use strict;
use warnings;
use Math::BigFloat;
use 5.22.0;

my %bits_table = (
 1 => '0001',
 2 => '0010',
 3 => '0011',
 4 => '0100',
 5 => '0101',
 6 => '0110',
 7 => '0111',
 8 => '1000',
 9 => '1001',
 a => '1010',
 A => '1010',
 b => '1011',
 B => '1011',
 c => '1100',
 C => '1100',
 d => '1101',
 D => '1101',
 e => '1110',
 E => '1110',
 f => '1111',
 F => '1111',
);

my %vals_table = (
0 => '1',
1 => '0.5',
2 => '0.25',
3 => '0.125',
4 => '0.0625',
5 => '0.03125',
6 => '0.015625',
7 => '0.0078125',
8 => '0.00390625',
9 => '0.001953125',
10 => '0.0009765625',
11 => '0.00048828125',
12 => '0.000244140625',
13 => '0.0001220703125',
14 => '0.00006103515625',
15 => '0.000030517578125',
16 => '0.0000152587890625',
17 => '0.00000762939453125',
18 => '0.000003814697265625',
19 => '0.0000019073486328125',
20 => '0.00000095367431640625',
21 => '0.000000476837158203125',
22 => '0.0000002384185791015625',
23 => '0.00000011920928955078125',
24 => '0.000000059604644775390625',
25 => '0.0000000298023223876953125',
26 => '0.00000001490116119384765625',
27 => '0.000000007450580596923828125',
28 => '0.0000000037252902984619140625',
29 => '0.00000000186264514923095703125',
30 => '0.000000000931322574615478515625',
31 => '0.0000000004656612873077392578125',
32 => '0.00000000023283064365386962890625',
33 => '0.000000000116415321826934814453125',
34 => '0.0000000000582076609134674072265625',
35 => '0.00000000002910383045673370361328125',
36 => '0.000000000014551915228366851806640625',
37 => '0.0000000000072759576141834259033203125',
38 => '0.00000000000363797880709171295166015625',
39 => '0.000000000001818989403545856475830078125',
40 => '0.0000000000009094947017729282379150390625',
41 => '0.00000000000045474735088646411895751953125',
42 => '0.000000000000227373675443232059478759765625',
43 => '0.0000000000001136868377216160297393798828125',
44 => '0.00000000000005684341886080801486968994140625',
45 => '0.000000000000028421709430404007434844970703125',
46 => '0.0000000000000142108547152020037174224853515625',
47 => '0.00000000000000710542735760100185871124267578125',
48 => '0.000000000000003552713678800500929355621337890625',
49 => '0.0000000000000017763568394002504646778106689453125',
50 => '0.00000000000000088817841970012523233890533447265625',
51 => '0.000000000000000444089209850062616169452667236328125',
52 => '0.0000000000000002220446049250313080847263336181640625',
53 => '0.00000000000000011102230246251565404236316680908203125',
54 => '0.000000000000000055511151231257827021181583404541015625',
55 => '0.0000000000000000277555756156289135105907917022705078125',
56 => '0.00000000000000001387778780781445675529539585113525390625',
57 => '0.000000000000000006938893903907228377647697925567626953125',
58 => '0.0000000000000000034694469519536141888238489627838134765625',
59 => '0.00000000000000000173472347597680709441192448139190673828125',
60 => '0.000000000000000000867361737988403547205962240695953369140625',
61 => '0.0000000000000000004336808689942017736029811203479766845703125',
62 => '0.00000000000000000021684043449710088680149056017398834228515625',
63 => '0.000000000000000000108420217248550443400745280086994171142578125',
64 => '0.0000000000000000000542101086242752217003726400434970855712890625',
65 => '0.00000000000000000002710505431213761085018632002174854278564453125',
66 => '0.000000000000000000013552527156068805425093160010874271392822265625',
67 => '0.0000000000000000000067762635780344027125465800054371356964111328125',
68 => '0.00000000000000000000338813178901720135627329000271856784820556640625',
69 => '0.000000000000000000001694065894508600678136645001359283924102783203125',
70 => '0.0000000000000000000008470329472543003390683225006796419620513916015625',
71 => '0.00000000000000000000042351647362715016953416125033982098102569580078125',
72 => '0.00000000000000000000021175823681357508476708062516991049051284790039062',
73 => '0.00000000000000000000010587911840678754238354031258495524525642395019531',
74 => '0.000000000000000000000052939559203393771191770156292477622628211975097656',
75 => '0.000000000000000000000026469779601696885595885078146238811314105987548828',
76 => '0.000000000000000000000013234889800848442797942539073119405657052993774414',
77 => '0.000000000000000000000006617444900424221398971269536559702828526496887207',
78 => '0.0000000000000000000000033087224502121106994856347682798514142632484436035',
79 => '0.0000000000000000000000016543612251060553497428173841399257071316242218018',
80 => '0.00000000000000000000000082718061255302767487140869206996285356581211090088',
81 => '0.00000000000000000000000041359030627651383743570434603498142678290605545044',
82 => '0.00000000000000000000000020679515313825691871785217301749071339145302772522',
83 => '0.00000000000000000000000010339757656912845935892608650874535669572651386261',
84 => '0.000000000000000000000000051698788284564229679463043254372678347863256931305',
85 => '0.000000000000000000000000025849394142282114839731521627186339173931628465652',
86 => '0.000000000000000000000000012924697071141057419865760813593169586965814232826',
87 => '0.0000000000000000000000000064623485355705287099328804067965847934829071164131',
88 => '0.0000000000000000000000000032311742677852643549664402033982923967414535582066',
89 => '0.0000000000000000000000000016155871338926321774832201016991461983707267791033',
90 => '0.00000000000000000000000000080779356694631608874161005084957309918536338955164',
91 => '0.00000000000000000000000000040389678347315804437080502542478654959268169477582',
92 => '0.00000000000000000000000000020194839173657902218540251271239327479634084738791',
93 => '0.00000000000000000000000000010097419586828951109270125635619663739817042369395',
94 => '0.000000000000000000000000000050487097934144755546350628178098318699085211846977',
95 => '0.000000000000000000000000000025243548967072377773175314089049159349542605923489',
96 => '0.000000000000000000000000000012621774483536188886587657044524579674771302961744',
97 => '0.0000000000000000000000000000063108872417680944432938285222622898373856514808722',
