supermario/base/SuperMarioProj.1994-02-09/OS/FPUEmulation/XSNAN.a
2019-06-29 23:17:50 +08:00

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;
; File: XSNAN.a
;
; Contains: Routines for handling the SNAN exception
;
; Originally Written by: Motorola Inc.
; Adapted to Apple/MPW: Jon Okada
;
; Copyright: © 1990, 1991 by Apple Computer, Inc., all rights reserved.
;
; This file is used in these builds: Mac32
;
; Change History (most recent first):
;
; <2+> 6/24/91 BG Changed snanwrt_dn: for opclass 0/2 enabled case,
; sign of destination NaN has priority.
; <2> 3/30/91 BG Rolling in Jon Okada's latest changes.
; <1> 12/14/90 BG First checked into TERROR/BBS.
; xsnan.a
; Based upon Motorola file 'x_snan.sa'.
; CHANGE LOG:
; 09 Jan 91 JPO Inserted label "snan" at beginning of code.
; Deleted unreferenced labels "ck_inex", "take_inex",
; "wrt_word", and "dst_nan". Renamed labels "loop1",
; "loop2", and "wrt_dn" to "snanloop1", "snanloop2",
; and "snanwrt_dn", respectively. Modified branching
; to user SNAN and INEX handlers. Modified code to
; read DST register number in "snanwrt_dn". Modified
; subroutine 'move_out' to avoid calling 'mem_write'.
; Changed "bra fpsp_done" to "rte".
; 27 May 91 JPO For opclass 0/2 enabled case, sign of destination NaN
; has priority.
;
*
* x_snan.sa 3.1 12/10/90
*
* fpsp_snan --- FPSP handler for signalling NAN exception
*
* SNAN for float -> integer conversions (integer conversion of
* an SNAN) is a non-maskable run-time exception.
*
* For trap disabled the 040 does the following:
* If the dest data format is s, d, or x, then the SNAN bit in the NAN
* is set to one and the resulting non-signaling NAN (truncated if
* necessary) is transferred to the dest. If the dest format is b, w,
* or l, then garbage is written to the dest (actually the upper 32 bits
* of the mantissa are sent to the integer unit).
*
* For trap enabled the 040 does the following:
* If the inst is move_out, then the results are the same as for trap
* disabled with the exception posted. If the instruction is not move_
* out, the dest. is not modified, and the exception is posted.
*
* Copyright (C) Motorola, Inc. 1990
* All Rights Reserved
*
* THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA
* The copyright notice above does not evidence any
* actual or intended publication of such source code.
* X_SNAN IDNT 2,1 Motorola 040 Floating Point Software Package
snan: ; label inserted <1/9/91, JPO>
fpsp_snan:
link a6,#-LOCAL_SIZE
fsave -(a7)
movem.l d0-d1/a0-a1,USER_DA(a6)
fmovem.x fp0-fp3,USER_FP0(a6)
fmovem.l fpcr/fpsr/fpiar,USER_FPCR(a6)
*
* Check if trap enabled
*
btst.b #snan_bit,FPCR_ENABLE(a6)
bne.b ena ;If enabled, then branch
bsr move_out ;else SNAN disabled
*
* It is possible to have an inex1 exception with the
* snan. If the inex enable bit is set in the FPCR, and either
* inex2 or inex1 occured, we must clean up and branch to the
* real inex handler.
*
;ck_inex: ; label DELETED <1/9/91, JPO>
move.b FPCR_ENABLE(a6),d0
and.b FPSR_EXCEPT(a6),d0
andi.b #$3,d0
beq.b end_snan
*
* Inexact enabled and reported, and we must take an inexact exception.
*
;take_inex: ; label DELETED <1/9/91, JPO>
move.b #INEX_VEC,EXC_VEC+1(a6)
movem.l USER_DA(a6),d0-d1/a0-a1
fmovem.x USER_FP0(a6),fp0-fp3
fmovem.l USER_FPCR(a6),fpcr/fpsr/fpiar
frestore (a7)+
unlk a6
; bra.l real_inex ; DELETED <1/9/91, JPO>
move.l ($00C4).W,-(sp) ; push vector to user INEX handler <1/9/91, JPO>
rts ; execute user's handler <1/9/91, JPO>
*
* SNAN is enabled. Check if inst is move_out.
