1994-10-26 10:48:18 +03:00
|
|
|
* $NetBSD: sgetem.sa,v 1.2 1994/10/26 07:49:45 cgd Exp $
|
|
|
|
|
1994-07-05 21:50:24 +04:00
|
|
|
* MOTOROLA MICROPROCESSOR & MEMORY TECHNOLOGY GROUP
|
|
|
|
* M68000 Hi-Performance Microprocessor Division
|
|
|
|
* M68040 Software Package
|
|
|
|
*
|
|
|
|
* M68040 Software Package Copyright (c) 1993, 1994 Motorola Inc.
|
|
|
|
* All rights reserved.
|
|
|
|
*
|
|
|
|
* THE SOFTWARE is provided on an "AS IS" basis and without warranty.
|
|
|
|
* To the maximum extent permitted by applicable law,
|
|
|
|
* MOTOROLA DISCLAIMS ALL WARRANTIES WHETHER EXPRESS OR IMPLIED,
|
|
|
|
* INCLUDING IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A
|
|
|
|
* PARTICULAR PURPOSE and any warranty against infringement with
|
|
|
|
* regard to the SOFTWARE (INCLUDING ANY MODIFIED VERSIONS THEREOF)
|
|
|
|
* and any accompanying written materials.
|
|
|
|
*
|
|
|
|
* To the maximum extent permitted by applicable law,
|
|
|
|
* IN NO EVENT SHALL MOTOROLA BE LIABLE FOR ANY DAMAGES WHATSOEVER
|
|
|
|
* (INCLUDING WITHOUT LIMITATION, DAMAGES FOR LOSS OF BUSINESS
|
|
|
|
* PROFITS, BUSINESS INTERRUPTION, LOSS OF BUSINESS INFORMATION, OR
|
|
|
|
* OTHER PECUNIARY LOSS) ARISING OF THE USE OR INABILITY TO USE THE
|
|
|
|
* SOFTWARE. Motorola assumes no responsibility for the maintenance
|
|
|
|
* and support of the SOFTWARE.
|
|
|
|
*
|
|
|
|
* You are hereby granted a copyright license to use, modify, and
|
|
|
|
* distribute the SOFTWARE so long as this entire notice is retained
|
|
|
|
* without alteration in any modified and/or redistributed versions,
|
|
|
|
* and that such modified versions are clearly identified as such.
|
|
|
|
* No licenses are granted by implication, estoppel or otherwise
|
|
|
|
* under any patents or trademarks of Motorola, Inc.
|
|
|
|
|
|
|
|
*
|
|
|
|
* sgetem.sa 3.1 12/10/90
|
|
|
|
*
|
|
|
|
* The entry point sGETEXP returns the exponent portion
|
|
|
|
* of the input argument. The exponent bias is removed
|
|
|
|
* and the exponent value is returned as an extended
|
|
|
|
* precision number in fp0. sGETEXPD handles denormalized
|
|
|
|
* numbers.
|
|
|
|
*
|
|
|
|
* The entry point sGETMAN extracts the mantissa of the
|
|
|
|
* input argument. The mantissa is converted to an
|
|
|
|
* extended precision number and returned in fp0. The
|
|
|
|
* range of the result is [1.0 - 2.0).
|
|
|
|
*
|
|
|
|
*
|
|
|
|
* Input: Double-extended number X in the ETEMP space in
|
|
|
|
* the floating-point save stack.
|
|
|
|
*
|
|
|
|
* Output: The functions return exp(X) or man(X) in fp0.
|
|
|
|
*
|
|
|
|
* Modified: fp0.
|
|
|
|
*
|
|
|
|
|
|
|
|
SGETEM IDNT 2,1 Motorola 040 Floating Point Software Package
|
|
|
|
|
|
|
|
section 8
|
|
|
|
|
|
|
|
include fpsp.h
|
|
|
|
|
|
|
|
xref nrm_set
|
|
|
|
|
|
|
|
*
|
|
|
|
* This entry point is used by the unimplemented instruction exception
|
|
|
|
* handler. It points a0 to the input operand.
|
|
|
|
*
|
|
|
|
*
|
|
|
|
*
|
|
|
|
* SGETEXP
|
|
|
|
*
|
|
|
|
|
|
|
|
xdef sgetexp
|
|
|
|
sgetexp:
|
|
|
|
move.w LOCAL_EX(a0),d0 ;get the exponent
|
|
|
|
bclr.l #15,d0 ;clear the sign bit
|
|
|
|
sub.w #$3fff,d0 ;subtract off the bias
|
|
|
|
fmove.w d0,fp0 ;move the exp to fp0
|
|
|
|
rts
|
|
|
|
|
|
|
|
xdef sgetexpd
|
|
|
|
sgetexpd:
|
|
|
|
bclr.b #sign_bit,LOCAL_EX(a0)
|
|
|
|
bsr nrm_set ;normalize (exp will go negative)
|
|
|
|
move.w LOCAL_EX(a0),d0 ;load resulting exponent into d0
|
|
|
|
sub.w #$3fff,d0 ;subtract off the bias
|
|
|
|
fmove.w d0,fp0 ;move the exp to fp0
|
|
|
|
rts
|
|
|
|
*
|
|
|
|
*
|
|
|
|
* This entry point is used by the unimplemented instruction exception
|
|
|
|
* handler. It points a0 to the input operand.
