daniel@swagg-htpc-02:~/test$ gcc a.c -o a -lgmp
daniel@swagg-htpc-02:~/test$ cat /proc/cpuinfo 
processor	: 0
vendor_id	: GenuineIntel
cpu family	: 15
model		: 6
model name	: Intel(R) Pentium(R) 4 CPU 3.00GHz
stepping	: 4
microcode	: 0x4
cpu MHz		: 2400.000
cache size	: 2048 KB
physical id	: 0
siblings	: 2
core id		: 0
cpu cores	: 1
apicid		: 0
initial apicid	: 0
fpu		: yes
fpu_exception	: yes
cpuid level	: 6
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc pebs bts nopl pni dtes64 monitor ds_cpl est tm2 cid cx16 xtpr pdcm lahf_lm kaiser
bugs		: cpu_meltdown spectre_v1 spectre_v2 spec_store_bypass l1tf
bogomips	: 5985.16
clflush size	: 64
cache_alignment	: 128
address sizes	: 36 bits physical, 48 bits virtual
power management:

processor	: 1
vendor_id	: GenuineIntel
cpu family	: 15
model		: 6
model name	: Intel(R) Pentium(R) 4 CPU 3.00GHz
stepping	: 4
microcode	: 0x4
cpu MHz		: 2400.000
cache size	: 2048 KB
physical id	: 0
siblings	: 2
core id		: 0
cpu cores	: 1
apicid		: 1
initial apicid	: 1
fpu		: yes
fpu_exception	: yes
cpuid level	: 6
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc pebs bts nopl pni dtes64 monitor ds_cpl est tm2 cid cx16 xtpr pdcm lahf_lm kaiser
bugs		: cpu_meltdown spectre_v1 spectre_v2 spec_store_bypass l1tf
bogomips	: 5985.16
clflush size	: 64
cache_alignment	: 128
address sizes	: 36 bits physical, 48 bits virtual
power management:

daniel@swagg-htpc-02:~/test$ sudo slackpkg search gmp
Password: 


NOTICE: pkglist is older than 24h; you are encouraged to re-run 'slackpkg update'

Looking for gmp in package list. Please wait... DONE

The list below shows all packages with name matching "gmp".

[ Status           ] [ Repository               ] [ Package                                  ]
   installed               multilib                     gmp-compat32-6.1.1-x86_64-1compat32       
   installed               slackware64                  gmp-6.1.1-x86_64-1                        

You can search specific files using "slackpkg file-search file".


daniel@swagg-htpc-02:~/test$ time ./a 
Read n=6314466083072888893799357126131292332363298818330841375588990772701957128924885547308446055753206513618346628848948088663500368480396588171361987660521897267810162280557475393838308261759713218926668611776954526391570120690939973680089721274464666423319187806830552067951253070082020241246233982410737753705127344494169501180975241890667963858754856319805507273709904397119733614666701543905360152543373982524579313575317653646331989064651402133985265800341991903982192844710212464887459388853582070318084289023209710907032396934919962778995323320184064522476463966355937367009369212758092086293198727008292431243681 has 2046 bits.

answer 1=4994097331495993759590792520652782896298040702842052804596091316575363414862676472297324459047461969855851762208911221321241374084825500814598324057817295157460163428748617431743371535373584519311479667686627715728864057273036107427545351441992333703764148710086798963155916759426741193579376396522818496357335032139598670494577520161356987154136310419315797156777208723685881823376284494131513590136899083068033919977865483124290662185228944009736543594763905898717659641198560483737149541481094888019426062490884384838074953205628739379413727850315986194387378032781404281175230300985834217585463046424665894367379
done 40000000 iterations in time=354 sec.

answer 2=4994097331495993759590792520652782896298040702842052804596091316575363414862676472297324459047461969855851762208911221321241374084825500814598324057817295157460163428748617431743371535373584519311479667686627715728864057273036107427545351441992333703764148710086798963155916759426741193579376396522818496357335032139598670494577520161356987154136310419315797156777208723685881823376284494131513590136899083068033919977865483124290662185228944009736543594763905898717659641198560483737149541481094888019426062490884384838074953205628739379413727850315986194387378032781404281175230300985834217585463046424665894367379
done 40000000 iterations in time=317 sec.


real	11m11.156s
user	11m10.668s
sys	0m0.107s