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Can someone help me with this question?

Its from the ARM instruction sheet, I need help understanding
this specific problem.
Thanks!!!
UBFX R5,R6, #12, #6

1 Answer

4 votes

Final answer:

The ARM instruction UBFX R5,R6, #12, #6 is used to extract a 6-bit field starting from the 12th bit position in register R6 and place it into register R5, clearing the upper bits in R5.

Step-by-step explanation:

The UBFX (Unsigned Bit Field Extract) instruction in ARM assembly language is used to extract a bit field from one register and place it into the least significant bits of another register, zeroing the upper bits. The instruction format is UBFX destination_register, source_register, #lsb, #width, where:

  • destination_register is where the extracted bit field will be placed.
  • source_register is the register from which bits will be extracted.
  • #lsb indicates the least significant bit position (starting from 0) of the bit field in the source register.
  • #width specifies the number of bits to extract.

In the provided question, the instruction UBFX R5,R6, #12, #6 will extract 6 bits starting from bit position 12 in R6 and will place them into the lower bits of R5, while the rest of R5 will be filled with zeros.

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