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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|       THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA 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