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TSKDOS.ASM
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Assembly Source File
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1993-06-08
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42KB
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1,924 lines
;
; --- Version 2.2 93-06-08 10:18 ---
;
; CTask - DOS access module.
;
; Public Domain Software written by
; Thomas Wagner
; Ferrari electronic Gmbh
; Beusselstrasse 27
; D-1000 Berlin 21
; Germany
;
; NOTE: Some routines have been moved to "tsksec.asm" in Version 2.1
; to support a minimal secondary kernel.
;
; The support for the critical section interrupt was dropped in
; version 2.1. Swapping the DOS variable area eliminates
; the need for maintaining critical sections across calls.
;
; The DOS interrupt (and the related direct disk I/O interrupts) are
; not reentrant. Access to DOS thus has to be channelled such that no
; two tasks use DOS services simultaneously. However, there is one
; exception to this rule. Whenever DOS is waiting for the keyboard, it
; issues a special interrupt, INT 28h, to signal that background
; processing for functions > 0Ch may be performed. This is used in the
; DOS interface for CTask in the following manner:
;
; A task issuing a DOS interrupt will request one of two resources:
; "lower_dos" for functions <= 0C, "upper_dos" for functions > 0C.
; If a task gets access to "lower_dos", it will also request the
; "upper_dos" resource to lock out other tasks from interrupting.
; This "upper_dos" resource is shortly released on each INT 28, and
; then immediately reclaimed, with task priority temporarily raised
; to the maximum value. The first task waiting to execute a
; function > 0C will thus be scheduled to execute the request, but
; the resource will be reassigned to the INT 28 handler as soon as
; this request terminates, so the waiting task will not be delayed too
; long.
;
; There are two additional safety measures which have to be taken to
; avoid getting into conflicts with other resident background programs,
; especially the DOS PRINT background spooler:
;
; Before actually executing the request, the status of the DOS in-use
; flag is checked. If this flag is set, the task enters a busy waiting
; loop, calling the scheduler so that the processor is not tied up.
;
; NOTE: The method for checking the status of DOS is described in-depth
; in the book "The MS-DOS Encyclopedia" from Microsoft Press, in
; the chapter on TSR programming. The logic in this module was
; developed without the help of this book, so if you compare
; the code here with the routines in the Encyclopedia, you may
; notice that not all re-entry conditions are checked here.
; According to my experience with debugging TSR's and CTask, the
; logic should be sufficient for all but the most obscure TSR's.
; If you want to be completely on the safe side, you might consider
; adding the more thorough checks listed in the Encyclopedia.
;
; CAUTION: This module is not ROMable, and it can only be
; installed in the primary kernel.
;
name tskdos
;
include tsk.mac
;
IF DOS
fatal_pmd = 1
;
.tsk_model
;
include tskdeb.h
;
Pubfunc tsk_install_dos
Pubfunc tsk_remove_dos
Pubfunc tsk_fatal
;
IF CHECKING
Pubfunc tsk_fatal_pmd
Globext tsk_set_currdis
Globext tsk_set_dualdis
Globext tsk_rputc
Globext tsk_rputs
Globext tsk_vrprintf
CGlbext tsk_rprintf
ENDIF
;
IF DEBUG AND DEB_DOSTRBUF
Pubfunc dump_dostrace
ENDIF
IF DEBUG AND (DEB_DOSTRACE OR DEB_DOSTRBUF)
CGlbext tsk_cprintf
CGlbext tsk_vcprintf
ENDIF
;
public tsk_emergency_exit
;
Globext create_resource
Globext delete_resource
Globext request_resource
Globext request_cresource
Globext release_resource
Globext create_flag
Globext delete_flag
Globext set_flag
Globext clear_flag
Globext wait_flag_clear
Globext schedule
Globext yield
Globext preempt_off
;
Locext tsk_switch_stack
Locext tsk_old_stack
Locext tsk_remove_group
Locext tsk_kill_group
Globext tsk_remove_tasker
;
extrn tsk_instflags: word
;
extrn tsk_glob_rec: byte
IF NOT SINGLE_DATA
extrn tsk_global: dword
ENDIF
;;
IF DEBUG AND DEB_DOSTRBUF
public i2fcount,i31count
ENDIF
;
; Special function range
;
MIN_SPFUNC = 2300h
MAX_SPFUNC = 2301h
;
;
get_in_use_flag = 34h ; DOS-function to get in_use_flag address
get_invars = 5d06h ; DOS-function to get DOS-variables area
;
psp_offset = 10h-2 ; Offset of current PSP in DOS save area
; ; (-2 because we add 2 to the start)
;
; Structure of the start of a PSP, including undocumented fields
;
psp_record struc
;
dw ? ; INT 20
dw ? ; alloc block end
db ? ; reserved
db 5 dup(?) ; system call
psp_exit_addr dd ? ; exit routine address
psp_ctlc_addr dd ? ; control C routine address
psp_cerr_addr dd ? ; critical error routine address
parent_psp dw ? ; PSP of parent process
db 20 dup(?) ; files table
psp_envseg dw ? ; environment segment
psp_ustack dd ? ; ss/sp of caller
dw ? ; file table length
dd ? ; file table pointer
dd ? ; pointer to nested PSP (?)
;
psp_record ends
;
;
intseg segment at 0
org 10h*4
vidoff dw ? ; video interrupt
vidseg dw ?
org 13h*4
diskoff dw ? ; disk i/o interrupt
diskseg dw ?
org 20h*4
termoff dw ? ; program terminate vector
termseg dw ?
org 21h*4
idosoff dw ? ; dos interrupt
idosseg dw ?
org 25h*4
absreadoff dw ? ; absolute disk read
absreadseg dw ?
org 26h*4
abswriteoff dw ? ; absolute disk write
abswriteseg dw ?
org 27h*4
keepoff dw ? ; Terminate but stay resident
keepseg dw ?
org 28h*4
idleoff dw ? ; dos idle interrupt
idleseg dw ?
org 2ah*4
csectoff dw ? ; dos critical section
csectseg dw ?
org 2fh*4
muxoff dw ? ; multiplex int
muxseg dw ?
org 31h*4
dpmioff dw ? ; DPMI services
dpmiseg dw ?
org 40h*4
fdiskoff dw ? ; redirected floppy disk I/O interrupt
fdiskseg dw ?
