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FreeDOS/kernel/kernel.asm

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FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
;
; File:
; kernel.asm
; Description:
; kernel start-up code
;
; Copyright (c) 1995, 1996
; Pasquale J. Villani
; All Rights Reserved
;
; This file is part of DOS-C.
;
; DOS-C 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, or (at your option) any later version.
;
; DOS-C 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 DOS-C; see the file COPYING. If not,
; write to the Free Software Foundation, 675 Mass Ave,
; Cambridge, MA 02139, USA.
;
; $Id: kernel.asm 1705 2012-02-07 08:10:33Z perditionc $
;
%include "segs.inc"
Introduce popargs and arg macros to distinguish PASCAL/STDCALL conventions. GCC has -mrtd but the args are pushed in reverse versus PASCAL. So asm routines have to use macros to obtain the stack arguments. For the complex call_nls assembly, revert the arguments in C using a preprocessor macro.
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%include "stacks.inc"
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
%include "ludivmul.inc"
segment PSP
ia16-elf-gcc port: compile all asm files with -f elf. Because ia16-elf-gcc and the GNU linker do not understand OMF we need to use ELF everywhere. This also means we cannot use "wrt", "seg" and "call/jmp far". Most wrt's are superfluous, and seg and call/jmp far can be replaced by explicit ?GROUP references (to be defined in the linker script).
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extern _ReqPktPtr
FreeDOS kernel current - 2041+svn1709
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STACK_SIZE equ 384/2 ; stack allocated in words
;************************************************************
; KERNEL BEGINS HERE, i.e. this is byte 0 of KERNEL.SYS
;************************************************************
ia16-elf-gcc port: compile all asm files with -f elf. Because ia16-elf-gcc and the GNU linker do not understand OMF we need to use ELF everywhere. This also means we cannot use "wrt", "seg" and "call/jmp far". Most wrt's are superfluous, and seg and call/jmp far can be replaced by explicit ?GROUP references (to be defined in the linker script).
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%ifidn __OUTPUT_FORMAT__, obj
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
..start:
ia16-elf-gcc port: compile all asm files with -f elf. Because ia16-elf-gcc and the GNU linker do not understand OMF we need to use ELF everywhere. This also means we cannot use "wrt", "seg" and "call/jmp far". Most wrt's are superfluous, and seg and call/jmp far can be replaced by explicit ?GROUP references (to be defined in the linker script).
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%endif
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
entry:
jmp short realentry
;************************************************************
; KERNEL CONFIGURATION AREA
; this is copied up on the very beginning
; it's a good idea to keep this in sync with KConfig.h
;************************************************************
global _LowKernelConfig
_LowKernelConfig:
kernel: copy CONFIG block from UPX help data early in kernel.asm Here we depend on the signal instruction that is patched by exeflat to indicate whether we were compressed. This replaces the prior check that detected the UPX help data solely by checking the CONFIG signature at 05E2h.
2022-05-21 15:17:01 +02:00
config_signature:
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
db 'CONFIG' ; constant
dw configend-configstart; size of config area
; to be checked !!!
configstart:
DLASortByDriveNo db 0 ; sort disks by drive order
InitDiskShowDriveAssignment db 1 ;
SkipConfigSeconds db 2 ;
ForceLBA db 0 ;
GlobalEnableLBAsupport db 1 ;
BootHarddiskSeconds db 0 ;
Tell version info without booting kernel
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; The following VERSION resource must be keep in sync with VERSION.H
Version_OemID db 0xFD ; OEM_ID
Version_Major db 2
Version_Revision dw 41 ; REVISION_SEQ
Version_Release dw 1 ; 0=release build, >0=svn#
kernel, main: add debugger_present variable and skip ints 0, 1, 3, 6 Also adds a CheckDebugger byte to the CONFIG block and support for reading and writing this setting in the SYS CONFIG program. Default is 0 (no check assume absent).
2022-05-21 15:22:48 +02:00
CheckDebugger: db 0 ; 0 = no check, 1 = check, 2 = assume present
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
configend:
kernel: copy CONFIG block from UPX help data early in kernel.asm Here we depend on the signal instruction that is patched by exeflat to indicate whether we were compressed. This replaces the prior check that detected the UPX help data solely by checking the CONFIG signature at 05E2h.
2022-05-21 15:17:01 +02:00
kernel_config_size: equ configend - config_signature
; must be below-or-equal the size of struct _KernelConfig
; in the file kconfig.h !
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
;************************************************************
; KERNEL CONFIGURATION AREA END
;************************************************************
;************************************************************
; KERNEL real entry (at ~60:20)
;
; moves the INIT part of kernel.sys to high memory (~9000:0)
; then jumps there
; to aid debugging, some '123' messages are output
; this area is discardable and used as temporary PSP for the
; init sequence
;************************************************************
display error for unsupported CPU from C. Masloch
2012-10-15 18:41:25 +02:00
cpu 8086 ; (keep initial entry compatible)
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
kernel: copy CONFIG block from UPX help data early in kernel.asm Here we depend on the signal instruction that is patched by exeflat to indicate whether we were compressed. This replaces the prior check that detected the UPX help data solely by checking the CONFIG signature at 05E2h.
2022-05-21 15:17:01 +02:00
global realentry
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
realentry: ; execution continues here
kernel: copy CONFIG block from UPX help data early in kernel.asm Here we depend on the signal instruction that is patched by exeflat to indicate whether we were compressed. This replaces the prior check that detected the UPX help data solely by checking the CONFIG signature at 05E2h.
2022-05-21 15:17:01 +02:00
clc ; this is patched to stc by exeflat
adc byte [cs:use_upx_config], 0
kernel, main: read kernel command line into init segment buffer The protocol for this extension is based on what lDebug already does given the PROTOCOL=FREEDOS with the switch CMDLINE=1 (which was originally defined for the lDOS and RxDOS load protocols). Therefore the stack frame mirrors that of the lDOS protocol.
2022-05-21 15:27:06 +02:00
; ! ZF used later in initialise_command_line_buffer
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
push ax
push bx
pushf
mov ax, 0e31h ; '1' Tracecode - kernel entered
mov bx, 00f0h
int 010h
popf
pop bx
pop ax
ia16-elf-gcc port: compile all asm files with -f elf. Because ia16-elf-gcc and the GNU linker do not understand OMF we need to use ELF everywhere. This also means we cannot use "wrt", "seg" and "call/jmp far". Most wrt's are superfluous, and seg and call/jmp far can be replaced by explicit ?GROUP references (to be defined in the linker script).
2017-12-19 14:22:58 +01:00
jmp IGROUP:kernel_start
kernel: copy CONFIG block from UPX help data early in kernel.asm Here we depend on the signal instruction that is patched by exeflat to indicate whether we were compressed. This replaces the prior check that detected the UPX help data solely by checking the CONFIG signature at 05E2h.
