/*
* (C) Copyright 2002
* Daniel Engström, Omicron Ceti AB, daniel@omicron.se
- *
+ *
* See file CREDITS for list of people who contributed to this
* project.
*
*----------------------------------------------------------------------
*/
+#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
* 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
+ /* a call to f000:0 should warmboot */
+ jmp realmode_reset
.globl rm_int00
rm_int00:
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 */
+ MAKE_BIOS_STACK
gs movw OFFS_VECTOR(%bp), %ax
cmpw $0x10, %ax
- je Lint_10h
+ 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:
+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_16h: /* keyboard services */
call bios_16h
jmp Lout
-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
+ * 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 */
+ RESTORE_CALLERS_STACK
addw $2,%sp /* dump vector number */
iret /* return from interrupt */
/*
************************************************************
- * BIOS interrupt 10h -- VGA services
+ * BIOS interrupt 10h -- VGA services
************************************************************
*/
bios_10h:
*/
bios_11h:
- movw bios_equipment, %ax
-gs movw %ax, OFFS_AX(%bp)
+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
je Lfunc_15h
movw $0xffff, %ax
ret
-Lfunc_15h:
+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
-
-
+
/*
***********************************************************
movw $0xffff, %ax
ret
-Lfunc_c0h: /* Return System Configuration Parameters (PS2 only) */
+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
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 */
+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)
- xorw %ax, %ax
-gs movw %ax, OFFS_BX(%bp) /* set BX and DX to 0*/
-gs movw %ax, OFFS_DX(%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
-
-Lmore_than_16mb:
- subw $0x100, %ax /* subtract 16MB */
-
-gs movw $0x3c00, OFFS_AX(%bp) /* return 0x3c00 (16MB-384k) in AX and CX */
+
+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 - 256 */
-gs movw %ax, OFFS_DX(%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 */
ret
Lfunc_88h:
- movw ram_in_64kb_chunks, %ax
- subw $16, %ax
+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
-
-gs movw %ax, OFFS_AX(%bp) /* return number of kilobytes in 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 */
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
ram_in_64kb_chunks:
- .word 0
+ .word 0
.globl bios_equipment
bios_equipment:
- .word 0
-
+ .word 0
projects / u-boot / blobdiff