bic

Bit Clear (A32)

BIC{S}<c> <Rd>, <Rn>, <Rm> {, <shift>}

Performs AND NOT (Rd = Rn & ~Rm).

Pseudocode Operation

result ← Rn AND NOT(Rm shifted by shift_amount)
Rd ← result
if S == 1 then
  N ← result[31]
  Z ← (result == 0)
  C ← shifter_carry_out
else
  condition_flags unchanged

Example

BIC r0, r1, r2

Encoding

Binary Layout

cond

31:28

00011

27:23

22:21

19:16

15:12

imm5

11:7

stype

6:5

3:0

Format Data Proc

Opcode 0x01C00000

Extension A32 (Base)

Operands

Rd
Destination general-purpose register
Rn
First source / base general-purpose register
Rm
Second source / offset general-purpose register

Other forms of bic

bic Bitwise Bit Clear (Shifted Register)
bic Bitwise Bit Clear (Shifted Register 64-bit)
bic Vector Bitwise Bit Clear
bic SVE Bitwise Bit Clear (Predicated)

Reference

View in Arm A64 ISA Reference ↗ Arm AArch32 ISA

Instruction Forms

Encoding	Instruction	ISA	Bit pattern
0x03C00000	BIC{<c>}{<q>} {<Rd>,} <Rn>, #<const>	A32	cond \| 00111 \| 10 \| 0 \| Rn \| Rd \| imm12
0xF0200000	BIC{<c>}{<q>} {<Rd>,} <Rn>, #<const>	T32	11110 \| i \| 0 \| 0001 \| 0 \| Rn \| 0 \| imm3 \| Rd \| imm8
0x01C00060	BIC{<c>}{<q>} {<Rd>,} <Rn>, <Rm>, RRX	A32	cond \| 00011 \| 10 \| 0 \| Rn \| Rd \| 00000 \| 11 \| 0 \| Rm
0x01C00000	BIC{<c>}{<q>} {<Rd>,} <Rn>, <Rm> {, <shift> #<amount>}	A32	cond \| 00011 \| 10 \| 0 \| Rn \| Rd \| imm5 \| stype \| 0 \| Rm
0x4380	BIC<c>{<q>} {<Rdn>,} <Rdn>, <Rm>	T32	010000 \| 1110 \| Rm \| Rdn
0xEA200030	BIC{<c>}{<q>} {<Rd>,} <Rn>, <Rm>, RRX	T32	1110101 \| 0001 \| 0 \| Rn \| 0 \| 000 \| Rd \| 00 \| 11 \| Rm
0xEA200000	BIC<c>.W {<Rd>,} <Rn>, <Rm>	T32	1110101 \| 0001 \| 0 \| Rn \| 0 \| imm3 \| Rd \| imm2 \| stype \| Rm
0x01C00010	BIC{<c>}{<q>} {<Rd>,} <Rn>, <Rm>, <shift> <Rs>	A32	cond \| 00011 \| 10 \| 0 \| Rn \| Rd \| Rs \| 0 \| stype \| 1 \| Rm

Description

Bitwise Bit Clear (register) performs a bitwise AND of a register value and the complement of an optionally-shifted register value, and writes the result to the destination register. If the destination register is not the PC, the BICS variant of the instruction updates the condition flags based on the result. The field descriptions for <Rd> identify the encodings where the PC is permitted as the destination register. Arm deprecates any use of these encodings. However, when the destination register is the PC:

Operation

if ConditionPassed() then
    EncodingSpecificOperations();
    (shifted, carry) = Shift_C(R[m], shift_t, shift_n, PSTATE.C);
    result = R[n] AND NOT(shifted);
    if d == 15 then          // Can only occur for A32 encoding
        if setflags then
            ALUExceptionReturn(result);
        else
            ALUWritePC(result);
    else
        R[d] = result;
        if setflags then
            PSTATE.N = result<31>;
            PSTATE.Z = IsZeroBit(result);
            PSTATE.C = carry;
            // PSTATE.V unchanged

bic