;
intseg ends
;
;----------------------------------------------------------------------------
;
; Variables
;
.tsk_data
;
idle_active db 0 ; Idle-Interrupt active
dos310 db 0 ; DOS version >= 3.10
;
IF TSK_NAMEPAR
udos_name db "DOSUPPER",0
ldos_name db "DOSLOWER",0
hdio_name db "HARDDISK",0
fdio_name db "FLEXDISK",0
vid_name db "VIDEO",0
ENDIF
;
;
in_error dd ? ; Adress of DOS error-mode-flag
;
lower_dos resource <>
upper_dos resource <>
hdisk_io resource <>
fdisk_io resource <>
video resource <>
;
vid_flags dw ?
i13h_flags dw ?
i13f_flags dw ?
;
IF DEBUG AND (DEB_DOSTRACE OR DEB_DOSTRBUF)
;
IF DEBUG AND DEB_DOSTRBUF
TR_ENTRIES = 32
ELSE
TR_ENTRIES = 1
ENDIF
;
tr_none db "No "
tr_head db "DOS Calls",0ah,0
tr_string db "AX=%04X BX=%04X DS=%04X PSP=%04X TCB=%FP Tb=%02HX Bs=%02HX Er=%02HX Id=%02HX Fl=%02HX",0ah,0
;AX=1234 BX=1234 DS=1234 PSP=1234 TCB=1234:1234 Tb=12 Bs=12 Er=12 Id=12 Fl=1234\n",0
;
trrec struc
tr_ax dw ? ; AX on entry
tr_bx dw ? ; BX on entry
tr_ds dw ? ; DS on entry
tr_psp dw ? ; current PSP
tr_tcb_o dw ? ; TCB pointer
tr_tcb_s dw ?
tr_tindos db ? ; Task in-DOS flag
tr_indos db ? ; DOS Busy flag
tr_inerr db ? ; Critical error flag
tr_idle db ?
tr_flags db ?
;
; 01: Doslower busy
; 02: Task owns doslower
; 04: Dosupper busy
; 08: Task owns dosupper
trrec ends
;
tr_ptr dw 0
tr_count dw 0
tr_buffer trrec TR_ENTRIES dup(<>)
;
ENDIF
;
.tsk_edata
.tsk_code
;;
IF DEBUG AND DEB_DOSTRBUF
i2fcount dw 0
i31count dw 0
ENDIF
;
;---------------------------------------------------------------------------
;
; Original Interrupt-Entries
;
savvid label dword ; original Video entry
savvidoff dw ?
savvidseg dw ?
;
savdisk label dword ; original Disk I/O entry
savdiskoff dw ?
savdiskseg dw ?
;
savfdisk label dword ; original Floppy Disk I/O entry
savfdiskoff dw ?
savfdiskseg dw ?
;
savterm label dword
savtermoff dw ? ; Terminate vector save
savtermseg dw ?
;
savdos label dword ; original DOS-Entry
savdosoff dw ?
savdosseg dw ?
;
savidle label dword ; original IDLE-Entry
savidleoff dw ?
savidleseg dw ?
;
savcsect label dword ; Critical Section save
savcsectoff dw ?
savcsectseg dw ?
;
savabsread label dword ; Absolute Disk Read save
savabsreadoff dw ?
savabsreadseg dw ?
;
savabswrite label dword ; Absolute Disk Write save
savabswriteoff dw ?
savabswriteseg dw ?
;
savkeep label dword
savkeepoff dw ? ; Terminate resident vector save
savkeepseg dw ?
;
IF (DEBUG AND DEB_DOSTRBUF)
savmux label dword ; Multiplex int save
savmuxoff dw ?
savmuxseg dw ?
ENDIF
;
IF DEBUG AND DEB_DOSTRBUF
savdpmi label dword ; DPMI int save
savdpmioff dw ?
savdpmiseg dw ?
ENDIF
;
dos_version dw ? ; DOS version
;
temp_1 dw ?
;
tsk_dgroup dw @CTASK_DATA
;
zero db 0
;
calldos macro
pushf
cli
call cs:savdos
endm
;
;---------------------------------------------------------------------------
;
; void tsk_install_dos (void)
;
; Install DOS handler
;
Localfunc tsk_install_dos,<uses si>
;
; create needed resources & flags
;
IFDEF LOAD_DS
push ds
mov ax,@CTASK_DATA
mov ds,ax
ENDIF
;
IF TSK_NAMEPAR
callp create_resource,<<ds,#upper_dos>,<ds,#udos_name>>
ELSE
callp create_resource,<<ds,#upper_dos>>
ENDIF
;
IF TSK_NAMEPAR
callp create_resource,<<ds,#lower_dos>,<ds,#ldos_name>>
ELSE
callp create_resource,<<ds,#lower_dos>>
ENDIF
;
test tsk_instflags,IFL_DISK
jz inst_nodsk1
IF TSK_NAMEPAR
callp create_resource,<<ds,#hdisk_io>,<ds,#hdio_name>>
ELSE
callp create_resource,<<ds,#hdisk_io>>
ENDIF
;
IF TSK_NAMEPAR
callp create_resource,<<ds,#fdisk_io>,<ds,#fdio_name>>
ELSE
callp create_resource,<<ds,#fdisk_io>>
ENDIF
;
inst_nodsk1:
test tsk_instflags,IFL_VIDEO
jz inst_novid1
IF TSK_NAMEPAR
callp create_resource,<<ds,#video>,<ds,#vid_name>>
ELSE
callp create_resource,<<ds,#video>>
ENDIF
;
inst_novid1:
;
mov tsk_glob_rec.l_swap,0 ; init swap area length to 0
;
; Get the DOS version. Only versions 3.1 and up support the
; DOS variable swap, so disable swapping if it's an earlier version,
; or if it's the OS/2 box.
;
mov ah,30h
int 21h
mov cs:dos_version,ax
cmp al,3
jb not_dos3
cmp al,0ah
je not_dos3 ; OS/2 compatibility box
cmp al,3
jne is_dos3 ; DOS 4.x
cmp ah,10
jb not_dos3
is_dos3:
inc dos310
;
; Get address and length of the DOS internal variable area.
; This call is not documented, and not available in versions
; prior to 3.1. It returns the address of the area in DS:SI,
; and the length of the area that must be swapped between calls
; from different groups in DX.