2022-05-21 15:17:01 +02:00
use_upx_config: db 0
ia16-elf-gcc port: compile all asm files with -f elf. Because ia16-elf-gcc and the GNU linker do not understand OMF we need to use ELF everywhere. This also means we cannot use "wrt", "seg" and "call/jmp far". Most wrt's are superfluous, and seg and call/jmp far can be replaced by explicit ?GROUP references (to be defined in the linker script).
2017-12-19 14:22:58 +01:00
beyond_entry: times 256-(beyond_entry-entry) db 0
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
; scratch area for data (DOS_PSP)
segment INIT_TEXT
extern _FreeDOSmain
extern _query_cpu
;
; kernel start-up
;
kernel_start:
push bx
pushf
mov ax, 0e32h ; '2' Tracecode - kernel entered
mov bx, 00f0h
int 010h
popf
pop bx
kernel, main: read kernel command line into init segment buffer The protocol for this extension is based on what lDebug already does given the PROTOCOL=FREEDOS with the switch CMDLINE=1 (which was originally defined for the lDOS and RxDOS load protocols). Therefore the stack frame mirrors that of the lDOS protocol.
2022-05-21 15:27:06 +02:00
extern _kernel_command_line
; preserve unit in bl
initialise_command_line_buffer:
mov dx, I_GROUP
mov es, dx
mov ax, ss
mov ds, ax
mov ax, sp ; ds:ax = ss:sp
mov si, bp ; si = bp
jz .notupx ; ! ZF still left by adc
xor ax, ax
mov ds, ax ; :5E0h -> UPX help data
lds si, [5E0h + 1Ch] ; -> original ss:sp - 2
lea ax, [si + 2] ; ax = original sp
mov si, word [si] ; si = original bp
.notupx:
; Note that the kernel command line buffer in
; the init data segment is pre-initialised to
; hold 0x00 0xFF in the first two bytes. This
; is used to indicate no command line present,
; as opposed to an empty command line which
; will hold 0x00 0x00.
; If any of the branches to .none are taken then
; the buffer is not modified so it retains the
; 0x00 0xFF contents.
cmp si, 114h ; buffer fits below ss:bp ?
jb .none ; no -->
cmp word [si - 14h], "CL" ; signature passed to us ?
jne .none ; no -->
lea si, [si - 114h] ; -> command line buffer
cmp ax, si ; stack top starts below-or-equal buffer ?
ja .none ; no -->
mov di, _kernel_command_line ; our buffer
mov cx, 255
xor ax, ax
push di
rep movsb ; copy up to 255 bytes
stosb ; truncate
pop di
mov ch, 1 ; cx = 256
repne scasb ; scan for terminator
rep stosb ; clear remainder of buffer
; (make sure we do not have 0x00 0xFF
; even if the command line given is
; actually the empty string)
.none:
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
cli
kernel, main: read kernel command line into init segment buffer The protocol for this extension is based on what lDebug already does given the PROTOCOL=FREEDOS with the switch CMDLINE=1 (which was originally defined for the lDOS and RxDOS load protocols). Therefore the stack frame mirrors that of the lDOS protocol.
2022-05-21 15:27:06 +02:00
mov ss, dx
mov sp, init_tos
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
int 12h ; move init text+data to higher memory
mov cl,6
shl ax,cl ; convert kb to para
ia16-elf-gcc port: compile all asm files with -f elf. Because ia16-elf-gcc and the GNU linker do not understand OMF we need to use ELF everywhere. This also means we cannot use "wrt", "seg" and "call/jmp far". Most wrt's are superfluous, and seg and call/jmp far can be replaced by explicit ?GROUP references (to be defined in the linker script).
2017-12-19 14:22:58 +01:00
mov dx,15 + INITSIZE
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
mov cl,4
shr dx,cl
sub ax,dx
mov es,ax
ia16-elf-gcc port: compile all asm files with -f elf. Because ia16-elf-gcc and the GNU linker do not understand OMF we need to use ELF everywhere. This also means we cannot use "wrt", "seg" and "call/jmp far". Most wrt's are superfluous, and seg and call/jmp far can be replaced by explicit ?GROUP references (to be defined in the linker script).
2017-12-19 14:22:58 +01:00
mov dx,INITTEXTSIZE ; para aligned
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
shr dx,cl
add ax,dx
mov ss,ax ; set SS to init data segment
sti ; now enable them
mov ax,cs
ia16-elf-gcc port: compile all asm files with -f elf. Because ia16-elf-gcc and the GNU linker do not understand OMF we need to use ELF everywhere. This also means we cannot use "wrt", "seg" and "call/jmp far". Most wrt's are superfluous, and seg and call/jmp far can be replaced by explicit ?GROUP references (to be defined in the linker script).
2017-12-19 14:22:58 +01:00
mov dx,__HMATextEnd ; para aligned
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
shr dx,cl
%ifdef WATCOM
add ax,dx
%endif
mov ds,ax
ia16-elf-gcc port: compile all asm files with -f elf. Because ia16-elf-gcc and the GNU linker do not understand OMF we need to use ELF everywhere. This also means we cannot use "wrt", "seg" and "call/jmp far". Most wrt's are superfluous, and seg and call/jmp far can be replaced by explicit ?GROUP references (to be defined in the linker script).
2017-12-19 14:22:58 +01:00
mov si,-2 + INITSIZE; word aligned
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
lea cx,[si+2]
mov di,si
shr cx,1
std ; if there's overlap only std is safe
rep movsw
; move HMA_TEXT to higher memory
sub ax,dx
mov ds,ax ; ds = HMA_TEXT
mov ax,es
sub ax,dx
mov es,ax ; es = new HMA_TEXT
ia16-elf-gcc port: compile all asm files with -f elf. Because ia16-elf-gcc and the GNU linker do not understand OMF we need to use ELF everywhere. This also means we cannot use "wrt", "seg" and "call/jmp far". Most wrt's are superfluous, and seg and call/jmp far can be replaced by explicit ?GROUP references (to be defined in the linker script).
2017-12-19 14:22:58 +01:00
mov si,-2 + __HMATextEnd
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
lea cx,[si+2]
mov di,si
shr cx,1
rep movsw
cld
%ifndef WATCOM ; for WATCOM: CS equal for HMA and INIT
add ax,dx
mov es,ax ; otherwise CS -> init_text
%endif
push es
mov ax,cont
push ax
retf
cont: ; Now set up call frame
mov ds,[cs:_INIT_DGROUP]
mov bp,sp ; and set up stack frame for c
push bx
pushf
mov ax, 0e33h ; '3' Tracecode - kernel entered
mov bx, 00f0h
int 010h
popf
pop bx
mov byte [_BootDrive],bl ; tell where we came from
;!! int 11h
;!! mov cl,6
;!! shr al,cl
;!! inc al
;!! mov byte [_NumFloppies],al ; and how many
call _query_cpu
display error for unsupported CPU from C. Masloch
2012-10-15 18:41:25 +02:00
%if XCPU != 86
%if XCPU < 186 || (XCPU % 100) != 86 || (XCPU / 100) > 9
%fatal Unknown CPU level defined
%endif
cmp al, (XCPU / 100)
jb cpu_abort ; if CPU not supported -->
cpu XCPU
%endif
mov [_CPULevel], al
kernel: copy CONFIG block from UPX help data early in kernel.asm Here we depend on the signal instruction that is patched by exeflat to indicate whether we were compressed. This replaces the prior check that detected the UPX help data solely by checking the CONFIG signature at 05E2h.
