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175 lines
4.8 KiB
Plaintext
175 lines
4.8 KiB
Plaintext
;
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; File: MoveCR.a
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;
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; Contains: Emulation of the unimplemented FMOVECR instruction
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;
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; Originally Written by: Motorola Inc.
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; Adapted to Apple/MPW: Jon Okada
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;
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; Copyright: © 1990, 1991 by Apple Computer, Inc., all rights reserved.
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;
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; This file is used in these builds: Mac32
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;
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; Change History (most recent first):
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;
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; <1> 3/30/91 BG First checked into TERROR/BBS.
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;
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; movecr.a
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; Based upon Motorola file 'smovecr.sa'.
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; CHANGE LOG:
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; 07 Jan 91 JPO Deleted constant FZERO and embedded its value in
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; the FMOVE instruction which referenced it. Renamed
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; label "not_ext" to "cr_notext" to avoid duplicate symbol.
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;
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*
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* smovecr.sa 3.1 12/10/90
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*
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* The entry point sMOVECR returns the constant at the
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* offset given in the instruction field.
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*
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* Input: An offset in the instruction word.
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*
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* Output: The constant rounded to the user's rounding
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* mode unchecked for overflow.
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*
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* Modified: fp0.
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*
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*
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* Copyright (C) Motorola, Inc. 1990
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* All Rights Reserved
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*
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* THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA
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* The copyright notice above does not evidence any
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* actual or intended publication of such source code.
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* SMOVECR IDNT 2,1 Motorola 040 Floating Point Software Package
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;FZERO dc.l 00000000 ; deleted <1/7/91, JPO>
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*
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* FMOVECR
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*
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smovcr:
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bfextu CMDREG1B(a6){9:7},d0 ;get offset
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bfextu USER_FPCR(a6){26:2},d1 ;get rmode
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*
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* check range of offset
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*
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tst.b d0 ;if zero, offset is to pi
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beq.b PI_TBL ;it is pi
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cmpi.b #$0a,d0 ;check range $01 - $0a
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ble.b Z_VAL ;if in this range, return zero
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cmpi.b #$0e,d0 ;check range $0b - $0e
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ble.b SM_TBL ;valid constants in this range
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cmpi.b #$2f,d0 ;check range $10 - $2f
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ble.b Z_VAL ;if in this range, return zero
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cmpi.b #$3f,d0 ;check range $30 - $3f
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ble.b BG_TBL ;valid constants in this range
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Z_VAL:
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fmove.b #0,fp0 ; return zero <1/7/91, JPO>
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rts
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PI_TBL:
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tst.b d1 ;offset is zero, check for rmode
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beq.b PI_RN ;if zero, rn mode
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cmpi.b #$3,d1 ;check for rp
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beq.b PI_RP ;if 3, rp mode
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PI_RZRM:
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lea.l PIRZRM,a0 ;rmode is rz or rm, load PIRZRM in a0
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bra set_finx
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PI_RN:
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lea.l PIRN,a0 ;rmode is rn, load PIRN in a0
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bra set_finx
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PI_RP:
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lea.l PIRP,a0 ;rmode is rp, load PIRP in a0
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bra.b set_finx
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SM_TBL:
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subi.l #$b,d0 ;make offset in 0 - 4 range
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tst.b d1 ;check for rmode
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beq.b SM_RN ;if zero, rn mode
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cmpi.b #$3,d1 ;check for rp
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beq.b SM_RP ;if 3, rp mode
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SM_RZRM:
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lea.l SMALRZRM,a0 ;rmode is rz or rm, load SMRZRM in a0
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cmpi.b #$2,d0 ;check if result is inex
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ble.b set_finx ;if 0 - 2, it is inexact
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bra.b no_finx ;if 3, it is exact
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SM_RN:
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lea.l SMALRN,a0 ;rmode is rn, load SMRN in a0
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cmpi.b #$2,d0 ;check if result is inex
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ble.b set_finx ;if 0 - 2, it is inexact
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bra.b no_finx ;if 3, it is exact
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SM_RP:
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lea.l SMALRP,a0 ;rmode is rp, load SMRP in a0
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cmpi.b #$2,d0 ;check if result is inex
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ble.b set_finx ;if 0 - 2, it is inexact
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bra.b no_finx ;if 3, it is exact
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BG_TBL:
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subi.l #$30,d0 ;make offset in 0 - f range
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tst.b d1 ;check for rmode
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beq.b BG_RN ;if zero, rn mode
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cmpi.b #$3,d1 ;check for rp
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beq.b BG_RP ;if 3, rp mode
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BG_RZRM:
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lea.l BIGRZRM,a0 ;rmode is rz or rm, load BGRZRM in a0
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cmpi.b #$1,d0 ;check if result is inex
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ble.b set_finx ;if 0 - 1, it is inexact
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cmpi.b #$7,d0 ;second check
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ble.b no_finx ;if 0 - 7, it is exact
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bra.b set_finx ;if 8 - f, it is inexact
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BG_RN:
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lea.l BIGRN,a0 ;rmode is rn, load BGRN in a0
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cmpi.b #$1,d0 ;check if result is inex
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ble.b set_finx ;if 0 - 1, it is inexact
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cmpi.b #$7,d0 ;second check
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ble.b no_finx ;if 0 - 7, it is exact
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bra.b set_finx ;if 8 - f, it is inexact
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BG_RP:
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lea.l BIGRP,a0 ;rmode is rp, load SMRP in a0
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cmpi.b #$1,d0 ;check if result is inex
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ble.b set_finx ;if 0 - 1, it is inexact
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cmpi.b #$7,d0 ;second check
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ble.b no_finx ;if 0 - 7, it is exact
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* bra set_finx ;if 8 - f, it is inexact
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set_finx:
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or.l #inx2a_mask,USER_FPSR(a6) ;set inex2/ainex
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no_finx:
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mulu.l #12,d0 ;use offset to point into tables
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move.l d1,L_SCR1(a6) ;load mode for round call
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bfextu USER_FPCR(a6){24:2},d1 ;get precision
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tst.l d1 ;check if extended precision
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*
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* Precision is extended
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*
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bne.b cr_notext ;if extended, do not call round - label renamed <1/7/91, JPO>
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fmovem.x (a0,d0),fp0 ;return result in fp0
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rts
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*
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* Precision is single or double
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*
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cr_notext: ; label renamed <1/7/91, JPO>
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swap d1 ;rnd prec in upper word of d1
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add.l L_SCR1(a6),d1 ;merge rmode in low word of d1
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move.l (a0,d0),FP_SCR1(a6) ;load first word to temp storage
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move.l 4(a0,d0),FP_SCR1+4(a6) ;load second word
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move.l 8(a0,d0),FP_SCR1+8(a6) ;load third word
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clr.l d0 ;clear g,r,s
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lea FP_SCR1(a6),a0
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btst.b #sign_bit,LOCAL_EX(a0)
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sne LOCAL_SGN(a0) ;convert to internal ext. format
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bsr round ;go round the mantissa
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bfclr LOCAL_SGN(a0){0:8} ;convert back to IEEE ext format
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beq.b fin_fcr
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bset.b #sign_bit,LOCAL_EX(a0)
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fin_fcr:
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fmovem.x (a0),fp0
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rts
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