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+/*
+ * (C) Copyright 2002
+ * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+/*
+ * Based on msbios.c from rolo 1.6:
+ *----------------------------------------------------------------------
+ * (C) Copyright 2000
+ * Sysgo Real-Time Solutions GmbH
+ * Klein-Winternheim, Germany
+ *----------------------------------------------------------------------
+ */
+
+#include "bios.h"
+
+/*
+ * During it's initialization phase, before switching to protected
+ * mode, the Linux Kernel makes a few BIOS calls. This won't work
+ * if the board does not have a BIOS.
+ *
+ * This is a very minimalisic BIOS that supplies just enough
+ * functionality to keep the Linux Kernel happy. It is NOT
+ * a general purpose replacement for a real BIOS !!
+ */
+
+.section .bios, "ax"
+.code16
+.org 0
+ /* a call to f000:0 should warmboot */
+ jmp realmode_reset
+
+.globl rm_int00
+.hidden rm_int00
+.type rm_int00, @function
+rm_int00:
+ pushw $0
+ jmp any_interrupt16
+.globl rm_int01
+.hidden rm_int01
+.type rm_int01, @function
+rm_int01:
+ pushw $1
+ jmp any_interrupt16
+.globl rm_int02
+.hidden rm_int02
+.type rm_int02, @function
+rm_int02:
+ pushw $2
+ jmp any_interrupt16
+.globl rm_int03
+.hidden rm_int03
+.type rm_int03, @function
+rm_int03:
+ pushw $3
+ jmp any_interrupt16
+.globl rm_int04
+.hidden rm_int04
+.type rm_int04, @function
+rm_int04:
+ pushw $4
+ jmp any_interrupt16
+.globl rm_int05
+.hidden rm_int05
+.type rm_int05, @function
+rm_int05:
+ pushw $5
+ jmp any_interrupt16
+.globl rm_int06
+.hidden rm_int06
+.type rm_int06, @function
+rm_int06:
+ pushw $6
+ jmp any_interrupt16
+.globl rm_int07
+.hidden rm_int07
+.type rm_int07, @function
+rm_int07:
+ pushw $7
+ jmp any_interrupt16
+.globl rm_int08
+.hidden rm_int08
+.type rm_int08, @function
+rm_int08:
+ pushw $8
+ jmp any_interrupt16
+.globl rm_int09
+.hidden rm_int09
+.type rm_int09, @function
+rm_int09:
+ pushw $9
+ jmp any_interrupt16
+.globl rm_int0a
+.hidden rm_int0a
+.type rm_int0a, @function
+rm_int0a:
+ pushw $10
+ jmp any_interrupt16
+.globl rm_int0b
+.hidden rm_int0b
+.type rm_int0b, @function
+rm_int0b:
+ pushw $11
+ jmp any_interrupt16
+.globl rm_int0c
+.hidden rm_int0c
+.type rm_int0c, @function
+rm_int0c:
+ pushw $12
+ jmp any_interrupt16
+.globl rm_int0d
+.hidden rm_int0d
+.type rm_int0d, @function
+rm_int0d:
+ pushw $13
+ jmp any_interrupt16
+.globl rm_int0e
+.hidden rm_int0e
+.type rm_int0e, @function
+rm_int0e:
+ pushw $14
+ jmp any_interrupt16
+.globl rm_int0f
+.hidden rm_int0f
+.type rm_int0f, @function
+rm_int0f:
+ pushw $15
+ jmp any_interrupt16
+.globl rm_int10
+.hidden rm_int10
+.type rm_int10, @function