2022-05-21 15:17:01 +02:00
initialise_kernel_config:
extern _InitKernelConfig
push ds
pop es ; => DOS data segment (for _BootDrive)
mov ax, ss ; => init data segment
mov si, 60h
mov ds, si ; => entry section
mov si, _LowKernelConfig ; -> our own CONFIG block
; This block is part of what got decompressed if
; the kernel is UPX-compressed. And if UPX was
; used in .SYS mode then the first several words
; are overwritten with pseudo device header fields.
cmp byte [use_upx_config], 0 ; from UPX ?
je .notupx ; no, use own CONFIG block -->
mov si, 5Eh
mov ds, si
mov si, 2 ; -> CONFIG block of compressed entry
mov bl, [0] ; 05E0h has the boot load unit
mov byte [es:_BootDrive], bl ; overwrite the value in DOS data segment
.notupx:
mov es, ax ; => init data segment
mov di, _InitKernelConfig ; -> init's CONFIG block buffer
mov cx, kernel_config_size / 2 ; size that we support
rep movsw ; copy it over
%if kernel_config_size & 1
movsb ; allow odd size
%endif
mov ds, ax ; => init data segment
kernel, main: add debugger_present variable and skip ints 0, 1, 3, 6 Also adds a CheckDebugger byte to the CONFIG block and support for reading and writing this setting in the SYS CONFIG program. Default is 0 (no check assume absent).
2022-05-21 15:22:48 +02:00
check_debugger_present:
extern _debugger_present
mov al, 1 ; assume debugger present
cmp byte [di - kernel_config_size + (CheckDebugger - config_signature)], 1
ja .skip_ints_00_06 ; 2 means assume present
jb .absent ; 0 means assume absent
clc ; 1 means check
int3 ; break to debugger
jc .skip_ints_00_06
; The debugger should set CY here to indicate its
; presence. The flag set is checked later to skip
; overwriting the interrupt vectors 00h, 01h, 03h,
; and 06h. This logic is taken from lDOS init.
.absent:
xor ax, ax ; no debugger present
.skip_ints_00_06:
mov byte [_debugger_present], al
kernel: copy CONFIG block from UPX help data early in kernel.asm Here we depend on the signal instruction that is patched by exeflat to indicate whether we were compressed. This replaces the prior check that detected the UPX help data solely by checking the CONFIG signature at 05E2h.
2022-05-21 15:17:01 +02:00
jmp _FreeDOSmain
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
display error for unsupported CPU from C. Masloch
2012-10-15 18:41:25 +02:00
%if XCPU != 86
cpu 8086
cpu_abort:
mov ah, 0Fh
int 10h ; get video mode, bh = active page
From Evelyn, CPU unsupported message missing loading error msg address (pop si)
2016-01-16 04:34:38 +01:00
call .first ; print string that follows (address pushed by call)
display error for unsupported CPU from C. Masloch
2012-10-15 18:41:25 +02:00
%define LOADNAME "FreeDOS"
db 13,10 ; (to emit a blank line after the tracecodes)
db 13,10
db LOADNAME, " load error: An 80", '0'+(XCPU / 100)
db "86 processor or higher is required by this build.",13,10
db "To use ", LOADNAME, " on this processor please"
db " obtain a compatible build.",13,10
db 13,10
db "Press any key to reboot.",13,10
db 0
.display:
mov ah, 0Eh
mov bl, 07h ; page in bh, bl = colour for some modes
int 10h ; write character (may change bp!)
From Evelyn, CPU unsupported message missing loading error msg address (pop si)
2016-01-16 04:34:38 +01:00
db 0A8h ; [test al,imm8] skip "pop si" [=imm8] after the first iteration
display error for unsupported CPU from C. Masloch
2012-10-15 18:41:25 +02:00
.first:
From Evelyn, CPU unsupported message missing loading error msg address (pop si)
2016-01-16 04:34:38 +01:00
pop si ; (first iteration only) get message address from stack
display error for unsupported CPU from C. Masloch
2012-10-15 18:41:25 +02:00
cs lodsb ; get character
test al, al ; zero ?
jnz .display ; no, display and get next character -->
xor ax, ax
xor dx, dx
int 13h ; reset floppy disks
xor ax, ax
mov dl, 80h
int 13h ; reset hard disks
; this "test ax, imm16" opcode is used to
From Evelyn, CPU unsupported message missing loading error msg address (pop si)
2016-01-16 04:34:38 +01:00
db 0A9h ; skip "sti" \ "hlt" [=imm16] during first iteration
display error for unsupported CPU from C. Masloch
2012-10-15 18:41:25 +02:00
.wait:
sti
hlt ; idle while waiting for keystroke
mov ah, 01h
int 16h ; get keystroke
jz .wait ; none available, loop -->
mov ah, 00h
int 16h ; remove keystroke from buffer
int 19h ; reboot
jmp short $ ; (in case it returns, which it shouldn't)
cpu XCPU
%endif ; XCPU != 86
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
segment INIT_TEXT_END
;************************************************************
; KERNEL CODE AREA END
; the NUL device
;************************************************************
segment CONST
;
; NUL device strategy
;
global _nul_strtgy
Fix memory break in NUL device
2016-02-06 05:43:34 +01:00
extern GenStrategy
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
_nul_strtgy:
ia16-elf-gcc port: compile all asm files with -f elf. Because ia16-elf-gcc and the GNU linker do not understand OMF we need to use ELF everywhere. This also means we cannot use "wrt", "seg" and "call/jmp far". Most wrt's are superfluous, and seg and call/jmp far can be replaced by explicit ?GROUP references (to be defined in the linker script).
