Libris Britannia 4/science library(b).zip/science library(b)/DJGPP/DJSRC111.ZIP/go32/dpmisim.asm

Assembly Source File | 1993-08-07 | 5KB | 291 lines

; This is file DPMISIM.ASM
;
; Copyright (C) 1993 DJ Delorie, 24 Kirsten Ave, Rochester NH 03867-2954
;
; This file is distributed under the terms listed in the document
; "copying.dj", available from DJ Delorie at the address above.
; A copy of "copying.dj" should accompany this file; if not, a copy
; should be available from where this file was obtained.  This file
; may not be distributed without a verbatim copy of "copying.dj".
;
; This file is distributed WITHOUT ANY WARRANTY; without even the implied
; warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
;

    title    dpmisim
    .386p

    include    segdefs.inc
    include tss.inc
    include gdt.inc
    include idt.inc

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

    start_data16

    extrn    _r_tss:tss_s
    extrn    _arena_cs:word
    extrn    _arena_ds:word
    extrn    _core_selector:word
    extrn    _tss_ptr:word
    extrn    _ARENA:dword

    public    _dpmisim_type
_dpmisim_type    db    0

    public    _dpmisim_vec
_dpmisim_vec    db    0

    public    _dpmisim_regs
_dpmisim_regs    label    dword
ds_edi    dd    ?
ds_esi    dd    ?
ds_ebp    dd    ?
ds_res    dd    ?
ds_ebx    dd    ?
ds_edx    dd    ?
ds_ecx    dd    ?
ds_eax    dd    ?
ds_flg    dw    ?
ds_es    dw    ?
ds_ds    dw    ?
ds_fs    dw    ?
ds_gs    dw    ?
ds_ip    dw    ?
ds_cs    dw    ?
ds_sp    dw    ?
ds_ss    dw    ?

    public    _dpmisim_rmcb
_dpmisim_rmcb    dd    32 dup(?)

    dd    128 dup (?)
rmcb_temp_stack32    label    dword
    dd    offset rmcb_task_switch
    dw    g_rcode

    dw    128 dup (?)
rmcb_temp_stack16    label    word

    end_data16

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

    start_code16

    extrn    _memput:near
    extrn    _memget:near
    extrn    _go_til_stop:near

ds_savesp    dw    ?
ds_savess    dw    ?
ds_tmpds    dw    ?

    public    _dpmisim
_dpmisim:

    pusha
    push    es

    mov    cs:[ds_savesp], sp
    mov    cs:[ds_savess], ss

    mov    ax,ds_flg
    and    ax,0fcffh
    push    ax
    popf

    mov    edi, ds_edi
    mov    esi, ds_esi
    mov    ebp, ds_ebp
    mov    ebx, ds_ebx
    mov    edx, ds_edx
    mov    ecx, ds_ecx
    mov    eax, ds_eax
    mov    es, ds_es
    mov    fs, ds_fs
    mov    gs, ds_gs
    mov    ss, ds_ss
    mov    sp, ds_sp

    push    cs
    push    offset dpmisim_return
    push    ds_cs
    push    ds_ip
    mov    ds, ds_ds
    retf    ; actually a far call in disguise
dpmisim_return:

    mov    cs:[ds_tmpds], ds
    push    DGROUP
    pop    ds
    pushf
    pop    ds_flg

    mov    ds_edi, edi
    mov    ds_esi, esi
    mov    ds_ebp, ebp
    mov    ds_ebx, ebx
    mov    ds_edx, edx
    mov    ds_ecx, ecx
    mov    ds_eax, eax
    mov    ds_es, es
    mov    ds_fs, fs
    mov    ds_gs, gs
    mov    ds_ss, ss
    mov    ds_sp, sp

    mov    ax, cs:[ds_tmpds]
    mov    ds_ds, ax

    mov    ss, cs:[ds_savess]
    mov    sp, cs:[ds_savesp]

    pop    es
    popa
    ret

rmcb_number    db    ?

rmcb    macro    n
    mov    cs:[rmcb_number],n
    jmp    short rmcb_common
    endm

    public    _dpmisim_rmcb0
_dpmisim_rmcb0:
    rmcb    0
    public    _dpmisim_rmcb1
_dpmisim_rmcb1:
    x=1
    rept 15
     rmcb x
     x=x+1
    endm

rmcb_common:
    mov    cs:[ds_tmpds], ds
    push    DGROUP
    pop    ds
    pushf
    pop    ds_flg

    mov    ds_edi, edi        ; save registers
    mov    ds_esi, esi
    mov    ds_ebp, ebp
    mov    ds_ebx, ebx
    mov    ds_edx, edx
    mov    ds_ecx, ecx
    mov    ds_eax, eax
    mov    ds_es, es
    mov    ds_fs, fs
    mov    ds_gs, gs
    mov    ds_ss, ss
    mov    ds_sp, sp

    mov    ax,ds            ; set up our local stack
    mov    ss,ax
    mov    sp, offset rmcb_temp_stack16

    push    ds
    pop    es

    mov    bl, cs:[rmcb_number]
    mov    bh,0
    shl    bx,3

    push    bx
    push    50            ; copy the registers to protected memory
    push    ds
    push    offset _dpmisim_regs
    mov    eax,_dpmisim_rmcb[bx+4]
    add    eax,_ARENA
    push    eax
    call    _memput
    add    sp,10
    pop    bx

    mov    ax, _arena_cs        ; cs:eip for function to call
    mov    _r_tss.tss_cs, ax
    mov    eax, _dpmisim_rmcb[bx]
    mov    _r_tss.tss_eip, eax

    mov    ax, _arena_ds        ; es:edi for pointer to registers
    mov    _r_tss.tss_es, ax
    mov    eax, _dpmisim_rmcb[bx+4]
    mov    _r_tss.tss_edi, eax

    mov    ax, _core_selector    ; ds:esi for pointer to caller stack
    mov    _r_tss.tss_ds, ax
    mov    eax,0
    mov    ax,ds_ss
    shl    eax,4
    mov    ebx,0
    mov    bx,ds_sp
    add    eax,ebx
    mov    _r_tss.tss_esi, eax

    mov    ax, _core_selector    ; ss:esp for pointer to temp stack
    mov    _r_tss.tss_ss, ax
    mov    eax,0
    mov    ax,ds
    shl    eax,4
    mov    ebx,0
    mov    bx,offset rmcb_temp_stack32
    add    eax,ebx
    and    eax,0fffffffch
    mov    _r_tss.tss_esp, eax

    push    _tss_ptr
    mov    ax,offset _r_tss
    mov    _tss_ptr,ax

    call    _go_til_stop

    pop    _tss_ptr

    mov    bl, cs:[rmcb_number]
    mov    bh,0
    shl    bx,3

    push    bx
    push    50            ; copy the registers from protected memory
    push    ds
    push    offset _dpmisim_regs
    mov    eax,_dpmisim_rmcb[bx+4]
    add    eax,_ARENA
    push    eax
    call    _memget
    add    sp,10
    pop    bx

    mov    ss,ds_ss
    mov    sp,ds_sp

    mov    edi, ds_edi
    mov    esi, ds_esi
    mov    ebp, ds_ebp
    mov    ebx, ds_ebx
    mov    edx, ds_edx
    mov    ecx, ds_ecx
    mov    eax, ds_eax
    mov    es, ds_es
    mov    fs, ds_fs
    mov    gs, ds_gs

    push    ds_flg
    push    ds_cs
    push    ds_ip
    mov    ds, ds_ds
    iret            ; jmp to wherever the regs said to

rmcb_task_switch:
    jmpt    g_ctss

    end_code16

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

    end