98 => '0.0000000000000000000000000000031554436208840472216469142611311449186928257404361',
99 => '0.000000000000000000000000000001577721810442023610823457130565572459346412870218',
100 => '0.00000000000000000000000000000078886090522101180541172856528278622967320643510902',
101 => '0.00000000000000000000000000000039443045261050590270586428264139311483660321755451',
102 => '0.00000000000000000000000000000019721522630525295135293214132069655741830160877726',
103 => '0.000000000000000000000000000000098607613152626475676466070660348278709150804388628',
104 => '0.000000000000000000000000000000049303806576313237838233035330174139354575402194314',
105 => '0.000000000000000000000000000000024651903288156618919116517665087069677287701097157',
106 => '0.000000000000000000000000000000012325951644078309459558258832543534838643850548578',
107 => '0.0000000000000000000000000000000061629758220391547297791294162717674193219252742892',
108 => '0.0000000000000000000000000000000030814879110195773648895647081358837096609626371446',
109 => '0.0000000000000000000000000000000015407439555097886824447823540679418548304813185723',
110 => '0.00000000000000000000000000000000077037197775489434122239117703397092741524065928616',
111 => '0.00000000000000000000000000000000038518598887744717061119558851698546370762032964308',
112 => '0.00000000000000000000000000000000019259299443872358530559779425849273185381016482154',
113 => '0.000000000000000000000000000000000096296497219361792652798897129246365926905082410769',
114 => '0.000000000000000000000000000000000048148248609680896326399448564623182963452541205385',
115 => '0.000000000000000000000000000000000024074124304840448163199724282311591481726270602692',
116 => '0.000000000000000000000000000000000012037062152420224081599862141155795740863135301346',
117 => '0.0000000000000000000000000000000000060185310762101120407999310705778978704315676506731',
118 => '0.0000000000000000000000000000000000030092655381050560203999655352889489352157838253365',
119 => '0.0000000000000000000000000000000000015046327690525280101999827676444744676078919126683',
120 => '0.00000000000000000000000000000000000075231638452626400509999138382223723380394595633414',
121 => '0.00000000000000000000000000000000000037615819226313200254999569191111861690197297816707',
122 => '0.00000000000000000000000000000000000018807909613156600127499784595555930845098648908353',
123 => '0.000000000000000000000000000000000000094039548065783000637498922977779654225493244541767',
124 => '0.000000000000000000000000000000000000047019774032891500318749461488889827112746622270884',
125 => '0.000000000000000000000000000000000000023509887016445750159374730744444913556373311135442',
126 => '0.000000000000000000000000000000000000011754943508222875079687365372222456778186655567721',
127 => '0.0000000000000000000000000000000000000058774717541114375398436826861112283890933277838604',
128 => '0.0000000000000000000000000000000000000029387358770557187699218413430556141945466638919302',
129 => '0.0000000000000000000000000000000000000014693679385278593849609206715278070972733319459651',
130 => '0.00000000000000000000000000000000000000073468396926392969248046033576390354863666597298255',
131 => '0.00000000000000000000000000000000000000036734198463196484624023016788195177431833298649128',
132 => '0.00000000000000000000000000000000000000018367099231598242312011508394097588715916649324564',
133 => '0.000000000000000000000000000000000000000091835496157991211560057541970487943579583246622819',
134 => '0.00000000000000000000000000000000000000004591774807899560578002877098524397178979162331141',
135 => '0.000000000000000000000000000000000000000022958874039497802890014385492621985894895811655705',
136 => '0.000000000000000000000000000000000000000011479437019748901445007192746310992947447905827852',
137 => '0.0000000000000000000000000000000000000000057397185098744507225035963731554964737239529139262',
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139 => '0.0000000000000000000000000000000000000000014349296274686126806258990932888741184309882284816',
140 => '0.00000000000000000000000000000000000000000071746481373430634031294954664443705921549411424078',
141 => '0.00000000000000000000000000000000000000000035873240686715317015647477332221852960774705712039',
142 => '0.00000000000000000000000000000000000000000017936620343357658507823738666110926480387352856019',
143 => '0.000000000000000000000000000000000000000000089683101716788292539118693330554632401936764280097',
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146 => '0.000000000000000000000000000000000000000000011210387714598536567389836666319329050242095535012',
147 => '0.0000000000000000000000000000000000000000000056051938572992682836949183331596645251210477675061',
148 => '0.000000000000000000000000000000000000000000002802596928649634141847459166579832262560523883753',
149 => '0.0000000000000000000000000000000000000000000014012984643248170709237295832899161312802619418765',
150 => '0.00000000000000000000000000000000000000000000070064923216240853546186479164495806564013097093826',
151 => '0.00000000000000000000000000000000000000000000035032461608120426773093239582247903282006548546913',
152 => '0.00000000000000000000000000000000000000000000017516230804060213386546619791123951641003274273456',
153 => '0.000000000000000000000000000000000000000000000087581154020301066932733098955619758205016371367282',
154 => '0.000000000000000000000000000000000000000000000043790577010150533466366549477809879102508185683641',
155 => '0.000000000000000000000000000000000000000000000021895288505075266733183274738904939551254092841821',
156 => '0.00000000000000000000000000000000000000000000001094764425253763336659163736945246977562704642091',
157 => '0.0000000000000000000000000000000000000000000000054738221262688166832958186847262348878135232104551',
158 => '0.0000000000000000000000000000000000000000000000027369110631344083416479093423631174439067616052276',
159 => '0.0000000000000000000000000000000000000000000000013684555315672041708239546711815587219533808026138',
);