; Additionally, the total length of the area, including
; the DOS-stacks, minus the length in DX, is returned in CX.
;
; The DOS in_error flag is at the start of this area, the
; in_use flag is the second byte. Both bytes are excluded
; from the swap.
;
test tsk_instflags,IFL_NODOSVARS
jnz not_dos3
;
push ds
mov ax,get_invars
int 21h
mov ax,ds
pop ds
mov word ptr in_error,si
mov word ptr in_error+2,ax
inc si
mov word ptr tsk_glob_rec.dos_in_use,si
mov word ptr tsk_glob_rec.dos_in_use+2,ax
inc si
mov word ptr tsk_glob_rec.dos_vars,si
mov word ptr tsk_glob_rec.dos_vars+2,ax
sub dx,2
mov tsk_glob_rec.l_swap,dx
jmp short save_ints
;
; For versions < 3.10, and if the IFL_NODOSVARS flag is set,
; get the address of DOS's in_use-flag. This flag indicates that
; DOS is already active. This might happen if there are other
; background tasks, like popups or print spoolers, active in
; parallel to CTask.
; This is also the address of the critical error flag in DOS. Beginning
; with DOS 3.10 the flag is located one byte before the in_use_flag.
; With older DOS versions, we would have to search through DOS for the
; address. This is omitted here, but you could include the code
; for pre 3.1 versions from pages 378-379 of the MS-DOS Encyclopedia.
;
not_dos3:
mov ah,get_in_use_flag
int 21h
mov word ptr tsk_glob_rec.dos_in_use,bx
mov word ptr tsk_glob_rec.dos_in_use+2,es
mov word ptr in_error+2,es
dec bx
mov word ptr in_error,bx
cmp dos310,0
jne save_ints ; OK for DOS >= 3.10
;
; For DOS < 3.1, we simply ignore the error flag.
; CTask's DOS handler will not work that great anyway with older
; versions.
;
mov word ptr in_error,offset zero
mov word ptr in_error+2,cs
;
; Save old interrupt vectors
;
save_ints:
push es
xor ax,ax
mov es,ax
;
assume es:intseg
;
test tsk_instflags,IFL_VIDEO
jz inst_novid2
mov ax,vidoff ; video
mov savvidoff,ax
mov ax,vidseg
mov savvidseg,ax
;
inst_novid2:
test tsk_instflags,IFL_DISK
jz inst_nodsk2
mov ax,diskoff ; Disk I/O
mov savdiskoff,ax
mov ax,diskseg
mov savdiskseg,ax
mov ax,fdiskoff ; Floppy Disk I/O
mov savfdiskoff,ax
mov ax,fdiskseg
mov savfdiskseg,ax
;
inst_nodsk2:
mov ax,termoff ; DOS
mov savtermoff,ax
mov ax,termseg
mov savtermseg,ax
;
mov ax,idosoff ; DOS
mov savdosoff,ax
mov ax,idosseg
mov savdosseg,ax
;
mov ax,idleoff ; IDLE
mov savidleoff,ax
mov ax,idleseg
mov savidleseg,ax
;
mov ax,csectoff ; Critical Section
mov savcsectoff,ax
mov ax,csectseg
mov savcsectseg,ax
;
mov ax,absreadoff ; Absolute Disk read
mov savabsreadoff,ax
mov ax,absreadseg
mov savabsreadseg,ax
;
mov ax,abswriteoff ; Absolute Disk write
mov savabswriteoff,ax
mov ax,abswriteseg
mov savabswriteseg,ax
;
mov ax,keepoff ; Terminate Resident
mov savkeepoff,ax
mov ax,keepseg
mov savkeepseg,ax
;
IF (DEBUG AND DEB_DOSTRBUF)
mov ax,muxoff ; Multiplex
mov savmuxoff,ax
mov ax,muxseg
mov savmuxseg,ax
ENDIF
;
IF DEBUG AND DEB_DOSTRBUF
mov ax,dpmioff ; Multiplex
mov savdpmioff,ax
mov ax,dpmiseg
mov savdpmiseg,ax
ENDIF
;
; Enter new Interrupt-Entries
;
cli
test tsk_instflags,IFL_VIDEO
jz inst_novid3
mov vidoff,offset @videntry ; Video Entry
mov vidseg,cs
;
inst_novid3:
test tsk_instflags,IFL_DISK
jz inst_nodsk3
mov diskoff,offset @diskentry ; Disk I/O Entry
mov diskseg,cs
mov fdiskoff,offset @fdiskentry ; Floppy Disk I/O Entry
mov fdiskseg,cs
;
inst_nodsk3:
mov idosoff,offset @dosentry ; DOS-Entry
mov idosseg,cs
mov idleoff,offset @idleentry ; Idle-Entry
mov idleseg,cs
mov termoff,offset terminate_int ; Terminate Process Entry
mov termseg,cs
mov csectoff,offset @critsectint ; Critical Section Entry
mov csectseg,cs
mov keepoff,offset keep_int ; Keep Process Entry
mov keepseg,cs
mov absreadoff,offset absread_int ; Absolute Disk Read Entry
mov absreadseg,cs
mov abswriteoff,offset abswrite_int ; Absolute Disk Write Entry
mov abswriteseg,cs
IF (DEBUG AND DEB_DOSTRBUF)
mov muxoff,offset multiplex_int ; Multiplex Int Entry
mov muxseg,cs
ENDIF
IF DEBUG AND DEB_DOSTRBUF
mov dpmioff,offset multiplex_int ; Multiplex Int Entry
mov dpmiseg,cs
ENDIF
sti
;
assume es:nothing
;
pop es
IFDEF LOAD_DS
pop ds
ENDIF
ret
;
;
tsk_install_dos endp
;
;---------------------------------------------------------------------------
;
; void tsk_remove_dos (void)
;
; Un-install DOS handler
;
Localfunc tsk_remove_dos
;
IFDEF LOAD_DS
push ds
mov ax,@CTASK_DATA
mov ds,ax
ENDIF
;
; Delete resources & flags
;
callp delete_resource,<<ds,#upper_dos>>
callp delete_resource,<<ds,#lower_dos>>
;
test tsk_instflags,IFL_DISK
jz rem_nodsk1
callp delete_resource,<<ds,#hdisk_io>>
callp delete_resource,<<ds,#fdisk_io>>
;
rem_nodsk1:
test tsk_instflags,IFL_VIDEO
jz rem_novid1
callp delete_resource,<<ds,#video>>
;
rem_novid1:
push es
xor ax,ax
mov es,ax
;
assume es:intseg
;
; Restore interrupt entries
;
cli
test tsk_instflags,IFL_VIDEO
jz rem_novid2
mov ax,savvidoff
