434 lines
12 KiB
PHP
434 lines
12 KiB
PHP
subttl em387.inc - Emulator Internal Format and Macros
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page
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;em387.inc - Emulator Internal Format and Macros
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; Microsoft Confidential
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; Copyright (c) Microsoft Corporation 1987, 1992
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; All Rights Reserved
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;Purpose:
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; Emulator Internal Format and Macros
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;Revision History: (also see emulator.hst)
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; 8/23/91 TP New tag definitions
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; 10/30/89 WAJ Added this header.
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; 02/12/89 WAJ Added local stack frame definition.
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GetEmData macro dest,use
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ifdef _CRUISER
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mov dest,[edataSEG]
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elseifdef _DOS32EXT
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ifdifi <use>,<ax>
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push eax
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call _SelKrnGetEmulData
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mov dest,ax
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pop eax
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else
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call _SelKrnGetEmulData
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mov dest,ax
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endif
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endif
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endm
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;The SKIP macro optimizes very short jumps by treating the code
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;as data to a "cmp" instruction. This reduces jump time from
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;8 clocks or more down to 2 clocks. It destroy the flags!
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SKIP macro dist,target
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if dist eq 4
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db 3DH ;cmp eax,<immed>
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elseif dist eq 3
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db 3DH,0 ;cmp eax,<immed>
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elseif dist eq 2
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db 66H,3DH ;cmp ax,<immed>
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elseif dist eq 1
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db 3CH ;cmp al,<immed>
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else
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.err
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endif
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ifnb <target>
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.erre $+dist eq target
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endif
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endm
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; 80x87 environment structures.
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Env80x87_32 struc
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E32_ControlWord dw ?
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reserved1 dw ?
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E32_StatusWord dw ?
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reserved2 dw ?
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E32_TagWord dw ?
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reserved3 dw ?
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E32_CodeOff dd ?
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E32_CodeSeg dw ?
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reserved4 dw ?
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E32_DataOff dd ?
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E32_DataSeg dw ?
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reserved5 dw ?
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Env80x87_32 ends
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; Emulator Internal Format:
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; +0 +1 +2 +3 +4 +5 +6 +7 +8 +9 +10 +11
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; .___.___.___.___.___.___.___.___.___.___.___.___.
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; ptr --> |___|___|___|___|___|___|___|___|___|___|___|___|
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; lsb msb tag sgn exl exh
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; |<--- mantissa --->| |exponent
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; The mantissa contains the leading 1 before the decimal point in the hi
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; bit of the msb. The exponent is not biased (signed two's complement).
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; The flag and tag bytes are as below.
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; bit: 7 6 5 4 3 2 1 0
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; .___.___.___.___.___.___.___.___.
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; Sign: |___|_X_|_X_|_X_|_X_|_X_|_X_|_X_| X = unused
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; ^
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; SIGN
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; bit: 7 6 5 4 3 2 1 0
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; .___.___.___.___.___.___.___.___.
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; Tag: |___|___|_X_|_X_|___|___|___|___| X = unused
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; ^ ^ ^ ^ ^ ^
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; | | | | | |
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; 387 tag -+---+ | | | |
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; | | | |
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; Special enumeration -----+---+ | |
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; | |
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; Internal tag --------------------+---+
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;There are four internal tags: Single, Double, Zero, Special. Within
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;Special, there is NAN, Infinity, Denormal, and Empty.
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;Representations for Single, Double, and Denormal are the same. Denormals
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;are not actually kept denormalized, although they are rounded to the
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;correct number of bits as if they were. The Single tag means the
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;low 32 bits of the mantissa are zero. This allows optimizing multiply
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;and divide.
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;Tag Mantissa Exponent Sign
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;Zero 0 0 valid
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;Empty ? ? ?
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;NAN valid TexpMax valid
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;Infinity 8000...000 TexpMax valid
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;The mantissa for a NAN distinguishes between a quiet NAN (QNAN) or a
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;signaling NAN (SNAN). If the bit below the MSB is 1, it is a QNAN,
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;otherwise it is an SNAN.
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;* Stack entry defineds with a struct.
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EmStackEntry struc
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bMan0 db ?
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bMan1 db ?
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bMan2 db ?
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bMan3 db ?
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bMan4 db ?
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bMan5 db ?
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bMan6 db ?
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bMan7 db ?
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bTag db ?
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bSgn db ?
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bExpLo db ?
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bExpHi db ?
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EmStackEntry ends
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wMantisa struc
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wMan0 dw ?
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wMan1 dw ?
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wMan2 dw ?
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wMan3 dw ?
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TagSgn dw ?
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wExp dw ?
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wMantisa ends
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lMantisa struc
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lManLo dd ?
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lManHi dd ?
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ExpSgn dd ?
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lMantisa ends
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.erre size lMantisa eq size wMantisa
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Reg87Len equ size lMantisa
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;* bFlags and bTag constants.
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;The rules for internal number formats:
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;1. Everything is either normalized or zero--unnormalized formats cannot
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;get in. So if the high half mantissa is zero, the number must be all zero.
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;2. Although the exponent bias is different, NANs and Infinities are in
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;standard IEEE format - exponent is TexpMax, mantissa indicates NAN vs.
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;infinity (mantissa for infinity is 800..000H).
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;3. Denormals have an exponent less than TexpMin.
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;4. If the low half of the mantissa is zero, it is tagged bTAG_SNGL
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;5. Everything else is bTAG_VALID
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bSign equ 80h
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;These are the INTERNAL flags
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TAG_MASK equ 3
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TAG_SHIFT equ 2
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TAG_SNGL equ 0 ;SINGLE: low 32 bits are zero
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TAG_VALID equ 1
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TAG_ZERO equ 2
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TAG_SPCL equ 3 ;NAN, Infinity, Denormal, Empty
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ZEROorSPCL equ 2 ;Test for Zero or Special
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;Enumeration of "special":
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TAG_SPCLBITS equ 0CH
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TAG_EMPTY equ TAG_SPCL+(0 shl TAG_SHIFT)
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TAG_INF equ TAG_SPCL+(1 shl TAG_SHIFT)
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TAG_NAN equ TAG_SPCL+(2 shl TAG_SHIFT)
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TAG_DEN equ TAG_SPCL+(3 shl TAG_SHIFT)
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;These are the tags used by the 387
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T87_VALID equ 0
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T87_ZERO equ 1
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T87_SPCL equ 2 ;NAN, Infinity, Denormal
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T87_EMPTY equ 3
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;The tag word for each stack entry combines these two tags.
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;Internal tags are in the low bits, 387 tags are in the high two bits
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bTAG_VALID equ (T87_VALID shl 6) or TAG_VALID
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bTAG_SNGL equ (T87_VALID shl 6) or TAG_SNGL
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bTAG_ZERO equ (T87_ZERO shl 6) or TAG_ZERO
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bTAG_NAN equ (T87_SPCL shl 6) or TAG_NAN
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bTAG_INF equ (T87_SPCL shl 6) or TAG_INF
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bTAG_EMPTY equ (T87_EMPTY shl 6) or TAG_EMPTY
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bTAG_DEN equ (T87_SPCL shl 6) or TAG_DEN
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bTAG_NOPOP equ -1
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bTAG_MASK equ 3
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MantissaByteCnt equ 8
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IexpBias equ 3FFFh ; 16,383
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IexpMax equ 7FFFh ; Biased Exponent for Infinity
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IexpMin equ 0 ; Biased Exponent for zero
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DexpBias equ 3FFh ; 1023
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DexpMax equ 7FFh ; Biased Exponent for Infinity
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DexpMin equ 0 ; Biased Exponent for zero
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SexpBias equ 07Fh ; 127
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SexpMax equ 0FFh ; Biased Exponent for Infinity
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SexpMin equ 0 ; Biased Exponent for zero
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TexpBias equ 0 ; Bias for internal format of temp real
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UnderBias equ 24576 ; 3 * 2^13. Extra bias for unmasked underflow
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TexpMax equ IexpMax - IexpBias + TexpBias ;NAN/Infinity exponent
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TexpMin equ IexpMin-IexpBias+1 ;Smallest non-denormal exponent
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; Control Word Format CWcntl
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RoundControl equ 0Ch
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RCchop equ 0Ch
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RCup equ 08h
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RCdown equ 04h
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RCnear equ 0
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PrecisionControl equ 03h
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PC24 equ 0
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PC53 equ 02h
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PC64 equ 03h
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; Status Word Format SWcc
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C0 equ 01h
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C1 equ 02h
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C2 equ 04h
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C3 equ 40h
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ConditionCode equ C3 or C2 or C1 or C0
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CCgreater equ 0
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CCless EQU C0
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CCequal equ C3
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CCincomprable equ C3 or C2 or C0
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RoundUp equ C1
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StackOverflow equ C1
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; Status Flags Format CURerr
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Invalid equ 1h ; chip status flags
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Denormal equ 2h
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ZeroDivide equ 4h
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Overflow equ 8h
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Underflow equ 10h
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Precision equ 20h
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StackFlag equ 40h
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Summary equ 80h
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SavedErrs equ Invalid or Denormal or ZeroDivide or Overflow or Underflow or Precision or StackFlag
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LongSavedFlags equ (CCincomprable SHL 16) OR (SavedErrs SHL 8) ; save C0, C2, C3 & errs
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;* Define emulator interrupt stack frame.