2017-12-19 14:22:58 +01:00
jmp LGROUP:GenStrategy
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
;
; NUL device interrupt
;
global _nul_intr
_nul_intr:
push es
push bx
Fix memory break in NUL device
2016-02-06 05:43:34 +01:00
mov bx,LGROUP
mov es,bx
les bx,[es:_ReqPktPtr] ;es:bx--> rqheadr
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
cmp byte [es:bx+2],4 ;if read, set 0 read
jne no_nul_read
mov word [es:bx+12h],0
no_nul_read:
or word [es:bx+3],100h ;set "done" flag
pop bx
pop es
retf
segment _LOWTEXT
; low interrupt vectors 10h,13h,15h,19h,1Bh
; these need to be at 0070:0100 (see RBIL memory.lst)
global _intvec_table
_intvec_table: db 10h
dd 0
initial windows 3 enhanced support based on unstable kernel branch
2021-08-19 17:46:10 +02:00
; used by int13 handler and get/set via int 2f/13h
global _BIOSInt13 ; BIOS provided disk handler
global _UserInt13 ; actual disk handler used by kernel
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
db 13h
initial windows 3 enhanced support based on unstable kernel branch
2021-08-19 17:46:10 +02:00
_BIOSInt13: dd 0
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
db 15h
dd 0
initial windows 3 enhanced support based on unstable kernel branch
2021-08-19 17:46:10 +02:00
; used for cleanup on reboot
global _BIOSInt19
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
db 19h
initial windows 3 enhanced support based on unstable kernel branch
2021-08-19 17:46:10 +02:00
_BIOSInt19: dd 0
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
db 1Bh
dd 0
initial windows 3 enhanced support based on unstable kernel branch
2021-08-19 17:46:10 +02:00
; default to using BIOS provided disk handler
db 13h
_UserInt13: dd 0
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
; floppy parameter table
global _int1e_table
_int1e_table: times 0eh db 0
;************************************************************
; KERNEL FIXED DATA AREA
;************************************************************
segment _FIXED_DATA
; Because of the following bytes of data, THIS MODULE MUST BE THE FIRST
; IN THE LINK SEQUENCE. THE BYTE AT DS:0004 determines the SDA format in
; use. A 0 indicates MS-DOS 3.X style, a 1 indicates MS-DOS 4.0-6.X style.
global DATASTART
DATASTART:
global _DATASTART
_DATASTART:
dos_data db 0
dw kernel_start
db 0 ; padding
dw 1 ; Hardcoded MS-DOS 4.0+ style
times (0eh - ($ - DATASTART)) db 0
global _NetBios
_NetBios dw 0 ; NetBios Number
times (26h - 0ch - ($ - DATASTART)) db 0
; Globally referenced variables - WARNING: DO NOT CHANGE ORDER
; BECAUSE THEY ARE DOCUMENTED AS UNDOCUMENTED (?) AND HAVE
; MANY MULTIPLEX PROGRAMS AND TSRs ACCESSING THEM
global _NetRetry
_NetRetry dw 3 ;-000c network retry count
global _NetDelay
_NetDelay dw 1 ;-000a network delay count
global _DskBuffer
_DskBuffer dd -1 ;-0008 current dos disk buffer
global _inputptr
_inputptr dw 0 ;-0004 Unread con input
global _first_mcb
_first_mcb dw 0 ;-0002 Start of user memory
global _DPBp
global MARK0026H
; A reference seems to indicate that this should start at offset 26h.
MARK0026H equ $
_DPBp dd 0 ; 0000 First drive Parameter Block
global _sfthead
_sfthead dd 0 ; 0004 System File Table head
global _clock
_clock dd 0 ; 0008 CLOCK$ device
global _syscon
ia16-elf-gcc port: compile all asm files with -f elf. Because ia16-elf-gcc and the GNU linker do not understand OMF we need to use ELF everywhere. This also means we cannot use "wrt", "seg" and "call/jmp far". Most wrt's are superfluous, and seg and call/jmp far can be replaced by explicit ?GROUP references (to be defined in the linker script).
2017-12-19 14:22:58 +01:00
_syscon dw _con_dev,LGROUP ; 000c console device
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
global _maxsecsize
_maxsecsize dw 512 ; 0010 maximum bytes/sector of any block device
dd 0 ; 0012 pointer to buffers info structure
global _CDSp
_CDSp dd 0 ; 0016 Current Directory Structure
global _FCBp
_FCBp dd 0 ; 001a FCB table pointer
global _nprotfcb
_nprotfcb dw 0 ; 001e number of protected fcbs
global _nblkdev
_nblkdev db 0 ; 0020 number of block devices
global _lastdrive
_lastdrive db 0 ; 0021 value of last drive
global _nul_dev
_nul_dev: ; 0022 device chain root
ia16-elf-gcc port: compile all asm files with -f elf. Because ia16-elf-gcc and the GNU linker do not understand OMF we need to use ELF everywhere. This also means we cannot use "wrt", "seg" and "call/jmp far". Most wrt's are superfluous, and seg and call/jmp far can be replaced by explicit ?GROUP references (to be defined in the linker script).
2017-12-19 14:22:58 +01:00
extern _con_dev
dw _con_dev, LGROUP
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
; next is con_dev at init time.
dw 8004h ; attributes = char device, NUL bit set
dw _nul_strtgy
dw _nul_intr
db 'NUL '
global _njoined
_njoined db 0 ; 0034 number of joined devices
dw 0 ; 0035 DOS 4 pointer to special names (always zero in DOS 5)
Implement version table support for int21/ah=4b, subfunctions 0 and 1
2021-03-10 22:18:07 +01:00
global _setverPtr
_setverPtr dw 0,0 ; 0037 setver list
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
dw 0 ; 003B cs offset for fix a20
dw 0 ; 003D psp of last umb exec
global _LoL_nbuffers
_LoL_nbuffers dw 1 ; 003F number of buffers
dw 1 ; 0041 size of pre-read buffer
global _BootDrive
_BootDrive db 1 ; 0043 drive we booted from
global _CPULevel
_CPULevel db 0 ; 0044 cpu type (MSDOS >0 indicates dword moves ok, ie 386+)
; unless compatibility issues arise FD uses
; 0=808x, 1=18x, 2=286, 3=386+
; see cpu.asm, use >= as may add checks for 486 ...
dw 0 ; 0045 Extended memory in KBytes
buf_info:
global _firstbuf
_firstbuf dd 0 ; 0047 disk buffer chain
dw 0 ; 004B Number of dirty buffers
dd 0 ; 004D pre-read buffer
dw 0 ; 0051 number of look-ahead buffers
global _bufloc
_bufloc db 0 ; 0053 00=conv 01=HMA
global _deblock_buf
_deblock_buf dd 0 ; 0054 deblock buffer
times 3 db 0 ; 0058 unknown
dw 0 ; 005B unknown
db 0, 0FFh, 0 ; 005D unknown
global _VgaSet
_VgaSet db 0 ; 0060 unknown
dw 0 ; 0061 unknown
global _uppermem_link
_uppermem_link db 0 ; 0063 upper memory link flag
_min_pars dw 0 ; 0064 minimum paragraphs of memory
; required by program being EXECed
global _uppermem_root
_uppermem_root dw 0ffffh ; 0066 dmd_upper_root (usually 9fff)
_last_para dw 0 ; 0068 para of last mem search
SysVarEnd:
;; FreeDOS specific entries
;; all variables below this point are subject to relocation.
