;; ;; Copyright (C) 2006-2011 Oracle Corporation ;; ;; This file is part of VirtualBox Open Source Edition (OSE), as ;; available from http://www.virtualbox.org. This file is free software; ;; you can redistribute it and/or modify it under the terms of the GNU ;; General Public License (GPL) as published by the Free Software ;; Foundation, in version 2 as it comes in the "COPYING" file of the ;; VirtualBox OSE distribution. VirtualBox OSE is distributed in the ;; hope that it will be useful, but WITHOUT ANY WARRANTY of any kind. ;; -------------------------------------------------------------------- ;; ;; This code is based on: ;; ;; ROM BIOS for use with Bochs/Plex86/QEMU emulation environment ;; ;; Copyright (C) 2002 MandrakeSoft S.A. ;; ;; MandrakeSoft S.A. ;; 43, rue d'Aboukir ;; 75002 Paris - France ;; http://www.linux-mandrake.com/ ;; http://www.mandrakesoft.com/ ;; ;; This library is free software; you can redistribute it and/or ;; modify it under the terms of the GNU Lesser General Public ;; License as published by the Free Software Foundation; either ;; version 2 of the License, or (at your option) any later version. ;; ;; This library 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 ;; Lesser General Public License for more details. ;; ;; You should have received a copy of the GNU Lesser General Public ;; License along with this library; if not, write to the Free Software ;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA ;; ;; EBDA_SEG equ 09FC0h ; starts at 639K EBDA_SIZE equ 1 ; 1K BASE_MEM_IN_K equ (640 - EBDA_SIZE) CMOS_ADDR equ 070h CMOS_DATA equ 071h PIC_CMD_EOI equ 020h PIC_MASTER equ 020h PIC_SLAVE equ 0A0h BIOS_FIX_BASE equ 0E000h SYS_MODEL_ID equ 0FCh ; PC/AT SYS_SUBMODEL_ID equ 0 BIOS_REVISION equ 1 BIOS_BUILD_DATE equ '06/23/99' BIOS_COPYRIGHT equ 'Oracle VM VirtualBox BIOS' ;BX_PCIBIOS equ 1 ; defined in pcicfg.inc BX_ROMBIOS32 equ 0 BX_CALL_INT15_4F equ 1 ;; Set a fixed BIOS location, with a marker for verification BIOSORG macro addr org addr - BIOS_FIX_BASE - 2 db 'XM' endm ;; Set an interrupt vector (not very efficient if multiple vectors are ;; programmed in one go) SET_INT_VECTOR macro vec, segm, offs mov ax, offs mov ds:[vec*4], ax mov ax, segm mov ds:[vec*4+2], ax endm ; Set up an environment C code expects. DS must point to the BIOS segment ; and the direction flag must be cleared(!) C_SETUP macro push cs pop ds cld endm ;; External function in separate modules extrn _dummy_isr_function:near extrn _log_bios_start:near extrn _nmi_handler_msg:near extrn _int18_panic_msg:near extrn _int09_function:near extrn _int13_diskette_function:near extrn _int13_eltorito:near extrn _int13_cdemu:near extrn _int13_cdrom:near extrn _cdemu_isactive:near extrn _cdemu_emulated_drive:near extrn _int13_harddisk:near extrn _int13_harddisk_ext:near extrn _int14_function:near extrn _int15_function:near extrn _int15_function_mouse:near extrn _int15_function32:near extrn _int16_function:near extrn _int17_function:near extrn _int19_function:near extrn _int1a_function:near extrn _int1a_function_pci:near extrn _int70_function:near extrn _int74_function:near extrn _ata_init:near extrn _ahci_init:near extrn _scsi_init:near extrn _ata_detect:near extrn _cdemu_init:near extrn _keyboard_init:near extrn _print_bios_banner:near ;; Symbols referenced from C code public _diskette_param_table public _pmode_IDT public _rmode_IDT public post public eoi_both_pics public rtc_post ;; Additional publics for easier disassembly and debugging ifndef DEBUG DEBUG equ 1 endif ifdef DEBUG public int08_handler public int0e_handler public int11_handler public int12_handler public int13_handler public int13_relocated public int15_handler public int17_handler public int19_handler public int19_relocated public dummy_iret public nmi public rom_fdpt public cpu_reset public normal_post public eoi_jmp_post public eoi_master_pic public ebda_post public hard_drive_post public int13_legacy public int70_handler public int75_handler public int15_handler32 public int15_handler_mouse public iret_modify_cf public rom_scan public rom_checksum public init_pic public floppy_post public int13_out public int13_disk public int13_notfloppy public int13_legacy public int13_noeltorito