Subversion Repositories or1k

//
//      $Id: smovecr.S,v 1.2 2001-09-27 12:01:22 chris Exp $
//
//      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//      THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA 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.defs"

        |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