udiv

Unsigned Divide (Thumb)

UDIV <Rd>, <Rn>, <Rm>

Unsigned integer division.

Details

Perform unsigned integer division of Rn by Rm and place the quotient in Rd. If Rm is zero, the result is UNPREDICTABLE. No condition flags are affected. This instruction is available in T32 (Thumb) and executes in all privilege levels.

Pseudocode Operation

if Rm == 0 then UNPREDICTABLE else Rd ← UnsignedDivide(Rn, Rm)

Example

UDIV r0, r1, r2

Encoding

Binary Layout
111110111
011
Rn
1111
Rd
1111
Rm
 
Format Thumb Div
Opcode 0xFBB0F0F0
Extension A32 (Base)

Operands

  • Rd
    Destination general-purpose register
  • Rn
    Dividend
  • Rm
    Divisor

Reference (Arm AArch32 ISA)

Instruction Forms

Encoding Instruction ISA Bit pattern
0x0730F010 UDIV{<c>}{<q>} {<Rd>,} <Rn>, <Rm> A32 cond | 01110 | 011 | Rd | 1111 | Rm | 000 | 1 | Rn
0xFBB0F0F0 UDIV{<c>}{<q>} {<Rd>,} <Rn>, <Rm> T32 111110111 | 011 | Rn | 1111 | Rd | 1111 | Rm

Description

Unsigned Divide divides a 32-bit unsigned integer register value by a 32-bit unsigned integer register value, and writes the result to the destination register. The condition flags are not affected. See Divide instructions for more information about this instruction.

Operation

if ConditionPassed() then
    EncodingSpecificOperations();
    integer result;
    if UInt(R[m]) == 0 then
        result = 0;
    else
        result = RoundTowardsZero(Real(UInt(R[n])) / Real(UInt(R[m])));
    R[d] = result<31:0>;