public int1c_handler public int10_handler public int74_handler public int76_handler public detect_parport public detect_serial public font8x8 endif ;; NOTE: The last 8K of the ROM BIOS are peppered with fixed locations which ;; must be retained for compatibility. As a consequence, some of the space is ;; going to be wasted, but the gaps should be filled with miscellaneous code ;; and data when possible. .286p BIOSSEG segment 'CODE' assume cs:BIOSSEG ;; ;; Start of fixed code - eoi_jmp_post is kept here to allow short jumps. ;; BIOSORG 0E030h eoi_jmp_post: call eoi_both_pics xor ax, ax mov ds, ax jmp dword ptr ds:[0467h] eoi_both_pics: mov al, PIC_CMD_EOI out PIC_SLAVE, al eoi_master_pic: mov al, PIC_CMD_EOI out PIC_MASTER, al ret ;; -------------------------------------------------------- ;; POST entry point ;; -------------------------------------------------------- BIOSORG 0E05Bh post: xor ax, ax ;; reset the DMA controllers out 00Dh, al out 0DAh, al ;; then initialize the DMA controllers mov al, 0C0h out 0D6h, al ; enable channel 4 cascade mov al, 0 out 0D4h, al ; unmask channel 4 ;; read the CMOS shutdown status mov al, 0Fh out CMOS_ADDR, al in al, CMOS_DATA ;; save status mov bl, al ;; reset the shutdown status in CMOS mov al, 0Fh out CMOS_ADDR, al mov al, 0 out CMOS_DATA, al ;; examine the shutdown status code mov al, bl cmp al, 0 jz normal_post cmp al, 0Dh jae normal_post cmp al, 9 je normal_post ;; TODO: really?! ;; 05h = EOI + jump through 40:67 cmp al, 5 je eoi_jmp_post ;; any other shutdown status values are ignored ;; OpenSolaris sets the status to 0Ah in some cases? ; jmp normal_post normal_post: ;; shutdown code 0: normal startup cli ;; Set up the stack top at 0:7800h. The stack should not be ;; located above 0:7C00h; that conflicts with PXE, which ;; considers anything above that address to be fair game. ;; The traditional locations are 30:100 (PC) or 0:400 (PC/AT). mov ax, 7800h mov sp, ax xor ax, ax mov ds, ax mov ss, ax ;; clear the bottom of memory except for the word at 40:72 ;; TODO: Why not clear all of it? What's the point? mov es, ax xor di, di cld mov cx, 0472h / 2 rep stosw inc di inc di mov cx, (1000h - 0472h - 2) / 2 rep stosw ;; clear the remaining base memory except for the top ;; of the EBDA (the MP table is planted there) xor bx, bx memory_zero_loop: add bx, 1000h cmp bx, 9000h jae memory_cleared mov es, bx xor di, di mov cx, 8000h ; 32K words rep stosw jmp memory_zero_loop memory_cleared: mov es, bx xor di, di mov cx, 7E00h ; all but the last 1K rep stosw xor bx, bx C_SETUP call _log_bios_start call pmode_setup ;; set all interrupts to default handler xor bx, bx mov ds, bx mov cx, 78h ; leave the rest as zeros mov ax, dummy_iret mov dx, BIOSSEG post_default_ints: mov [bx], ax mov [bx+2], dx add bx, 4 loop post_default_ints ;; set vector 79h to zero ;; this is used by 'guardian angel' protection system ;; TODO: Really? Why? ;; base memory in K to 40:13 mov ax, BASE_MEM_IN_K mov ds:[413h], ax ;; manufacturing test at 40:12 ;; zeroed out above ;; set up various service vectors ;; TODO: This should use the table at FEF3h instead SET_INT_VECTOR 11h, BIOSSEG, int11_handler SET_INT_VECTOR 12h, BIOSSEG, int12_handler SET_INT_VECTOR 15h, BIOSSEG, int15_handler SET_INT_VECTOR 17h, BIOSSEG, int17_handler SET_INT_VECTOR 18h, BIOSSEG, int18_handler SET_INT_VECTOR 19h, BIOSSEG, int19_handler SET_INT_VECTOR 1Ch, BIOSSEG, int1c_handler call ebda_post ;; PIT setup SET_INT_VECTOR 08h, BIOSSEG, int08_handler mov al, 34h ; timer 0, binary, 16-bit, mode 2 out 43h, al mov al, 0 ; max count -> ~18.2 Hz out 40h, al out 40h, al ;; keyboard setup SET_INT_VECTOR 09h, BIOSSEG, int09_handler SET_INT_VECTOR 16h, BIOSSEG, int16_handler xor ax, ax mov ds, ax ;; TODO: What's the point? The BDA is zeroed already?! mov ds:[417h], al ; keyboard shift flags, set 1 mov ds:[418h], al ; keyboard shift flags, set 2 mov ds:[419h], al ; keyboard Alt-numpad work area mov ds:[471h], al ; keyboard Ctrl-Break flag mov ds:[497h], al ; keyboard status flags 4 mov al, 10h mov ds:[496h], al ; keyboard status flags 3 mov bx, 1Eh mov ds:[41Ah], bx ; keyboard buffer head mov ds:[41Ch], bx ; keyboard buffer tail mov ds:[480h], bx ; keyboard buffer start mov