Updated kernel and programs so that the segment in which programs are loaded and executed from is no longer fixed and is specified by the kernel

hello.asm

@@ -1,14 +1,20 @@
-mov ax, 3000h
+push bp
+mov bp, sp
+
+mov ax, [bp + 6]
 mov ds, ax
 
 mov si, hello_world_str
 mov ah, 01h
 int 22h
 
+pop bp
 retf
 
 hello_world_str db "Hello, World!", 13, 10, 13, 10, 0
 new_line db 13, 10, 0
 
 buffer:
-  times 32 db 0
+  times 32 db 0
+
+program_segment dw 0

kernel.asm

@@ -92,15 +92,22 @@ clear_loop:
   cmp ax, 0
   je handle_error
 
-  ; If the file exists load it at 3000h:0
+  ; Define the segment where we will load our programs
+  program_segment equ 4000h
+
+  ; If the file exists load it at program_segment:0
   push ax
   push 0
-  push 3000h
+  push program_segment
   call load_file
 
-  ; Make a call to 3000h:0
+  ; Let programs know what segment they're loaded at
-  call 3000h:0
+  push program_segment
+  ; Make a call to program_segment:0
+  call program_segment:0
   ; We've now returned.
+  ; Clean up pushed segment
+  pop ax
 
 
 

print.asm

@@ -1,5 +1,9 @@
-  mov ax, 3000h
+  push bp
+  mov bp, sp
+
+  mov ax, [bp+6]
   mov ds, ax
+  mov word [program_segment], ax
 
   mov si, filename
   mov ah, 4
@@ -10,18 +14,22 @@
 
   mov si, ax
   mov di, 0
-  mov bx, 4000h
+  mov bx, word [program_segment]
+  add bx, 1000h
   mov ah, 3
   int 22h
 
-  mov ax, 4000h
+  push word [program_segment]
+  mov ax, word [program_segment]
+  add ax, 1000h
   mov ds, ax
   mov si, 0
   mov ah, 1
   int 22h
 
-  mov ax, 2000h
+  pop ax
   mov ds, ax
+
   jmp exit
 
 error:
@@ -30,7 +38,9 @@ error:
   int 22h
 
 exit:
-  retf
+  pop bp
+  retf 
 
 filename db "HELLO   TXT"
-err_msg db "HELLO.TXT Missing!"
+err_msg db "HELLO.TXT Missing!"
+program_segment dw 0