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* $NetBSD: sint.sa,v 1.2 1994/10/26 07:49:48 cgd Exp $
* 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.
*
* sint.sa 3.1 12/10/90
*
* The entry point sINT computes the rounded integer
* equivalent of the input argument, sINTRZ computes
* the integer rounded to zero of the input argument.
*
* Entry points sint and sintrz are called from do_func
* to emulate the fint and fintrz unimplemented instructions,
* respectively. Entry point sintdo is used by bindec.
*
* Input: (Entry points sint and sintrz) Double-extended
* number X in the ETEMP space in the floating-point
* save stack.
* (Entry point sintdo) Double-extended number X in
* location pointed to by the address register a0.
* (Entry point sintd) Double-extended denormalized
* number X in the ETEMP space in the floating-point
* save stack.
*
* Output: The function returns int(X) or intrz(X) in fp0.
*
* Modifies: fp0.
*
* Algorithm: (sint and sintrz)
*
* 1. If exp(X) >= 63, return X.
* If exp(X) < 0, return +/- 0 or +/- 1, according to
* the rounding mode.
*
* 2. (X is in range) set rsc = 63 - exp(X). Unnormalize the
* result to the exponent $403e.
*
* 3. Round the result in the mode given in USER_FPCR. For
* sintrz, force round-to-zero mode.
*
* 4. Normalize the rounded result; store in fp0.
*
* For the denormalized cases, force the correct result
* for the given sign and rounding mode.
*
* Sign(X)
* RMODE + -
* ----- --------
* RN +0 -0
* RZ +0 -0
* RM +0 -1
* RP +1 -0
*
SINT IDNT 2,1 Motorola 040 Floating Point Software Package
section 8
include fpsp.h
xref dnrm_lp
xref nrm_set
xref round
xref t_inx2
xref ld_pone
xref ld_mone
xref ld_pzero
xref ld_mzero
xref snzrinx
*
* FINT
*
xdef sint
sint:
bfextu FPCR_MODE(a6){2:2},d1 ;use user's mode for rounding
* ;implicity has extend precision
* ;in upper word.
move.l d1,L_SCR1(a6) ;save mode bits
bra.b sintexc
*
* FINT with extended denorm inputs.
*
xdef sintd
sintd:
btst.b #5,FPCR_MODE(a6)
beq snzrinx ;if round nearest or round zero, +/- 0
btst.b #4,FPCR_MODE(a6)
beq.b rnd_mns
rnd_pls:
btst.b #sign_bit,LOCAL_EX(a0)
bne.b sintmz
bsr ld_pone ;if round plus inf and pos, answer is +1
bra t_inx2
rnd_mns:
btst.b #sign_bit,LOCAL_EX(a0)
beq.b sintpz
bsr ld_mone ;if round mns inf and neg, answer is -1
bra t_inx2
sintpz:
bsr ld_pzero
bra t_inx2
sintmz:
bsr ld_mzero
bra t_inx2
*
* FINTRZ
*
xdef sintrz
sintrz:
move.l #1,L_SCR1(a6) ;use rz mode for rounding
* ;implicity has extend precision
* ;in upper word.
bra.b sintexc
*
* SINTDO
*
* Input: a0 points to an IEEE extended format operand
* Output: fp0 has the result
*
* Exeptions:
*
* If the subroutine results in an inexact operation, the inx2 and
* ainx bits in the USER_FPSR are set.
*
*
xdef sintdo
sintdo:
bfextu FPCR_MODE(a6){2:2},d1 ;use user's mode for rounding
* ;implicitly has ext precision
* ;in upper word.
move.l d1,L_SCR1(a6) ;save mode bits
*
* Real work of sint is in sintexc
*
sintexc:
bclr.b #sign_bit,LOCAL_EX(a0) ;convert to internal extended
* ;format
sne LOCAL_SGN(a0)
cmp.w #$403e,LOCAL_EX(a0) ;check if (unbiased) exp > 63
bgt.b out_rnge ;branch if exp < 63
cmp.w #$3ffd,LOCAL_EX(a0) ;check if (unbiased) exp < 0
bgt.w in_rnge ;if 63 >= exp > 0, do calc
*
* Input is less than zero. Restore sign, and check for directed
* rounding modes. L_SCR1 contains the rmode in the lower byte.
*
un_rnge:
btst.b #1,L_SCR1+3(a6) ;check for rn and rz
beq.b un_rnrz
tst.b LOCAL_SGN(a0) ;check for sign
bne.b un_rmrp_neg
*
* Sign is +. If rp, load +1.0, if rm, load +0.0
*
cmpi.b #3,L_SCR1+3(a6) ;check for rp
beq.b un_ldpone ;if rp, load +1.0
bsr ld_pzero ;if rm, load +0.0
bra t_inx2
un_ldpone:
bsr ld_pone
bra t_inx2
*
* Sign is -. If rm, load -1.0, if rp, load -0.0
*
un_rmrp_neg:
cmpi.b #2,L_SCR1+3(a6) ;check for rm
beq.b un_ldmone ;if rm, load -1.0
bsr ld_mzero ;if rp, load -0.0
bra t_inx2
un_ldmone:
bsr ld_mone
bra t_inx2
*
* Rmode is rn or rz; return signed zero
*
un_rnrz:
tst.b LOCAL_SGN(a0) ;check for sign
bne.b un_rnrz_neg
bsr ld_pzero
bra t_inx2
un_rnrz_neg:
bsr ld_mzero
bra t_inx2
*
* Input is greater than 2^63. All bits are significant. Return
* the input.
*
out_rnge:
bfclr LOCAL_SGN(a0){0:8} ;change back to IEEE ext format
beq.b intps
bset.b #sign_bit,LOCAL_EX(a0)
intps:
fmove.l fpcr,-(sp)
fmove.l #0,fpcr
fmove.x LOCAL_EX(a0),fp0 ;if exp > 63
* ;then return X to the user
* ;there are no fraction bits
fmove.l (sp)+,fpcr
rts
in_rnge:
* ;shift off fraction bits
clr.l d0 ;clear d0 - initial g,r,s for
* ;dnrm_lp
move.l #$403e,d1 ;set threshold for dnrm_lp
* ;assumes a0 points to operand
bsr dnrm_lp
* ;returns unnormalized number
* ;pointed by a0
* ;output d0 supplies g,r,s
* ;used by round
move.l L_SCR1(a6),d1 ;use selected rounding mode
*
*
bsr round ;round the unnorm based on users
* ;input a0 ptr to ext X
* ; d0 g,r,s bits
* ; d1 PREC/MODE info
* ;output a0 ptr to rounded result
* ;inexact flag set in USER_FPSR
* ;if initial grs set
*
* normalize the rounded result and store value in fp0
*
bsr nrm_set ;normalize the unnorm
* ;Input: a0 points to operand to
* ;be normalized
* ;Output: a0 points to normalized
* ;result
bfclr LOCAL_SGN(a0){0:8}
beq.b nrmrndp
bset.b #sign_bit,LOCAL_EX(a0) ;return to IEEE extended format
nrmrndp:
fmove.l fpcr,-(sp)
fmove.l #0,fpcr
fmove.x LOCAL_EX(a0),fp0 ;move result to fp0
fmove.l (sp)+,fpcr
rts
end
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