mirror of https://github.com/nmlgc/ReC98.git
472 lines
8.5 KiB
NASM
472 lines
8.5 KiB
NASM
ifdef FP87
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_Emu_ equ 0 ; no emulation, '87 required
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else
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_Emu_ equ 1 ; emulator
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endif
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public FIDRQQ ; wait, esc
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public FIARQQ ; wait, DS:
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public FICRQQ ; wait, CS:
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public FIERQQ ; wait, ES:
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public FISRQQ ; wait, SS:
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public FIWRQQ ; nop, wait
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public FJARQQ ; Esc nn -> DS:nn
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public FJCRQQ ; Esc nn -> CS:nn
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public FJSRQQ ; Esc nn -> ES:nn
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; Use full emulator if _Emu_ is true.
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if _Emu_
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FIDRQQ equ 05C32h
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FIARQQ equ 0FE32h
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FICRQQ equ 00E32h
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FIERQQ equ 01632h
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FISRQQ equ 00632h
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FIWRQQ equ 0A23Dh
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FJARQQ equ 04000h
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FJCRQQ equ 0C000h
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FJSRQQ equ 08000h
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else
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FIDRQQ equ 00000h
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FIARQQ equ 00000h
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FICRQQ equ 00000h
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FIERQQ equ 00000h
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FISRQQ equ 00000h
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FIWRQQ equ 00000h
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FJARQQ equ 00000h
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FJCRQQ equ 00000h
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FJSRQQ equ 00000h
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endif
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originalVectors dd 0Ch dup(?)
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FPEpriorVector dd ?
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fpinit_platform db 0
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fpinit_100B5 dw 0FFFFh
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fpinit_100B7 db ?
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fpinit_100B8 db 0
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plus_inf dd 7F800000h
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; borrowed from T. Pascal, DOS 3.1 BIOS
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; avoid DOS 3.2 stack swap
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int75handler proc far
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push ax
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xor al, al ; Clear BUSY latch
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out 0F0h, al
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mov al, 20H ; End-of-interrupt
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out 0A0h, al
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out 20h, al
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pop ax
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int 2
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iret
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int75handler endp
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nec_fpinit_100CC proc near
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push ax
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mov al, 20h
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out 8, al
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jmp short $+2
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mov al, 0Bh
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out 8, al
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jmp short $+2
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in al, 8
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or al, al
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jnz short @@loc_100E3
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mov al, 20h
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out 0, al
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@@loc_100E3:
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pop ax
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jmp short $+2
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nec_fpinit_100CC endp
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int2handler proc far
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push ax
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mov ax, seg __emu
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call e087_Trap
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jb short @@err
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pop ax
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; ---------------------------------------------------------------------------
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db 0EAh
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nmi dw 2 dup(?)
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; ---------------------------------------------------------------------------
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@@err:
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xchg ax, bx
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mov ax, seg __8087
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mov ds, ax
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call __fperror
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pop ax
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int2handler_ret:
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iret
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int2handler endp
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emu1st proc near
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push ds
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push si
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push di
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mov ax, seg __8087
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mov ds, ax
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; set end of FPU stack
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mov ax, offset __emu + SIZE_FPU
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mov word ptr ss:__emu+0Fh, ax
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add ax, 0C0h
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mov word ptr ss:__emu+11h, ax
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mov ax, __protected
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mov word ptr ss:__emu+7, ax
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push ds
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push cs
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pop ds
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; assume ds:nothing
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mov ax, ds
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xor ax, word ptr ss:__emu+7
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mov ds, ax
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; assume ds:DGROUP
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mov ax, 3534h
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mov cx, 11
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mov di, offset originalVectors
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@@rememberLoop:
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int 21h
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mov [di], bx
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mov word ptr [di+2], es
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add di, 4
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inc ax
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loop @@rememberLoop
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push ds
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push di
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mov cl, 0
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mov ax, seg __8087
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mov ds, ax
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cmp __8087, 0
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jz short @@IBM
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mov ah, 4
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xor cx, cx
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int 1Ah
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mov cl, 2
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cmp ch, 19h
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jz short @@IBM
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cmp ch, 20h
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jz short @@IBM
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mov cl, 1
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@@IBM:
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pop di
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pop ds
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assume ds:seg fpinit_platform
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mov ds:fpinit_platform, cl
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cmp cl, 2
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jnz short @@loc_10182
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; grab INT 75h
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mov ax, 3575h
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int 21h
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mov [di], bx
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mov word ptr [di+2], es
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add di, 4
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; grab INT 2
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mov ax, 3502h
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jmp short @@loc_10199
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@@loc_10182:
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cmp cl, 1
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jnz short @@loc_101B0
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push sp
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pop ax
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cmp ax, sp
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mov ax, 3510h
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jz short @@loc_10199
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in al, 0Ah
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and al, 40h
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mov ds:fpinit_100B7, al
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mov al, 16h
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@@loc_10199:
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mov bl, al
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mov bh, 25h
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mov ds:fpinit_100B5, bx
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int 21h
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mov [di], bx
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mov word ptr [di+2], es
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mov ds:nmi, bx
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mov ds:nmi+2, es
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@@loc_101B0:
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pop ds
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assume ds:seg __psp
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mov bx, -1
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mov es, __psp
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; Look for a "87" environment variable.
