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The RNDRRS characteristics are:
Reseeded Random Number. Returns a 64-bit random number which is reseeded from the True Random Number source immediately before the read of the random number.
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 is 0.
This register is present only when FEAT_RNG is implemented or FEAT_RNG_TRAP is implemented. Otherwise, direct accesses to RNDRRS are UNDEFINED.
RNDRRS is a 64-bit register.
63 | 62 | 61 | 60 | 59 | 58 | 57 | 56 | 55 | 54 | 53 | 52 | 51 | 50 | 49 | 48 | 47 | 46 | 45 | 44 | 43 | 42 | 41 | 40 | 39 | 38 | 37 | 36 | 35 | 34 | 33 | 32 |
31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
RNDRRS | |||||||||||||||||||||||||||||||
RNDRRS |
Reseeded Random Number. Returns a 64-bit Random Number which is reseeded from the True Random Number source immediately before this read.
The reset behaviour of this field is:
Accesses to this register use the following encodings in the System register encoding space:
op0 | op1 | CRn | CRm | op2 |
---|---|---|---|---|
0b11 | 0b011 | 0b0010 | 0b0100 | 0b001 |
if PSTATE.EL == EL0 then
if IsFeatureImplemented(FEAT_RNG_TRAP) && SCR_EL3.TRNDR == '1' then
AArch64.SystemAccessTrap(EL3, 0x18);
elsif !IsFeatureImplemented(FEAT_RNG) then
UNDEFINED;
else
return RNDRRS;
elsif PSTATE.EL == EL1 then
if IsFeatureImplemented(FEAT_RNG_TRAP) && SCR_EL3.TRNDR == '1' then
AArch64.SystemAccessTrap(EL3, 0x18);
elsif !IsFeatureImplemented(FEAT_RNG) then
UNDEFINED;
else
return RNDRRS;
elsif PSTATE.EL == EL2 then
if IsFeatureImplemented(FEAT_RNG_TRAP) && SCR_EL3.TRNDR == '1' then
AArch64.SystemAccessTrap(EL3, 0x18);
elsif !IsFeatureImplemented(FEAT_RNG) then
UNDEFINED;
else
return RNDRRS;
elsif PSTATE.EL == EL3 then
if IsFeatureImplemented(FEAT_RNG_TRAP) && SCR_EL3.TRNDR == '1' then
AArch64.SystemAccessTrap(EL3, 0x18);
elsif !IsFeatureImplemented(FEAT_RNG) then
UNDEFINED;
else
return RNDRRS;
30/06/2021 1509:2239; 2a17f7750cfd1ab239f20f6cf29877ba8041794f4f5dd962f4e34e1ac282f76da4d6e7fc4cab087e
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