bx, 3Eh mov ds:[482h], bx ; keyboard buffer end push ds C_SETUP call _keyboard_init pop ds ;; store CMOS equipment byte in BDA mov al, 14h out CMOS_ADDR, al in al, CMOS_DATA mov ds:[410h], al ;; parallel setup SET_INT_VECTOR 0Fh, BIOSSEG, dummy_iret xor ax, ax mov ds, ax xor bx, bx mov cl, 14h ; timeout value mov dx, 378h ; parallel port 1 call detect_parport mov dx, 278h ; parallel port 2 call detect_parport shl bx, 0Eh mov ax, ds:[410h] ; equipment word and ax, 3FFFh or ax, bx ; set number of parallel ports mov ds:[410h], ax ; store in BDA ;; Serial setup SET_INT_VECTOR 0Bh, BIOSSEG, dummy_isr SET_INT_VECTOR 0Ch, BIOSSEG, dummy_isr SET_INT_VECTOR 14h, BIOSSEG, int14_handler xor bx, bx mov cl, 0Ah ; timeout value mov dx, 3F8h ; first serial address call detect_serial mov dx, 2F8h ; second serial address call detect_serial mov dx, 3E8h ; third serial address call detect_serial mov dx, 2E8h ; fourth serial address call detect_serial shl bx, 9 mov ax, ds:[410h] ; equipment word and ax, 0F1FFh ; bits 9-11 determine serial ports or ax, bx mov ds:[410h], ax ;; CMOS RTC SET_INT_VECTOR 1Ah, BIOSSEG, int1a_handler SET_INT_VECTOR 4Ah, BIOSSEG, dummy_iret ; TODO: redundant? SET_INT_VECTOR 70h, BIOSSEG, int70_handler ;; BIOS DATA AREA 4CEh ??? call rtc_post ;; PS/2 mouse setup SET_INT_VECTOR 74h, BIOSSEG, int74_handler ;; IRQ 13h (FPU exception) setup SET_INT_VECTOR 75h, BIOSSEG, int75_handler ;; Video setup SET_INT_VECTOR 10h, BIOSSEG, int10_handler call init_pic call pcibios_init_iomem_bases call pcibios_init_irqs call rom_scan C_SETUP ;; ATA/ATAPI driver setup call _ata_init call _ata_detect ifdef VBOX_WITH_SCSI ; SCSI driver setup call _scsi_init endif ifdef VBOX_WITH_AHCI ; AHCI driver setup call _ahci_init endif ;; floppy setup call floppy_post ;; hard drive setup call hard_drive_post C_SETUP ; in case assembly code changed things call _print_bios_banner ;; El Torito floppy/hard disk emulation call _cdemu_init ; TODO: what's the point of enabling interrupts here?? sti ; enable interrupts int 19h ;; does not return here sti wait_forever: hlt jmp wait_forever cli hlt ;; -------------------------------------------------------- ;; NMI handler ;; -------------------------------------------------------- BIOSORG 0E2C3h nmi: C_SETUP call _nmi_handler_msg iret int75_handler: out 0F0h, al ; clear IRQ13 call eoi_both_pics int 2 ; emulate legacy NMI iret hard_drive_post proc near ;; TODO Why? And what about secondary controllers? mov al, 0Ah ; disable IRQ 14 mov dx, 03F6h out dx, al xor ax, ax mov ds, ax ;; TODO: Didn't we just clear the entire EBDA? mov ds:[474h], al ; last HD operation status mov ds:[477h], al ; HD port offset (XT only???) mov ds:[48Ch], al ; HD status register mov ds:[48Dh], al ; HD error register mov ds:[48Eh], al ; HD task complete flag mov al, 0C0h mov ds:[476h], al ; HD control byte ;; set up hard disk interrupt vectors SET_INT_VECTOR 13h, BIOSSEG, int13_handler SET_INT_VECTOR 76h, BIOSSEG, int76_handler ;; INT 41h/46h: hard disk 0/1 dpt ; TODO: This should be done from the code which ; builds the DPTs? SET_INT_VECTOR 41h, EBDA_SEG, 3Dh SET_INT_VECTOR 46h, EBDA_SEG, 4Dh ret hard_drive_post endp ;; -------------------------------------------------------- ;; INT 13h handler - Disk services ;; -------------------------------------------------------- BIOSORG 0E3FEh int13_handler: jmp int13_relocated ;; -------------------------------------------------------- ;; Fixed Disk Parameter Table ;; -------------------------------------------------------- ;; BIOSORG 0E401h - fixed wrt preceding rom_fdpt: ;; -------------------------------------------------------- ;; INT 19h handler - Boot load service ;; -------------------------------------------------------- BIOSORG 0E6F2h int19_handler: jmp int19_relocated ;; -------------------------------------------------------- ;; System BIOS Configuration Table ;; -------------------------------------------------------- ;; BIOSORG 0E6F5h - fixed wrt preceding ; must match BIOS_CONFIG_TABLE bios_cfg_table: dw 9 ; table size in bytes db SYS_MODEL_ID db SYS_SUBMODEL_ID db BIOS_REVISION ; Feature byte 1 ; b7: 1=DMA channel 3 used by hard disk ; b6: 1=2 interrupt controllers present ; b5: 1=RTC present ; b4: 