dosinite.esm

来自「开放源码的编译器open watcom 1.6.0版的源代码」· ESM 代码 · 共 246 行

.387
.386p
		PUBLIC	__sys_init_387_emulator
		PUBLIC	__sys_fini_387_emulator
		EXTRN	__8087cw:BYTE
		EXTRN	__8087:BYTE
		EXTRN	__X32VM:BYTE
		EXTRN	__x386_zero_base_selector:BYTE
		EXTRN	__Extender:BYTE
		EXTRN	__int7:BYTE
		EXTRN	__GDAptr:BYTE
		EXTRN	__D16Infoseg:BYTE
		EXTRN	__hook387:BYTE
		EXTRN	__int7_pl3:BYTE
		EXTRN	__unhook387:BYTE
DGROUP		GROUP	_DATA
_DATA		SEGMENT	DWORD PUBLIC USE32 'DATA'
L$1:
    DB	07H DUP(0,0,0,0,0,0,0,0)
    DB	0, 0, 0, 0, 0, 0, 0, 0
L$2:
    DB	0, 0, 0, 0
L$3:
    DB	0, 0
L$4:
    DB	0, 0
L$5:
    DB	0

_DATA		ENDS
_TEXT		SEGMENT	WORD PUBLIC USE32 'CODE'
		ASSUME CS:_TEXT, DS:DGROUP, SS:DGROUP
__sys_init_387_emulator:
    push        es
    push        ecx
    push        ebx
    push        edx
    fninit      
    push        eax
    fnstcw      word ptr [esp]
    pop         eax
    cmp         ah,3
    je          L$6
    inc         ebp
L$6:
    or          ebp,ebp
    je          L$7
    call        near ptr hook_in_emulator
L$7:
    finit       
    fldcw       word ptr DGROUP:__8087cw
    fldz        
    fldz        
    fldz        
    fldz        
    pop         edx
    pop         ebx
    pop         ecx
    pop         es
    ret         
hook_in_emulator:
    mov         byte ptr DGROUP:__8087,3
    mov         byte ptr DGROUP:L$5,1
    smsw        word ptr DGROUP:L$4
    and         word ptr DGROUP:L$4,6
    sub         esp,8
    sidt        fword ptr [esp]
    mov         ebx,dword ptr 2[esp]
    add         ebx,38H
    add         esp,8
    cmp         byte ptr DGROUP:__X32VM,0
    je          L$8
    call        near ptr create_IDT_entry
    mov         es,word ptr DGROUP:__x386_zero_base_selector
    mov         dword ptr es:[ebx],edx
    mov         dword ptr es:4[ebx],ecx
    call        near ptr _set_EM_MP_bits
    cmp         byte ptr DGROUP:__Extender,0
    jne         L$8
    mov         ax,2507H
    push        ds
    mov         cx,cs
    mov         ds,cx
    lea         edx,__int7
    int         21H
    pop         ds
    mov         al,4
    mov         ah,0f3H
    int         21H
    jmp         L$11
L$8:
    cmp         byte ptr DGROUP:__Extender,9
    jne         L$9
    call        near ptr create_IDT_entry
    mov         dword ptr [ebx],edx
    mov         dword ptr 4[ebx],ecx
    mov         eax,0e02H
    mov         ebx,4
    mov         ecx,dword ptr DGROUP:__GDAptr
    call        dword ptr 30H[ecx]
    jmp         L$11
L$9:
    cmp         byte ptr DGROUP:__Extender,1
    jne         L$10
    mov         dx,word ptr DGROUP:__D16Infoseg
    sub         eax,eax
    call        near ptr __hook387
    jmp         L$11
L$10:
    sub         dx,dx
    sub         eax,eax
    call        near ptr __hook387
    cmp         al,1
    je          L$11
    call        near ptr hook_pharlap
L$11:
    ret         
create_IDT_entry:
    lea         ecx,__int7
    mov         dx,cs
    shl         edx,10H
    mov         dx,cx
    mov         cx,cs
    and         cl,3
    shl         cx,0dH
    or          ch,8eH
    ret         
hook_pharlap:
    mov         cl,7
    mov         ax,2502H
    int         21H
    mov         dword ptr DGROUP:L$2,ebx
    mov         word ptr DGROUP:L$3,es
    cmp         byte ptr DGROUP:__Extender,3
    mov         cl,7
    mov         ax,2504H
    push        ds
    push        cs
    pop         ds
    jl          L$12
    lea         edx,__int7_pl3
    int         21H
    pop         ds
    call        near ptr _set_EM_MP_bits
    jmp         L$13
L$12:
    lea         edx,__int7
    int         21H
    pop         ds
    mov         ecx,cr0
    or          ecx,4
    and         ecx,0fffffffdH
    mov         cr0,ecx
L$13:
    ret         
_set_EM_MP_bits:
    xor         ebx,ebx
    lea         edx,DGROUP:L$1
    mov         ax,2535H
    int         21H
    or          dword ptr DGROUP:L$1,4
    and         dword ptr DGROUP:L$1,0fffffffdH
    inc         ebx
    int         21H
    ret         
__sys_fini_387_emulator:
    cmp         byte ptr DGROUP:L$5,1
    je          L$14
    ret         
L$14:
    push        ecx
    push        ebx
    push        edx
    mov         al,byte ptr DGROUP:__Extender
    cmp         byte ptr DGROUP:__X32VM,0
    je          L$15
    call        near ptr _reset_EM_MP_bits
    jmp         L$19
L$15:
    cmp         al,9
    jne         L$16
    mov         eax,0e02H
    mov         ebx,0
    mov         ecx,dword ptr DGROUP:__GDAptr
    call        dword ptr 30H[ecx]
    jmp         L$19
L$16:
    cmp         al,0
    jne         L$17
    mov         ax,word ptr DGROUP:L$4
    mov         ah,0f3H
    int         21H
    jmp         L$19
L$17:
    cmp         al,1
    jne         L$18
    mov         dx,word ptr DGROUP:__D16Infoseg
    sub         eax,eax
    call        near ptr __unhook387
    jmp         L$19
L$18:
    sub         edx,edx
    call        near ptr __unhook387
    cmp         al,1
    je          L$19
    call        near ptr unhook_pharlap
L$19:
    mov         byte ptr DGROUP:L$5,0
    pop         edx
    pop         ebx
    pop         ecx
    ret         
unhook_pharlap:
    mov         cl,7
    mov         ax,2504H
    mov         edx,dword ptr DGROUP:L$2
    push        ds
    mov         ds,word ptr DGROUP:L$3
    int         21H
    pop         ds
    cmp         byte ptr DGROUP:__Extender,3
    jl          L$20
    call        near ptr _reset_EM_MP_bits
    jmp         L$21
L$20:
    mov         ecx,cr0
    and         ecx,0fffffff9H
    mov         dx,word ptr DGROUP:L$4
    or          cx,dx
    mov         cr0,ecx
L$21:
    ret         
_reset_EM_MP_bits:
    xor         ebx,ebx
    lea         edx,DGROUP:L$1
    mov         ax,2535H
    int         21H
    xor         ecx,ecx
    mov         cx,word ptr DGROUP:L$4
    mov         dword ptr DGROUP:L$1,ecx
    inc         ebx
    int         21H
    ret         
_TEXT		ENDS
		END