+rm_int10:
+ pushw $16
+ jmp any_interrupt16
+.globl rm_int11
+.hidden rm_int11
+.type rm_int11, @function
+rm_int11:
+ pushw $17
+ jmp any_interrupt16
+.globl rm_int12
+.hidden rm_int12
+.type rm_int12, @function
+rm_int12:
+ pushw $18
+ jmp any_interrupt16
+.globl rm_int13
+.hidden rm_int13
+.type rm_int13, @function
+rm_int13:
+ pushw $19
+ jmp any_interrupt16
+.globl rm_int14
+.hidden rm_int14
+.type rm_int14, @function
+rm_int14:
+ pushw $20
+ jmp any_interrupt16
+.globl rm_int15
+.hidden rm_int15
+.type rm_int15, @function
+rm_int15:
+ pushw $21
+ jmp any_interrupt16
+.globl rm_int16
+.hidden rm_int16
+.type rm_int16, @function
+rm_int16:
+ pushw $22
+ jmp any_interrupt16
+.globl rm_int17
+.hidden rm_int17
+.type rm_int17, @function
+rm_int17:
+ pushw $23
+ jmp any_interrupt16
+.globl rm_int18
+.hidden rm_int18
+.type rm_int18, @function
+rm_int18:
+ pushw $24
+ jmp any_interrupt16
+.globl rm_int19
+.hidden rm_int19
+.type rm_int19, @function
+rm_int19:
+ pushw $25
+ jmp any_interrupt16
+.globl rm_int1a
+.hidden rm_int1a
+.type rm_int1a, @function
+rm_int1a:
+ pushw $26
+ jmp any_interrupt16
+.globl rm_int1b
+.hidden rm_int1b
+.type rm_int1b, @function
+rm_int1b:
+ pushw $27
+ jmp any_interrupt16
+.globl rm_int1c
+.hidden rm_int1c
+.type rm_int1c, @function
+rm_int1c:
+ pushw $28
+ jmp any_interrupt16
+.globl rm_int1d
+.hidden rm_int1d
+.type rm_int1d, @function
+rm_int1d:
+ pushw $29
+ jmp any_interrupt16
+.globl rm_int1e
+.hidden rm_int1e
+.type rm_int1e, @function
+rm_int1e:
+ pushw $30
+ jmp any_interrupt16
+.globl rm_int1f
+.hidden rm_int1f
+.type rm_int1f, @function
+rm_int1f:
+ pushw $31
+ jmp any_interrupt16
+.globl rm_def_int
+.hidden rm_def_int
+.type rm_def_int, @function
+rm_def_int:
+ iret
+
+
+ /*
+ * All interrupt jumptable entries jump to here
+ * after pushing the interrupt vector number onto the
+ * stack.
+ */
+any_interrupt16:
+ MAKE_BIOS_STACK
+
+gs movw OFFS_VECTOR(%bp), %ax
+ cmpw $0x10, %ax
+ je Lint_10h
+ cmpw $0x11, %ax
+ je Lint_11h
+ cmpw $0x12, %ax
+ je Lint_12h
+ cmpw $0x13, %ax
+ je Lint_13h
+ cmpw $0x15, %ax
+ je Lint_15h
+ cmpw $0x16, %ax
+ je Lint_16h
+ cmpw $0x1a, %ax
+ je Lint_1ah
+ movw $0xffff, %ax
+ jmp Lout
+Lint_10h: /* VGA BIOS services */
+ call bios_10h
+ jmp Lout
+Lint_11h:
+ call bios_11h
+ jmp Lout
+Lint_12h:
+ call bios_12h
+ jmp Lout
+Lint_13h: /* BIOS disk services */
+ call bios_13h
+ jmp Lout
+Lint_15h: /* Misc. BIOS services */
+ call bios_15h
+ jmp Lout
+Lint_16h: /* keyboard services */
+ call bios_16h
+ jmp Lout
+Lint_1ah: /* PCI bios */
+ call bios_1ah
+ jmp Lout
+Lout:
+ cmpw $0, %ax
+ je Lhandeled
+
+ /* Insert code for unhandeled INTs here.