mov vidoff,ax
mov ax,savvidseg
mov vidseg,ax
;
rem_novid2:
test tsk_instflags,IFL_DISK
jz rem_nodsk2
mov ax,savdiskoff
mov diskoff,ax
mov ax,savdiskseg
mov diskseg,ax
mov ax,savfdiskoff
mov fdiskoff,ax
mov ax,savfdiskseg
mov fdiskseg,ax
;
rem_nodsk2:
mov ax,savtermoff
mov termoff,ax
mov ax,savtermseg
mov termseg,ax
;
mov ax,savdosoff
mov idosoff,ax
mov ax,savdosseg
mov idosseg,ax
;
mov ax,savidleoff
mov idleoff,ax
mov ax,savidleseg
mov idleseg,ax
;
mov ax,savcsectoff
mov csectoff,ax
mov ax,savcsectseg
mov csectseg,ax
;
mov ax,savabsreadoff
mov absreadoff,ax
mov ax,savabsreadseg
mov absreadseg,ax
;
mov ax,savabswriteoff
mov abswriteoff,ax
mov ax,savabswriteseg
mov abswriteseg,ax
;
mov ax,savkeepoff
mov keepoff,ax
mov ax,savkeepseg
mov keepseg,ax
;
IF (DEBUG AND DEB_DOSTRBUF)
mov ax,savmuxoff
mov muxoff,ax
mov ax,savmuxseg
mov muxseg,ax
ENDIF
;
IF DEBUG AND DEB_DOSTRBUF
mov ax,savdpmioff
mov dpmioff,ax
mov ax,savdpmiseg
mov dpmiseg,ax
ENDIF
;
sti
;
pop es
IFDEF LOAD_DS
pop ds
ENDIF
ret
;
assume es:nothing
;
tsk_remove_dos endp
;
;
;---------------------------------------------------------------------------
;---------------------------------------------------------------------------
;
;
; INT 10: Video BIOS interrupt
;
@videntry proc far
;
call tsk_switch_stack
callp request_cresource,<<ds,#video>,0,0>
mov ax,caller_flags[bp]
mov vid_flags,ax
call tsk_old_stack
pushf
cli
call savvid
call tsk_switch_stack
mov ax,vid_flags
mov caller_flags[bp],ax
callp release_resource,<<ds,#video>>
iret
;
@videntry endp
;
;---------------------------------------------------------------------------
;
;
; INT 13 and INT 40: Disk I/O BIOS interrupt
;
@diskentry proc far
;
call tsk_switch_stack
test dl,80h ; fixed disk ?
jz disk_floppy ; jump if not
callp request_cresource,<<ds,#hdisk_io>,0,0>
call tsk_old_stack
pushf
cli
call savdisk
call tsk_switch_stack
callp release_resource,<<ds,#hdisk_io>>
mov ax,entry_flags[bp]
mov caller_flags[bp],ax
iret
;
disk_floppy:
callp request_cresource,<<ds,#fdisk_io>,0,0>
call tsk_old_stack
pushf
cli
call savdisk
call tsk_switch_stack
callp release_resource,<<ds,#fdisk_io>>
mov ax,entry_flags[bp]
mov caller_flags[bp],ax
iret
;
@diskentry endp
;
@fdiskentry proc far
;
call tsk_switch_stack
callp request_cresource,<<ds,#fdisk_io>,0,0>
call tsk_old_stack
pushf
cli
call savfdisk
call tsk_switch_stack
callp release_resource,<<ds,#fdisk_io>>
mov ax,entry_flags[bp]
mov caller_flags[bp],ax
iret
;
@fdiskentry endp
;
;---------------------------------------------------------------------------
;
; Stack-Offsets relative to BP
;
d_func = -2
;
;---------------------------------------------------------------------------
;
; INT 25: Absolute Disk Read
;
; This interrupt is channeled through the normal DOS-function
; processing, with function = 0x25 and special flag set.
; It is re-translated later after the necessary resources
; have been requested. INT 25 is handled like a function > 0C.
; Interrupts 25 und 26 leave the flag-word on the stack.
; Since flags are removed in normal processing, the flag-word
; has to be duplicated on the stack here.
;
absread_int:
sti
push bp ; reserve space
push bp ; save BP
mov bp,sp
push ax
mov ax,4[bp] ; Move return offset, segment down
mov 2[bp],ax
mov ax,6[bp]
mov 4[bp],ax
mov ax,8[bp] ; duplicate flags
mov 6[bp],ax
pop ax
pop bp
call tsk_switch_stack
mov ax,2501h
mov cx,ax
jmp dosentry_2
;
;
;---------------------------------------------------------------------------
;
; INT 26: Absolute Disk Write
;
; This interrupt is channeled through the normal DOS-function
; processing, with function = 0x26 and special flag set.
; It is re-translated later after the necessary resources
; have been requested. INT 26 is handled like a function > 0C.
; Interrupts 25 und 26 leave the flag-word on the stack.
; Since flags are removed in normal processing, the flag-word
; has to be duplicated on the stack here.
;
abswrite_int:
sti
push bp ; reserve space
push bp ; save BP
mov bp,sp
push ax
mov ax,4[bp] ; Move return offset, segment down
mov 2[bp],ax
mov ax,6[bp]
mov 4[bp],ax
mov ax,8[bp] ; duplicate flags
mov 6[bp],ax
pop ax
pop bp
call tsk_switch_stack
mov ax,2601h
mov cx,ax
jmp short dosentry_2
;
;---------------------------------------------------------------------------
;
; INT 27: Terminate But Stay Resident Interrupt
;
; This interrupt is translated to INT 21, function 31.
;
keep_int:
call tsk_switch_stack
;
add dx,0fh ; last addr + 0f to round
sub dx,caller_cs[bp] ; minus CS (= PSP)
mov cl,4
shr dx,cl ; div 16 = paragraphs
mov ax,3100h ; Keep process
mov save_ax[bp],ax
mov cx,ax
jmp short dosentry_2
;
;---------------------------------------------------------------------------
;
; INT 20: Terminate Program interrupt
;
; This interrupt is translated to INT 21, function 4c.