1=BIOS calls int 15h/4Fh for every key ; b3: 1=wait for extern event supported (Int 15h/41h) ; b2: 1=extended BIOS data area used ; b1: 0=AT or ESDI bus, 1=MicroChannel ; b0: 1=Dual bus (MicroChannel + ISA) ifdef BX_CALL_INT15_4F db 74h; or USE_EBDA else db 64h; or USE_EBDA endif ; Feature byte 2 ; b7: 1=32-bit DMA supported ; b6: 1=int16h, function 9 supported ; b5: 1=int15h/C6h (get POS data) supported ; b4: 1=int15h/C7h (get mem map info) supported ; b3: 1=int15h/C8h (en/dis CPU) supported ; b2: 1=non-8042 kb controller ; b1: 1=data streaming supported ; b0: reserved db 40h ; Feature byte 3 ; b7: not used ; b6: reserved ; b5: reserved ; b4: POST supports ROM-to-RAM enable/disable ; b3: SCSI on system board ; b2: info panel installed ; b1: Initial Machine Load (IML) system - BIOS on disk ; b0: SCSI supported in IML db 0 ; Feature byte 4 ; b7: IBM private ; b6: EEPROM present ; b5-3: ABIOS presence (011 = not supported) ; b2: private ; b1: memory split above 16Mb supported ; b0: POSTEXT directly supported by POST db 0 ; Feature byte 5 (IBM) ; b1: enhanced mouse ; b0: flash EPROM db 0 ;; -------------------------------------------------------- ;; Baud Rate Generator Table ;; -------------------------------------------------------- BIOSORG 0E729h ;; -------------------------------------------------------- ;; INT 14h handler - Serial Communication Service ;; -------------------------------------------------------- BIOSORG 0E739h int14_handler: push ds push es pusha C_SETUP call _int14_function popa pop es pop ds iret ;; ;; Handler for unexpected hardware interrupts ;; dummy_isr: push ds push es pusha C_SETUP call _dummy_isr_function popa pop es pop ds iret rom_checksum proc near push ax ifdef CHECKSUM_ROMS push bx push cx xor ax, ax xor bx, bx xor cx, cx mov ch, ds:[2] shl cx, 1 checksum_loop: add al, [bx] inc bx loop checksum_loop and al, 0FFh ; set flags pop cx pop bx else xor al, al endif pop ax ret rom_checksum endp ;; ;; ROM scan - scan for valid ROMs and initialize them ;; rom_scan: mov cx, 0C000h ; start at C000 rom_scan_loop: mov ds, cx mov ax, 4 ; scan in 2K increments cmp word ptr ds:[0], 0AA55h ; look for signature jne rom_scan_increment call rom_checksum jnz rom_scan_increment mov al, ds:[2] ; set increment to ROM length test al, 3 jz block_count_rounded and al, 0FCh ; round up add al, 4 ; to nearest 2K block_count_rounded: xor bx, bx mov ds, bx push ax push cx ; push segment... push 3 ; ...and offset of ROM entry mov bp, sp call dword ptr [bp] ; call ROM init routine cli ; in case ROM enabled interrupts add sp, 2 ; get rid of offset pop cx ; restore registers pop ax rom_scan_increment: shl ax, 5 ; convert to 16-byte increments add cx, ax cmp cx, 0E800h ; must encompass VBOX_LANBOOT_SEG! jbe rom_scan_loop xor ax, ax ; DS back to zero mov ds, ax ret init_pic proc near mov al, 11h ; send init commands out PIC_MASTER, al out PIC_SLAVE, al mov al, 08h ; base 08h out PIC_MASTER+1, al mov al, 70h ; base 70h out PIC_SLAVE+1, al mov al, 04h ; master PIC out PIC_MASTER+1, al mov al, 02h ; slave PIC out PIC_SLAVE+1, al mov al, 01h out PIC_MASTER+1, al out PIC_SLAVE+1, al mov al, 0B8h ; unmask IRQs 0/1/2/6 out PIC_MASTER+1, al mov al, 08Fh out PIC_SLAVE+1, al ; unmask IRQs 12/13/14 ret init_pic endp ebda_post proc near SET_INT_VECTOR 0Dh, BIOSSEG, dummy_isr ; IRQ 5 SET_INT_VECTOR 0Fh, BIOSSEG, dummy_isr ; IRQ 7 SET_INT_VECTOR 72h, BIOSSEG, dummy_isr ; IRQ 11 SET_INT_VECTOR 77h, BIOSSEG, dummy_isr ; IRQ 15 mov ax, EBDA_SEG mov ds, ax mov byte ptr ds:[0], EBDA_SIZE ;; store EBDA seg in 40:0E xor ax, ax mov ds, ax mov word ptr ds:[40Eh], EBDA_SEG ret ebda_post endp ;; -------------------------------------------------------- ;; INT 16h handler - Keyboard service ;; -------------------------------------------------------- BIOSORG 0E82Eh int16_handler: sti push es push ds pusha cmp ah, 0 je int16_F00 cmp ah, 10h je int16_F00 C_SETUP call _int16_function popa pop ds pop es iret int16_F00: mov bx, 40h ; TODO: why 40h here and 0 elsewhere? mov ds, bx int16_wait_for_key: cli mov bx, ds:[1Ah] cmp bx, ds:[1Ch] jne int16_key_found sti nop ; TODO: review/enable? if 0 push ax mov ax, 9002h int 15h pop ax endif jmp int16_wait_for_key int16_key_found: C_SETUP