1,1   ; boot.bin      - start: 1, size: 1
-    db 'filetable',0,'txt',0,2,1        ; filetable.txt - start: 2, size: 1
-    db 'kernel',0,0,0,0,'bin',0,3,2     ; kernel.bin    - start: 3, size: 2
-    db 'calc',0,0,0,0,0,0,'bin',0,5,1   ; calc.bin      - start: 5, size: 1
+    db 'filetable',0,     'txt',0,2,1   ; filetable.txt - start: 2, size: 1
+    db 'kernel',0,0,0,0,  'bin',0,3,3   ; kernel.bin    - start: 3, size: 3
+    db 'calc',0,0,0,0,0,0,'bin',0,6,1   ; calc.bin      - start: 6, size: 1
+    db 'message',0,0,0,   'txt',0,7,1   ; message.txt   - start: 7, size: 1
 
 times 512-($-$$) db 0

src/kernel.asm

@@ -4,7 +4,6 @@ start:
     ; Save the drive number from stack
     mov byte [driveNumber], dl
 
-
     mov bx, 0x8000
     mov es, bx
     xor bx, bx
@@ -112,7 +111,7 @@ loadProgram:
 .match:
     mov al, [es:bx]
     cmp al, 0       ; Check if we are at the end of a filename
-    je executeProgram
+    je foundProgram
 .restartSearch:
     mov di, userInput
     pop bx
@@ -123,19 +122,29 @@ loadProgram:
     call print
     jmp input
     
-executeProgram:
+foundProgram:
     mov al, [es:bx]
     cmp al, 0       ; Loop until we find the extension
     jne .getMetadata    
     inc bx
-    jmp executeProgram
+    jmp foundProgram
 .getMetadata:
-    add bx, 3       ; Skip the file extension
+    mov al, [es:bx]
+    mov [fileExt], al
+    inc bx
+    mov al, [es:bx]
+    mov [fileExt+1], al
+    inc bx
+    mov al, [es:bx]
+    mov [fileExt+2], al
+    inc bx
+
     inc bx          ; Ignore Number of FT entries for now
 
     mov cl, [es:bx] ; Starting sector
     inc bx
     mov al, [es:bx] ; Number of sectors to read
+    push ax         ; Save file size
 
     mov ah, 0       ; Reset disk system
     mov dl, byte [driveNumber]
@@ -157,6 +166,17 @@ executeProgram:
 
     jmp input
 .loaded:
+    ; Check file extension. If 'bin', then run, if 'txt', print
+    pop ax      ; Restore file size
+
+    mov cx, 3   ; Check file extension
+    mov si, fileExt 
+    mov ax, 0x2000
+    mov es, ax
+    mov di, binExt
+    repe cmpsb
+    jne .printText  ; TODO: Check for more file extensions
+
     mov ax, PROGRAM_LOC
     mov ds, ax
     mov es, ax
@@ -165,6 +185,27 @@ executeProgram:
     mov ss, ax
 
     jmp PROGRAM_LOC:0x0000
+.printText:
+    mov bx, PROGRAM_LOC
+    mov es, bx
+    xor bx, bx
+    mov cx, 512
+    mul cx
+    mov cx, ax
+    mov ah, 0x0e
+.textLoop:
+    mov al, [es:bx]
+    cmp al, 0
+    je .rep
+    int 0x10
+.rep:
+    inc bx
+    dec cx
+    jnz .textLoop
+
+    mov si, newline
+    call print
+    jmp input
 
 ;
 ; Help - Prints the help message (helpMsg)
@@ -259,6 +300,8 @@ printFiletable:
     inc bx
     mov al, ' '
     int 0x10
+    int 0x10
+    int 0x10
     ; File size
     mov al, [es:bx]
     inc bx
@@ -347,8 +390,8 @@ sectorLenText: db "512B", 0
 kilobyteText: db "kB", 0
 oneHalfText: db ".5kB", 0
 
-fileListMsg: db " Filename      E# St Size ", ENDL, \
-                "----------    ------------", ENDL, 0
+fileListMsg: db " Filename      E# St   Size ", ENDL, \
+                "----------    ------- ------", ENDL, 0
 
 helpMsg: db "Available Commands:", ENDL, \
             "clear - Clears the screen", ENDL, \
@@ -365,10 +408,15 @@ gfxCmd: db "gfx", 0
 rebootCmd: db "reboot", 0
 clearCmd: db "clear", 0
 
+; Files
+fileExt: db "   ", 0
+binExt: db "bin", 0
+txtExt: db "txt", 0
+
 inputLen: db 0
 userInput: db 0
 
 FILETAB_LOC equ 0x1000
 PROGRAM_LOC equ 0x8000
 
-times 2*512-($-$$) db 0
+times 3*512-($-$$) db 0

src/message.asm

@@ -0,0 +1,6 @@
+%define ENDL 0x0A, 0x0D
+
+db  "This is a very cool message!", ENDL, ENDL, \
+    "Kern is a 32-bit (16-bit for now) OS based on the x86 cpu architecture."
+
+times 512-($-$$) db 0