Arm® A32/T32 Instruction Set Architecture: Armv8, for Armv8-A architecture profile Documentation

VCLE (immediate #0)

Vector Compare Less Than or Equal to Zero takes each element in a vector, and compares it with zero. If it is less than or equal to zero, the corresponding element in the destination vector is set to all ones. Otherwise, it is set to all zeros.

The operand vector elements are the same type, and are signed integers or floating-point numbers. The result vector elements are fields the same size as the operand vector elements.

Depending on settings in the CPACR, NSACR, and HCPTR registers, and the Security state and PE mode in which the instruction is executed, an attempt to execute the instruction might be undefined, or trapped to Hyp mode. For more information see Enabling Advanced SIMD and floating-point support.

It has encodings from the following instruction sets: A32 ( A1 ) and T32 ( T1 ) .

A1

if size == '11' then UNDEFINED;
if F == '1' && ((size == '01' && !HaveFP16Ext()) || size == '00') then UNDEFINED;
if Q == '1' && (Vd<0> == '1' || Vm<0> == '1') then UNDEFINED;
floating_point = (F == '1');
esize = 8 << UInt(size);  elements = 64 DIV esize;
d = UInt(D:Vd);  m = UInt(M:Vm);  regs = if Q == '0' then 1 else 2;

T1

if size == '11' then UNDEFINED;
if F == '1' && ((size == '01' && !HaveFP16Ext()) || size == '00') then UNDEFINED;
if F == '1' && size == '01' && InITBlock() then UNPREDICTABLE;
if Q == '1' && (Vd<0> == '1' || Vm<0> == '1') then UNDEFINED;
floating_point = (F == '1');
esize = 8 << UInt(size);  elements = 64 DIV esize;
d = UInt(D:Vd);  m = UInt(M:Vm);  regs = if Q == '0' then 1 else 2;

CONSTRAINED UNPREDICTABLE behavior

If F == '1' && size == '01' && InITBlock(), then one of the following behaviors must occur:

• The instruction is undefined.
• The instruction executes as if it passes the Condition code check.
• The instruction executes as NOP. This means it behaves as if it fails the Condition code check.

Assembler Symbols

if ConditionPassed() then
    EncodingSpecificOperations();  CheckAdvSIMDEnabled();
    for r = 0 to regs-1
        for e = 0 to elements-1
            if floating_point then
                bits(esize) zero = FPZero('0');
                test_passed = FPCompareGE(zero, Elem[D[m+r],e,esize], StandardFPSCRValue());
            else
                test_passed = (SInt(Elem[D[m+r],e,esize]) <= 0);
            Elem[D[d+r],e,esize] = if test_passed then Ones(esize) else Zeros(esize);

Operational information

If CPSR.DIT is 1 and this instruction passes its condition execution check:

• The execution time of this instruction is independent of:
  • The values of the data supplied in any of its registers.
  • The values of the NZCV flags.
• The response of this instruction to asynchronous exceptions does not vary based on:
  • The values of the data supplied in any of its registers.
  • The values of the NZCV flags.