;;

;; Copyright (C) 2006-2012 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.

;;

;; --------------------------------------------------------------------

;;

;; Protected-mode APM implementation.

;;

;; 16-bit protected mode APM entry point

_TEXT segment public 'CODE'

extern _apm_function:near ; implemented in C code

public apm_pm16_entry

.286

; APM function dispatch table

apm_disp:

dw offset apmf_disconnect ; 04h

dw offset apmf_idle ; 05h

dw offset apmf_busy ; 06h

dw offset apmf_set_state ; 07h

dw offset apmf_enable ; 08h

dw offset apmf_restore ; 09h

dw offset apmf_get_status ; 0Ah

dw offset apmf_get_event ; 0Bh

dw offset apmf_pwr_state ; 0Ch

dw offset apmf_dev_pm ; 0Dh

dw offset apmf_version ; 0Eh

dw offset apmf_engage ; 0Fh

dw offset apmf_get_caps ; 10h

apm_disp_end:

;

; APM worker routine. Function code in AL; it is assumed that AL >= 4.

; Caller must preserve BP.

;

apm_worker proc near

sti ; TODO ?? necessary ??

push ax ; check if function is supported...

xor ah, ah

sub al, 4

mov bp, ax

shl bp, 1

cmp al, (apm_disp_end - apm_disp) / 2

pop ax

mov ah, 53h ; put back APM function

jae apmw_bad_func ; validate function range

jmp apm_disp[bp] ; and dispatch

apmf_disconnect: ; function 04h

jmp apmw_success

apmf_idle: ; function 05h

sti

hlt

jmp apmw_success

apmf_busy: ; function 06h

; jmp apmw_success

apmf_set_state: ; function 07h

; jmp apmw_success

apmf_enable: ; function 08h

jmp apmw_success

apmf_restore: ; function 09h

; jmp apmw_success

apmf_get_status: ; function 0Ah

jmp apmw_bad_func

apmf_get_event: ; function 0Bh

mov ah, 80h

jmp apmw_failure

apmf_pwr_state: ; function 0Ch

apmf_dev_pm: ; function 0Dh

jmp apmw_bad_func

apmf_version: ; function 0Eh

mov ax, 0102h

jmp apmw_success

apmf_engage: ; function 0Fh

; TODO do something?

jmp apmw_success

apmf_get_caps: ; function 10h

mov bl, 0 ; no batteries

mov cx, 0 ; no special caps

jmp apmw_success

apmw_success:

clc ; successful return

ret

apmw_bad_func:

mov ah, 09h ; unrecognized device ID - generic

apmw_failure:

stc ; error for unsupported functions

ret

apm_worker endp

;; 16-bit protected mode APM entry point

;; According to the APM spec, only CS (16-bit code selector) is defined.

;; The data selector can be derived from it.

apm_pm16_entry:

mov ah, 2 ; mark as originating in 16-bit PM

; fall through

apm_pm16_entry_from_32:

push ds ; save registers

push bp

push cs

pop bp

add bp, 8 ; calculate data selector

mov ds, bp ; load data segment

call apm_worker ; call APM handler

pop bp

pop ds ; restore registers

retf ; return to caller - 16-bit return

; even to 32-bit thunk!

_TEXT ends

.386

BIOS32 segment public 'CODE' use32

public apm_pm32_entry

;; 32-bit protected mode APM entry point and thunk

;; According to the APM spec, only CS (32-bit) is defined. 16-bit code

;; selector and the data selector can be derived from it.

;; WARNING: To simplify matters, we use 16-bit far return to go from 32-bit

;; code to 16-bit and back. As a consequence, the 32-bit APM code must lie

;; below 64K boundary in the 32-bit APM code segment.

apm_pm32_entry:

push ebp ; ebp is not used by APM

mov bp, cs ; return address for 16-bit code

push bp

mov ebp, apm_pm32_back

push bp ; Note: 16:16 address!

push cs

pop ebp

add ebp, 8 ; calculate 16-bit code selector

push bp ; push 16-bit code selector

mov ebp, apm_pm16_entry_from_32

push bp ; push 16-bit offset

mov ah, 3 ; mark as originating in 32-bit PM

db 66h ; force a 16-bit return

retf ; off to 16-bit code...

apm_pm32_back: ; return here from 16-bit code

pop ebp ; restore scratch register

retf

BIOS32 ends

end