RNDR, Random Number

The RNDR characteristics are:

Purpose

Random Number. Returns a 64-bit random number which is reseeded from the True Random Number source at an IMPLEMENTATION DEFINED rate.

If the hardware returns a genuine random number, PSTATE.NZCV is set to 0b0000.

If the instruction cannot return a genuine random number in a reasonable period of time, PSTATE.NZCV is set to 0b0100 and the data value returned in UNKNOWN.

Configuration

This register is present only when ARMv8.5-RNG is implemented. Otherwise, direct accesses to RNDR are UNDEFINED.

RW fields in this register reset to architecturally UNKNOWN values.

Attributes

RNDR is a 64-bit register.

Field descriptions

The RNDR bit assignments are:

RNDR, bits [63:0]

Random Number. Returns a 64-bit Random Number which is reseeded from the True Random Number source at an IMPLEMENTATION DEFINED rate.

This field resets to an architecturally UNKNOWN value.

if PSTATE.EL == EL0 then
    return RNDR;
elsif PSTATE.EL == EL1 then
    return RNDR;
elsif PSTATE.EL == EL2 then
    return RNDR;
elsif PSTATE.EL == EL3 then
    return RNDR;