Remove intr function not in line with int 21h

If we have them, use them for setting up ourselves

kernel/intr.asm

@@ -28,59 +28,3 @@ isr_intr_register:
   pop es
 
   iret
-
-; Register a interrupt handler
-; in:	AL	interrupt number
-;	ES:DI	far ptr to routine/data
-intr_register:
-  ; backup original values
-  push ax
-  push es
-  push di
-
-  ; pop as ax later
-  push es
-  push di
-
-  ; DI = AL * 4
-  mov ah, 4
-  mul ah
-  mov di, ax
-
-  ; ES = 0
-  xor ax, ax
-  mov es, ax
-
-  ; store offset
-  pop ax
-  stosw
-
-  ; store segment
-  pop ax
-  stosw
-
-  pop di
-  pop es
-  pop ax
-  ret
-
-; Get address for a interrupt vector
-; in	AL	interrupt number
-; out	DS:SI	far ptr to routine/data
-intr_load:
-  push ax
-
-  ; SI = AL * 4
-  mov ah, 4
-  mul ah
-  mov si, ax
-
-  ; DS = 0
-  xor ax, ax
-  mov ds, ax
-
-  ; load segment and offset in one go
-  lds si, [si]
-
-  pop ax
-  ret

kernel/main.asm

@@ -7,10 +7,12 @@ isr_dos_main:
   je isr_getc_echo
   cmp ah, 0x02
   je isr_putc
+  cmp ah, 0x25
+  je isr_intr_register
   jmp isr_invalid
 
-%include "chario.asm"
 %include "intr.asm"
+%include "chario.asm"
 
 %include "cache.asm"
 
@@ -32,14 +34,15 @@ isr_return:
   iret
 
 init:
-  push cs
-  pop es
-  mov di, isr_dos_main
-  mov ax, 0x21
-  call intr_register
+  mov ax, cs
+  mov ds, ax
+  mov es, ax
 
-  mov di, kernel_end
-  call cache_init
+  mov dx, isr_dos_main
+  mov ax, 0x2521
+  pushf
+  push cs
+  call isr_dos_main
 
   int3