call _int16_function popa pop ds pop es ; TODO: review/enable? If so, flags should be restored here? if 0 push ax mov ax, 9202h int 15h pop ax endif iret ;; Quick and dirty protected mode entry/exit routines include pmode.inc ;; Initialization code which needs to run in protected mode (LAPIC etc.) include pmsetup.inc KBDC_DISABLE EQU 0ADh KBDC_ENABLE EQU 0AEh KBC_CMD EQU 64h KBC_DATA EQU 60h ;; -------------------------------------------------------- ;; INT 09h handler - Keyboard ISR (IRQ 1) ;; -------------------------------------------------------- BIOSORG 0E987h int09_handler: cli ; TODO: why? they're off already! push ax mov al, KBDC_DISABLE out KBC_CMD, al mov al, 0Bh out PIC_MASTER, al in al, PIC_MASTER and al, 2 jz int09_finish in al, KBC_DATA push ds pusha cld ; Before INT 15h (and any C code) ifdef BX_CALL_INT15_4F mov ah, 4Fh stc int 15h ; keyboard intercept jnc int09_done endif sti ; Only after calling INT 15h ;; check for extended key cmp al, 0E0h jne int09_check_pause xor ax, ax mov ds, ax mov al, ds:[496h] ; mf2_state |= 0x02 or al, 2 ; TODO: why not RMW? mov ds:[496h], al jmp int09_done int09_check_pause: cmp al, 0E1h ; pause key? jne int09_process_key xor ax, ax mov ds, ax ; TODO: haven't we just done that?? mov al, ds:[496h] or al, 1 mov ds:[496h], al ; TODO: why not RMW? jmp int09_done int09_process_key: push es C_SETUP call _int09_function pop es int09_done: popa pop ds cli call eoi_master_pic int09_finish: mov al, KBDC_ENABLE out KBC_CMD, al pop ax iret ;; -------------------------------------------------------- ;; INT 13h handler - Diskette service ;; -------------------------------------------------------- BIOSORG 0EC59h int13_diskette: jmp int13_noeltorito ;; -------------------------------------------------------- ;; INT 13h handler - Disk service ;; -------------------------------------------------------- int13_relocated: ;; check for an El-Torito function cmp ah, 4Ah jb int13_not_eltorito cmp ah, 4Dh ja int13_not_eltorito pusha push es push ds C_SETUP ; TODO: setup C envrionment only once? push int13_out ; simulate a call jmp _int13_eltorito ; ELDX not used int13_not_eltorito: push es push ax ; TODO: better register save/restore push bx push cx push dx ;; check if emulation is active call _cdemu_isactive cmp al, 0 je int13_cdemu_inactive ;; check if access to the emulated drive call _cdemu_emulated_drive pop dx ; recover dx (destroyed by C code) push dx cmp al, dl ; INT 13h on emulated drive jne int13_nocdemu pop dx pop cx pop bx pop ax pop es pusha push es push ds C_SETUP ; TODO: setup environment only once? push int13_out ; simulate a call jmp _int13_cdemu ; ELDX not used int13_nocdemu: and dl, 0E0h ; mask to get device class cmp al, dl jne int13_cdemu_inactive pop dx pop cx pop bx pop ax pop es push ax push cx push dx push bx dec dl ; real drive is dl - 1 jmp int13_legacy int13_cdemu_inactive: pop dx pop cx pop bx pop ax pop es int13_noeltorito: push ax push cx push dx push bx int13_legacy: push dx ; push eltorito dx in place of sp push bp push si push di push es push ds C_SETUP ; TODO: setup environment only once? ;; now the registers can be restored with ;; pop ds; pop es; popa; iret test dl, 80h ; non-removable? jnz int13_notfloppy push int13_out ; simulate a near call jmp _int13_diskette_function int13_notfloppy: cmp dl, 0E0h jb int13_notcdrom ;; ebx may be modified, save here ;; TODO: check/review 32-bit register use .386 shr ebx, 16 push bx call _int13_cdrom pop bx shl ebx, 16 .286 jmp int13_out int13_notcdrom: int13_disk: cmp ah,40h ja int13x call _int13_harddisk jmp int13_out int13x: call _int13_harddisk_ext int13_out: pop ds pop es popa iret ; parallel port detection: port in dx, index in bx, timeout in cl detect_parport proc near push dx inc dx inc dx in al, dx and al, 0DFh ; clear input mode out dx, al pop dx mov al, 0AAh out dx, al in al, dx cmp al, 0AAh jne no_parport push bx shl bx, 1 mov [bx+408h], dx ; parallel I/O address pop bx mov [bx+478h], cl ; parallel printer timeout inc bx no_parport: ret detect_parport endp ; setial port detection: port in dx, index in bx, timeout in cl detect_serial proc near push dx inc dx mov al, 2 out dx, al in al, dx cmp al, 2 jne no_serial inc dx in al, dx cmp al, 2 