;; programs should not rely on any values below this point!!!
global _os_setver_minor
_os_setver_minor db 0
global _os_setver_major
_os_setver_major db 5
global _os_minor
_os_minor db 0
global _os_major
_os_major db 5
_rev_number db 0
global _version_flags
_version_flags db 0
global os_release
extern _os_release
os_release dw _os_release
%IFDEF WIN31SUPPORT
global _winStartupInfo, _winInstanced
_winInstanced dw 0 ; set to 1 on WinInit broadcast, 0 on WinExit broadcast
_winStartupInfo:
dw 0 ; structure version (same as windows version)
dd 0 ; next startup info structure, 0:0h marks end
dd 0 ; far pointer to name virtual device file or 0:0h
dd 0 ; far pointer, reference data for virtual device driver
dw instance_table,seg instance_table ; array of instance data
instance_table: ; should include stacks, Win may auto determine SDA region
; we simply include whole DOS data segment
initial windows 3 enhanced support based on unstable kernel branch
2021-08-19 17:46:10 +02:00
dw seg _DATASTART, 0 ; [SEG:OFF] address of region's base
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
dw markEndInstanceData wrt seg _DATASTART ; size in bytes
dd 0 ; 0 marks end of table
dw 0 ; and 0 length for end of instance_table entry
global _winPatchTable
_winPatchTable: ; returns offsets to various internal variables
dw 0x0006 ; DOS version, major# in low byte, eg. 6.00
dw save_DS ; where DS stored during int21h dispatch
dw save_BX ; where BX stored during int21h dispatch
dw _InDOS ; offset of InDOS flag
dw _MachineId ; offset to variable containing MachineID
since both refer to critical sections to patch and we have none, i.e. both empty lists, use same location for unused hard coded critical patch list and critical patch list passed to Win3
2021-07-23 05:12:56 +02:00
dw _CritPatch ; offset of to array of offsets to patch
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
; NOTE: this points to a null terminated
; array of offsets of critical section bytes
since both refer to critical sections to patch and we have none, i.e. both empty lists, use same location for unused hard coded critical patch list and critical patch list passed to Win3
2021-07-23 05:12:56 +02:00
; to patch, for now we can just point this
; to an empty table
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
; ie we just point to a 0 word to mark end
dw _uppermem_root ; seg of last arena header in conv memory
; this matches MS DOS's location, but
; do we have the same meaning?
%ENDIF ; WIN31SUPPORT
;; The first 5 sft entries appear to have to be at DS:00cc
times (0cch - ($ - DATASTART)) db 0
global _firstsftt
_firstsftt:
dd -1 ; link to next
dw 5 ; count
initial windows 3 enhanced support based on unstable kernel branch
2021-08-19 17:46:10 +02:00
times 5*59 db 0 ; reserve space for the 5 sft entries
db 0 ; pad byte so next value on even boundary
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
; Some references seem to indicate that this data should start at 01fbh in
; order to maintain 100% MS-DOS compatibility.
times (01fbh - ($ - DATASTART)) db 0
global MARK01FBH
MARK01FBH equ $
global _local_buffer ; local_buffer is 256 bytes long
; so it overflows into kb_buf!!
; only when kb_buf is used, local_buffer is limited to 128 bytes.
_local_buffer: times 128 db 0
global _kb_buf
_kb_buf db 128,0 ; initialise buffer to empty
times 128+1 db 0 ; room for 128 byte readline + LF
;
; Variables that follow are documented as part of the DOS 4.0-6.X swappable
; data area in Ralf Browns Interrupt List #56
;
; this byte is used for ^P support
global _PrinterEcho
_PrinterEcho db 0 ;-34 - 0 = no printer echo, ~0 echo
global _verify_ena
_verify_ena db 0 ; ~0, write with verify
; this byte is used for TABs (shared by all char device writes??)
global _scr_pos
_scr_pos db 0 ; Current Cursor Column
global _switchar
_switchar db '/' ;-31 - switch char
global _mem_access_mode
_mem_access_mode db 0 ;-30 - memory allocation strategy
global sharing_flag
sharing_flag db 0 ; 00 = sharing module not loaded
; 01 = sharing module loaded, but
; open/close for block devices
; disabled
; FF = sharing module loaded,
; open/close for block devices
; enabled (not implemented)
global _net_set_count
_net_set_count db 1 ;-28 - count the name below was set
global _net_name
_net_name db ' ' ;-27 - 15 Character Network Name
db 00 ; Terminating 0 byte
;
; Variables contained the the "STATE_DATA" segment contain
; information about the STATE of the current DOS Process. These
; variables must be preserved regardless of the state of the INDOS
; flag.
;
; All variables that appear in "STATE_DATA" **MUST** be declared
; in this file as the offsets from the INTERNAL_DATA variable are
; critical to the DOS applications that modify this data area.
;
;
global _ErrorMode, _InDOS
global _CritErrLocus, _CritErrCode
global _CritErrAction, _CritErrClass
global _CritErrDev, _CritErrDrive
global _dta
global _cu_psp, _default_drive
global _break_ena
global _return_code
global _internal_data
ensure offset to critical patch tables doesn't change - from https://github.com/dosemu2/fdpp/commit/a921e21edc4d264f208ef9f27a5a4e6c6a5b98e9 (add 0x315 mark)
2021-07-31 05:10:15 +02:00
; ensure offset of critical patch table remains fixed, some programs hard code offset
times (0315h - ($ - DATASTART)) db 0
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
global _CritPatch
from dosemu2/fdpp - zero out critical patch list Personal NetWare Server really writes to these addresses, so putting 0x0d0c the way DOS does, is not safe. See dosemu2/dosemu2#428 see https://github.com/dosemu2/fdpp/commit/94bd3eb4b53d3ccd533a5927f1915bef03d67579
2021-07-23 05:02:18 +02:00
_CritPatch dw 0 ;-11 zero list of patched critical
dw 0 ; section variables
dw 0 ; DOS puts 0d0ch here but some
dw 0 ; progs really write to that addr.
