CODEWITHSUNDEEP
armneonarmv8
surajrgupta
surajrgupta

Reputation: 63

What is arrangement specifier(.16b,.8b) in ARM assembly language instructions?

I want to what exactly is arrangement specifier in arm assembly instructions.

I have gone through ARM TRMs and i think if it is size of Neon register that will be used for computation

for e.g. TBL Vd.Ta, {Vn.16B,Vn+1.16B }, Vm.Ta

This is taken from http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0802a/TBL_advsimd_vector.html they mentioned Ta to be arrangement specifier of value 16B or 8B

I would like to know what it means to.(Size of Neon Register .. anything..)Taken from link above

Upvotes: 3

Views: 971

Answers (2)

confusedandsad
confusedandsad

Reputation: 322

I help myself remember this by thinking:

B = Bytes (8bit)

H = Halfwords (16bit)

S = Single words (32bit)

D = Double words (64bit)

I don't know if that is official, but it's how I remember it

Upvotes: 0

Capybara
Capybara

Reputation: 1473

The arrangement specifier is the number and size of the elements in the vector, for example 8B means that you are looking at 8 elements of one byte (this will be a 64-bit vector), and 16B is 16 elements of 1 byte (128-bit vector). This is taken from the ARM Reference Manual:

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Upvotes: 8

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