eon

Bitwise Exclusive OR NOT

EON <Wd>, <Wn>, <Wm> {, <shift> #<amount>}

XORs register with NOT of shifted register (XNOR).

Pseudocode Operation

result ← Wn XOR (NOT (Wm << shift_amount))
Wd ← result[31:0]
N ← result[31]
Z ← (result == 0)

Example

EON w0, w1, w2

Encoding

Binary Layout

0

31

10

30:29

01010

28:24

shift

23:22

1

21

Rm

20:16

imm6

15:10

Rn

9:5

Rd

4:0

 

Format Logical (Register)

Opcode 0x4A200000

Extension Base

Operands

• Wd
  Destination 32-bit integer register
• Wn
  First source / base 32-bit integer register
• Wm
  Second source / offset 32-bit integer register

Related

Other forms of eon

• eon Bitwise Exclusive OR NOT (64-bit)

More in Base

Reference

View in Arm A64 ISA Reference ↗ Arm A64 ISA

Instruction Forms

Encoding	Instruction		ISA		Bit pattern
0x4A200000	EON <Wd>, <Wn>, <Wm>{, <shift> #<amount>}		A64		0 | 10 | 01010 | shift | 1 | Rm | imm6 | Rn | Rd
0xCA200000	EON <Xd>, <Xn>, <Xm>{, <shift> #<amount>}		A64		1 | 10 | 01010 | shift | 1 | Rm | imm6 | Rn | Rd
0x05400000	EON <Zdn>.<T>, <Zdn>.<T>, #<const>		A64		00000101 | 0 | 1 | 0000 | imm13 | Zdn

Description

Bitwise Exclusive-OR NOT (shifted register) performs a bitwise exclusive-OR NOT of a register value and an optionally-shifted register value, and writes the result to the destination register.

Operation

bits(datasize) operand1 = X[n, datasize];
bits(datasize) operand2 = ShiftReg(m, shift_type, shift_amount, datasize);
bits(datasize) result;

operand2 = NOT(operand2);

result = operand1 EOR operand2;

X[d, datasize] = result;