;
terminate_int:
call tsk_switch_stack
mov ax,4c00h
mov save_ax[bp],ax
mov cx,ax
jmp short dosentry_2
;
;---------------------------------------------------------------------------
;
; INT 21: DOS-Interrupt
;
@dosentry proc far
;
; First, check for those special DOS functions that may be called
; even if DOS is busy. We don't want to block anyone from making
; those calls, lest we might kill the system.
;
cmp ah,33h ; set/get break flag
je non_block
cmp ah,50h ; set PSP
je non_block
cmp ah,51h ; get PSP
je non_block
cmp ah,62h
je non_block
cmp ah,64h
jne blocking
non_block:
jmp savdos
;
blocking:
call tsk_switch_stack
xor cl,cl
mov ch,ah
;
dosentry_2:
IF DEBUG AND (DEB_DOSTRACE OR DEB_DOSTRBUF)
push ax
push bx
push es
push si
cli
mov bx,tr_ptr
mov tr_buffer.tr_ax[bx],ax
mov ax,save_bx[bp]
mov tr_buffer.tr_bx[bx],ax
mov ax,save_ds[bp]
mov tr_buffer.tr_ds[bx],ax
les si,tsk_glob_rec.current_task
mov tr_buffer.tr_tcb_o[bx],si
mov tr_buffer.tr_tcb_s[bx],es
mov al,es:t_indos[si]
mov tr_buffer.tr_tindos[bx],al
les si,tsk_glob_rec.dos_vars
mov ax,es:[si+psp_offset] ; current PSP
mov tr_buffer.tr_psp[bx],ax
les si,in_error
mov al,byte ptr es:[si]
mov tr_buffer.tr_inerr[bx],al
les si,tsk_glob_rec.dos_in_use
mov al,byte ptr es:[si]
mov tr_buffer.tr_indos[bx],al
mov al,idle_active
mov tr_buffer.tr_idle[bx],al
xor al,al
mov tr_buffer.tr_flags[bx],al
cmp lower_dos.rcount,0
je trw_nolo
or tr_buffer.tr_flags[bx],1
mov ax,word ptr lower_dos.rowner
cmp tr_buffer.tr_tcb_o[bx],ax
jne trw_nolo
mov ax,word ptr lower_dos.rowner + 2
cmp tr_buffer.tr_tcb_s[bx],ax
jne trw_nolo
or tr_buffer.tr_flags[bx],2
trw_nolo:
cmp upper_dos.rcount,0
je trw_noup
or tr_buffer.tr_flags[bx],4
mov ax,word ptr upper_dos.rowner
cmp tr_buffer.tr_tcb_o[bx],ax
jne trw_noup
mov ax,word ptr upper_dos.rowner + 2
cmp tr_buffer.tr_tcb_s[bx],ax
jne trw_noup
or tr_buffer.tr_flags[bx],8
trw_noup:
IF DEBUG AND DEB_DOSTRBUF
add bx,TYPE trrec
cmp bx,TR_ENTRIES * TYPE trrec
jb trw_nowrap
xor bx,bx
trw_nowrap:
mov tr_ptr,bx
inc tr_count
ENDIF
pop si
IF DEBUG AND DEB_DOSTRACE
push cx
push dx
callp tsk_vcprintf,<<ds,#tr_string>,<ds,/tr_buffer[bx]>>
pop dx
pop cx
ENDIF
sti
pop es
pop bx
pop ax
ENDIF
;
push cx ; BP-2: func in CH, special flag in CL
or cl,cl
jnz dosent_x ; no function check if special
;
; Check if this is a special 'get dos version' call to determine
; if CTask is resident.
;
; A special call has
;
; AX = 3000h
;
; BX = 1234h - Get global variable block address
; then
; DS:DX = pointer to version string
; or
; BX = 1235h - CTask internal function
; then
; CX = function code
;
; Function codes for internal functions:
;
; 2300h Schedule
; 2301h Yield
;
cmp ax,3000h
jne no_spdos
cmp bx,1234h
jb no_spdos
je get_globvars
cmp bx,1235h
ja no_spdos
cmp save_cx[bp],MIN_SPFUNC
jb no_spdos
cmp save_cx[bp],MAX_SPFUNC
ja no_spdos
call @special_function
jmp short spec_ret
;
get_globvars:
cmp dx,0fff0h
jae no_spdos
push ds
mov si,dx
mov ds,save_ds[bp]
mov di,offset tsk_glob_rec
mov cx,8
repe cmpsb
pop ds
jz is_spdos
jmp short no_spdos
;
; Special version call returns global variable block address
; in BX (offset) and CX (segment).
;
is_spdos:
mov save_bx[bp],offset tsk_glob_rec
mov save_cx[bp],@CTASK_DATA
;
spec_ret:
add sp,2
call tsk_old_stack
mov ax,cs:dos_version
clc
iret
;
;---------------------------------------------------------------------------
;
;
no_spdos:
mov ax,d_func[bp]
or ah,ah ; terminate?
jne dosent_x
mov save_ax[bp],4c00h ; translate to fn 4c, retcode 0
mov d_func[bp],4c00h
;
; Now the real fun begins.
;
dosent_x:
sti ; Interrupts allowed now
;
; DL is used as an "emergency" marker. If nonzero, no resources
; are to be requested, and the in-dos flag is not to be checked.
; There is an "emergency" if the task is marked as owning
; DOS resources, but re-enters INT 21.
;
xor dl,dl
les bx,tsk_glob_rec.current_task
test es:t_indos[bx],OWN_UPPER OR OWN_LOWER
jz no_reenter ; no trouble if task doesn't own DOS
;
call @dosbusy ; this sets DL nonzero if busy
jnz no_reenter ; Don't release resources if busy
;
; If the task owns DOS resources, but DOS is not busy, something
; strange is going on (this case should have been handled by the
; 'schedent' routine). Anyway, we assume that DOS is right about
; not being busy, and release the resources. Although the resources
; will be requested again a few instructions later, this is sensible
; to give other tasks that might be waiting on the resource a chance
; to execute.
;
call @relres
xor dl,dl
;
; The preliminaries are done with, we now have to distinguish
; between functions 00-0C and 0D-FF.
