verbose_malloc:
  call malloc
  push si ; both backup and input value for kprintf
  mov si,.fmt
  push di
  call kprintf
  pop di
  pop si
  ret
.fmt:
  db "malloc %X", 0

; Allocates memory on the kernel heap
; Strategy: smallest fit
; in	cx	size in bytes
;       dl	node type
; out	ds:di	pointer
;
; Header:
;	word	ptr to next item (this implies its size)
;	byte	00 = free, >0 used (refcount)
;	byte	high-level type
malloc:
  push ax
  push bx
  mov di,heap
  add cx, 0x04 ; header length
  jmp .check
.next:
  add di,[di]
.check:
  mov ax,[di]
  test ax,0xFFFF
  jz .append ; we are on last entry
  cmp byte [di+2],0x00
  jne .next ; entry is in use
  sub ax,cx
  je .reuse ; entry has exact length
  jc .next ; entry too short
  jmp .next ; we'd have to split, not implemented yet
.reuse: ; exact length
  mov byte [di+2],0xFF
  jmp .end
.append: ; append to last item
  mov word [di], cx
  mov byte [di+2], 0x00
  mov byte [di+3], dl
  push di
  add word di, [di]
  mov byte [di],0x0000
  pop di
.end:
  pop bx
  pop ax
  ret

; Deallocates memory on the kernel heap
free: