852 lines
32 KiB
NASM
852 lines
32 KiB
NASM
;*****************************************************************************
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;*
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;* Open Watcom Project
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;*
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;* Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
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;*
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;* ========================================================================
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;*
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;* This file contains Original Code and/or Modifications of Original
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;* Code as defined in and that are subject to the Sybase Open Watcom
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;* Public License version 1.0 (the 'License'). You may not use this file
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;* except in compliance with the License. BY USING THIS FILE YOU AGREE TO
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;* ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is
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;* provided with the Original Code and Modifications, and is also
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;* available at www.sybase.com/developer/opensource.
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;*
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;* The Original Code and all software distributed under the License are
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;* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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;* EXPRESS OR IMPLIED, AND SYBASE AND ALL CONTRIBUTORS HEREBY DISCLAIM
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;* ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF
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;* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR
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;* NON-INFRINGEMENT. Please see the License for the specific language
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;* governing rights and limitations under the License.
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;*
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;* ========================================================================
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;*
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;* Description: WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
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;* DESCRIBE IT HERE!
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;*
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;*****************************************************************************
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; static char sccs_id[] = "@(#)fprem32.asm 1.5 12/22/94 12:48:07";
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;
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; This code is being published by Intel to users of the Pentium(tm)
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; processor. Recipients are authorized to copy, modify, compile, use and
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; distribute the code.
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;
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; Intel makes no warranty of any kind with regard to this code, including
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; but not limited to, implied warranties or merchantability and fitness for
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; a particular purpose. Intel assumes no responsibility for any errors that
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; may appear in this code.
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;
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; No patent licenses are granted, express or implied.
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;
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;
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include mdef.inc
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.386
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.387
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;
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; PRELIMINARY VERSION of the software patch for the floating
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; point remainder.
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;
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CHECKSW MACRO
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ifdef DEBUG
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fnstsw [fpsw]
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fnstcw [fpcw]
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endif
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ENDM
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DATA32 SEGMENT DWORD USE32 PUBLIC 'DATA'
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;
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; Stack variables for remainder routines.
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;
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FLT_SIZE EQU 12
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DENOM EQU 0
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DENOM_SAVE EQU DENOM + FLT_SIZE
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NUMER EQU DENOM_SAVE + FLT_SIZE
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PREV_CW EQU NUMER + FLT_SIZE
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PATCH_CW EQU PREV_CW + 4
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FPREM_SW EQU PATCH_CW + 4
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STACK_SIZE EQU FPREM_SW + 4
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RET_SIZE EQU 4
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PUSH_SIZE EQU 4
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MAIN_FUDGE EQU RET_SIZE + PUSH_SIZE + PUSH_SIZE + PUSH_SIZE
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MAIN_DENOM EQU DENOM + MAIN_FUDGE
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MAIN_DENOM_SAVE EQU DENOM_SAVE + MAIN_FUDGE
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MAIN_NUMER EQU NUMER + MAIN_FUDGE
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MAIN_PREV_CW EQU PREV_CW + MAIN_FUDGE
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MAIN_PATCH_CW EQU PATCH_CW + MAIN_FUDGE
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MAIN_FPREM_SW EQU FPREM_SW + MAIN_FUDGE
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ONESMASK EQU 700h
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fprem_risc_table DB 0, 1, 0, 0, 4, 0, 0, 7, 0, 0, 10, 0, 0, 13, 0, 0
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fprem_scale DB 0, 0, 0, 0, 0, 0, 0eeh, 03fh
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one_shl_64 DB 0, 0, 0, 0, 0, 0, 0f0h, 043h
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one_shr_64 DB 0, 0, 0, 0, 0, 0, 0f0h, 03bh
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one DB 0, 0, 0, 0, 0, 0, 0f0h, 03fh
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half DB 0, 0, 0, 0, 0, 0, 0e0h, 03fh
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big_number DB 0, 0, 0, 0, 0, 0, 0ffh, 0ffh, 0feh, 07fh
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ifdef DEBUG
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public fpcw
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public fpsw
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fpcw dw 0
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fpsw dw 0
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endif
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FPU_STATE STRUC
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CONTROL_WORD DW ?
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reserved_1 DW ?
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STATUS_WORD DD ?
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TAG_WORD DW ?
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reserved_3 DW ?
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IP_OFFSET DD ?
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CS_SLCT DW ?
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OPCODE DW ?
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DATA_OFFSET DD ?
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OPERAND_SLCT DW ?
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reserved_4 DW ?
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FPU_STATE ENDS
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ENV_SIZE EQU 28
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DATA32 ENDS
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_TEXT SEGMENT DWORD USE32 PUBLIC 'CODE'
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_TEXT ENDS
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DATA32 SEGMENT DWORD USE32 PUBLIC 'DATA'
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DATA32 ENDS
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CONST32 SEGMENT DWORD USE32 PUBLIC 'CONST'
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CONST32 ENDS
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BSS32 SEGMENT DWORD USE32 PUBLIC 'BSS'
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BSS32 ENDS
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DGROUP GROUP CONST32, BSS32, DATA32
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CODE32 SEGMENT DWORD USE32 PUBLIC 'CODE'
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assume cs:_TEXT, ds:DGROUP, es:DGROUP, ss:nothing
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fprem_common PROC NEAR
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push eax
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push ebx
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push ecx
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mov eax, [MAIN_DENOM+6+esp] ; exponent and high 16 bits of mantissa
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xor eax, ONESMASK ; invert bits that have to be one
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test eax, ONESMASK ; check bits that have to be one
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jnz remainder_hardware_ok
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shr eax, 11
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and eax, 0fh
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cmp byte ptr fprem_risc_table[eax], 0 ; check for (1,4,7,a,d)
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jz remainder_hardware_ok
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; The denominator has the bit pattern. Weed out the funny cases like NaNs
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; before applying the software version. Our caller guarantees that the
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; denominator is not a denormal. Here we check for:
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; denominator inf, NaN, unnormal
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; numerator inf, NaN, unnormal, denormal
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mov eax, [MAIN_DENOM+6+esp] ; exponent and high 16 bits of mantissa
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and eax, 07fff0000h ; mask the exponent only
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cmp eax, 07fff0000h ; check for INF or NaN
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je remainder_hardware_ok
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mov eax, [MAIN_NUMER+6+esp] ; exponent and high 16 bits of mantissa
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and eax, 07fff0000h ; mask the exponent only
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jz remainder_hardware_ok ; jif numerator denormal
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cmp eax, 07fff0000h ; check for INF or NaN
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je remainder_hardware_ok
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mov eax, [esp + MAIN_NUMER + 4] ; high mantissa bits - numerator
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add eax, eax ; set carry if explicit bit set
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jnz remainder_hardware_ok ; jmp if numerator is unnormal
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mov eax, [esp + MAIN_DENOM + 4] ; high mantissa bits - denominator
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add eax, eax ; set carry if explicit bit set
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jnz remainder_hardware_ok ; jmp if denominator is unnormal
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rem_patch:
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mov eax, [MAIN_DENOM+8+esp] ; sign and exponent of y (denominator)
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and eax, 07fffh ; clear sy
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add eax, 63 ; evaluate ey + 63
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mov ebx, [MAIN_NUMER+8+esp] ; sign and exponent of x (numerator)
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and ebx, 07fffh ; clear sx
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sub ebx, eax ; evaluate the exponent difference (ex - ey)
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ja rem_large ; if ex > ey + 63, case of large arguments
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rem_patch_loop:
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mov eax, [MAIN_DENOM+8+esp] ; sign and exponent of y (denominator)
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and eax, 07fffh ; clear sy
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add eax, 10 ; evaluate ey + 10
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mov ebx, [MAIN_NUMER+8+esp] ; sign and exponent of x (numerator)
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and ebx, 07fffh ; clear sx
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sub ebx, eax ; evaluate the exponent difference (ex - ey)
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js remainder_hardware_ok ; safe if ey + 10 > ex
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fld tbyte ptr [MAIN_NUMER+esp] ; load the numerator
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mov eax, [MAIN_DENOM+8+esp] ; sign and exponent of y (denominator)
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mov ebx, [MAIN_NUMER+8+esp] ; sign and exponent of x (numerator)
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and ebx, 07fffh ; clear sx
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mov ecx, ebx
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sub ebx, eax
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and ebx, 07h
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or ebx, 04h
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sub ecx, ebx
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mov ebx, eax
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and ebx, 08000h ; keep sy
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or ecx, ebx ; merge the sign of y
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mov dword ptr [MAIN_DENOM+8+esp], ecx
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fld tbyte ptr [MAIN_DENOM+esp] ; load the shifted denominator
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mov dword ptr [MAIN_DENOM+8+esp], eax ; restore the initial denominator
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fxch
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fprem ; this rem is safe
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fstp tbyte ptr [MAIN_NUMER+esp] ; update the numerator
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fstp st(0) ; pop the stack
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jmp rem_patch_loop
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rem_large:
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test edx, 02h ; is denominator already saved
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jnz already_saved
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fld tbyte ptr[esp + MAIN_DENOM]
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fstp tbyte ptr[esp + MAIN_DENOM_SAVE] ; save denominator
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already_saved:
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; Save user's precision control and institute 80. The fp ops in
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; rem_large_loop must not round to user's precision (if it is less
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; than 80) because the hardware would not have done so. We are
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; aping the hardware here, which is all extended.
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fnstcw [esp+MAIN_PREV_CW] ; save caller's control word
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mov eax, dword ptr[esp + MAIN_PREV_CW]
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or eax, 033fh ; mask exceptions, pc=80
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mov [esp + MAIN_PATCH_CW], eax
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fldcw [esp + MAIN_PATCH_CW]
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mov eax, [MAIN_DENOM+8+esp] ; sign and exponent of y (denominator)
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and eax, 07fffh ; clear sy
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mov ebx, [MAIN_NUMER+8+esp] ; sign and exponent of x (numerator)
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and ebx, 07fffh ; clear sx
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sub ebx, eax ; evaluate the exponent difference
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and ebx, 03fh
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or ebx, 020h
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add ebx, 1
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mov ecx, ebx
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mov eax, [MAIN_DENOM+8+esp] ; sign and exponent of y (denominator)
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mov ebx, [MAIN_NUMER+8+esp] ; sign and exponent of x (numerator)
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and ebx, 07fffh ; clear sx
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and eax, 08000h ; keep sy
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or ebx, eax ; merge the sign of y
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mov dword ptr[MAIN_DENOM+8+esp], ebx ; make ey equal to ex (scaled denominator)
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fld tbyte ptr [MAIN_DENOM+esp] ; load the scaled denominator
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fabs
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fld tbyte ptr [MAIN_NUMER+esp] ; load the numerator
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fabs
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rem_large_loop:
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fcom
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fstsw ax
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and eax, 00100h
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jnz rem_no_sub
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fsub st, st(1)
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rem_no_sub:
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fxch
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fmul qword ptr half
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fxch
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sub ecx, 1 ; decrement the loop counter
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jnz rem_large_loop
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mov ebx, [MAIN_NUMER+8+esp] ; sign and exponent of x (numerator)
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fstp tbyte ptr[esp + MAIN_NUMER] ; save result
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fstp st ; toss modified denom
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fld tbyte ptr[esp + MAIN_DENOM_SAVE]
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fld tbyte ptr[big_number] ; force C2 to be set
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fprem
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fstp st
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fld tbyte ptr[esp + MAIN_NUMER] ; restore saved result
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fldcw [esp + MAIN_PREV_CW] ; restore caller's control word
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and ebx, 08000h ; keep sx
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jz rem_done
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fchs
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jmp rem_done
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remainder_hardware_ok:
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fld tbyte ptr [MAIN_DENOM+esp] ; load the denominator
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fld tbyte ptr [MAIN_NUMER+esp] ; load the numerator
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fprem ; and finally do a remainder
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; prem_main_routine end
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rem_done:
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test edx, 03h
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jz rem_exit
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fnstsw [esp + MAIN_FPREM_SW] ; save Q0 Q1 and Q2
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test edx, 01h
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jz do_not_de_scale
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; De-scale the result. Go to pc=80 to prevent from fmul
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; from user precision (fprem does not round the result).
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fnstcw [esp + MAIN_PREV_CW] ; save callers control word
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mov eax, [esp + MAIN_PREV_CW]
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or eax, 0300h ; pc = 80
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mov [esp + MAIN_PATCH_CW], eax
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fldcw [esp + MAIN_PATCH_CW]
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fmul qword ptr one_shr_64
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fldcw [esp + MAIN_PREV_CW] ; restore callers CW
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do_not_de_scale:
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mov eax, [esp + MAIN_FPREM_SW]
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fxch
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fstp st
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fld tbyte ptr[esp + MAIN_DENOM_SAVE]
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fxch
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and eax, 04300h ; restore saved Q0, Q1, Q2
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sub esp, ENV_SIZE
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fnstenv [esp]
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and [esp].STATUS_WORD, 0bcffh
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or [esp].STATUS_WORD, eax
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fldenv [esp]
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add esp, ENV_SIZE
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rem_exit:
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pop ecx
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pop ebx
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pop eax
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CHECKSW ; debug only: save status
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ret
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fprem_common ENDP
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comment ~****************************************************************
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;
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; float frem_chk (float numer, float denom)
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;
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public frem_chk
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frem_chk PROC NEAR
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push edx
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sub esp, STACK_SIZE
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fld dword ptr [STACK_SIZE+8+esp]
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fstp tbyte ptr [NUMER+esp]
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fld dword ptr [STACK_SIZE+12+esp]
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fstp tbyte ptr [DENOM+esp]
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mov edx, 0 ; dx = 1 if denormal extended divisor
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call fprem_common
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fxch
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fstp st
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add esp, STACK_SIZE
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pop edx
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ret
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frem_chk ENDP
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; end frem_chk
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;
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; double drem_chk (double numer, double denom)
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;
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public drem_chk
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drem_chk PROC NEAR
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push edx
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sub esp, STACK_SIZE
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fld qword ptr [STACK_SIZE+8+esp]
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fstp tbyte ptr [NUMER+esp]
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fld qword ptr [STACK_SIZE+16+esp]
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fstp tbyte ptr [DENOM+esp]
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mov edx, 0 ; dx = 1 if denormal extended divisor
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call fprem_common
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fxch
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fstp st
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add esp, STACK_SIZE
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pop edx
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ret
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drem_chk ENDP
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; end drem_chk
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;
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; long double lrem_chk(long double number,long double denom)
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;
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public lrem_chk
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lrem_chk PROC NEAR
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fld tbyte ptr [20+esp]
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fld tbyte ptr [4+esp]
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call fprem_chk
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fxch
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fstp st
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ret
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lrem_chk ENDP
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**********************************************************************~
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;
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; FPREM: ST = remainder(ST, ST(1))
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;
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; Compiler version of the FPREM must preserve the arguments in the floating
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; point stack.
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public __fprem_chk
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defpe __fprem_chk
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push edx
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sub esp, STACK_SIZE
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fstp tbyte ptr [NUMER+esp]
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fstp tbyte ptr [DENOM+esp]
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xor edx, edx
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; prem_main_routine begin
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mov eax,[DENOM+6+esp] ; exponent and high 16 bits of mantissa
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test eax,07fff0000h ; check for denormal
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jz denormal
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call fprem_common
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add esp, STACK_SIZE
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pop edx
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ret
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denormal:
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fld tbyte ptr [DENOM+esp] ; load the denominator
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fld tbyte ptr [NUMER+esp] ; load the numerator
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mov eax, [DENOM+esp] ; test for whole mantissa == 0
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or eax, [DENOM+4+esp] ; test for whole mantissa == 0
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jz remainder_hardware_ok_l ; denominator is zero
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fxch
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fstp tbyte ptr[esp + DENOM_SAVE] ; save org denominator
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fld tbyte ptr[esp + DENOM]
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fxch
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or edx, 02h
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;
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; For this we need pc=80. Also, mask exceptions so we don't take any
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; denormal operand exceptions. It is guaranteed that the descaling
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; later on will take underflow, which is what the hardware would have done
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; on a normal fprem.
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;
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fnstcw [PREV_CW+esp] ; save caller's control word
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mov eax, [PREV_CW+esp]
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or eax, 0033fh ; mask exceptions, pc=80
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mov [PATCH_CW+esp], eax
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fldcw [PATCH_CW+esp] ; mask exceptions & pc=80
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; The denominator is a denormal. For most numerators, scale both numerator
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; and denominator to get rid of denormals. Then execute the common code
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; with the flag set to indicate that the result must be de-scaled.
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; For large numerators this won't work because the scaling would cause
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; overflow. In this case we know the numerator is large, the denominator
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; is small (denormal), so the exponent difference is also large. This means
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; the rem_large code will be used and this code depends on the difference
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; in exponents modulo 64. Adding 64 to the denominators exponent
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; doesn't change the modulo 64 difference. So we can scale the denominator
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; by 64, making it not denormal, and this won't effect the result.
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;
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; To start with, figure out if numerator is large
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mov eax, [esp + NUMER + 8] ; load numerator exponent
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and eax, 7fffh ; isolate numerator exponent
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cmp eax, 7fbeh ; compare Nexp to Maxexp-64
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ja big_numer_rem_de ; jif big numerator
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; So the numerator is not large scale both numerator and denominator
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or edx, 1 ; edx = 1, if denormal extended divisor
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fmul qword ptr one_shl_64 ; make numerator not denormal
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fstp tbyte ptr[esp + NUMER]
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fmul qword ptr one_shl_64 ; make denominator not denormal
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fstp tbyte ptr[esp + DENOM]
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jmp scaling_done
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; The numerator is large. Scale only the denominator, which will not
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; change the result which we know will be partial. Set the scale flag
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; to false.
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big_numer_rem_de:
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; We must do this with pc=80 to avoid rounding to single/double.
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; In this case we do not mask exceptions so that we will take
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; denormal operand, as would the hardware.
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fnstcw [PREV_CW+esp] ; save caller's control word
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mov eax, [PREV_CW+esp]
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or eax, 00300h ; pc=80
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mov [PATCH_CW+esp], eax
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fldcw [PATCH_CW+esp] ; pc=80
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fstp st ; Toss numerator
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fmul qword ptr one_shl_64 ; make denominator not denormal
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fstp tbyte ptr[esp + DENOM]
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; Restore the control word which was fiddled to scale at 80-bit precision.
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; Then call the common code.
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scaling_done:
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fldcw [esp + PREV_CW] ; restore callers control word
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|
call fprem_common
|
|
add esp, STACK_SIZE
|
|
pop edx
|
|
ret
|
|
|
|
remainder_hardware_ok_l:
|
|
fprem ; and finally do a remainder
|
|
|
|
CHECKSW
|
|
|
|
add esp, STACK_SIZE
|
|
pop edx
|
|
ret
|
|
__fprem_chk ENDP
|
|
; end fprem_chk
|
|
|
|
|
|
;
|
|
; FPREM1 code begins here
|
|
;
|
|
|
|
|
|
fprem1_common PROC NEAR
|
|
|
|
push eax
|
|
push ebx
|
|
push ecx
|
|
mov eax, [MAIN_DENOM+6+esp] ; exponent and high 16 bits of mantissa
|
|
xor eax, ONESMASK ; invert bits that have to be one
|
|
test eax, ONESMASK ; check bits that have to be one
|
|
jnz remainder1_hardware_ok
|
|
shr eax, 11
|
|
and eax, 0fh
|
|
cmp byte ptr fprem_risc_table[eax], 0 ; check for (1,4,7,a,d)
|
|
jz remainder1_hardware_ok
|
|
|
|
; The denominator has the bit pattern. Weed out the funny cases like NaNs
|
|
; before applying the software version. Our caller guarantees that the
|
|
; denominator is not a denormal. Here we check for:
|
|
; denominator inf, NaN, unnormal
|
|
; numerator inf, NaN, unnormal, denormal
|
|
|
|
mov eax, [MAIN_DENOM+6+esp] ; exponent and high 16 bits of mantissa
|
|
and eax, 07fff0000h ; mask the exponent only
|
|
cmp eax, 07fff0000h ; check for INF or NaN
|
|
je remainder1_hardware_ok
|
|
mov eax, [MAIN_NUMER+6+esp] ; exponent and high 16 bits of mantissa
|
|
and eax, 07fff0000h ; mask the exponent only
|
|
jz remainder1_hardware_ok ; jif numerator denormal
|
|
cmp eax, 07fff0000h ; check for INF or NaN
|
|
je remainder1_hardware_ok
|
|
mov eax, [esp + MAIN_NUMER + 4] ; high mantissa bits - numerator
|
|
add eax, eax ; set carry if explicit bit set
|
|
jnz remainder1_hardware_ok ; jmp if numerator is unnormal
|
|
mov eax, [esp + MAIN_DENOM + 4] ; high mantissa bits - denominator
|
|
add eax, eax ; set carry if explicit bit set
|
|
jnz remainder1_hardware_ok ; jmp if denominator is unnormal
|
|
|
|
rem1_patch:
|
|
mov eax, [MAIN_DENOM+8+esp] ; sign and exponent of y (denominator)
|
|
and eax, 07fffh ; clear sy
|
|
add eax, 63 ; evaluate ey + 63
|
|
mov ebx, [MAIN_NUMER+8+esp] ; sign and exponent of x (numerator)
|
|
and ebx, 07fffh ; clear sx
|
|
sub ebx, eax ; evaluate the exponent difference (ex - ey)
|
|
ja rem1_large ; if ex > ey + 63, case of large arguments
|
|
rem1_patch_loop:
|
|
mov eax, [MAIN_DENOM+8+esp] ; sign and exponent of y (denominator)
|
|