* Make any corrections to the 040 output as necessary.
*
ena:
btst.b #5,CMDREG1B(a6) ;if set, inst is move out
beq.w not_out
bsr move_out
report_snan:
move.b (a7),VER_TMP(a6)
cmpi.b #VER_40,(a7) ;test for orig unimp frame
bne.b ck_rev
moveq.l #13,d0 ;need to zero 14 lwords
bra.b rep_con
ck_rev:
moveq.l #11,d0 ;need to zero 12 lwords
rep_con:
clr.l (a7)
snanloop1: ; label renamed <1/9/91, JPO>
clr.l -(a7) ;clear and dec a7
dbra.w d0,snanloop1 ; label renamed <1/9/91, JPO>
move.b VER_TMP(a6),(a7) ;format a busy frame
move.b #BUSY_SIZE-4,1(a7)
move.l USER_FPSR(a6),FPSR_SHADOW(a6)
or.l #sx_mask,E_BYTE(a6)
movem.l USER_DA(a6),d0-d1/a0-a1
fmovem.x USER_FP0(a6),fp0-fp3
fmovem.l USER_FPCR(a6),fpcr/fpsr/fpiar
frestore (a7)+
unlk a6
; bra.l real_snan ; DELETED <1/9/91, JPO>
move.l (FPSNAN_VEC040).W,-(sp) ; push vector to user handler <1/9/91, JPO>
rts ; execute user handler <1/9/91, JPO>
*
* Exit snan handler by expanding the unimp frame into a busy frame
*
end_snan:
bclr.b #E1,E_BYTE(a6)
move.b (a7),VER_TMP(a6)
cmpi.b #VER_40,(a7) ;test for orig unimp frame
bne.b ck_rev2
moveq.l #13,d0 ;need to zero 14 lwords
bra.b rep_con2
ck_rev2:
moveq.l #11,d0 ;need to zero 12 lwords
rep_con2:
clr.l (a7)
snanloop2: ; label renamed <1/9/91, JPO>
clr.l -(a7) ;clear and dec a7
dbra.w d0,snanloop2 ; label renamed <1/9/91, JPO>
move.b VER_TMP(a6),(a7) ;format a busy frame
move.b #BUSY_SIZE-4,1(a7) ;write busy size
move.l USER_FPSR(a6),FPSR_SHADOW(a6)
or.l #sx_mask,E_BYTE(a6)
movem.l USER_DA(a6),d0-d1/a0-a1
fmovem.x USER_FP0(a6),fp0-fp3
fmovem.l USER_FPCR(a6),fpcr/fpsr/fpiar
frestore (a7)+
unlk a6
; bra.l fpsp_done ; deleted <1/9/91, JPO>
rte ; <1/9/91, JPO>
*
* Move_out
*
move_out:
move.l EXC_EA(a6),a0 ;get <ea> from exc frame
bfextu CMDREG1B(a6){3:3},d0 ;move rx field to d0{2:0}
cmpi.l #0,d0 ;check for long
beq.b sto_long ;branch if move_out long
cmpi.l #4,d0 ;check for word
beq.b sto_word ;branch if move_out word
cmpi.l #6,d0 ;check for byte
beq.b sto_byte ;branch if move_out byte
*
* Not byte, word or long
*
rts
*
* Get the 32 most significant bits of etemp mantissa
*
sto_long:
move.l ETEMP_HI(a6),d1
move.l #4,d0 ;load byte count
*
* Set signalling nan bit
*
bset.l #30,d1
*
* Store to the users destination address
*
tst.l a0 ;check if <ea> is 0
beq.b snanwrt_dn ;destination is a data register - label renamed <1/9/91, JPO>
; move.l d1,-(a7) ;move the snan onto the stack - DELETED <1/9/91, JPO>
; move.l a0,a1 ;load dest addr into a1 - DELETED <1/9/91, JPO>
; move.l a7,a0 ;load src addr of snan into a0 - DELETED <1/9/91, JPO>
; bsr mem_write ;write snan to user memory - DELETED <1/9/91, JPO>
; move.l (a7)+,d1 ;clear off stack - DELETED <1/9/91, JPO>
move.l d1,(a0) ; write snan to <ea> <1/9/91, JPO>
rts
*
* Get the 16 most significant bits of etemp mantissa
*
sto_word:
move.l ETEMP_HI(a6),d1
move.l #2,d0 ;load byte count
*