;
no_reenter:
mov ax,d_func[bp]
cmp ah,0ch
jbe lower_funcs
jmp upper_funcs
;
;
; Functions 00-0C
;
lower_funcs:
;
; first, request the "lower_dos" resource unless this is an emergency.
;
or dl,dl
jnz lower_emergency
callp request_resource,<<ds,#lower_dos>,0,0>
;
; we have it, now let's get the upper_dos resource, too
;
callp request_resource,<<ds,#upper_dos>,0,0>
;
les bx,tsk_glob_rec.current_task
mov es:t_indos[bx],OWN_UPPER or OWN_LOWER
;
; both resources gained, now we may execute the function if dos is free
;
call @wait_dos_free
;
; Set the scheduler entry function
;
cli
mov word ptr es:sched_ent_func[bx],offset @schedent
mov word ptr es:sched_ent_func+2[bx],cs
sti
;
lower_emergency:
add sp,2
push caller_flags[bp]
popf
call tsk_old_stack
;
calldos ; execute function
;
; Now we have to release the resources, unless DOS still indicates
; that it is busy. This would indicate that a critical error has
; occurred, and DOS processing is not really complete.
;
call tsk_switch_stack
;
call @dosbusy
jnz no_relc ; return if DOS still busy
;
; Clear the flags in the TCB, and the scheduler entry function.
;
les bx,tsk_glob_rec.current_task
cli
mov es:t_indos[bx],0
mov word ptr es:sched_ent_func[bx],0
mov word ptr es:sched_ent_func+2[bx],0
sti
;
callp release_resource,<<ds,#upper_dos>>
callp release_resource,<<ds,#lower_dos>>
;
; All done, restore registers and return.
;
no_relc:
cli
mov ax,entry_flags[bp]
mov caller_flags[bp],ax
iret
;
;--------------------------------------------------------------------------
;
; Functions 0D and above
;
upper_funcs:
;
; first, request the "upper_dos" resource unless this is an emergency.
;
or dl,dl
jnz upper_emergency
;
callp request_resource,<<ds,#upper_dos>,0,0>
;
les bx,tsk_glob_rec.current_task
mov es:t_indos[bx],OWN_UPPER
;
; resource gained, now we may execute the function if dos is free
;
call @wait_dos_free
;
; Set the scheduler entry function
;
cli
mov word ptr es:sched_ent_func[bx],offset @schedent
mov word ptr es:sched_ent_func+2[bx],cs
sti
;
upper_emergency:
cmp byte ptr d_func[bp],0
jne no_term
mov ax,save_ax[bp]
cmp ah,31h ; terminate resident?
jne ckfunc1
jmp term_resident
ckfunc1:
cmp ax,4b00h ; spawn new process?
jne ckfunc2
jmp terminate
ckfunc2:
cmp ah,4ch ; terminate program?
jne no_term
jmp terminate
;
no_term:
;
; Filter special-functions 25/26 (Absolute Read/Write)
;
pop ax
cmp ax,2501h
jne uf_exec1
push caller_flags[bp]
popf
call tsk_old_stack
pushf
cli
call cs:savabsread
pop cs:temp_1 ; remove flags
jmp short uf_complete
;
uf_exec1:
cmp ax,2601h
jne uf_exec2
push caller_flags[bp]
popf
call tsk_old_stack
pushf
cli
call cs:savabswrite
pop cs:temp_1 ; remove flags
jmp short uf_complete
;
uf_exec2:
push caller_flags[bp]
popf
call tsk_old_stack
;
calldos ; execute function
;
; Now we have to release the resources, unless DOS still indicates
; that it is busy. This would indicate that a critical error has
; occurred, and DOS processing is not really complete.
; However, if we were called from INT 28, DOS must still be busy,
; so we only check the in_error flag.
;
uf_complete:
call tsk_switch_stack
;
cmp idle_active,0
jnz uf_nobsychk ; don't check busy if INT 28 call
les bx,tsk_glob_rec.dos_in_use
cmp es:byte ptr [bx],0
jne no_relc_uf ; don't release if busy
;
uf_nobsychk:
les bx,in_error
cmp es:byte ptr [bx],0
jnz no_relc_uf ; don't release if in error
;
les bx,tsk_glob_rec.current_task
cli
mov es:t_indos[bx],0
mov word ptr es:sched_ent_func[bx],0
mov word ptr es:sched_ent_func+2[bx],0
sti
;
callp release_resource,<<ds,#upper_dos>>
;
; All done, restore registers and return.
;
no_relc_uf:
cli
mov ax,entry_flags[bp]
mov caller_flags[bp],ax
iret
;
;--------------------------------------------------------------------------
;
; Terminate, TSR and Spawn calls go directly to DOS.
; TSR has to reset the exit address if it's the PSP of the
; current group, so the group is not deleted.
;
term_resident:
les bx,tsk_glob_rec.dos_vars
mov ax,es:[bx+psp_offset] ; current PSP
les bx,tsk_glob_rec.current_task
les bx,es:tgroup[bx]
cmp es:gcreate_psp[bx],ax
jne terminate
push ds
mov ds,ax
mov ax,word ptr es:grp_exit_addr[bx]
mov word ptr ds:psp_exit_addr,ax
mov ax,word ptr es:grp_exit_addr+2[bx]
mov word ptr ds:psp_exit_addr+2,ax
pop ds
;
terminate:
add sp,2
push caller_flags[bp]
popf
call tsk_old_stack
cli
jmp cs:savdos
;
@dosentry endp
;
;--------------------------------------------------------------------------
;
; 'dosbusy' checks the DOS busy flags.
;
; Entry: -
; Exit: DL is nonzero if DOS is busy.
;
@dosbusy proc near
;
push bx
push es
les bx,in_error
mov dl,es:byte ptr [bx]
les bx,tsk_glob_rec.dos_in_use
or dl,es:byte ptr [bx]
pop es
pop bx
ret
;
@dosbusy endp
;
;--------------------------------------------------------------------------
;
; Wait_dos_free uses busy waiting (calling _yield) in case
; some other background program has entered DOS without going
; through our INT 21 interface.