and eax, 07fffh ; clear sy
|
|
add eax, 10 ; evaluate ey + 10
|
|
mov ebx, [MAIN_NUMER+8+esp] ; sign and exponent of x (numerator)
|
|
and ebx, 07fffh ; clear sx
|
|
sub ebx, eax ; evaluate the exponent difference (ex - ey)
|
|
js remainder1_hardware_ok ; safe if ey + 10 > ex
|
|
fld tbyte ptr [MAIN_NUMER+esp] ; load the numerator
|
|
mov eax, [MAIN_DENOM+8+esp] ; sign and exponent of y (denominator)
|
|
mov ebx, [MAIN_NUMER+8+esp] ; sign and exponent of x (numerator)
|
|
and ebx, 07fffh ; clear sx
|
|
mov ecx, ebx
|
|
sub ebx, eax
|
|
and ebx, 07h
|
|
or ebx, 04h
|
|
sub ecx, ebx
|
|
mov ebx, eax
|
|
and ebx, 08000h ; keep sy
|
|
or ecx, ebx ; merge the sign of y
|
|
mov dword ptr [MAIN_DENOM+8+esp], ecx
|
|
fld tbyte ptr [MAIN_DENOM+esp] ; load the shifted denominator
|
|
mov dword ptr [MAIN_DENOM+8+esp], eax ; restore the initial denominator
|
|
fxch
|
|
fprem ; this rem is safe
|
|
fstp tbyte ptr [MAIN_NUMER+esp] ; update the numerator
|
|
fstp st(0) ; pop the stack
|
|
jmp rem1_patch_loop
|
|
rem1_large:
|
|
test ebx, 02h ; is denominator already saved
|
|
jnz already_saved1
|
|
fld tbyte ptr[esp + MAIN_DENOM]
|
|
fstp tbyte ptr[esp + MAIN_DENOM_SAVE] ; save denominator
|
|
already_saved1:
|
|
; Save user's precision control and institute 80. The fp ops in
|
|
; rem1_large_loop must not round to user's precision (if it is less
|
|
; than 80) because the hardware would not have done so. We are
|
|
; aping the hardware here, which is all extended.
|
|
|
|
fnstcw [esp+MAIN_PREV_CW] ; save caller's control word
|
|
mov eax, dword ptr[esp + MAIN_PREV_CW]
|
|
or eax, 033fh ; mask exceptions, pc=80
|
|
mov [esp + MAIN_PATCH_CW], eax
|
|
fldcw [esp + MAIN_PATCH_CW]
|
|
|
|
mov eax, [MAIN_DENOM+8+esp] ; sign and exponent of y (denominator)
|
|
and eax, 07fffh ; clear sy
|
|
mov ebx, [MAIN_NUMER+8+esp] ; sign and exponent of x (numerator)
|
|
and ebx, 07fffh ; clear sx
|
|
sub ebx, eax ; evaluate the exponent difference
|
|
and ebx, 03fh
|
|
or ebx, 020h
|
|
add ebx, 1
|
|
mov ecx, ebx
|
|
mov eax, [MAIN_DENOM+8+esp] ; sign and exponent of y (denominator)
|
|
mov ebx, [MAIN_NUMER+8+esp] ; sign and exponent of x (numerator)
|
|
and ebx, 07fffh ; clear sx
|
|
and eax, 08000h ; keep sy
|
|
or ebx, eax ; merge the sign of y
|
|
mov dword ptr[MAIN_DENOM+8+esp], ebx ; make ey equal to ex (scaled denominator)
|
|
fld tbyte ptr [MAIN_DENOM+esp] ; load the scaled denominator
|
|
fabs
|
|
fld tbyte ptr [MAIN_NUMER+esp] ; load the numerator
|
|
fabs
|
|
rem1_large_loop:
|
|
fcom
|
|
fstsw ax
|
|
and eax, 00100h
|
|
jnz rem1_no_sub
|
|
fsub st, st(1)
|
|
rem1_no_sub:
|
|
fxch
|
|
fmul qword ptr half
|
|
fxch
|
|
sub ecx, 1 ; decrement the loop counter
|
|
jnz rem1_large_loop
|
|
mov ebx, [MAIN_NUMER+8+esp] ; sign and exponent of x (numerator)
|
|
fstp tbyte ptr[esp + MAIN_NUMER] ; save result
|
|
fstp st ; toss modified denom
|
|
fld tbyte ptr[esp + MAIN_DENOM_SAVE]
|
|
fld tbyte ptr[big_number] ; force C2 to be set
|
|
fprem1
|
|
fstp st
|
|
fld tbyte ptr[esp + MAIN_NUMER] ; restore saved result
|
|
|
|
fldcw [esp + MAIN_PREV_CW] ; restore caller's control word
|
|
and ebx, 08000h ; keep sx
|
|
jz rem1_done
|
|
fchs
|
|
jmp rem1_done
|
|
remainder1_hardware_ok:
|
|
fld tbyte ptr [MAIN_DENOM+esp] ; load the denominator
|
|
fld tbyte ptr [MAIN_NUMER+esp] ; load the numerator
|
|
fprem1 ; and finally do a remainder
|
|
; prem1_main_routine end
|
|
rem1_done:
|
|
test edx, 03h
|
|
jz rem1_exit
|
|
fnstsw [esp + MAIN_FPREM_SW] ; save Q0 Q1 and Q2
|
|
test edx, 01h
|
|
jz do_not_de_scale1
|
|
; De-scale the result. Go to pc=80 to prevent from fmul
|
|
; from user precision (fprem does not round the result).