+ *
+ * ROLO prints a message to the console
+ * (we could do that but then we're in 16bit mode
+ * so we'll have to get back into 32bit mode
+ * to use the console I/O routines (if we do this
+ * we shuls make int 0x10 and int 0x16 work as well))
+ */
+Lhandeled:
+ RESTORE_CALLERS_STACK
+ addw $2,%sp /* dump vector number */
+ iret /* return from interrupt */
+
+
+/*
+ ************************************************************
+ * BIOS interrupt 10h -- VGA services
+ ************************************************************
+ */
+bios_10h:
+gs movw OFFS_AX(%bp), %ax
+ shrw $8, %ax
+ cmpw $0x3, %ax
+ je Lcur_pos
+ cmpw $0xf, %ax
+ je Lvid_state
+ cmpw $0x12, %ax
+ je Lvid_cfg
+ movw $0xffff, %ax
+ ret
+Lcur_pos: /* Read Cursor Position and Size */
+gs movw $0, OFFS_CX(%bp)
+gs movw $0, OFFS_DX(%bp)
+ xorw %ax, %ax
+ ret
+Lvid_state: /* Get Video State */
+gs movw $(80 << 8|0x03), OFFS_AX(%bp) /* 80 columns, 80x25, 16 colors */
+gs movw $0, OFFS_BX(%bp)
+ xorw %ax, %ax
+ ret
+Lvid_cfg: /* Video Subsystem Configuration (EGA/VGA) */
+gs movw $0x10, OFFS_BX(%bp) /* indicate CGA/MDA/HGA */
+ xorw %ax, %ax
+ ret
+
+
+/*
+ ************************************************************
+ * BIOS interrupt 11h -- Equipment determination
+ ************************************************************
+ */
+
+bios_11h:
+cs movw bios_equipment, %ax
+gs movw %ax, OFFS_AX(%bp)
+ xorw %ax, %ax
+ ret
+
+
+/*
+ ************************************************************
+ * BIOS interrupt 12h -- Get Memory Size
+ ************************************************************
+ */
+bios_12h:
+cs movw ram_in_64kb_chunks, %ax
+ cmpw $0xa, %ax
+ ja b12_more_than_640k
+ shlw $6, %ax
+ jmp b12_return
+b12_more_than_640k:
+ movw $0x280, %ax
+b12_return:
+gs movw %ax, OFFS_AX(%bp) /* return number of kilobytes in ax */
+
+gs movw OFFS_FLAGS(%bp), %ax
+ andw $0xfffe, %ax /* clear carry -- function succeeded */
+gs movw %ax, OFFS_FLAGS(%bp)
+
+ xorw %ax, %ax
+ ret
+
+
+/*
+ ************************************************************
+ * BIOS interrupt 13h -- Disk services
+ ************************************************************
+ */
+bios_13h:
+gs movw OFFS_AX(%bp), %ax
+ shrw $8, %ax
+ cmpw $0x15, %ax
+ je Lfunc_15h
+ movw $0xffff, %ax
+ ret
+Lfunc_15h:
+gs movw OFFS_AX(%bp), %ax
+ andw $0xff, %ax /* return AH=0->drive not present */
+gs movw %ax, OFFS_AX(%bp)
+ xorw %ax, %ax
+ ret
+
+
+/*
+ ***********************************************************
+ * BIOS interrupt 15h -- Miscellaneous services
+ ***********************************************************
+ */
+bios_15h:
+gs movw OFFS_AX(%bp), %ax
+ shrw $8, %ax
+ cmpw $0xc0, %ax
+ je Lfunc_c0h
+ cmpw $0xe8, %ax
+ je Lfunc_e8h
+ cmpw $0x88, %ax
+ je Lfunc_88h
+ movw $0xffff, %ax
+ ret
+
+Lfunc_c0h: /* Return System Configuration Parameters (PS2 only) */
