; Utilities to help with far pointers

; exchange DS:SI with ES:DI
xchgs:	push ds
	push es
	pop ds
	pop es
	xchg si, di
	ret

; far pointer load
; IN	ES:BX	far pointer to data
;	CX	number of bytes to copy
;	0:DX	destination buffer

lod:	push es

	; ES:DI := DS:DX
	mov ax, ds
	mov es, ax
	mov di, dx
	; DS:SI := 0:BX
	xor ax, ax
	mov ds, ax
	mov si, bx
	; copy
	pushf
	cld
	rep movsb
	popf
	; reset DS to kernel data
	mov ds, cx

	pop es
	ret

; far pointer store
; IN	ES:BX	far ptr
;	CX	number of bytes
;	0:DX	source buffer
; only CX is trashed

sto:	mov si, dx
	mov di, bx
	cld
	rep movsb
	ret