|
|
fnstcw [esp + MAIN_PREV_CW] ; save callers control word
|
|
mov eax, [esp + MAIN_PREV_CW]
|
|
or eax, 0300h ; pc = 80
|
|
mov [esp + MAIN_PATCH_CW], eax
|
|
fldcw [esp + MAIN_PATCH_CW]
|
|
fmul qword ptr one_shr_64
|
|
fldcw [esp + MAIN_PREV_CW] ; restore callers CW
|
|
do_not_de_scale1:
|
|
mov eax, [esp + MAIN_FPREM_SW]
|
|
fxch
|
|
fstp st
|
|
fld tbyte ptr[esp + MAIN_DENOM_SAVE]
|
|
fxch
|
|
and eax, 04300h ; restore saved Q0, Q1, Q2
|
|
sub esp, ENV_SIZE
|
|
fnstenv [esp]
|
|
and [esp].STATUS_WORD, 0bcffh
|
|
or [esp].STATUS_WORD, eax
|
|
fldenv [esp]
|
|
add esp, ENV_SIZE
|
|
rem1_exit:
|
|
pop ecx
|
|
pop ebx
|
|
pop eax
|
|
CHECKSW ; debug only: save status
|
|
ret
|
|
fprem1_common ENDP
|
|
|
|
|
|
comment ~***************************************************************
|
|
;
|
|
; float frem1_chk (float numer, float denom)
|
|
;
|
|
public frem1_chk
|
|
frem1_chk PROC NEAR
|
|
push edx
|
|
sub esp, STACK_SIZE
|
|
fld dword ptr [STACK_SIZE+8+esp]
|
|
fstp tbyte ptr [NUMER+esp]
|
|
fld dword ptr [STACK_SIZE+12+esp]
|
|
fstp tbyte ptr [DENOM+esp]
|
|
mov edx, 0 ; dx = 1 if denormal extended divisor
|
|
call fprem1_common
|
|
fxch
|
|
fstp st
|
|
add esp, STACK_SIZE
|
|
pop edx
|
|
ret
|
|
frem1_chk ENDP
|
|
; end frem1_chk
|
|
|
|
;
|
|
; double drem1_chk (double numer, double denom)
|
|
;
|
|
public drem1_chk
|
|
drem1_chk PROC NEAR
|
|
push edx
|
|
sub esp, STACK_SIZE
|
|
fld qword ptr [STACK_SIZE+8+esp]
|
|
fstp tbyte ptr [NUMER+esp]
|
|
fld qword ptr [STACK_SIZE+16+esp]
|
|
fstp tbyte ptr [DENOM+esp]
|
|
mov edx, 0 ; dx = 1 if denormal extended divisor
|
|
call fprem1_common
|
|
fxch
|
|
fstp st
|
|
add esp, STACK_SIZE
|
|
pop edx
|
|
ret
|
|
|
|
drem1_chk ENDP
|
|
; end drem1_chk
|
|
|
|
;
|
|
; long double lrem1_chk(long double number,long double denom)
|
|
;
|
|
public lrem1_chk
|
|
lrem1_chk PROC NEAR
|
|
fld tbyte ptr [20+esp]
|
|
fld tbyte ptr [4+esp]
|
|
call fprem1_chk
|
|
fxch
|
|
fstp st
|
|
ret
|
|
lrem1_chk ENDP
|
|
********************************************************************~
|
|
|
|
;
|
|
; FPREM1: ST = remainder(ST, ST(1)) - IEEE version of rounding
|
|
;
|
|
; Compiler version of the FPREM must preserve the arguments in the floating
|
|
; point stack.