my $pi = '3.1415926535897932384626433832795';
my ($msd, $lsd) = i2dd($pi, \%bits_table, \%vals_table);
print "$msd $lsd\n";
printf "%a %a\n", $msd, $lsd ;


sub i2dd {
  my $str = $_[0];
  my $sign = $str =~ s/^\-// ? -1 : 1;
  my $val = Math::BigFloat->new($str);
  my $msd = 0 + $val->bstr;
  my ($bin, $exp) = d2bin($msd, $_[1]);
  my $to_subtract = bin2val($bin, $_[2]) * (2 ** $exp);
  $val -= $to_subtract;
  my $lsd = 0 + $val->bstr;
  return ($msd * $sign, $lsd * $sign);
}


sub d2bin {
  my ($mant, $exp) = split /p/, sprintf("%a", $_[0]);
  my %bits = %{$_[1]};
  $mant =~ s/-?0x//i;
  my $bin = $mant =~ /^1/ ? 1 : 0;
  $mant =~ s/.+\.//;
  for(1 .. length($mant)) {
    $bin .= $bits{substr($mant, $_ - 1, 1)};
  }
  return ($bin, $exp);
}

sub bin2val {
  my $bin = $_[0];
  my %vals = %{$_[1]};
  my $val = Math::BigFloat->new(0);

  for(1 .. length($bin)) {
    $val += Math::BigFloat->new($vals{$_ - 1}) if substr($bin, $_ - 1, 1);  
  }
  return $val;
}

__END__

Outputs:
3.14159265358979 1.22464679914735e-016
0x1.921fb54442d18p+1 0x1.1a62633145c07p-53