;
@wait_dos_free proc near
push es
push bx
;
in_use_loop:
les bx,in_error
cmp byte ptr es:[bx],0
jne is_in_use ; wait if in_error set
;
cmp idle_active,0 ; idle interrupt active?
je ck_inuse ; check for flag if no
pop bx
pop es
ret ; else return immediately
;
ck_inuse:
les bx,tsk_glob_rec.dos_in_use
cmp byte ptr es:[bx],0
jne is_in_use
pop bx
pop es
ret
;
is_in_use:
call yield
jmp in_use_loop
;
@wait_dos_free endp
;
;----------------------------------------------------------------------------
;
; 'relres' releases the DOS-resources of a task.
;
; Entry:
; ES:BX = TCB pointer
;
@relres proc near
;
test es:t_indos[bx],OWN_UPPER
jz rel_lower
xor es:t_indos[bx],OWN_UPPER
push bx
push es
callp release_resource,<<ds,#upper_dos>>
pop es
pop bx
;
rel_lower:
test es:t_indos[bx],OWN_LOWER
jz rel_exit
xor es:t_indos[bx],OWN_LOWER
push bx
push es
callp release_resource,<<ds,#lower_dos>>
pop es
pop bx
;
rel_exit:
ret
;
@relres endp
;
;----------------------------------------------------------------------------
;
; The 'schedent' function is called by the scheduler if the
; scheduler is entered and the current task owns one of the
; DOS resources.
; This routine checks whether the DOS busy flags are clear now,
; which would mean that the task left DOS without passing through
; the return address. If that's the case, we release the resources.
;
; The only catch is that there is a race condition if we just check
; the busy flags. There is a time slot where the function is set in
; the TCB, but the busy flag is clear because DOS has not yet been
; entered. Since we have no control over what will happen, and how
; long it will take to reach the point where the in_use flag is
; incremented, we can't simply disable preemption. So what we have
; to do is to wait for some other indication that DOS has begun
; executing the request, and mark this in the TCB. In all versions
; starting at 3.1, DOS will call the 'critical section' INT 2A
; with AX=8200 on functions > 0C after incrementing the in_use flag.
; We also have some indication that DOS is active if the 'idle'
; INT 28 is called, or if the in_use flag is set when we get here.
;
; Entry:
; DS CTask data segment
; BX Global data block offset
; ES:DI Task control block
;
@schedent proc far
;
call @dosbusy ; DOS still busy ?
jz schedent_relres ; release resources if not busy
or es:t_indos[di],DOS_ENTERED
ret
;
schedent_relres:
test es:t_indos[di],DOS_ENTERED
jz schedent_ret ; don't release if DOS not yet entered
;
mov bx,di
call @relres
;
schedent_ret:
ret
;
@schedent endp
;
;----------------------------------------------------------------------------
;
; INT 28: DOS Idle Interrupt
;
@idleentry proc far
;
call tsk_switch_stack
;
; check the in_use flag. If it's set, set the DOS_ENTERED flag
; in the current TCB.
;
les bx,tsk_glob_rec.dos_in_use
cmp byte ptr es:[bx],0
je no_entermark
;
les bx,tsk_glob_rec.current_task
or es:t_indos[bx],DOS_ENTERED
;
; Check if someone is waiting for upper_dos. If not, we can return
; immediately.
;
no_entermark:
les bx,upper_dos.rwaiting.q_first
test es:q_kind[bx],Q_HEAD
jnz idle_exit
;
; Also make sure this is not a second invocation of INT 28, and
; that the in_error flag is not set.
; Normally, this should never happen, but better safe than sorry.
;
cmp idle_active,0
jne idle_exit
les bx,in_error
cmp byte ptr es:[bx],0
jne idle_exit
;
inc idle_active
;
; someone is waiting, let's please him by releasing the resource.
; temporarily increase priority
;
les bx,tsk_glob_rec.current_task
push es:cqueue.q_el.q_prior[bx]
push es:cqueue.q_el.q_ini_prior[bx]
mov es:cqueue.q_el.q_prior[bx],0ffffh
mov es:cqueue.q_el.q_ini_prior[bx],0ffffh
push bx
push es
;
; release resource & request it again
;
callp release_resource,<<ds,#upper_dos>>
callp request_resource,<<ds,#upper_dos>,0,0>
;
; ready, restore priority
;
cli
pop es
pop bx
pop es:cqueue.q_el.q_ini_prior[bx]
pop es:cqueue.q_el.q_prior[bx]
;
mov idle_active,0
;
idle_exit:
push caller_flags[bp]
popf
call tsk_old_stack
cli
;
jmp cs:savidle ; chain to original interrupt
;
@idleentry endp
;
;----------------------------------------------------------------------------
;
; INT 2A: DOS Critical Section Interrupt
;
; Not documented.
; Is used by DOS PRINT to mark Critical Regions.
; Usage by PRINT:
; AX = 8700 - Begin Critical Region
; Returns:
; Carry set if already active.
; AX = 8701 - End Critical Region
;
; Other usage in DOS, function unknown:
; AH = 82 (AL undefined)
; seems to be called on DOS-Functions > 0C
; AH = 84 (AL undefined)
; seems to be called when DOS is idle
;
; We only handle function number 82 in this version,
; it is used to mark that DOS has been entered. All functions
; are passed on to the next in chain.
;
@critsectint proc far
;
cmp ah,82h
jne cs_exit
push ds
push es
push bx
mov ds,cs:tsk_dgroup
;
; check the in_use flag. If it's set, set the DOS_ENTERED flag
; in the current TCB.
;
les bx,tsk_glob_rec.dos_in_use
cmp byte ptr es:[bx],0
je cs_no_enter
;
les bx,tsk_glob_rec.current_task
or es:t_indos[bx],DOS_ENTERED
;
cs_no_enter:
pop bx
pop es
pop ds
;
cs_exit:
jmp cs:savcsect
;
@critsectint endp
;
;---------------------------------------------------------------------------
;---------------------------------------------------------------------------
;
term_err_msg db 0dh,0ah,"Program terminated - CTask uninstalled"
db 0dh,0ah,'$'
;
group_term_msg db 0dh,0ah,"Program terminated - Task Group removed"
db 0dh,0ah,'$'
;
gcb_mixup_err db 0dh,0ah,"Group chain damaged - System halted"
db 07h,'$'
;
;---------------------------------------------------------------------------
;
; tsk_emergency_exit is entered by DOS when a task group exits
; without releasing the current group.
; Registers are set up, remove_group is called, and the program
; is terminated by jumping to the terminate_address.