dw 0 ;-03 - critical patch list terminator
adjust padding to be same as in PC-DOS (90h/nop) see https://github.com/dosemu2/fdpp/commit/1dc244b09b010bbbc120fec7882c4a6005c719d5
2021-07-23 05:32:22 +02:00
db 90h ;-01 - unused, NOP pad byte
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
_internal_data: ; <-- Address returned by INT21/5D06
_ErrorMode db 0 ; 00 - Critical Error Flag
_InDOS db 0 ; 01 - Indos Flag
_CritErrDrive db 0 ; 02 - Drive on write protect error
_CritErrLocus db 0 ; 03 - Error Locus
_CritErrCode dw 0 ; 04 - DOS format error Code
_CritErrAction db 0 ; 06 - Error Action Code
_CritErrClass db 0 ; 07 - Error Class
_CritErrDev dd 0 ; 08 - Failing Device Address
_dta dd 0 ; 0C - current DTA
_cu_psp dw 0 ; 10 - Current PSP
break_sp dw 0 ; 12 - used in int 23
_return_code dw 0 ; 14 - return code from process
_default_drive db 0 ; 16 - Current Drive
_break_ena db 1 ; 17 - Break Flag (default TRUE)
db 0 ; 18 - flag, code page switching
db 0 ; 19 - flag, copy of 18 on int 24h abort
global _swap_always, _swap_indos
_swap_always:
global _Int21AX
_Int21AX dw 0 ; 1A - AX from last Int 21
global owning_psp, _MachineId
owning_psp dw 0 ; 1C - owning psp
_MachineId dw 0 ; 1E - remote machine ID
dw 0 ; 20 - First usable mcb
dw 0 ; 22 - Best usable mcb
dw 0 ; 24 - Last usable mcb
dw 0 ; 26 - memory size in paragraphs
dw 0 ; 28 - unknown
db 0 ; 2A - unknown
db 0 ; 2B - unknown
db 0 ; 2C - unknown
global _break_flg
_break_flg db 0 ; 2D - Program aborted by ^C
db 0 ; 2E - unknown
db 0 ; 2F - not referenced
global _DayOfMonth
_DayOfMonth db 1 ; 30 - day of month
global _Month
_Month db 1 ; 31 - month
global _YearsSince1980
_YearsSince1980 dw 0 ; 32 - year since 1980
daysSince1980 dw 0FFFFh ; 34 - number of days since epoch
; force rebuild on first clock read
global _DayOfWeek
_DayOfWeek db 2 ; 36 - day of week
_console_swap db 0 ; 37 console swapped during read from dev
global _dosidle_flag
_dosidle_flag db 1 ; 38 - safe to call int28 if nonzero
_abort_progress db 0 ; 39 - abort in progress
global _CharReqHdr
_CharReqHdr:
global _ClkReqHdr
_ClkReqHdr times 30 db 0 ; 3A - Device driver request header
dd 0 ; 58 - pointer to driver entry
global _MediaReqHdr
_MediaReqHdr times 22 db 0 ; 5C - Device driver request header
global _IoReqHdr
_IoReqHdr times 30 db 0 ; 72 - Device driver request header
times 6 db 0 ; 90 - unknown
global _ClkRecord
_ClkRecord times 6 db 0 ; 96 - CLOCK$ transfer record
dw 0 ; 9C - unknown
global __PriPathBuffer
__PriPathBuffer times 80h db 0 ; 9E - buffer for file name
global __SecPathBuffer
__SecPathBuffer times 80h db 0 ;11E - buffer for file name
global _sda_tmp_dm
_sda_tmp_dm times 21 db 0 ;19E - 21 byte srch state
global _SearchDir
_SearchDir times 32 db 0 ;1B3 - 32 byte dir entry
global _TempCDS
_TempCDS times 88 db 0 ;1D3 - TemporaryCDS buffer
global _DirEntBuffer
_DirEntBuffer times 32 db 0 ;22B - space enough for 1 dir entry
global _wAttr
_wAttr dw 0 ;24B - extended FCB file attribute
global _SAttr
_SAttr db 0 ;24D - Attribute Mask for Dir Search
global _OpenMode
_OpenMode db 0 ;24E - File Open Attribute
times 3 db 0
global _Server_Call
_Server_Call db 0 ;252 - Server call Func 5D sub 0
db 0
; Pad to 05CCh
times (25ch - ($ - _internal_data)) db 0
global _tsr ; used by break and critical error
_tsr db 0 ;25C - handlers during termination
db 0 ;25D - padding
global term_psp
term_psp dw 0 ;25E - 0??
global int24_esbp
int24_esbp times 2 dw 0 ;260 - pointer to criticalerr DPB
global _user_r, int21regs_off, int21regs_seg
_user_r:
int21regs_off dw 0 ;264 - pointer to int21h stack frame
int21regs_seg dw 0
global critical_sp
critical_sp dw 0 ;268 - critical error internal stack
global current_ddsc
current_ddsc times 2 dw 0
; Pad to 059ah
times (27ah - ($ - _internal_data)) db 0
global current_device
current_device times 2 dw 0 ;27A - 0??
global _lpCurSft
_lpCurSft times 2 dw 0 ;27e - Current SFT
global _current_ldt
_current_ldt times 2 dw 0 ;282 - Current CDS
global _sda_lpFcb
_sda_lpFcb times 2 dw 0 ;286 - pointer to callers FCB
global _current_sft_idx
_current_sft_idx dw 0 ;28A - SFT index for next open
; used by MS NET
; Pad to 05b2h
times (292h - ($ - _internal_data)) db 0
dw __PriPathBuffer ; 292 - "sda_WFP_START" offset in DOS DS of first filename argument
dw __SecPathBuffer ; 294 - "sda_REN_WFP" offset in DOS DS of second filename argument
; Pad to 05ceh
times (2aeh - ($ - _internal_data)) db 0
global _current_filepos
_current_filepos times 2 dw 0 ;2AE - current offset in file
; Pad to 05eah
times (2cah - ($ - _internal_data)) db 0
;global _save_BX
;global _save_DS
save_BX dw 0 ;2CA - unused by FreeDOS, for Win3.x
save_DS dw 0 ; compatibility, match MS's positions
dw 0
global _prev_user_r
global prev_int21regs_off
global prev_int21regs_seg
_prev_user_r:
prev_int21regs_off dw 0 ;2D0 - pointer to prev int 21 frame
prev_int21regs_seg dw 0
; Pad to 05fdh
times (2ddh - ($ - _internal_data)) db 0
global _ext_open_action
global _ext_open_attrib
global _ext_open_mode
_ext_open_action dw 0 ;2DD - extended open action
_ext_open_attrib dw 0 ;2DF - extended open attrib
_ext_open_mode dw 0 ;2E1 - extended open mode
; Pad to 0620h
times (300h - ($ - _internal_data)) db 0
global apistk_bottom
apistk_bottom:
; use bottom of error stack as scratch buffer
; - only used during int 21 call
global _sda_tmp_dm_ren
_sda_tmp_dm_ren:times 21 db 0x90 ;300 - 21 byte srch state for rename
global _SearchDir_ren
_SearchDir_ren: times 32 db 0x90 ;315 - 32 byte dir entry for rename
; stacks are made to initialize to no-ops so that high-water
; testing can be performed
times STACK_SIZE*2-($-apistk_bottom) db 0x90
;300 - Error Processing Stack
global _error_tos
_error_tos:
times STACK_SIZE dw 0x9090 ;480 - Disk Function Stack
global _disk_api_tos
_disk_api_tos:
times STACK_SIZE dw 0x9090 ;600 - Char Function Stack
global _char_api_tos
_char_api_tos:
apistk_top:
db 0 ; 780 ???