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StackFrame struc
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regEAX dd ?
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regECX dd ?
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regEDX dd ?
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regEBX dd ?
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regESP dd ?
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regEBP dd ?
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regESI dd ?
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regEDI dd ?
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OldCodeOff dd ?
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OldLongStatus dd ?
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regDS dd ?
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regEIP dd ?
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regCS dd ?
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regFlg dd ?
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StackFrame ends
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regAX equ word ptr regEAX
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; .erre StatusWord eq LongStatusWord+1
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OldStatus equ word ptr OldLongStatus+1
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;* Define emulator entry point macro.
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EM_ENTRY macro entryname
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ifdef NT386
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public ___&entryname
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___&entryname:
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endif ; ifdef NT386
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endm
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Em87Busy EQU 1
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Em87Idle EQU 0
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ifdef NT386
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; Emulator TEB Layout ;
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.errnz (TbSystemReserved1 and 3) ; Make sure TB is dword aligned
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Numlev equ 8 ; Number of stack registers
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InitControlWord equ 37FH ; Default - Round near,
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; 64 bits, all exceptions masked
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DefaultControlWord equ 27FH ; Default - Round near,
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; 53 bits, all exceptions masked
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EmulatorTebData struc
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TbSystemResrvd db TbSystemReserved1 DUP (?) ; Skip to Emulator area
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RoundMode dd ? ; Address of rounding routine
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SavedRoundMode dd ? ; For restoring RoundMode
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ZeroVector dd ? ; Address of sum-to-zero routine
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TransRound dd ? ; Round mode w/o precision
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Result dd ? ; Result pointer
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PrevCodeOff dd ?
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PrevDataOff dd ?
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;(See comment below on 'emulator stack area'
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CURstk dd ? ; init to start of stack
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BEGstk db (Numlev-1)*Reg87Len dup(?) ;Allocate register 1 - 7
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INITstk db Reg87Len dup(?)
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FloatTemp db Reg87Len dup(?)
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ArgTemp db Reg87Len dup(?)
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Einstall db 0 ; Emulator installed flag
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SWerr db ? ; Initially no exceptions (sticky flags)
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SWcc db ? ; Condition codes from various operations
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CURerr db ? ; initially 8087 exception flags clear
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; this is the internal flag reset after
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; each operation to detect per instruction
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; errors
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CWmask db ? ; exception masks
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CWcntl db ? ; arithmetic control flags
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ErrMask db ?
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dummy db ?
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EmulatorTebData ends
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ENDstk equ byte ptr INITstk + Reg87Len
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LongStatusWord equ dword ptr Einstall ;Combine Einstall, CURerr, StatusWord
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StatusWord equ word ptr SWerr ;Combine SWerr, SWcc
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CurErrCond equ word ptr SWcc ;Combine SWcc, CURErr
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LongControlWord equ dword ptr CWmask ;Combine CWMask, CWcntl, ErrMask, dummy
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ControlWord equ word ptr CWmask ;Combine CWMask, CWcntl
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YFloatTemp equ FloatTemp
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YArgTemp equ ArgTemp
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.errnz (SWerr - Einstall -1)
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.errnz (SWcc - Einstall -2)
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.errnz (CURerr - Einstall -3)
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.errnz (CWcntl - CWmask -1)
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.errnz (ErrMask - CWmask -2)
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.errnz (dummy - CWmask -3)
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; Emulator stack area
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;The top of stack pointer CURstk is initialized to the last register
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;in the list; on a real 8087, this corresponds to hardware register 0.
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;The stack grows toward lower addresses, so the first push (which is
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;hardware register 7) is stored into the second-to-last slot. This gives
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;the following relationship between hardware registers and memory
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;locations:
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; BEGstk --> | reg 1 | (lowest memory address)
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; | reg 2 |
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; | reg 3 |
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; | reg 4 |
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; | reg 5 |
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; | reg 6 |
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; | reg 7 |
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; | reg 0 | <-- Initial top of stack (empty)
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; ENDstk -->
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;This means that the wrap-around case on decrementing CURstk will not
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;occur until the last (8th) item is pushed.
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;Note that the physical register numbers are only used in regard to
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;the tag word. All other operations are relative the current top.
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endif |