* Set signalling nan bit
*
bset.l #30,d1
*
* Store to the users destination address
*
tst.l a0 ;check if <ea> is 0
beq.b snanwrt_dn ;destination is a data register - label renamed <1/9/91, JPO>
; move.l d1,-(a7) ;move the snan onto the stack - DELETED <1/9/91, JPO>
; move.l a0,a1 ;load dest addr into a1 - DELETED <1/9/91, JPO>
; move.l a7,a0 ;point to low word - DELETED <1/9/91, JPO>
; bsr mem_write ;write snan to user memory - DELETED <1/9/91, JPO>
; move.l (a7)+,d1 ;clear off stack - DELETED <1/9/91, JPO>
swap d1 ; write high word of d1 to <ea> <1/9/91, JPO>
move.w d1,(a0)
swap d1 ; restore d1 <1/9/91, JPO>
rts
*
* Get the 8 most significant bits of etemp mantissa
*
sto_byte:
move.l ETEMP_HI(a6),d1
move.l #1,d0 ;load byte count
*
* Set signalling nan bit
*
bset.l #30,d1
*
* Store to the users destination address
*
tst.l a0 ;check if <ea> is 0
beq.b snanwrt_dn ;destination is a data register - label renamed <1/9/91, JPO>
; move.l d1,-(a7) ;move the snan onto the stack - DELETED <1/9/91, JPO>
; move.l a0,a1 ;load dest addr into a1 - DELETED <1/9/91, JPO>
; move.l a7,a0 ;point to source byte - DELETED <1/9/91, JPO>
; bsr mem_write ;write snan to user memory - DELETED <1/9/91, JPO>
; move.l (a7)+,d1 ;clear off stack - DELETED <1/9/91, JPO>
rol.l #8,d1 ; write high byte of d1 to <ea> <1/9/91, JPO>
move.b d1,(a0)
ror.l #8,d1 ; restore d1 <1/9/91, JPO>
rts
*
* snanwrt_dn --- write to a data register - label renamed <1/9/91, JPO>
*
* We get here with D1 containing the data to write and D0 the
* number of bytes to write: 1=byte,2=word,4=long.
*
snanwrt_dn: ; label renamed <1/9/91, JPO>
move.l d1,L_SCR1(a6) ;data
; move.l d0,-(a7) ;size - DELETED <1/9/91, JPO>
; bsr.l get_fline ;returns fline word in d0 - DELETED <1/9/91, JPO>
; move.l d0,d1 ; DELETED <1/9/91, JPO>
; andi.l #$7,d1 ;d1 now holds register number - DELETED <1/9/91, JPO>
; move.l (sp)+,d0 ;get original size - DELETED <1/9/91, JPO>
movea.l USER_FPIAR(a6),a0 ; return fline word in d1.w <1/9/91, JPO>
move.w (a0),d1 ; <1/9/91, JPO>
andi.l #7,d1 ; get register number <1/9/91, JPO>
cmpi.l #4,d0
beq.b wrt_long
cmpi.l #2,d0
bne.b wrt_byte
;wrt_word: ; label DELETED <1/9/91, JPO>
or.l #$8,d1
bra reg_dest
wrt_long:
or.l #$10,d1
bra reg_dest
wrt_byte:
bra reg_dest
*
* Check if it is a src nan or dst nan
*
not_out:
move.l DTAG(a6),d0
bfextu d0{0:3},d0 ;isolate dtag in lsbs
cmpi.b #3,d0 ;check for nan in destination
bne.b issrc ;destination nan has priority
;dst_nan: ; label DELETED <1/9/91, JPO>
; btst.b #6,FPTEMP_HI(a6) ;check if dest nan is an snan - DELETED <5/27/91> <T3>
; bne.b issrc ;no, so check source for snan - DELETED <5/27/91> <T3>
move.w FPTEMP_EX(a6),d0
bra.b cont
issrc:
move.w ETEMP_EX(a6),d0
cont:
btst.l #15,d0 ;test for sign of snan
beq.b clr_neg
bset.b #neg_bit,FPSR_CC(a6)
bra.w report_snan
clr_neg:
bclr.b #neg_bit,FPSR_CC(a6)
bra.w report_snan