_VolChange db 0 ;781 - volume change
_VirtOpen db 0 ;782 - virtual open flag
; controlled variables end at offset 78Ch so pad to end
times (78ch - ($ - _internal_data)) db 0
;
; end of controlled variables
;
segment _BSS
;!! global _NumFloppies
;!!_NumFloppies resw 1
;!!intr_dos_stk resw 1
;!!intr_dos_seg resw 1
; mark front and end of bss area to clear
segment IB_B
global __ib_start
__ib_start:
segment IB_E
global __ib_end
__ib_end:
;; do not clear the other init BSS variables + STACK: too late.
; kernel startup stack
global init_tos
resw 512
init_tos:
; the last paragraph of conventional memory might become an MCB
resb 16
global __init_end
__init_end:
init_end:
segment _DATA
; blockdev private stack
global blk_stk_top
times 256 dw 0
blk_stk_top:
; clockdev private stack
global clk_stk_top
times 128 dw 0
clk_stk_top:
int2f: fix call interface around int2F_12_handler( ) This changes the interface between reloc_call_int2f_handler (int2f.asm) and int2F_12_handler( ) (inthndlr.c) so that - int2F_12_handler( ) will not try to output values to its caller by passing "back" input parameter values - reloc_call_int2f_handler will switch to an internal stack before calling int2F_12_handler( ), so that SS == DGROUP as expected by the latter. This partly addresses https://github.com/FDOS/kernel/issues/11 . (The call to syscall_MUX14( ) in int2f.asm seems to have similar issues, and should probably also be updated.)
2019-12-06 15:30:27 +01:00
; int2fh private stack
global int2f_stk_top
times 128 dw 0
int2f_stk_top:
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
; Dynamic data:
; member of the DOS DATA GROUP
; and marks definitive end of all used data in kernel data segment
;
segment _DATAEND
_swap_indos:
; we don't know precisely what needs to be swapped before this, so set it here.
; this is just after FIXED_DATA+BSS+DATA and before (D)CONST+BSS
; probably, the clock and block stacks and disktransferbuffer should go past
; _swap_indos but only if int2a ah=80/81 (critical section start/end)
; are called upon entry and exit of the device drivers
times 96 dw 0x9090 ; Process 0 Stack
global _p_0_tos
_p_0_tos:
segment DYN_DATA
global _Dyn
_Dyn:
DynAllocated dw 0
markEndInstanceData: ; mark end of DOS data seg we say needs instancing
segment ID_B
global __INIT_DATA_START
__INIT_DATA_START:
segment ID_E
global __INIT_DATA_END
__INIT_DATA_END:
segment INIT_TEXT_START
global __InitTextStart
__InitTextStart: ; and c version
segment INIT_TEXT_END
global __InitTextEnd
__InitTextEnd: ; and c version
;
; start end end of HMA area
segment HMA_TEXT_START
global __HMATextAvailable
__HMATextAvailable:
global __HMATextStart
__HMATextStart:
;
; the HMA area is filled with 1eh+3(=sizeof VDISK) = 33 byte dummy data,
; so nothing will ever be below 0xffff:0031
;
segment HMA_TEXT
begin_hma:
times 10h db 0 ; filler [ffff:0..ffff:10]
times 20h db 0
db 0
; to minimize relocations
global _DGROUP_
_DGROUP_ dw DGROUP
%ifdef WATCOM
; 32 bit multiplication + division
global __U4M
__U4M:
LMULU
global __U4D
__U4D:
LDIVMODU
%endif
ia16-elf-gcc: provide GNU LD linker script and symbols to link kernel. The resulting kernel and sys.com do not work yet (kernel prints 123 only). Some functions in sys.com are placeholders.
2017-12-19 16:40:39 +01:00
%ifdef gcc
Create init varieties for unsigned long helper functions. An INITPATCH is used to make sure the correct symbols are used. The GCC kernel now shows the copyright string and boots a little further.
2017-12-19 19:46:49 +01:00
%macro ULONG_HELPERS 1
global %1udivsi3
%1udivsi3: call %1ldivmodu
ia16-elf-gcc: provide GNU LD linker script and symbols to link kernel. The resulting kernel and sys.com do not work yet (kernel prints 123 only). Some functions in sys.com are placeholders.
2017-12-19 16:40:39 +01:00
ret 8
Create init varieties for unsigned long helper functions. An INITPATCH is used to make sure the correct symbols are used. The GCC kernel now shows the copyright string and boots a little further.
2017-12-19 19:46:49 +01:00
global %1umodsi3
%1umodsi3: call %1ldivmodu
ia16-elf-gcc: provide GNU LD linker script and symbols to link kernel. The resulting kernel and sys.com do not work yet (kernel prints 123 only). Some functions in sys.com are placeholders.
2017-12-19 16:40:39 +01:00
mov dx, cx
mov ax, bx
ret 8
Create init varieties for unsigned long helper functions. An INITPATCH is used to make sure the correct symbols are used. The GCC kernel now shows the copyright string and boots a little further.
2017-12-19 19:46:49 +01:00
%1ldivmodu: LDIVMODU
ia16-elf-gcc: provide GNU LD linker script and symbols to link kernel. The resulting kernel and sys.com do not work yet (kernel prints 123 only). Some functions in sys.com are placeholders.
2017-12-19 16:40:39 +01:00
Create init varieties for unsigned long helper functions. An INITPATCH is used to make sure the correct symbols are used. The GCC kernel now shows the copyright string and boots a little further.
2017-12-19 19:46:49 +01:00
global %1ashlsi3
%1ashlsi3: LSHLU
ia16-elf-gcc: provide GNU LD linker script and symbols to link kernel. The resulting kernel and sys.com do not work yet (kernel prints 123 only). Some functions in sys.com are placeholders.
2017-12-19 16:40:39 +01:00
Create init varieties for unsigned long helper functions. An INITPATCH is used to make sure the correct symbols are used. The GCC kernel now shows the copyright string and boots a little further.
2017-12-19 19:46:49 +01:00
global %1lshrsi3
%1lshrsi3: LSHRU
%endmacro
ULONG_HELPERS ___
ia16-elf-gcc: provide GNU LD linker script and symbols to link kernel. The resulting kernel and sys.com do not work yet (kernel prints 123 only). Some functions in sys.com are placeholders.
2017-12-19 16:40:39 +01:00
%endif
ia16-elf-gcc port: compile all asm files with -f elf. Because ia16-elf-gcc and the GNU linker do not understand OMF we need to use ELF everywhere. This also means we cannot use "wrt", "seg" and "call/jmp far". Most wrt's are superfluous, and seg and call/jmp far can be replaced by explicit ?GROUP references (to be defined in the linker script).
2017-12-19 14:22:58 +01:00
times 0xd0 - ($-begin_hma) db 0
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
; reserve space for far jump to cp/m routine
ia16-elf-gcc port: compile all asm files with -f elf. Because ia16-elf-gcc and the GNU linker do not understand OMF we need to use ELF everywhere. This also means we cannot use "wrt", "seg" and "call/jmp far". Most wrt's are superfluous, and seg and call/jmp far can be replaced by explicit ?GROUP references (to be defined in the linker script).
