Cfrtjryk

How can I tell if floating point arithmetic is performed in hardware or software?

I could find the processor's name and Google it, but is there a way to do it in a BASH script? For instance, is there something saved in a system file that I could read?

UPDATE:
output of /proc/cpuinfo on Intel:

processor       : 0

vendor_id       : GenuineIntel

cpu family      : 6

model           : 69

model name      : Intel(R) Core(TM) i3-4010U CPU @ 1.70GHz

stepping        : 1

microcode       : 0x17

cpu MHz         : 782.000

cache size      : 3072 KB

physical id     : 0

siblings        : 4

core id         : 0

cpu cores       : 2

apicid          : 0

initial apicid  : 0

fpu             : yes  <-- !!!

fpu_exception   : yes

cpuid level     : 13

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 pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm ida arat epb xsaveopt pln pts dtherm tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid

bogomips        : 3392.25

clflush size    : 64

cache_alignment : 64

address sizes   : 39 bits physical, 48 bits virtual

power management:

output of /proc/cpuinfo on RPi (using Raspian v7):

processor       : 0

model name      : ARMv6-compatible processor rev 7 (v6l)

BogoMIPS        : 2.00

Features        : swp half thumb fastmult vfp edsp java tls

CPU implementer : 0x41

CPU architecture: 7

CPU variant     : 0x0

CPU part        : 0xb76

CPU revision    : 7



Hardware        : BCM2708

Revision        : 000e

Serial          : 000000007b455c14

Well, you can tell if your CPU has FPU capabilities with the data stored in
/proc/cpuinfo and filter it with grep fpu

$ grep "fpu" /proc/cpuinfo

fpu     : yes

fpu_exception   : yes

flags       : fpu vme de pse ...

And for info, what type of CPU are you playing with? :)

EDIT
for ARM proc, look for vector floating point unit (vfp), some info here.

Ex:

# cat /proc/cpuinfo

Processor       : ARMv6-compatible processor rev 7 (v6l)

BogoMIPS        : 697.95

Features        : ... vfp ...

I think that what you want is to do some benchmarks, and compare with other processors. Otherwise, whether floating-point is performed is hardware or software doesn't make much sense. Actually, it can be both. For instance, subnormals are sometimes emulated in software. Some operations may also be implemented in software but still based on some other hardware FP instructions: division and square root on the Itanium (thanks to the FMA); and elementary functions (exp, log, sin, cos...) in general (x86 processors have hardware implementation of such functions, but with limitations concerning the accuracy). In C, the long double type has a mixed hardware-software implementation on PowerPC (the double-double arithmetic).

If you want to get system information that could be related to the floating-point implementation, then get most information from /proc/cpuinfo, but the C library version may be also useful (for math functions).