Diff of /trunk/mkinitrd-magellan/isolinux/rllpack.inc

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	revision 1132 by niro, Sat Sep 1 22:45:15 2007 UTC	revision 1133 by niro, Thu Aug 19 09:50:43 2010 UTC
#	Line 1	Line 1
1	; -*- fundamental -*-	; -*- fundamental -*- ---------------------------------------------------
2	; -----------------------------------------------------------------------	;
3	;	;   Copyright 2007-2009 H. Peter Anvin - All Rights Reserved
4	;   Copyright 2004 H. Peter Anvin - All Rights Reserved	;   Copyright 2009 Intel Corporation; author: H. Peter Anvin
5	;	;
6	;   This program is free software; you can redistribute it and/or modify	;   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	;   it under the terms of the GNU General Public License as published by
#	Line 10	Line 10
10	;   (at your option) any later version; incorporated herein by reference.	;   (at your option) any later version; incorporated herein by reference.
11	;	;
12	; -----------------------------------------------------------------------	; -----------------------------------------------------------------------
	; $Id: rllpack.inc,v 1.1 2007-09-01 22:44:05 niro Exp $
13
14	;	;
15	; rllpack.inc	; rllpack.inc
#	Line 20	Line 19
19	;	;
20	; Format of leading byte	; Format of leading byte
21	; 1-128 = x verbatim bytes follow	; 1-128 = x verbatim bytes follow
22	; 129-255 = (x-126) times subsequent byte	; 129-223 = (x-126) times subsequent byte
23		; 224-255 = (x-224)*256+(next byte) times the following byte
24	; 0 = end of data	; 0 = end of data
25	;	;
26		; These structures are stored *in reverse order* in high memory.
27		; High memory pointers point to one byte beyond the end.
28		;
29
30	section .text	section .text
31
32	;	;
33	; rllpack:	; rllpack:
34	; Pack CX bytes from DS:SI into ES:DI	; Pack ECX bytes from ESI into EDI.
35	; Returns updated SI, DI and CX = number of bytes output	; Returns updated ESI and EDI.
36	;	;
37	rllpack:	rllpack:
38	push ax	push word .pmentry
39	push bx	call simple_pm_call
40	push cx	ret
41	push bp
42	push di	bits 32
43		.pmentry:
44		push ecx
45		push ebx
46		push edx
47	.startseq:	.startseq:
48	xor ax,ax ; Zero byte	xor eax,eax ; Zero byte
49	xor bx,bx ; Run length zero	xor ebx,ebx ; Run length zero
50	mov bp,di ; Pointer to header byte	dec edi
51	stosb ; Store header byte (might be zero)	mov edx,edi ; Pointer to header byte
52	jcxz .done_null	mov [edi],al ; Create header byte
53		jcxz .done ; If done, this was the terminator
54	.stdbyte:	.stdbyte:
55	lodsb	lodsb
56	stosb	dec edi
57	dec cx	mov [edi],al
58		dec ecx
59	cmp ah,al	cmp ah,al
60	je .same	je .same
61	.diff:	.diff:
62	mov ah,al	mov ah,al
63	xor bx,bx	xor ebx,ebx
64	.plainbyte:	.plainbyte:
65	inc bx	inc ebx
66	inc byte [es:bp]	inc byte [edx]
67	jcxz .done	jcxz .startseq
68	jns .stdbyte	jns .stdbyte
69	jmp .startseq	jmp .startseq
70	.same:	.same:
71	cmp bl,2	cmp bl,2
72	jb .plainbyte	jb .plainbyte
73	; 3 bytes or more in a row, time to convert sequence	; 3 bytes or more in a row, time to convert sequence
74	sub byte [es:bp],bl	sub [edx],bl
75	jnz .normal	jnz .normal
76	dec di ; We killed a whole stretch, remove start byte	inc edi ; We killed a whole stretch,
77		; drop start byte
78	.normal:	.normal:
79	inc bx	inc ebx
80	sub di,bx	add edi,ebx ; Remove the stored run bytes
	mov bp,di
	mov al,bl
	add al,126
	stosb
	mov al,ah
	stosb
81	.getrun:	.getrun:
82	jcxz .done	jcxz .nomatch
	cmp bl,255-126
	jae .startseq
83	lodsb	lodsb
84	cmp al,ah	cmp al,ah
85	jne .nomatch	jne .nomatch
86	inc bx	cmp bx,(256-224)*256-1 ; Maximum run size
87	inc byte [es:bp]	jae .nomatch
88	dec cx	inc ebx
89		dec ecx
90	jmp .getrun	jmp .getrun
91	.nomatch:	.nomatch:
92	dec si	cmp bx,224-126
93		jae .twobyte
94		.onebyte:
95		add bl,126
96		dec edi
97		mov [edi],bl
98		jmp .storebyte
99		.twobyte:
100		add bh,224
101		sub edi,2
102		mov [edi],bx
103		.storebyte:
104		dec edi
105		mov [edi],ah
106		dec esi ; Reload subsequent byte
107	jmp .startseq	jmp .startseq
108	.done:	.done:
109	xor al,al	pop edx
110	stosb	pop ebx
111	.done_null:	pop ecx
	pop dx
	sub dx,di
	neg dx
	pop bp
	pop cx
	pop bx
	pop ax
112	ret	ret
113
114		bits 16
115	;	;
116	; rllunpack:	; rllunpack:
117	; Unpack bytes from DS:SI into ES:DI	; Unpack bytes from ESI into EDI
118	; On return SI, DI are updated and CX contains number of bytes output	; On return ESI, EDI are updated and
119	;	; ECX contains number of bytes output.
120		;
121	rllunpack:	rllunpack:
122	push ax	push word .pmentry
123	push di	call simple_pm_call
124	xor cx,cx	ret
125
126		bits 32
127		.pmentry:
128		push edi
129		xor ecx,ecx
130	.header:	.header:
131	lodsb	dec esi
132	and al,al	mov cl,[esi]
133	jz .done	jcxz .done
134	cmp al,129	cmp cl,129
135	jae .isrun	jae .isrun
136	; Not a run	; Not a run
137	mov cl,al	.copy:
138	rep movsb	dec esi
139		mov al,[esi]
140		stosb
141		loop .copy
142	jmp .header	jmp .header
143	.isrun:	.isrun:
144	sub al,126	cmp cl,224
145	mov cl,al	jae .longrun
146	lodsb	sub cl,126
147		.dorun:
148		dec esi
149		mov al,[esi]
150	rep stosb	rep stosb
151	jmp .header	jmp .header
152		.longrun:
153		sub cl,224
154		mov ch,cl
155		dec esi
156		mov cl,[esi]
157		jmp .dorun
158	.done:	.done:
159	pop cx	pop ecx
160	sub cx,di	sub ecx,edi
161	neg cx	neg ecx
	pop ax
162	ret	ret
163
164		bits 16

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