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341 lines
9.2 KiB
Plaintext
341 lines
9.2 KiB
Plaintext
;
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; File: XSNAN.a
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;
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; Contains: Routines for handling the SNAN exception
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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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; <2+> 6/24/91 BG Changed snanwrt_dn: for opclass 0/2 enabled case,
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; sign of destination NaN has priority.
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; <2> 3/30/91 BG Rolling in Jon Okada's latest changes.
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; <1> 12/14/90 BG First checked into TERROR/BBS.
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; xsnan.a
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; Based upon Motorola file 'x_snan.sa'.
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; CHANGE LOG:
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; 09 Jan 91 JPO Inserted label "snan" at beginning of code.
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; Deleted unreferenced labels "ck_inex", "take_inex",
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; "wrt_word", and "dst_nan". Renamed labels "loop1",
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; "loop2", and "wrt_dn" to "snanloop1", "snanloop2",
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; and "snanwrt_dn", respectively. Modified branching
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; to user SNAN and INEX handlers. Modified code to
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; read DST register number in "snanwrt_dn". Modified
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; subroutine 'move_out' to avoid calling 'mem_write'.
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; Changed "bra fpsp_done" to "rte".
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; 27 May 91 JPO For opclass 0/2 enabled case, sign of destination NaN
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; has priority.
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;
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*
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* x_snan.sa 3.1 12/10/90
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*
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* fpsp_snan --- FPSP handler for signalling NAN exception
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*
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* SNAN for float -> integer conversions (integer conversion of
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* an SNAN) is a non-maskable run-time exception.
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*
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* For trap disabled the 040 does the following:
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* If the dest data format is s, d, or x, then the SNAN bit in the NAN
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* is set to one and the resulting non-signaling NAN (truncated if
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* necessary) is transferred to the dest. If the dest format is b, w,
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* or l, then garbage is written to the dest (actually the upper 32 bits
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* of the mantissa are sent to the integer unit).
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*
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* For trap enabled the 040 does the following:
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* If the inst is move_out, then the results are the same as for trap
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* disabled with the exception posted. If the instruction is not move_
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* out, the dest. is not modified, and the exception is posted.
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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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* X_SNAN IDNT 2,1 Motorola 040 Floating Point Software Package
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snan: ; label inserted <1/9/91, JPO>
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fpsp_snan:
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link a6,#-LOCAL_SIZE
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fsave -(a7)
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movem.l d0-d1/a0-a1,USER_DA(a6)
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fmovem.x fp0-fp3,USER_FP0(a6)
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fmovem.l fpcr/fpsr/fpiar,USER_FPCR(a6)
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*
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* Check if trap enabled
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*
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btst.b #snan_bit,FPCR_ENABLE(a6)
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bne.b ena ;If enabled, then branch
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bsr move_out ;else SNAN disabled
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*
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* It is possible to have an inex1 exception with the
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* snan. If the inex enable bit is set in the FPCR, and either
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* inex2 or inex1 occured, we must clean up and branch to the
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* real inex handler.
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*
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;ck_inex: ; label DELETED <1/9/91, JPO>
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move.b FPCR_ENABLE(a6),d0
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and.b FPSR_EXCEPT(a6),d0
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andi.b #$3,d0
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beq.b end_snan
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*
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* Inexact enabled and reported, and we must take an inexact exception.
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*
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;take_inex: ; label DELETED <1/9/91, JPO>
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move.b #INEX_VEC,EXC_VEC+1(a6)
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movem.l USER_DA(a6),d0-d1/a0-a1
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fmovem.x USER_FP0(a6),fp0-fp3
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fmovem.l USER_FPCR(a6),fpcr/fpsr/fpiar
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frestore (a7)+
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unlk a6
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; bra.l real_inex ; DELETED <1/9/91, JPO>
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move.l ($00C4).W,-(sp) ; push vector to user INEX handler <1/9/91, JPO>
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rts ; execute user's handler <1/9/91, JPO>
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*
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* SNAN is enabled. Check if inst is move_out.
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* Make any corrections to the 040 output as necessary.