2017-12-19 14:22:58 +01:00
times 5 db 0
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
;End of HMA segment
segment HMA_TEXT_END
global __HMATextEnd
__HMATextEnd: ; and c version
; The default stack (_TEXT:0) will overwrite the data area, so I create a dummy
; stack here to ease debugging. -- ror4
ia16-elf-gcc port: compile all asm files with -f elf. Because ia16-elf-gcc and the GNU linker do not understand OMF we need to use ELF everywhere. This also means we cannot use "wrt", "seg" and "call/jmp far". Most wrt's are superfluous, and seg and call/jmp far can be replaced by explicit ?GROUP references (to be defined in the linker script).
2017-12-19 14:22:58 +01:00
segment _STACK class(STACK) nobits stack
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
segment CONST
; dummy interrupt return handlers
global _int22_handler
global _int28_handler
global _int2a_handler
global _empty_handler
_int22_handler:
_int28_handler:
_int2a_handler:
_empty_handler:
iret
global _initforceEnableA20
initforceEnableA20:
call near forceEnableA20
retf
global __HMARelocationTableStart
__HMARelocationTableStart:
global _int2f_handler
extern reloc_call_int2f_handler
_int2f_handler: jmp 0:reloc_call_int2f_handler
call near forceEnableA20
global _int20_handler
extern reloc_call_int20_handler
_int20_handler: jmp 0:reloc_call_int20_handler
call near forceEnableA20
global _int21_handler
extern reloc_call_int21_handler
_int21_handler: jmp 0:reloc_call_int21_handler
call near forceEnableA20
global _low_int25_handler
extern reloc_call_low_int25_handler
_low_int25_handler: jmp 0:reloc_call_low_int25_handler
call near forceEnableA20
global _low_int26_handler
extern reloc_call_low_int26_handler
_low_int26_handler: jmp 0:reloc_call_low_int26_handler
call near forceEnableA20
global _int27_handler
extern reloc_call_int27_handler
_int27_handler: jmp 0:reloc_call_int27_handler
call near forceEnableA20
global _int0_handler
extern reloc_call_int0_handler
_int0_handler: jmp 0:reloc_call_int0_handler
call near forceEnableA20
global _int6_handler
extern reloc_call_int6_handler
_int6_handler: jmp 0:reloc_call_int6_handler
call near forceEnableA20
global _int19_handler
extern reloc_call_int19_handler
_int19_handler: jmp 0:reloc_call_int19_handler
call near forceEnableA20
global _cpm_entry
extern reloc_call_cpm_entry
_cpm_entry: jmp 0:reloc_call_cpm_entry
call near forceEnableA20
global _reloc_call_blk_driver
extern _blk_driver
_reloc_call_blk_driver:
jmp 0:_blk_driver
call near forceEnableA20
global _reloc_call_clk_driver
extern _clk_driver
_reloc_call_clk_driver:
jmp 0:_clk_driver
call near forceEnableA20
global _CharMapSrvc ; in _DATA (see AARD)
extern _reloc_call_CharMapSrvc
_CharMapSrvc: jmp 0:_reloc_call_CharMapSrvc
call near forceEnableA20
global _init_call_p_0
extern reloc_call_p_0
_init_call_p_0: jmp 0:reloc_call_p_0
call near forceEnableA20
global __HMARelocationTableEnd
__HMARelocationTableEnd:
;
; if we were lucky, we found all entries from the outside to the kernel.
; if not, BUMS
;
;
; this routine makes the HMA area available. PERIOD.
; must conserve ALL registers
; will be only ever called, if HMA (DOS=HIGH) is enabled.
; for obvious reasons it should be located at the relocation table
;
global _XMSDriverAddress
_XMSDriverAddress:
dw 0 ; XMS driver, if detected
dw 0
global _ENABLEA20
_ENABLEA20:
mov ah,5
UsingXMSdriver:
push bx
call far [cs:_XMSDriverAddress]
pop bx
retf
global _DISABLEA20
_DISABLEA20:
mov ah,6
jmp short UsingXMSdriver
dslowmem dw 0
eshighmem dw 0ffffh
global forceEnableA20
forceEnableA20:
push ds
push es
push ax
forceEnableA20retry:
mov ds, [cs:dslowmem]
mov es, [cs:eshighmem]
mov ax, [ds:00000h]
cmp ax, [es:00010h]
jne forceEnableA20success
mov ax, [ds:00002h]
cmp ax, [es:00012h]
jne forceEnableA20success
mov ax, [ds:00004h]
cmp ax, [es:00014h]
jne forceEnableA20success
mov ax, [ds:00006h]
cmp ax, [es:00016h]
jne forceEnableA20success
;
; ok, we have to enable A20 )at least seems so
;
ia16-elf-gcc port: compile all asm files with -f elf. Because ia16-elf-gcc and the GNU linker do not understand OMF we need to use ELF everywhere. This also means we cannot use "wrt", "seg" and "call/jmp far". Most wrt's are superfluous, and seg and call/jmp far can be replaced by explicit ?GROUP references (to be defined in the linker script).
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call DGROUP:_ENABLEA20
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
jmp short forceEnableA20retry
forceEnableA20success:
pop ax
pop es
pop ds
ret
;
; global f*cking compatibility issues:
;
; very old brain dead software (PKLITE, copyright 1990)
; forces us to execute with A20 disabled
;
global _ExecUserDisableA20
_ExecUserDisableA20:
cmp word [cs:_XMSDriverAddress], byte 0
jne NeedToDisable
cmp word [cs:_XMSDriverAddress+2], byte 0
je noNeedToDisable
NeedToDisable:
push ax
ia16-elf-gcc port: compile all asm files with -f elf. Because ia16-elf-gcc and the GNU linker do not understand OMF we need to use ELF everywhere. This also means we cannot use "wrt", "seg" and "call/jmp far". Most wrt's are superfluous, and seg and call/jmp far can be replaced by explicit ?GROUP references (to be defined in the linker script).
2017-12-19 14:22:58 +01:00
call DGROUP:_DISABLEA20
FreeDOS kernel current - 2041+svn1709
2012-10-15 02:08:06 +02:00
pop ax
noNeedToDisable:
iret
;
; Default Int 24h handler -- always returns fail
; so we have not to relocate it (now)
;
FAIL equ 03h
global _int24_handler
_int24_handler: mov al,FAIL
iret
;
; this makes some things easier
;
segment _LOWTEXT
global _TEXT_DGROUP
_TEXT_DGROUP dw DGROUP
segment INIT_TEXT
global _INIT_DGROUP
_INIT_DGROUP dw DGROUP
Create init varieties for unsigned long helper functions. An INITPATCH is used to make sure the correct symbols are used. The GCC kernel now shows the copyright string and boots a little further.
2017-12-19 19:46:49 +01:00
%ifdef gcc
ULONG_HELPERS _init_
%endif
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