jne no_serial dec dx xor al, al pop dx push bx shl bx, 1 mov [bx+400h], dx ; serial I/O address pop bx mov [bx+47Ch], cl ; serial timeout inc bx ret no_serial: pop dx ret detect_serial endp ;; ;; POST: Floppy drive ;; floppy_post proc near xor ax, ax mov ds, ax ;; TODO: This code is really stupid. Zeroing the BDA byte ;; by byte is dumb, and it's been already zeroed elsewhere! mov al, 0 mov ds:[43Eh], al ; drive 0/1 uncalibrated, no IRQ mov ds:[43Fh], al ; motor status mov ds:[440h], al ; motor timeout counter mov ds:[441h], al ; controller status return code mov ds:[442h], al ; hd/floppy ctlr status register mov ds:[443h], al ; controller status register 1 mov ds:[444h], al ; controller status register 2 mov ds:[445h], al ; cylinder number mov ds:[446h], al ; head number mov ds:[447h], al ; sector number mov ds:[448h], al ; bytes written mov ds:[48Bh], al ; configuration data mov al, 10h ; floppy drive type out CMOS_ADDR, al in al, CMOS_DATA mov ah, al ; save drive type byte look_drive0: ; TODO: pre-init bl to reduce jumps shr al, 4 ; drive 0 in high nibble jz f0_missing ; jump if no drive mov bl, 7 ; drv0 determined, multi-rate, chgline jmp look_drive1 f0_missing: mov bl, 0 ; no drive 0 look_drive1: mov al, ah ; restore CMOS data and al, 0Fh ; drive 1 in low nibble jz f1_missing or bl, 70h ; drv1 determined, multi-rate, chgline f1_missing: mov ds:[48Fh], bl ; store in BDA ;; TODO: See above. Dumb *and* redundant! mov al, 0 mov ds:[490h], al ; drv0 media state mov ds:[491h], al ; drv1 media state mov ds:[492h], al ; drv0 operational state mov ds:[493h], al ; drv1 operational state mov ds:[494h], al ; drv0 current cylinder mov ds:[495h], al ; drv1 current cylinder mov al, 2 out 0Ah, al ; unmask DMA channel 2 SET_INT_VECTOR 1Eh, BIOSSEG, _diskette_param_table SET_INT_VECTOR 40h, BIOSSEG, int13_diskette SET_INT_VECTOR 0Eh, BIOSSEG, int0e_handler ; IRQ 6 ret floppy_post endp bcd_to_bin proc near ;; in : AL in packed BCD format ;; out: AL in binary, AH always 0 shl ax, 4 shr al, 4 aad ret bcd_to_bin endp rtc_post proc near .386 ;; get RTC seconds xor eax, eax mov al, 0 out CMOS_ADDR, al in al, CMOS_DATA ; RTC seconds, in BCD call bcd_to_bin ; eax now has seconds in binary mov edx, 18206507 mul edx mov ebx, 1000000 xor edx, edx div ebx mov ecx, eax ; total ticks in ecx ;; get RTC minutes xor eax, eax mov al, 2 out CMOS_ADDR, al in al, CMOS_DATA ; RTC minutes, in BCD call bcd_to_bin ; eax now has minutes in binary mov edx, 10923904 mul edx mov ebx, 10000 xor edx, edx div ebx add ecx, eax ; add to total ticks ;; get RTC hours xor eax, eax mov al, 4 out CMOS_ADDR, al in al, CMOS_DATA ; RTC hours, in BCD call bcd_to_bin ; eax now has hours in binary mov edx, 65543427 mul edx mov ebx, 1000 xor edx, edx div ebx add ecx, eax ; add to total ticks mov ds:[46Ch], ecx ; timer tick count xor al, al ; TODO: redundant? mov ds:[470h], al ; rollover flag .286 ret rtc_post endp ;; -------------------------------------------------------- ;; INT 0Eh handler - Diskette IRQ 6 ISR ;; -------------------------------------------------------- BIOSORG 0EF57h int0e_handler: push ax push dx mov dx, 3F4h in al, dx and al, 0C0h cmp al, 0C0h je int0e_normal mov dx, 3F5h mov al, 08h ; sense interrupt out dx, al int0e_loop1: mov dx, 3F4h ; TODO: move out of the loop? in al, dx and al, 0C0h cmp al, 0C0h jne int0e_loop1 int0e_loop2: mov dx, 3F5h ; TODO: inc/dec dx instead in al, dx mov dx, 3F4h in al, dx and al, 0C0h cmp al, 0C0h je int0e_loop2 int0e_normal: push ds xor ax, ax mov ds, ax call eoi_master_pic ; indicate that an interrupt occurred or byte ptr ds:[43Eh], 80h pop ds pop dx pop ax iret ;; -------------------------------------------------------- ;; Diskette Parameter Table ;; -------------------------------------------------------- BIOSORG 0EFC7h _diskette_param_table: db 0AFh db 2 ; HLT=1, DMA mode db 025h db 2 db 18 ; SPT (good for 1.44MB media) db 01Bh db 0FFh db 06Ch db 0F6h ; format filler db 15 db 8 ;; -------------------------------------------------------- ;; INT 17h handler - Printer service ;; -------------------------------------------------------- ;; BIOSORG 0EFD2h - fixed WRT preceding code int17_handler: push ds push es pusha C_SETUP call _int17_function popa