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*
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ena:
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btst.b #5,CMDREG1B(a6) ;if set, inst is move out
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beq.w not_out
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bsr move_out
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report_snan:
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move.b (a7),VER_TMP(a6)
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cmpi.b #VER_40,(a7) ;test for orig unimp frame
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bne.b ck_rev
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moveq.l #13,d0 ;need to zero 14 lwords
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bra.b rep_con
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ck_rev:
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moveq.l #11,d0 ;need to zero 12 lwords
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rep_con:
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clr.l (a7)
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snanloop1: ; label renamed <1/9/91, JPO>
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clr.l -(a7) ;clear and dec a7
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dbra.w d0,snanloop1 ; label renamed <1/9/91, JPO>
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move.b VER_TMP(a6),(a7) ;format a busy frame
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move.b #BUSY_SIZE-4,1(a7)
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move.l USER_FPSR(a6),FPSR_SHADOW(a6)
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or.l #sx_mask,E_BYTE(a6)
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movem.l USER_DA(a6),d0-d1/a0-a1
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fmovem.x USER_FP0(a6),fp0-fp3
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fmovem.l USER_FPCR(a6),fpcr/fpsr/fpiar
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frestore (a7)+
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unlk a6
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; bra.l real_snan ; DELETED <1/9/91, JPO>
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move.l (FPSNAN_VEC040).W,-(sp) ; push vector to user handler <1/9/91, JPO>
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rts ; execute user handler <1/9/91, JPO>
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*
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* Exit snan handler by expanding the unimp frame into a busy frame
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*
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end_snan:
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bclr.b #E1,E_BYTE(a6)
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move.b (a7),VER_TMP(a6)
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cmpi.b #VER_40,(a7) ;test for orig unimp frame
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bne.b ck_rev2
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moveq.l #13,d0 ;need to zero 14 lwords
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bra.b rep_con2
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ck_rev2:
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moveq.l #11,d0 ;need to zero 12 lwords
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rep_con2:
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clr.l (a7)
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snanloop2: ; label renamed <1/9/91, JPO>
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clr.l -(a7) ;clear and dec a7
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dbra.w d0,snanloop2 ; label renamed <1/9/91, JPO>
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move.b VER_TMP(a6),(a7) ;format a busy frame
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move.b #BUSY_SIZE-4,1(a7) ;write busy size
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move.l USER_FPSR(a6),FPSR_SHADOW(a6)
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or.l #sx_mask,E_BYTE(a6)
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movem.l USER_DA(a6),d0-d1/a0-a1
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fmovem.x USER_FP0(a6),fp0-fp3
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fmovem.l USER_FPCR(a6),fpcr/fpsr/fpiar
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frestore (a7)+
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unlk a6
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; bra.l fpsp_done ; deleted <1/9/91, JPO>
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rte ; <1/9/91, JPO>
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*
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* Move_out
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*
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move_out:
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move.l EXC_EA(a6),a0 ;get <ea> from exc frame
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bfextu CMDREG1B(a6){3:3},d0 ;move rx field to d0{2:0}
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cmpi.l #0,d0 ;check for long
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beq.b sto_long ;branch if move_out long
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cmpi.l #4,d0 ;check for word
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beq.b sto_word ;branch if move_out word
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cmpi.l #6,d0 ;check for byte
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beq.b sto_byte ;branch if move_out byte
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*
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* Not byte, word or long
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*
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rts
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*
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* Get the 32 most significant bits of etemp mantissa
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*
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sto_long:
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move.l ETEMP_HI(a6),d1
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move.l #4,d0 ;load byte count
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*
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* Set signalling nan bit
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*
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bset.l #30,d1
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*
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* Store to the users destination address
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*
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tst.l a0 ;check if <ea> is 0
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beq.b snanwrt_dn ;destination is a data register - label renamed <1/9/91, JPO>
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; move.l d1,-(a7) ;move the snan onto the stack - DELETED <1/9/91, JPO>
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; move.l a0,a1 ;load dest addr into a1 - DELETED <1/9/91, JPO>
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; move.l a7,a0 ;load src addr of snan into a0 - DELETED <1/9/91, JPO>
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; bsr mem_write ;write snan to user memory - DELETED <1/9/91, JPO>
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; move.l (a7)+,d1 ;clear off stack - DELETED <1/9/91, JPO>
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move.l d1,(a0) ; write snan to <ea> <1/9/91, JPO>
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rts
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*
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* Get the 16 most significant bits of etemp mantissa
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*
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sto_word:
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move.l ETEMP_HI(a6),d1
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move.l #2,d0 ;load byte count
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*
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* Set signalling nan bit
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*
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bset.l #30,d1
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*
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* Store to the users destination address
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*
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tst.l a0 ;check if <ea> is 0
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beq.b snanwrt_dn ;destination is a data register - label renamed <1/9/91, JPO>
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; move.l d1,-(a7) ;move the snan onto the stack - DELETED <1/9/91, JPO>
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; move.l a0,a1 ;load dest addr into a1 - DELETED <1/9/91, JPO>
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; move.l a7,a0 ;point to low word - DELETED <1/9/91, JPO>
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; bsr mem_write ;write snan to user memory - DELETED <1/9/91, JPO>
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; move.l (a7)+,d1 ;clear off stack - DELETED <1/9/91, JPO>
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swap d1 ; write high word of d1 to <ea> <1/9/91, JPO>
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move.w d1,(a0)
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swap d1 ; restore d1 <1/9/91, JPO>
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rts
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*
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* Get the 8 most significant bits of etemp mantissa
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*
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sto_byte:
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move.l ETEMP_HI(a6),d1
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move.l #1,d0 ;load byte count
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*
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* Set signalling nan bit
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*
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bset.l #30,d1
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*
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* Store to the users destination address
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*
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tst.l a0 ;check if <ea> is 0
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beq.b snanwrt_dn ;destination is a data register - label renamed <1/9/91, JPO>
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; move.l d1,-(a7) ;move the snan onto the stack - DELETED <1/9/91, JPO>
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; move.l a0,a1 ;load dest addr into a1 - DELETED <1/9/91, JPO>
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; move.l a7,a0 ;point to source byte - DELETED <1/9/91, JPO>
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; bsr mem_write ;write snan to user memory - DELETED <1/9/91, JPO>
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; move.l (a7)+,d1 ;clear off stack - DELETED <1/9/91, JPO>
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rol.l #8,d1 ; write high byte of d1 to <ea> <1/9/91, JPO>
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move.b d1,(a0)
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ror.l #8,d1 ; restore d1 <1/9/91, JPO>
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rts
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*
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* snanwrt_dn --- write to a data register - label renamed <1/9/91, JPO>
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*
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* We get here with D1 containing the data to write and D0 the
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* number of bytes to write: 1=byte,2=word,4=long.
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*
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snanwrt_dn: ; label renamed <1/9/91, JPO>
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move.l d1,L_SCR1(a6) ;data
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; move.l d0,-(a7) ;size - DELETED <1/9/91, JPO>
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; bsr.l get_fline ;returns fline word in d0 - DELETED <1/9/91, JPO>
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; move.l d0,d1 ; DELETED <1/9/91, JPO>
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; andi.l #$7,d1 ;d1 now holds register number - DELETED <1/9/91, JPO>
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; move.l (sp)+,d0 ;get original size - DELETED <1/9/91, JPO>
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movea.l USER_FPIAR(a6),a0 ; return fline word in d1.w <1/9/91, JPO>
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move.w (a0),d1 ; <1/9/91, JPO>
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andi.l #7,d1 ; get register number <1/9/91, JPO>
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cmpi.l #4,d0
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beq.b wrt_long
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cmpi.l #2,d0
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bne.b wrt_byte
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;wrt_word: ; label DELETED <1/9/91, JPO>
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or.l #$8,d1
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bra reg_dest
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wrt_long:
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or.l #$10,d1
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bra reg_dest
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wrt_byte:
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bra reg_dest
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*
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* Check if it is a src nan or dst nan
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*
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not_out:
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move.l DTAG(a6),d0
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bfextu d0{0:3},d0 ;isolate dtag in lsbs
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cmpi.b #3,d0 ;check for nan in destination
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bne.b issrc ;destination nan has priority
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;dst_nan: ; label DELETED <1/9/91, JPO>
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; btst.b #6,FPTEMP_HI(a6) ;check if dest nan is an snan - DELETED <5/27/91> <T3>
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; bne.b issrc ;no, so check source for snan - DELETED <5/27/91> <T3>
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move.w FPTEMP_EX(a6),d0
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bra.b cont
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issrc:
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move.w ETEMP_EX(a6),d0
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cont:
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btst.l #15,d0 ;test for sign of snan
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beq.b clr_neg
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bset.b #neg_bit,FPSR_CC(a6)
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bra.w report_snan
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clr_neg:
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bclr.b #neg_bit,FPSR_CC(a6)
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bra.w report_snan
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