|
|
|
|
*
|
|
|
|
*
|
|
|
|
*
|
|
|
|
* SGETMAN
|
|
|
|
*
|
|
|
|
*
|
|
|
|
* For normalized numbers, leave the mantissa alone, simply load
|
|
|
|
* with an exponent of +/- $3fff.
|
|
|
|
*
|
|
|
|
xdef sgetman
|
|
|
|
sgetman:
|
|
|
|
move.l USER_FPCR(a6),d0
|
|
|
|
andi.l #$ffffff00,d0 ;clear rounding precision and mode
|
|
|
|
fmove.l d0,fpcr ;this fpcr setting is used by the 882
|
|
|
|
move.w LOCAL_EX(a0),d0 ;get the exp (really just want sign bit)
|
|
|
|
or.w #$7fff,d0 ;clear old exp
|
|
|
|
bclr.l #14,d0 ;make it the new exp +-3fff
|
|
|
|
move.w d0,LOCAL_EX(a0) ;move the sign & exp back to fsave stack
|
|
|
|
fmove.x (a0),fp0 ;put new value back in fp0
|
|
|
|
rts
|
|
|
|
|
|
|
|
*
|
|
|
|
* For denormalized numbers, shift the mantissa until the j-bit = 1,
|
|
|
|
* then load the exponent with +/1 $3fff.
|
|
|
|
*
|
|
|
|
xdef sgetmand
|
|
|
|
sgetmand:
|
|
|
|
move.l LOCAL_HI(a0),d0 ;load ms mant in d0
|
|
|
|
move.l LOCAL_LO(a0),d1 ;load ls mant in d1
|
|
|
|
bsr shft ;shift mantissa bits till msbit is set
|
|
|
|
move.l d0,LOCAL_HI(a0) ;put ms mant back on stack
|
|
|
|
move.l d1,LOCAL_LO(a0) ;put ls mant back on stack
|
|
|
|
bra.b sgetman
|
|
|
|
|
|
|
|
*
|
|
|
|
* SHFT
|
|
|
|
*
|
|
|
|
* Shifts the mantissa bits until msbit is set.
|
|
|
|
* input:
|
|
|
|
* ms mantissa part in d0
|
|
|
|
* ls mantissa part in d1
|
|
|
|
* output:
|
|
|
|
* shifted bits in d0 and d1
|
|
|
|
shft:
|
|
|
|
tst.l d0 ;if any bits set in ms mant
|
|
|
|
bne.b upper ;then branch
|
|
|
|
* ;else no bits set in ms mant
|
|
|
|
tst.l d1 ;test if any bits set in ls mant
|
|
|
|
bne.b cont ;if set then continue
|
|
|
|
bra.b shft_end ;else return
|
|
|
|
cont:
|
|
|
|
move.l d3,-(a7) ;save d3
|
|
|
|
exg d0,d1 ;shift ls mant to ms mant
|
|
|
|
bfffo d0{0:32},d3 ;find first 1 in ls mant to d0
|
|
|
|
lsl.l d3,d0 ;shift first 1 to integer bit in ms mant
|
|
|
|
move.l (a7)+,d3 ;restore d3
|
|
|
|
bra.b shft_end
|
|
|
|
upper:
|
|
|
|
|
|
|
|
movem.l d3/d5/d6,-(a7) ;save registers
|
|
|
|
bfffo d0{0:32},d3 ;find first 1 in ls mant to d0
|
|
|
|
lsl.l d3,d0 ;shift ms mant until j-bit is set
|
|
|
|
move.l d1,d6 ;save ls mant in d6
|
|
|
|
lsl.l d3,d1 ;shift ls mant by count
|
|
|
|
move.l #32,d5
|
|
|
|
sub.l d3,d5 ;sub 32 from shift for ls mant
|
|
|
|
lsr.l d5,d6 ;shift off all bits but those that will
|
|
|
|
* ;be shifted into ms mant
|
|
|
|
or.l d6,d0 ;shift the ls mant bits into the ms mant
|
|
|
|
movem.l (a7)+,d3/d5/d6 ;restore registers
|
|
|
|
shft_end:
|
|
|
|
rts
|
|
|
|
|
|
|
|
end
|