|
|
|
|
public __fprem1_chk
|
|
defpe __fprem1_chk
|
|
push edx
|
|
sub esp, STACK_SIZE
|
|
fstp tbyte ptr [NUMER+esp]
|
|
fstp tbyte ptr [DENOM+esp]
|
|
mov edx, 0
|
|
; prem1_main_routine begin
|
|
mov eax,[DENOM+6+esp] ; exponent and high 16 bits of mantissa
|
|
test eax,07fff0000h ; check for denormal
|
|
jz denormal1
|
|
call fprem1_common
|
|
add esp, STACK_SIZE
|
|
pop edx
|
|
ret
|
|
|
|
denormal1:
|
|
fld tbyte ptr [DENOM+esp] ; load the denominator
|
|
fld tbyte ptr [NUMER+esp] ; load the numerator
|
|
mov eax, [DENOM+esp] ; test for whole mantissa == 0
|
|
or eax, [DENOM+4+esp] ; test for whole mantissa == 0
|
|
jz remainder1_hardware_ok_l ; denominator is zero
|
|
fxch
|
|
fstp tbyte ptr[esp + DENOM_SAVE] ; save org denominator
|
|
fld tbyte ptr[esp + DENOM]
|
|
fxch
|
|
or edx, 02h
|
|
;
|
|
; For this we need pc=80. Also, mask exceptions so we don't take any
|
|
; denormal operand exceptions. It is guaranteed that the descaling
|
|
; later on will take underflow, which is what the hardware would have done
|
|
; on a normal fprem.
|
|
;
|
|
fnstcw [PREV_CW+esp] ; save caller's control word
|
|
mov eax, [PREV_CW+esp]
|
|
or eax, 0033fh ; mask exceptions, pc=80
|
|
mov [PATCH_CW+esp], eax
|
|
fldcw [PATCH_CW+esp] ; mask exceptions & pc=80
|
|
|
|
; The denominator is a denormal. For most numerators, scale both numerator
|
|
; and denominator to get rid of denormals. Then execute the common code
|
|
; with the flag set to indicate that the result must be de-scaled.
|
|
; For large numerators this won't work because the scaling would cause
|
|
; overflow. In this case we know the numerator is large, the denominator
|
|
; is small (denormal), so the exponent difference is also large. This means
|
|
; the rem1_large code will be used and this code depends on the difference
|
|
; in exponents modulo 64. Adding 64 to the denominators exponent
|
|
; doesn't change the modulo 64 difference. So we can scale the denominator
|
|
; by 64, making it not denormal, and this won't effect the result.
|
|
;
|
|
; To start with, figure out if numerator is large
|
|
|
|
mov eax, [esp + NUMER + 8] ; load numerator exponent
|
|
and eax, 7fffh ; isolate numerator exponent
|
|
cmp eax, 7fbeh ; compare Nexp to Maxexp-64
|
|
ja big_numer_rem1_de ; jif big numerator
|
|
|
|
; So the numerator is not large scale both numerator and denominator
|
|
|
|
or edx, 1 ; edx = 1, if denormal extended divisor
|
|
fmul qword ptr one_shl_64 ; make numerator not denormal
|
|
fstp tbyte ptr[esp + NUMER]
|
|
fmul qword ptr one_shl_64 ; make denominator not denormal
|
|
fstp tbyte ptr[esp + DENOM]
|
|
jmp scaling_done1
|
|
|
|
; The numerator is large. Scale only the denominator, which will not
|
|
; change the result which we know will be partial. Set the scale flag
|
|
; to false.
|
|
big_numer_rem1_de:
|
|
; We must do this with pc=80 to avoid rounding to single/double.
|
|
; In this case we do not mask exceptions so that we will take
|
|
; denormal operand, as would the hardware.
|
|
fnstcw [PREV_CW+esp] ; save caller's control word
|
|
mov eax, [PREV_CW+esp]
|
|
or eax, 00300h ; pc=80
|
|
mov [PATCH_CW+esp], eax
|
|
fldcw [PATCH_CW+esp] ; pc=80
|
|
|
|
fstp st ; Toss numerator
|
|
fmul qword ptr one_shl_64 ; make denominator not denormal
|
|
fstp tbyte ptr[esp + DENOM]
|
|
|
|
; Restore the control word which was fiddled to scale at 80-bit precision.
|
|
; Then call the common code.
|
|
scaling_done1:
|
|
fldcw [esp + PREV_CW] ; restore callers control word
|
|
call fprem1_common
|
|
add esp, STACK_SIZE
|
|
pop edx
|
|
ret
|
|
|
|
remainder1_hardware_ok_l:
|
|
fprem ; and finally do a remainder
|
|
|
|
CHECKSW
|
|
|
|
add esp, STACK_SIZE
|
|
pop edx
|
|
ret
|
|
__fprem1_chk ENDP
|
|
; end fprem1_chk
|
|
|
|
ifdef DEBUG
|
|
public fpinit
|
|
fpinit PROC NEAR
|
|
fninit
|
|
ret
|
|
fpinit ENDP
|
|
endif
|
|
|
|
CODE32 ENDS
|
|
END
|