pop es pop ds iret ;; Protected mode IDT descriptor ;; ;; The limit is 0 to cause a shutdown if an exception occurs ;; in protected mode. TODO: Is that what we really want? ;; ;; Set base to F0000 to correspond to beginning of BIOS, ;; in case an IDT is defined later. _pmode_IDT: dw 0 ; limit 15:0 dw 0 ; base 15:0 dw 0Fh ; base 23:16 ;; Real mode IDT descriptor ;; ;; Set to typical real-mode values. ;; base = 000000 ;; limit = 03ff _rmode_IDT: dw 3FFh ; limit 15:00 dw 0 ; base 15:00 dw 0 ; base 23:16 ;; ;; INT 1Ch ;; ;; TODO: Why does this need a special handler? int1c_handler: ;; user timer tick iret ;; -------------------------------------------------------- ;; INT 10h functions 0-Fh entry point ;; -------------------------------------------------------- BIOSORG 0F045h i10f0f_entry: iret ;; -------------------------------------------------------- ;; INT 10h handler - MDA/CGA video ;; -------------------------------------------------------- BIOSORG 0F065h int10_handler: ;; do nothing - assumes VGA iret ;; -------------------------------------------------------- ;; MDA/CGA Video Parameter Table (INT 1Dh) ;; -------------------------------------------------------- BIOSORG 0F0A4h mdacga_vpt: ;; ;; INT 18h - boot failure ;; int18_handler: C_SETUP call _int18_panic_msg ;; TODO: handle failure better? hlt iret ;; ;; INT 19h - boot service - relocated ;; int19_relocated: ; If an already booted OS calls int 0x19 to reboot, it is not sufficient ; just to try booting from the configured drives. All BIOS variables and ; interrupt vectors need to be reset, otherwise strange things may happen. ; The approach used is faking a warm reboot (which just skips showing the ; logo), which is a bit more than what we need, but hey, it's fast. mov bp, sp mov ax, [bp+2] ; TODO: redundant? address via sp? cmp ax, BIOSSEG ; check caller's segment jz bios_initiated_boot xor ax, ax mov ds, ax mov ax, 1234h mov ds:[472], ax jmp post bios_initiated_boot: ;; The C worker function returns the boot drive in bl and ;; the boot segment in ax. In case of failure, the boot ;; segment will be zero. C_SETUP ; TODO: Here? Now? push bp mov bp, sp ;; 1st boot device mov ax, 1 push ax call _int19_function inc sp inc sp test ax, ax ; if 0, try next device jnz boot_setup ;; 2nd boot device mov ax, 2 push ax call _int19_function inc sp inc sp test ax, ax ; if 0, try next device jnz boot_setup ; 3rd boot device mov ax, 3 push 3 call _int19_function inc sp inc sp test ax, ax ; if 0, try next device jnz boot_setup ; 4th boot device mov ax, 4 push ax call _int19_function inc sp inc sp test ax, ax ; if 0, invoke INT 18h jz int18_handler boot_setup: ; TODO: the drive should be in dl already?? ;; mov dl, bl ; tell guest OS what boot drive is .386 ; NB: We're getting garbage into high eax bits shl eax, 4 ; convert seg to ip mov [bp+2], ax ; set ip shr eax, 4 ; get cs back .286 and ax, BIOSSEG ; remove what went in ip mov [bp+4], ax ; set cs xor ax, ax mov ds, ax mov es, ax mov [bp], ax ; TODO: what's this?! mov ax, 0AA55h ; set ok flag ; TODO: and this? pop bp ; TODO: why'd we just zero it?? iret ; beam me up scotty ;; PCI BIOS include pcibios.inc include pirq.inc ;; -------------------------------------------------------- ;; INT 12h handler - Memory size ;; -------------------------------------------------------- BIOSORG 0F841h int12_handler: ;; Don't touch - fixed size! sti push ds mov ax, 40h mov ds, ax mov ax, ds:[13h] pop ds iret ;; -------------------------------------------------------- ;; INT 11h handler - Equipment list service ;; -------------------------------------------------------- ;; BIOSORG 0F84Dh - fixed wrt preceding code int11_handler: ;; Don't touch - fixed size! sti push ds mov ax, 40h mov ds, ax mov ax, ds:[10h] pop ds iret ;; -------------------------------------------------------- ;; INT 15h handler - System services ;; -------------------------------------------------------- ;; BIOSORG 0F859h - fixed wrt preceding code int15_handler: pushf cmp ah, 53h ; APM function? je apm_call push ds push es C_SETUP cmp ah, 86h je int15_handler32 cmp ah, 0E8h je int15_handler32 pusha cmp ah, 0C2h je int15_handler_mouse call _int15_function int15_handler_mouse_ret: popa int15_handler32_ret: pop es pop ds popf jmp iret_modify_cf apm_call: ; TODO!! popf stc jmp iret_modify_cf ; jmp apmreal_entry int15_handler_mouse: call _int15_function_mouse jmp int15_handler_mouse_ret int15_handler32: ;; need to save/restore 32-bit registers .386 pushad call _int15_function32 popad .286 jmp int15_handler32_ret ;; ;; Perform an IRET but retain the current carry flag value ;; iret_modify_cf: jc carry_set push bp mov bp, sp and byte ptr [bp + 6], 0FEh pop bp iret carry_set: push bp mov bp, sp or byte ptr [bp + 6], 1 pop bp iret ;; ;; INT 74h handler - PS/2 mouse (IRQ 12) ;; int74_handler proc sti pusha push es push ds push 0 ; placeholder for status push 0 ; placeholder for X push 0 ; placeholder for Y push 0 ; placeholder for Z push 0 ; placeholder for make_far_call bool C_SETUP call _int74_function pop cx ; pop make_far_call flag jcxz int74_done ;; make far call to EBDA:0022 push 0 pop ds push ds:[40Eh] pop ds call far ptr ds:[22h] int74_done: cli call eoi_both_pics add sp, 8 ; remove status, X, Y, Z pop ds pop es popa iret int74_handler endp int76_handler proc ;; record completion in BIOS task complete flag push ax push ds mov ax, 40h mov ds, ax mov byte ptr ds:[8Eh], 0FFh call eoi_both_pics pop ds pop ax iret int76_handler endp ;; -------------------------------------------------------- ;; 8x8 font (first 128 characters) ;; -------------------------------------------------------- BIOSORG 0FA6Eh include font8x8.inc ;; -------------------------------------------------------- ;; INT 1Ah handler - Time of the day + PCI BIOS ;; -------------------------------------------------------- ;; BIOSORG 0FE6Eh - fixed wrt preceding table int1a_handler: cmp ah, 0B1h jne int1a_normal call pcibios_real jc pcibios_error jmp iret_modify_cf ; don't trash caller's flags! pcibios_error: ; mov bl, ah ; mov ah, 0B1h pusha ; mov ax, ss ; set readable descriptor to DS for calling ; mov ds, ax ; PCI BIOS from 16-bit protected mode ; TODO: C environment?! call _int1a_function_pci popa iret int1a_normal: push es push ds pusha C_SETUP int1a_callfunction: call _int1a_function popa pop ds pop es iret ;; ;; IRQ 8 handler (RTC) ;; int70_handler: push es push ds pusha C_SETUP call _int70_function popa pop ds pop es iret ;; -------------------------------------------------------- ;; Timer tick - IRQ 0 handler ;; -------------------------------------------------------- BIOSORG 0FEA5h int08_handler: .386 sti push eax push ds xor ax, ax mov ds, ax ;; time to turn off floppy driv motor(s)? mov al, ds:[440h] or al, al jz int08_floppy_off ;; turn motor(s) off push dx mov dx, 03F2h in al, dx and al, 0CFh out dx, al pop dx int08_floppy_off: mov eax, ds:[46Ch] ; get ticks dword inc eax ;; compare eax to one day's worth of ticks (at 18.2 Hz) cmp eax, 1800B0h jb int08_store_ticks ;; there has been a midnight rollover xor eax, eax inc byte ptr ds:[470h] ; increment rollover flag int08_store_ticks: mov ds:[46Ch], eax int 1Ch ; call the user timer handler cli call eoi_master_pic pop ds pop eax .286 iret ;; -------------------------------------------------------- ;; Initial interrupt vector offsets for POST ;; -------------------------------------------------------- BIOSORG 0FEF3h vector_table: ;; -------------------------------------------------------- ;; BIOS copyright string ;; -------------------------------------------------------- BIOSORG 0FF00h bios_string: db BIOS_COPYRIGHT ;; -------------------------------------------------------- ;; IRET - default interrupt handler ;; -------------------------------------------------------- BIOSORG 0FF53h dummy_iret: iret ;; -------------------------------------------------------- ;; INT 05h - Print Screen service ;; -------------------------------------------------------- ;; BIOSORG 0FF54h - fixed wrt preceding int05_handler: ;; Not implemented iret include smidmi.inc ;; -------------------------------------------------------- ;; Processor reset entry point ;; -------------------------------------------------------- BIOSORG 0FFF0h cpu_reset: ;; This is where the CPU starts executing after a reset jmp far ptr post ;; BIOS build date db BIOS_BUILD_DATE db 0 ; padding ;; System model ID db SYS_MODEL_ID ;; Checksum byte db 0FFh BIOSSEG ends end