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+|
+|       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.
+|
+|
+|               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+|       THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA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.
+
+|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
+|
+
+        .global sgetexp
+sgetexp:
+        movew   LOCAL_EX(%a0),%d0       |get the exponent
+        bclrl   #15,%d0         |clear the sign bit
+        subw    #0x3fff,%d0     |subtract off the bias
+        fmovew  %d0,%fp0                |move the exp to fp0
+        rts
+
+        .global sgetexpd
+sgetexpd:
+        bclrb   #sign_bit,LOCAL_EX(%a0)
+        bsr     nrm_set         |normalize (exp will go negative)
+        movew   LOCAL_EX(%a0),%d0       |load resulting exponent into d0
+        subw    #0x3fff,%d0     |subtract off the bias
+        fmovew  %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.
+|
+        .global sgetman
+sgetman:
+        movel   USER_FPCR(%a6),%d0
+        andil   #0xffffff00,%d0 |clear rounding precision and mode
+        fmovel  %d0,%fpcr               |this fpcr setting is used by the 882
+        movew   LOCAL_EX(%a0),%d0       |get the exp (really just want sign bit)
+        orw     #0x7fff,%d0     |clear old exp
+        bclrl   #14,%d0         |make it the new exp +-3fff
+        movew   %d0,LOCAL_EX(%a0)       |move the sign & exp back to fsave stack
+        fmovex  (%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.
+|
+        .global sgetmand
+sgetmand:
+        movel   LOCAL_HI(%a0),%d0       |load ms mant in d0
+        movel   LOCAL_LO(%a0),%d1       |load ls mant in d1
+        bsr     shft            |shift mantissa bits till msbit is set
+        movel   %d0,LOCAL_HI(%a0)       |put ms mant back on stack
+        movel   %d1,LOCAL_LO(%a0)       |put ls mant back on stack
+        bras    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:
+        tstl    %d0             |if any bits set in ms mant
+        bnes    upper           |then branch
+|                               ;else no bits set in ms mant
+        tstl    %d1             |test if any bits set in ls mant
+        bnes    cont            |if set then continue
+        bras    shft_end        |else return
+cont:
+        movel   %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
+        lsll    %d3,%d0         |shift first 1 to integer bit in ms mant
+        movel   (%a7)+,%d3      |restore d3
+        bras    shft_end
+upper:
+
+        moveml  %d3/%d5/%d6,-(%a7)      |save registers
+        bfffo   %d0{#0:#32},%d3 |find first 1 in ls mant to d0
+        lsll    %d3,%d0         |shift ms mant until j-bit is set
+        movel   %d1,%d6         |save ls mant in d6
+        lsll    %d3,%d1         |shift ls mant by count
+        movel   #32,%d5
+        subl    %d3,%d5         |sub 32 from shift for ls mant
+        lsrl    %d5,%d6         |shift off all bits but those that will
+|                               ;be shifted into ms mant
+        orl     %d6,%d0         |shift the ls mant bits into the ms mant
+        moveml  (%a7)+,%d3/%d5/%d6      |restore registers
+shft_end:
+        rts
+
+        |end