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; Each variable is ended by a 0 and a zero-length variable stops
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; the environment. The environment can NOT be greater than 32k.
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; assume es:nothing
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mov es, word ptr es:2Ch ; environment segment
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; assume es:nothing
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sub di, di ; ES:[di] points to environ
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mov cx, 7FFFh ; Environment cannot be > 32 Kbytes
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mov al, 0
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cld
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@@env87next:
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repne scasb ; direction flag is clear
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jcxz short @@env87done ; count exhausted imply end
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cmp al, es:[di] ; double zero bytes imply end
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jz short @@env87done
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cmp word ptr es:[di], '78'
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jnz short @@env87next
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mov dx, es:[di+2]
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cmp dl, '='
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jnz short @@env87next
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inc bx
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and dh, not ('y' - 'Y')
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cmp dh, 'Y'
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jnz short @@env87done
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inc bx
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@@env87done:
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pop di
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pop si
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xor ax, ax
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or bx, bx
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jz short @@set_flag
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jg short @@loc_1022E
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mov cx, __8087
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jcxz short @@loc_10250
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@@TestPresence:
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fninit
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mov __8087, 0
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fnstcw __8087
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mov cx, 20
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@@delay_1:
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loop @@delay_1 ; Delay awhile
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mov cx, __8087 ; Get NPX control word
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and cx, 0F3Fh ; Mask off undefined bits
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cmp cx, 33Fh ; Do we have a math coprocessor
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jnz short @@test_done ; No ...
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mov __8087, -1
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fnstsw __8087 ; Store the status word
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mov cx, 14h
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@@delay_2:
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loop @@delay_2 ; Delay awhile
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test __8087, 0B8BFh ; All bits off that should be?
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jnz short @@test_done
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@@loc_1022E:
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inc ax
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push sp
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pop cx
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cmp cx, sp
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jnz short @@test_done
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fninit
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fld cs:plus_inf
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fchs
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fcomp cs:plus_inf ; compare +INF to -INF
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fstsw ax ; we have a 287 or better
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sahf
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mov al, 2
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jz short @@test_done ; equal on 80287 only
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inc ax
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@@test_done:
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cbw
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@@set_flag:
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mov __8087, ax
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@@loc_10250:
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mov ss:__emu+6, al
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pop ds
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emu1st endp
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option emulator
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public ___fpreset
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___fpreset proc near
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@@temp1 = dword ptr -8
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@@temp2 = dword ptr -4
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push ds
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push bp
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mov bp, sp
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sub sp, 8
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mov bx, seg __8087
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mov ds, bx
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cmp __8087, 0
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mov word ptr [bp+@@temp1], offset e087_Entry
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mov word ptr [bp+@@temp1+2], seg e087_Entry
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mov word ptr [bp+@@temp2], offset e087_Shortcut
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mov word ptr [bp+@@temp2+2], seg e087_Shortcut
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jnz short @@doCapture
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mov word ptr [bp+@@temp1], offset e086_Entry
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mov word ptr [bp+@@temp1+2], seg e086_Entry
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mov word ptr [bp+@@temp2], offset e086_Shortcut
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mov word ptr [bp+@@temp2+2], seg e086_Shortcut
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@@doCapture:
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mov ax, 2534h
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mov cx, 10
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lds dx, [bp+@@temp1]
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@@captureLoop:
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int 21h
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inc ax
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loop @@captureLoop
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mov ax, 253Eh
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lds dx, [bp+@@temp2]
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int 21h
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mov ds, bx
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cmp __8087, 0
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jnz short @@loc_102D8
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mov word ptr ss:__emu+41h, offset int2handler
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mov word ptr ss:__emu+43h, cs
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push cs
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pop ds
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mov ax, ds
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xor ax, word ptr ss:__emu+7
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mov ds, ax
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assume ds:seg nmi