;
tsk_emergency_exit proc far
;
pushf
sub sp,4 ; make room for return addr
push bp
mov bp,sp
push ax
push bx
push cx
push dx
push si
push di
push ds
push es
mov ax,@CTASK_DATA
mov ds,ax
;
les bx,tsk_glob_rec.current_task[bx]
les bx,es:tgroup[bx]
mov ax,word ptr es:grp_exit_addr[bx]
mov 2[bp],ax
mov ax,word ptr es:grp_exit_addr+2[bx]
mov 4[bp],ax
;
callp tsk_remove_group,<<es,bx>,0>
;
mov dx,offset group_term_msg
cmp ax,0
je emergency_end
jb pg_fatal
;
les bx,tsk_glob_rec.current_task[bx]
les bx,es:tgroup[bx]
callp tsk_kill_group,<<es,bx>>
call tsk_remove_tasker
;
mov dx,offset term_err_msg
;
emergency_end:
;
mov ax,cs
mov ds,ax
mov ah,9
int 21h
;
pop es
pop ds
pop di
pop si
pop dx
pop cx
pop bx
pop ax
pop bp
iret
;
pg_fatal:
mov si,offset gcb_mixup_err
jmp short fatal_error
;
tsk_emergency_exit endp
;
;--------------------------------------------------------------------------
;
; fatal_error can be called if the system can't continue for
; some reason. It issues an error message and halts the system.
; SI must point to the '$'-terminated error message.
;
; tsk_fatal does the same, but assumes C calling sequence and
; a zero-terminated string.
;
Globalfunc tsk_fatal,<strp: far ptr>
;
cld
lds si,strp
jmp short dis_err
;
tsk_fatal endp
;
fatal_error:
mov ax,cs
mov ds,ax
;
dis_err:
IF IBM
xor ax,ax
int 10h ; re-init display
fatal_loop:
lodsb
cmp al,'$'
je fatal_end
or al,al
jz fatal_end
mov bx,7
mov ah,14
int 10h
jmp fatal_loop
ELSE
mov dx,si
mov ah,9
int 21h
ENDIF
fatal_end:
sti
jmp fatal_end
;
;--------------------------------------------------------------------------
;
; void CGlobalfunc tsk_fatal_pmd (byteptr string, ...)
;
; tsk_fatal_pmd is only present in "checking" mode.
; It does a minimal "post mortem dump", and displays the
; error message passed as parameter.
; The messages are output to both the primary and secondary
; monitor via the "regen" printf routines in tskprf.
; The system is then halted, this routine never returns.
;
IF CHECKING
;
;
CGlobalfunc tsk_fatal_pmd,<txt: far ptr,argp:far ptr>
;
; int 3 ; uncomment to break to debugger
push sp
push ss
push es
push ds
push di
push si
push dx
push cx
push bx
push ax
;
mov ds,tsk_dgroup
callp preempt_off
callp tsk_set_currdis
;
callp tsk_rputc,<0ch>
les di,txt
lea bx,argp
call @fatal_dump
;
callp tsk_set_dualdis
or ax,ax
jz no_second
;
callp tsk_rputc,<0ch>
les di,txt
lea bx,argp
call @fatal_dump
;
no_second:
jmp fatal_end
;
tsk_fatal_pmd endp
;
;
pmd1 db 0ah
db 'AX = %04X BX = %04X CX = %04X DX = %04X',0ah
db 'SI = %04X DI = %04X DS = %04X ES = %04X',0ah
db 'SS = %04X SP = %04X BP = %04X',0ah
db 'IP = %04X CS = %04X',0ah,0
pmd2 db 'Current Task = %FP'
IF TSK_NAMED
db ' (%s)'
ENDIF
db 0ah,0
pmde db 'System Halted',0
;
;
@fatal_dump proc near
;
callp tsk_vrprintf,<<es,di>,<ss,bx>>
mov bx,sp
add bx,2
callp tsk_vrprintf,<<cs,#pmd1>,<ss,bx>>
;
IF SINGLE_DATA
mov bx,offset tsk_glob_rec
push ds
pop es
ELSE
les bx,tsk_global
ENDIF
les bx,es:current_task[bx]
IF TSK_NAMED
lea dx,tname.nname[bx]
callp tsk_rprintf,<<cs,#pmd2>,<es,bx>,<es,dx>>
ELSE
callp tsk_rprintf,<<cs,#pmd2>,<es,bx>>
ENDIF
callp tsk_rprintf,<<cs,#pmde>>
ret
;
@fatal_dump endp
;
ENDIF
;
;---------------------------------------------------------------
;
@sp_schedule proc near
call schedule
ret
@sp_schedule endp
;
@sp_yield proc near
call yield
ret
@sp_yield endp
;
;
spfunctab label word
dw @sp_schedule
dw @sp_yield
;
@special_function proc near
;
mov bx,save_cx[bp]
xor bh,bh
add bx,bx
jmp spfunctab[bx]
;
@special_function endp
;
;---------------------------------------------------------------
;
IF DEBUG AND DEB_DOSTRBUF
;
dpmi_int proc far
;
inc cs:i31count
pushf
call savdpmi
pushf
dec cs:i31count
popf
ret 2
;
dpmi_int endp
;
ENDIF
IF DEBUG AND DEB_DOSTRBUF
;
multiplex_int proc far
;
inc cs:i2fcount
pushf
call savmux
pushf
dec cs:i2fcount
popf
ret 2
;
multiplex_int endp
;
dump_dostrace proc far
;
mov bx,tr_ptr
mov cx,TR_ENTRIES
lea ax,tr_head
cmp tr_count,cx
jae dtr_cok
xor bx,bx
mov cx,tr_count
or cx,cx
jnz dtr_cok
lea ax,tr_none
;
dtr_cok:
push bx
push cx
callp tsk_cprintf,<<ds,#tr_string>>
pop cx
pop bx
jcxz dtr_end
;
dtr_loop:
push bx
push cx
;
callp tsk_vcprintf,<<ds,#tr_string>,<ds,/tr_buffer[bx]>>
;
pop cx
pop bx
add bx,TYPE trrec
cmp bx,TR_ENTRIES * TYPE trrec
jb dtr_nowrap
xor bx,bx
dtr_nowrap:
loop dtr_loop
xor bx,bx
mov tr_ptr,cx
mov tr_count,cx
dtr_end:
ret
;
dump_dostrace endp
;
ENDIF
;
.tsk_ecode
;
ENDIF
;
end