mkinitrd-magellan/isolinux/loadhigh.inc

;; $Id: loadhigh.inc,v 1.1 2007-09-01 22:44:05 niro Exp $
;; -----------------------------------------------------------------------
;;   
;;   Copyright 1994-2002 H. Peter Anvin - All Rights Reserved
;;
;;   This program is free software; you can redistribute it and/or modify
;;   it under the terms of the GNU General Public License as published by
;;   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
;;   Boston MA 02111-1307, USA; either version 2 of the License, or
;;   (at your option) any later version; incorporated herein by reference.
;;
;; -----------------------------------------------------------------------

;;
;; loadhigh.inc
;; 
;; Load a file into high memory
;;

		section .text

;
; load_high:	loads (the remainder of) a file into high memory.
;		This routine prints dots for each 64K transferred, and
;		calls abort_check periodically.
; 
;		The xfer_buf_seg is used as a bounce buffer.
;
;		The input address (EDI) should be dword aligned, and the final
;		stretch is padded with zeroes if necessary.
;
; Inputs:	SI  = file handle/cluster pointer
;		EDI = target address in high memory
;		EAX = size of remaining file in bytes
;		DX   = zero-padding mask (e.g. 0003h for pad to dword)
;
; Outputs:	SI  = file handle/cluster pointer
;		EDI = first untouched address (not including padding)
;
load_high:
		push es

		mov bx,xfer_buf_seg
		mov es,bx

.read_loop:
		and si,si			; If SI == 0 then we have end of file
		jz .eof
		push si
		mov si,dot_msg
		call cwritestr
		pop si
		call abort_check

		push eax			; <A> Total bytes to transfer
		cmp eax,(1 << 16)		; Max 64K in one transfer
		jna .size_ok
		mov eax,(1 << 16)
.size_ok:
		push eax			; <B> Bytes transferred this chunk
		add eax,SECTOR_SIZE-1
		shr eax,SECTOR_SHIFT		; Convert to sectors

		; Now (e)ax contains the number of sectors to get
		push edi			; <C> Target buffer
		mov cx,ax
		xor bx,bx			; ES:0
		call getfssec			; Load the data into xfer_buf_seg
		pop edi				; <C> Target buffer
		pop ecx				; <B> Byte count this round
		push ecx			; <B> Byte count this round 
		push edi			; <C> Target buffer
.fix_slop:
		test cx,dx
		jz .noslop
		; The last dword fractional - pad with zeroes
		; Zero-padding is critical for multi-file initramfs.
		mov byte [es:ecx],0
		inc ecx
		jmp short .fix_slop
.noslop:
		push esi			; <D> File handle/cluster pointer
		mov esi,(xfer_buf_seg << 4)	; Source address
		call bcopy			; Copy to high memory
		pop esi				; <D> File handle/cluster pointer
		pop edi				; <C> Target buffer
		pop ecx				; <B> Byte count this round
		pop eax				; <A> Total bytes to transfer
		add edi,ecx
		sub eax,ecx
		jnz .read_loop			; More to read...
		
.eof:
		pop es
		ret

1	;; $Id: loadhigh.inc,v 1.1 2007-09-01 22:44:05 niro Exp $
2	;; -----------------------------------------------------------------------
3	;;
4	;; Copyright 1994-2002 H. Peter Anvin - All Rights Reserved
5	;;
6	;; This program is free software; you can redistribute it and/or modify
7	;; it under the terms of the GNU General Public License as published by
8	;; the Free Software Foundation, Inc., 53 Temple Place Ste 330,
9	;; Boston MA 02111-1307, USA; either version 2 of the License, or
10	;; (at your option) any later version; incorporated herein by reference.
11	;;
12	;; -----------------------------------------------------------------------
13
14	;;
15	;; loadhigh.inc
16	;;
17	;; Load a file into high memory
18	;;
19
20	section .text
21
22	;
23	; load_high: loads (the remainder of) a file into high memory.
24	; This routine prints dots for each 64K transferred, and
25	; calls abort_check periodically.
26	;
27	; The xfer_buf_seg is used as a bounce buffer.
28	;
29	; The input address (EDI) should be dword aligned, and the final
30	; stretch is padded with zeroes if necessary.
31	;
32	; Inputs: SI = file handle/cluster pointer
33	; EDI = target address in high memory
34	; EAX = size of remaining file in bytes
35	; DX = zero-padding mask (e.g. 0003h for pad to dword)
36	;
37	; Outputs: SI = file handle/cluster pointer
38	; EDI = first untouched address (not including padding)
39	;
40	load_high:
41	push es
42
43	mov bx,xfer_buf_seg
44	mov es,bx
45
46	.read_loop:
47	and si,si ; If SI == 0 then we have end of file
48	jz .eof
49	push si
50	mov si,dot_msg
51	call cwritestr
52	pop si
53	call abort_check
54
55	push eax ; <A> Total bytes to transfer
56	cmp eax,(1 << 16) ; Max 64K in one transfer
57	jna .size_ok
58	mov eax,(1 << 16)
59	.size_ok:
60	push eax ; <B> Bytes transferred this chunk
61	add eax,SECTOR_SIZE-1
62	shr eax,SECTOR_SHIFT ; Convert to sectors
63
64	; Now (e)ax contains the number of sectors to get
65	push edi ; <C> Target buffer
66	mov cx,ax
67	xor bx,bx ; ES:0
68	call getfssec ; Load the data into xfer_buf_seg
69	pop edi ; <C> Target buffer
70	pop ecx ; <B> Byte count this round
71	push ecx ; <B> Byte count this round
72	push edi ; <C> Target buffer
73	.fix_slop:
74	test cx,dx
75	jz .noslop
76	; The last dword fractional - pad with zeroes
77	; Zero-padding is critical for multi-file initramfs.
78	mov byte [es:ecx],0
79	inc ecx
80	jmp short .fix_slop
81	.noslop:
82	push esi ; <D> File handle/cluster pointer
83	mov esi,(xfer_buf_seg << 4) ; Source address
84	call bcopy ; Copy to high memory
85	pop esi ; <D> File handle/cluster pointer
86	pop edi ; <C> Target buffer
87	pop ecx ; <B> Byte count this round
88	pop eax ; <A> Total bytes to transfer
89	add edi,ecx
90	sub eax,ecx
91	jnz .read_loop ; More to read...
92
93	.eof:
94	pop es
95	ret
96