Index

TST (immediate)

Test bits (immediate), setting the condition flags and discarding the result

: Rn AND imm.

This is an alias of ANDS (immediate). This means:

31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
sf 1 1 1 0 0 1 0 0 N immr imms Rn 1 1 1 1 1
opc Rd

32-bit (sf == 0 && N == 0)

TST <Wn>, #<imm>

is equivalent to

ANDS WZR, <Wn>, #<imm>

and is always the preferred disassembly.

64-bit (sf == 1)

TST <Xn>, #<imm>

is equivalent to

ANDS XZR, <Xn>, #<imm>

and is always the preferred disassembly.

Assembler Symbols

<Wn>

Is the 32-bit name of the general-purpose source register, encoded in the "Rn" field.
<Xn>

Is the 64-bit name of the general-purpose source register, encoded in the "Rn" field.
<imm>

For the 32-bit variant: is the bitmask immediate, encoded in "imms:immr".

For the 64-bit variant: is the bitmask immediate, encoded in "N:imms:immr".

Operation

The description of ANDS (immediate) gives the operational pseudocode for this instruction.