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mov ds:nmi, offset int2handler_ret
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mov ds:nmi+2, cs
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mov ds:fpinit_100B5, -1
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jmp short @@init87
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@@loc_102D8:
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push cs
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pop ds
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cmp ds:fpinit_platform, 2
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jnz short @@loc_10306
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mov ax, ds:fpinit_100B5
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mov dx, offset int2handler
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int 21h
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mov ds, bx
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assume ds:seg __8087
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cmp __8087, 0
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jz short @@init87
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mov ax, __version
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xchg ah, al
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cmp ax, 1403h
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jnz short @@init87
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mov ax, 2575h
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push cs
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pop ds
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assume ds:seg fpinit_platform
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mov dx, offset int75handler
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int 21h
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@@loc_10306:
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cmp ds:fpinit_platform, 1
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jnz short @@init87
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mov ax, ds:fpinit_100B5
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mov dx, offset int2handler
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cmp al, 16h
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jnz short @@loc_1031A
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mov dx, offset nec_fpinit_100CC
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@@loc_1031A:
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int 21h
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cmp al, 16h
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jnz short @@init87
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pushf
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cli
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in al, 0Ah
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and al, 0BFh
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out 0Ah, al
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popf
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@@init87:
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mov ds, bx
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mov cs:fpinit_100B8, 1
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; Hack (this is not assembling to an emulated fninit for some reason?)
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db 0CDh, 037h, 0E3h
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mov word ptr ss:__emu+21h, 0
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mov word ptr ss:__emu+23h, 0
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assume ds:seg __default87
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mov ax, __default87
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mov word ptr [bp+@@temp1], ax
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cmp __8087, 3
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jl short @@control
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or word ptr [bp+@@temp1], 2
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@@control:
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push si
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fldcw word ptr [bp+@@temp1]
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pop si
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mov ax, word ptr [bp+@@temp1]
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and word ptr ss:__emu+2, ax
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xor ax, ax
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cwd
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mov sp, bp
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pop bp
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pop ds
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ret
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___fpreset endp
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public emuLast
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emuLast proc near
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push ds
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mov ax, seg __8087
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mov ds, ax
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cmp cs:fpinit_100B8, 0
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jz short @@done
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push ds
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finit
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mov ax, 2534h
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mov bx, offset originalVectors
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mov cx, 11
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@@restoreLoop:
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lds dx, cs:[bx]
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assume ds:seg __8087
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int 21h
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add bx, 4
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inc ax
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loop @@restoreLoop
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pop ds
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cmp __8087, 0
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jz short @@done
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cmp cs:fpinit_platform, 2
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jnz short @@loc_103AA
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mov ax, 2575h
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lds dx, cs:[bx]
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int 21h
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add bx, 4
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@@loc_103AA:
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mov ax, cs:fpinit_100B5
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cmp cs:fpinit_platform, 1
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jnz short @@loc_103C8
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cmp al, 16h
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jnz short @@loc_103C8
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xchg ax, dx
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pushf
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cli
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in al, 0Ah
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or al, cs:fpinit_100B7
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out 0Ah, al
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popf
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xchg ax, dx
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@@loc_103C8:
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lds dx, cs:[bx]
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int 21h
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@@done:
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mov cs:fpinit_100B8, 0
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pop ds
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ret
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emuLast endp
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public __fpuint
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__fpuint proc far
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mov ax, cs:fpinit_100B5
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ret
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__fpuint endp
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