+gs movw OFFS_FLAGS(%bp), %ax
+ orw $1, %ax /* return carry -- function not supported */
+gs movw %ax, OFFS_FLAGS(%bp)
+ xorw %ax, %ax
+ ret
+
+Lfunc_e8h:
+gs movw OFFS_AX(%bp), %ax
+ andw $0xff, %ax
+ cmpw $1, %ax
+ je Lfunc_e801h
+gs movw OFFS_FLAGS(%bp), %ax
+ orw $1, %ax /* return carry -- function not supported */
+gs movw %ax, OFFS_FLAGS(%bp)
+ xorw %ax, %ax
+ ret
+
+Lfunc_e801h: /* Get memory size for >64M Configurations */
+cs movw ram_in_64kb_chunks, %ax
+ cmpw $0x100, %ax
+ ja e801_more_than_16mb
+ shlw $6, %ax /* multiply by 64 */
+ subw $0x400, %ax /* 1st meg does not count */
+
+gs movw %ax, OFFS_AX(%bp) /* return memory size between 1M and 16M in 1kb chunks in AX and CX */
+gs movw %ax, OFFS_CX(%bp)
+gs movw $0, OFFS_BX(%bp) /* set BX and DX to 0*/
+gs movw $0, OFFS_DX(%bp)
+gs movw OFFS_FLAGS(%bp), %ax
+ andw $0xfffe, %ax /* clear carry -- function succeeded */
+gs movw %ax, OFFS_FLAGS(%bp)
+ xorw %ax, %ax
+ ret
+
+e801_more_than_16mb:
+ subw $0x100, %ax /* subtract 16MB */
+
+gs movw $0x3c00, OFFS_AX(%bp) /* return 0x3c00 (16MB-1MB) in AX and CX */
+gs movw $0x3c00, OFFS_CX(%bp)
+gs movw %ax, OFFS_BX(%bp) /* set BX and DX to number of 64kb chunks above 16MB */
+gs movw %ax, OFFS_DX(%bp)
+
+gs movw OFFS_FLAGS(%bp), %ax
+ andw $0xfffe, %ax /* clear carry -- function succeeded */
+gs movw %ax, OFFS_FLAGS(%bp)
+ xorw %ax, %ax
+ ret
+
+Lfunc_88h:
+cs movw ram_in_64kb_chunks, %ax
+ cmpw $0x100, %ax
+ jna b88_not_more_than16
+ movw $0x100, %ax
+b88_not_more_than16:
+ shlw $6, %ax
+ subw $0x400, %ax /* 1st meg does not count */
+
+gs movw %ax, OFFS_AX(%bp) /* return number of kilobytes between 16MB and 16MB in ax */
+
+gs movw OFFS_FLAGS(%bp), %ax
+ andw $0xfffe, %ax /* clear carry -- function succeeded */
+gs movw %ax, OFFS_FLAGS(%bp)
+
+ xorw %ax, %ax
+ ret
+
+
+/*
+ ************************************************************
+ * BIOS interrupt 16h -- keyboard services
+ ************************************************************
+ */
+bios_16h:
+gs movw OFFS_AX(%bp), %ax
+ shrw $8, %ax
+ cmpw $0x03, %ax
+ je Lfunc_03h
+ movw $0xffff, %ax
+ ret
+Lfunc_03h:
+ xorw %ax, %ax /* do nothing -- function not supported */
+ ret
+
+/*
+ ************************************************************
+ * BIOS interrupt 1ah -- PCI bios
+ ************************************************************
+ */
+bios_1ah:
+gs movw OFFS_AX(%bp), %ax
+ cmpb $0xb1, %ah
+ je Lfunc_b1h
+ movw $0xffff, %ax
+ ret
+Lfunc_b1h:
+ call realmode_pci_bios
+ xorw %ax, %ax /* do nothing -- function not supported */
+ ret
+
+
+.globl ram_in_64kb_chunks
+.hidden ram_in_64kb_chunks
+.type ram_in_64kb_chunks, @function
+ram_in_64kb_chunks:
+ .word 0
+
+.globl bios_equipment
+.hidden bios_equipment
+.type bios_equipment, @function
+bios_equipment:
+ .word 0
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