* Patch by Daniel Engström, 13 Nov 2002:
Add support for i386 architecture and AMD SC520 board
* Patch by Pierre Aubert, 12 Nov 2002:
Add support for DOS filesystem and booting from DOS floppy disk
diff --git a/lib_i386/bios.S b/lib_i386/bios.S
new file mode 100644
index 0000000..2f5ea8c
--- /dev/null
+++ b/lib_i386/bios.S
@@ -0,0 +1,443 @@
+/*
+ * (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
+ *----------------------------------------------------------------------
+ */
+
+/*
+ * 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 !!
+ */
+
+#define OFFS_ES 0
+#define OFFS_GS 2
+#define OFFS_DS 4
+#define OFFS_DI 6
+#define OFFS_SI 8
+#define OFFS_BP 10
+#define OFFS_SP 12
+#define OFFS_BX 14
+#define OFFS_DX 16
+#define OFFS_CX 18
+#define OFFS_AX 20
+#define OFFS_VECTOR 22
+#define OFFS_IP 24
+#define OFFS_CS 26
+#define OFFS_FLAGS 28
+
+#define SEGMENT 0x40
+#define STACK 0x800 /* stack at 0x40:0x800 -> 0x800 */
+
+.section .bios, "ax"
+.code16
+.org 0
+
+.globl rm_int00
+rm_int00:
+ pushw $0
+ jmp any_interrupt16
+.globl rm_int01
+rm_int01:
+ pushw $1
+ jmp any_interrupt16
+.globl rm_int02
+rm_int02:
+ pushw $2
+ jmp any_interrupt16
+.globl rm_int03
+rm_int03:
+ pushw $3
+ jmp any_interrupt16
+.globl rm_int04
+rm_int04:
+ pushw $4
+ jmp any_interrupt16
+.globl rm_int05
+rm_int05:
+ pushw $5
+ jmp any_interrupt16
+.globl rm_int06
+rm_int06:
+ pushw $6
+ jmp any_interrupt16
+.globl rm_int07
+rm_int07:
+ pushw $7
+ jmp any_interrupt16
+.globl rm_int08
+rm_int08:
+ pushw $8
+ jmp any_interrupt16
+.globl rm_int09
+rm_int09:
+ pushw $9
+ jmp any_interrupt16
+.globl rm_int0a
+rm_int0a:
+ pushw $10
+ jmp any_interrupt16
+.globl rm_int0b
+rm_int0b:
+ pushw $11
+ jmp any_interrupt16
+.globl rm_int0c
+rm_int0c:
+ pushw $12
+ jmp any_interrupt16
+.globl rm_int0d
+rm_int0d:
+ pushw $13
+ jmp any_interrupt16
+.globl rm_int0e
+rm_int0e:
+ pushw $14
+ jmp any_interrupt16
+.globl rm_int0f
+rm_int0f:
+ pushw $15
+ jmp any_interrupt16
+.globl rm_int10
+rm_int10:
+ pushw $16
+ jmp any_interrupt16
+.globl rm_int11
+rm_int11:
+ pushw $17
+ jmp any_interrupt16
+.globl rm_int12
+rm_int12:
+ pushw $18
+ jmp any_interrupt16
+.globl rm_int13
+rm_int13:
+ pushw $19
+ jmp any_interrupt16
+.globl rm_int14
+rm_int14:
+ pushw $20
+ jmp any_interrupt16
+.globl rm_int15
+rm_int15:
+ pushw $21
+ jmp any_interrupt16
+.globl rm_int16
+rm_int16:
+ pushw $22
+ jmp any_interrupt16
+.globl rm_int17
+rm_int17:
+ pushw $23
+ jmp any_interrupt16
+.globl rm_int18
+rm_int18:
+ pushw $24
+ jmp any_interrupt16
+.globl rm_int19
+rm_int19:
+ pushw $25
+ jmp any_interrupt16
+.globl rm_int1a
+rm_int1a:
+ pushw $26
+ jmp any_interrupt16
+.globl rm_int1b
+rm_int1b:
+ pushw $27
+ jmp any_interrupt16
+.globl rm_int1c
+rm_int1c:
+ pushw $28
+ jmp any_interrupt16
+.globl rm_int1d
+rm_int1d:
+ pushw $29
+ jmp any_interrupt16
+.globl rm_int1e
+rm_int1e:
+ pushw $30
+ jmp any_interrupt16
+.globl rm_int1f
+rm_int1f:
+ pushw $31
+ jmp any_interrupt16
+.globl rm_def_int
+rm_def_int:
+ iret
+
+
+ /*
+ * All interrupt jumptable entries jump to here
+ * after pushing the interrupt vector number onto the
+ * stack.
+ */
+any_interrupt16:
+ pusha /* save general registers */
+ pushw %ds /* save some segments */
+ pushw %gs
+ pushw %es
+ pushw %ss /* save callers stack segment .. */
+ popw %gs /* ... in gs */
+ movw $SEGMENT,%ax /* setup my segments */
+ movw %ax,%ds
+ movw %ax,%es
+ movw %ax,%ss
+ movw %sp,%bp
+ movw $STACK,%sp /* setup BIOS stackpointer */
+
+gs movw OFFS_VECTOR(%bp), %ax
+ cmpw $0x10, %ax
+ je Lint_10h
+ cmpw $0x11, %ax
+ je Lint_11h
+ cmpw $0x13, %ax
+ je Lint_13h
+ cmpw $0x15, %ax
+ je Lint_15h
+ cmpw $0x16, %ax
+ je Lint_16h
+ movw $0xffff, %ax
+ jmp Lout
+Lint_10h: /* VGA BIOS services */
+ call bios_10h
+ jmp Lout
+Lint_11h:
+ call bios_11h
+ 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
+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:
+
+ pushw %gs /* restore callers stack segment */
+ popw %ss
+ movw %bp,%sp /* restore stackpointer */
+
+ popw %es /* restore segment selectors */
+ popw %gs
+ popw %ds
+
+ popa /* restore GP registers */
+ 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:
+ movw bios_equipment, %ax
+gs movw %ax, OFFS_AX(%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 */
+ movw $ram_in_64kb_chunks, %ax
+ cmpw $256, %ax
+ ja Lmore_than_16mb
+ shlw $6, %ax /* multiply by 64 */
+gs movw %ax, OFFS_AX(%bp) /* return memory size in 1kb chunks in AX and CX */
+gs movw %ax, OFFS_CX(%bp)
+ xorw %ax, %ax
+gs movw %ax, OFFS_BX(%bp) /* set BX and DX to 0*/
+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
+
+Lmore_than_16mb:
+ subw $0x100, %ax /* subtract 16MB */
+
+gs movw $0x3c00, OFFS_AX(%bp) /* return 0x3c00 (16MB-384k) 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 - 256 */
+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:
+ movw ram_in_64kb_chunks, %ax
+ subw $16, %ax
+ shlw $6, %ax
+
+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 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
+
+
+.globl ram_in_64kb_chunks
+ram_in_64kb_chunks:
+ .word 0
+
+.globl bios_equipment
+bios_equipment:
+ .word 0
+