diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/m68k/fpsp040/sgetem.S |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/m68k/fpsp040/sgetem.S')
-rw-r--r-- | arch/m68k/fpsp040/sgetem.S | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/arch/m68k/fpsp040/sgetem.S b/arch/m68k/fpsp040/sgetem.S new file mode 100644 index 00000000000..0fcbd045ba7 --- /dev/null +++ b/arch/m68k/fpsp040/sgetem.S @@ -0,0 +1,141 @@ +| +| 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 +| +| +| Copyright (C) Motorola, Inc. 1990 +| All Rights Reserved +| +| THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA +| The copyright notice above does not evidence any +| actual or intended publication of such source code.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 |