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|
|
| smovecr.sa 3.1 12/10/90
|
| The entry point sMOVECR returns the constant at the
| offset given in the instruction field.
|
| Input: An offset in the instruction word.
|
| Output: The constant rounded to the user's rounding
| mode unchecked for overflow.
|
| Modified: fp0.
|
|
| 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| THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA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.
|SMOVECR idnt 2,1 | Motorola 040 Floating Point Software Package
|section 8
.include "fpsp.h"
|xref nrm_set
|xref round
|xref PIRN
|xref PIRZRM
|xref PIRP
|xref SMALRN
|xref SMALRZRM
|xref SMALRP
|xref BIGRN
|xref BIGRZRM
|xref BIGRP
FZERO: .long 00000000
|
| FMOVECR
|
.global smovcr
smovcr:
bfextu CMDREG1B(%a6){#9:#7},%d0 |get offset
bfextu USER_FPCR(%a6){#26:#2},%d1 |get rmode
|
| check range of offset
|
tstb %d0 |if zero, offset is to pi
beqs PI_TBL |it is pi
cmpib #0x0a,%d0 |check range $01 - $0a
bles Z_VAL |if in this range, return zero
cmpib #0x0e,%d0 |check range $0b - $0e
bles SM_TBL |valid constants in this range
cmpib #0x2f,%d0 |check range $10 - $2f
bles Z_VAL |if in this range, return zero
cmpib #0x3f,%d0 |check range $30 - $3f
ble BG_TBL |valid constants in this range
Z_VAL:
fmoves FZERO,%fp0
rts
PI_TBL:
tstb %d1 |offset is zero, check for rmode
beqs PI_RN |if zero, rn mode
cmpib #0x3,%d1 |check for rp
beqs PI_RP |if 3, rp mode
PI_RZRM:
leal PIRZRM,%a0 |rmode is rz or rm, load PIRZRM in a0
bra set_finx
PI_RN:
leal PIRN,%a0 |rmode is rn, load PIRN in a0
bra set_finx
PI_RP:
leal PIRP,%a0 |rmode is rp, load PIRP in a0
bra set_finx
SM_TBL:
subil #0xb,%d0 |make offset in 0 - 4 range
tstb %d1 |check for rmode
beqs SM_RN |if zero, rn mode
cmpib #0x3,%d1 |check for rp
beqs SM_RP |if 3, rp mode
SM_RZRM:
leal SMALRZRM,%a0 |rmode is rz or rm, load SMRZRM in a0
cmpib #0x2,%d0 |check if result is inex
ble set_finx |if 0 - 2, it is inexact
bra no_finx |if 3, it is exact
SM_RN:
leal SMALRN,%a0 |rmode is rn, load SMRN in a0
cmpib #0x2,%d0 |check if result is inex
ble set_finx |if 0 - 2, it is inexact
bra no_finx |if 3, it is exact
SM_RP:
leal SMALRP,%a0 |rmode is rp, load SMRP in a0
cmpib #0x2,%d0 |check if result is inex
ble set_finx |if 0 - 2, it is inexact
bra no_finx |if 3, it is exact
BG_TBL:
subil #0x30,%d0 |make offset in 0 - f range
tstb %d1 |check for rmode
beqs BG_RN |if zero, rn mode
cmpib #0x3,%d1 |check for rp
beqs BG_RP |if 3, rp mode
BG_RZRM:
leal BIGRZRM,%a0 |rmode is rz or rm, load BGRZRM in a0
cmpib #0x1,%d0 |check if result is inex
ble set_finx |if 0 - 1, it is inexact
cmpib #0x7,%d0 |second check
ble no_finx |if 0 - 7, it is exact
bra set_finx |if 8 - f, it is inexact
BG_RN:
leal BIGRN,%a0 |rmode is rn, load BGRN in a0
cmpib #0x1,%d0 |check if result is inex
ble set_finx |if 0 - 1, it is inexact
cmpib #0x7,%d0 |second check
ble no_finx |if 0 - 7, it is exact
bra set_finx |if 8 - f, it is inexact
BG_RP:
leal BIGRP,%a0 |rmode is rp, load SMRP in a0
cmpib #0x1,%d0 |check if result is inex
ble set_finx |if 0 - 1, it is inexact
cmpib #0x7,%d0 |second check
ble no_finx |if 0 - 7, it is exact
| bra set_finx ;if 8 - f, it is inexact
set_finx:
orl #inx2a_mask,USER_FPSR(%a6) |set inex2/ainex
no_finx:
mulul #12,%d0 |use offset to point into tables
movel %d1,L_SCR1(%a6) |load mode for round call
bfextu USER_FPCR(%a6){#24:#2},%d1 |get precision
tstl %d1 |check if extended precision
|
| Precision is extended
|
bnes not_ext |if extended, do not call round
fmovemx (%a0,%d0),%fp0-%fp0 |return result in fp0
rts
|
| Precision is single or double
|
not_ext:
swap %d1 |rnd prec in upper word of d1
addl L_SCR1(%a6),%d1 |merge rmode in low word of d1
movel (%a0,%d0),FP_SCR1(%a6) |load first word to temp storage
movel 4(%a0,%d0),FP_SCR1+4(%a6) |load second word
movel 8(%a0,%d0),FP_SCR1+8(%a6) |load third word
clrl %d0 |clear g,r,s
lea FP_SCR1(%a6),%a0
btstb #sign_bit,LOCAL_EX(%a0)
sne LOCAL_SGN(%a0) |convert to internal ext. format
bsr round |go round the mantissa
bfclr LOCAL_SGN(%a0){#0:#8} |convert back to IEEE ext format
beqs fin_fcr
bsetb #sign_bit,LOCAL_EX(%a0)
fin_fcr:
fmovemx (%a0),%fp0-%fp0
rts
|end
|
