uxtab

Unsigned Extend and Add Byte

UXTAB<c> <Rd>, <Rn>, <Rm> {, <rotation>}

Zero-extends a byte and adds to Rn.

Pseudocode Operation

rotated ← ROR(Rm, rotation)
byte_value ← rotated[7:0]
zero_extended ← ZeroExtend(byte_value, 32)
Rd ← Rn + zero_extended

Example

UXTAB r0, r1, r2

Encoding

Binary Layout

cond

31:28

01101

27:23

1

22

10

21:20

Rn

19:16

Rd

15:12

rotate

11:10

0

9

0

8

0111

7:4

Rm

3:0

 

Format Data Proc

Opcode 0x06E00070

Extension A32 (DSP)

Operands

• Rd
  Destination general-purpose register
• Rn
  Accumulator
• Rm
  Second source / offset general-purpose register

Related

More in A32 (DSP)

Reference

View in Arm A64 ISA Reference ↗ Arm AArch32 ISA

Instruction Forms

Encoding	Instruction		ISA		Bit pattern
0x06E00070	UXTAB{<c>}{<q>} {<Rd>,} <Rn>, <Rm> {, ROR #<amount>}		A32		cond | 01101 | 1 | 10 | Rn | Rd | rotate | 0 | 0 | 0111 | Rm
0xFA50F080	UXTAB{<c>}{<q>} {<Rd>,} <Rn>, <Rm> {, ROR #<amount>}		T32		111110100 | 10 | 1 | Rn | 1111 | Rd | 1 | 0 | rotate | Rm

Description

Unsigned Extend and Add Byte extracts an 8-bit value from a register, zero-extends it to 32 bits, adds the result to the value in another register, and writes the final result to the destination register. The instruction can specify a rotation by 0, 8, 16, or 24 bits before extracting the 8-bit value.

Operation

if ConditionPassed() then
    EncodingSpecificOperations();
    rotated = ROR(R[m], rotation);
    R[d] = R[n] + ZeroExtend(rotated<7:0>, 32);