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; $Id:
;; @file
; Protected-mode APM implementation.
;
;
; Copyright (C) 2006-2023 Oracle and/or its affiliates.
;
; This file is part of VirtualBox base platform packages, as
; available from https://www.virtualbox.org.
;
; 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, in version 3 of the
; License.
;
; 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, see <https://www.gnu.org/licenses>.
;
; SPDX-License-Identifier: GPL-3.0-only
;
include commondefs.inc
;; 16-bit protected mode APM entry point
_TEXT segment public 'CODE'
extern _apm_function:near ; implemented in C code
public apm_pm16_entry
SET_DEFAULT_CPU_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
;
; Windows 3.1 POWER.DRV in Standard mode calls into APM
; with CPL=3. If that happens, the HLT instruction will fault
; and Windows will crash. To prevent that, we check the CPL
; and do nothing (better than crashing).
;
push cs
pop ax
test ax, 3 ; CPL > 0?
jnz apmw_success
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
if VBOX_BIOS_CPU ge 80386
.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
endif ; 32-bit code
end
|
