xref: /openbmc/u-boot/arch/x86/lib/bios.h (revision e89516f0)
1 /*
2  * (C) Copyright 2002
3  * Daniel Engstr�m, Omicron Ceti AB, <daniel@omicron.se>
4  *
5  * See file CREDITS for list of people who contributed to this
6  * project.
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License as
10  * published by the Free Software Foundation; either version 2 of
11  * the License, or (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
21  * MA 02111-1307 USA
22  */
23 
24 #ifndef _BIOS_H_
25 #define _BIOS_H_
26 
27 #define OFFS_ES      0     /* 16bit */
28 #define OFFS_GS      2     /* 16bit */
29 #define OFFS_DS      4     /* 16bit */
30 #define OFFS_EDI     6     /* 32bit */
31 #define OFFS_DI      6     /* low 16 bits of EDI */
32 #define OFFS_ESI     10    /* 32bit */
33 #define OFFS_SI      10    /* low 16 bits of ESI */
34 #define OFFS_EBP     14    /* 32bit */
35 #define OFFS_BP      14    /* low 16 bits of EBP */
36 #define OFFS_ESP     18    /* 32bit */
37 #define OFFS_SP      18    /* low 16 bits of ESP */
38 #define OFFS_EBX     22    /* 32bit */
39 #define OFFS_BX      22    /* low 16 bits of EBX */
40 #define OFFS_BL      22    /* low  8 bits of BX */
41 #define OFFS_BH      23    /* high 8 bits of BX */
42 #define OFFS_EDX     26    /* 32bit */
43 #define OFFS_DX      26    /* low 16 bits of EBX */
44 #define OFFS_DL      26    /* low  8 bits of BX */
45 #define OFFS_DH      27    /* high 8 bits of BX */
46 #define OFFS_ECX     30    /* 32bit */
47 #define OFFS_CX      30    /* low 16 bits of EBX */
48 #define OFFS_CL      30    /* low  8 bits of BX */
49 #define OFFS_CH      31    /* high 8 bits of BX */
50 #define OFFS_EAX     34    /* 32bit */
51 #define OFFS_AX      34    /* low 16 bits of EBX */
52 #define OFFS_AL      34    /* low  8 bits of BX */
53 #define OFFS_AH      35    /* high 8 bits of BX */
54 #define OFFS_VECTOR  38    /* 16bit */
55 #define OFFS_IP      40    /* 16bit */
56 #define OFFS_CS      42    /* 16bit */
57 #define OFFS_FLAGS   44    /* 16bit */
58 
59 #define SEGMENT      0x40
60 #define STACK	     0x800	/* stack at 0x40:0x800 -> 0x800 */
61 
62 /* save general registers */
63 /* save some segments     */
64 /* save callers stack segment .. */
65 /* ... in gs */
66 	/* setup my segments */
67 	/* setup BIOS stackpointer */
68 
69 #define MAKE_BIOS_STACK \
70 	pushal; \
71 	pushw	%ds; \
72 	pushw	%gs; \
73 	pushw	%es; \
74 	pushw	%ss; \
75 	popw	%gs; \
76 	movw	$SEGMENT, %ax; \
77 	movw	%ax, %ds; \
78 	movw	%ax, %es; \
79 	movw	%ax, %ss; \
80 	movw	%sp, %bp; \
81 	movw	$STACK, %sp
82 
83 #define RESTORE_CALLERS_STACK \
84 	pushw	%gs;		/* restore callers stack segment */ \
85 	popw	%ss; \
86 	movw	%bp, %sp;	/* restore stackpointer */ \
87 	popw	%es;		/* restore segment selectors */ \
88 	popw	%gs; \
89 	popw	%ds; \
90 	popal			/* restore GP registers */
91 
92 #endif
93